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Pea protein concentrate substituting fish meal or soybean meal in diets for Atlantic salmon (Salmo salar)—Effect on growth performance, nutrient digestibility, carcass composition, gut health, and physical feed quality
Abstract
The effect of pea protein concentrate in diets for Atlantic salmon (Salmo salar) on growth performance, nutrient digestibility, carcass composition, blood chemistry, histology of the gastro-intestinal tract (GIT), and physical feed quality was investigated. A 12-week study was conducted using triplicate groups of Atlantic salmon with 0.16 kg initial weight kept in sea water. The dietary treatments consisted of one control diet based on high-quality fish meal (FM diet), one control diet containing 200 g kg-1 soybean meal (SBM diet), and two experimental diets containing 200 g kg-1 pea protein concentrate with either 350 or 500 g kg -1 crude protein (PPC 35% CP and PPC 50% CP diet), substituting fish meal protein. There were no significant differences among dietary treatments for weight gain or feed intake, but there was a tendency (P < 0.07) towards a lower feed conversion ratio in the fish receiving the PPC 50% CP diet. There were no differences in the digestibility of protein, fat, starch and most essential amino acids between the fish fed the FM and the PPC 35% CP and PPC 50% CP diets, but the PPC diets gave lower energy digestibility. The SBM diet gave reduced digestibility for protein, fat, starch, essential amino acids, and energy compared with the FM and the PPC diets. Also, feeding the PPC diets had no effect on body composition, while the SBM diet reduced (P < 0.05) the content of carcass fat and energy compared with the FM diet. Feeding the PPC diets did not induce morphological changes in the intestine, or affect the size of the GIT. Brush border maltase activity and fecal trypsin activity were unaffected. Feeding the SBM diet increased the size of the stomach, decreased the size of the distal intestine (DI), induced morphological changes in the DI, reduced brush border maltase activity, and increased fecal trypsin activity compared with the FM and PPC diets. In conclusion, pea protein concentrate was shown to be a promising new protein ingredient for salmonids and could replace 20% of high-quality fish meal protein in the feed without adverse effect on growth performance, carcass composition or histology of the DI.
... Animals growing in the wild have a non-specific but largely varied diet whereas reared animals are fed with specific feeds to meet the market requirement. The diet of animals has been proven to affect the chemical composition of their muscles and other edible tissues (Al Hafedh, 1999;Izquierdo et al., 2003;Øverland et al., 2009;Webster et al., 1999). These changes are reflected in the NIR spectra of the fish tissue and thus aid in differentiating easily between wild and artificially reared fish. ...
... These changes are reflected in the NIR spectra of the fish tissue and thus aid in differentiating easily between wild and artificially reared fish. Even differences in diets of artificially reared fish can be quantified with the help of fish meal composition (Izquierdo et al., 2003;Øverland et al., 2009;Webster et al., 1999). Another important factor to consider is the sampling time. ...
Food authentication is a growing concern with rising complexities of the food supply network, with fish being an easy target of food fraud. In this regard, NIR spectroscopy has been used as an efficient tool for food authentication. This article reviews the latest research advances on NIR based fish authentication. The process from sampling/sample preparation to data analysis has been covered. Special attention was given to NIR spectra pre-processing and its unsupervised and supervised analysis. Sampling is an important aspect of traceability study and samples chosen ought to be a true representative of the population. NIR spectra acquired is often laden with overlapping bands, scattering and highly multicollinear. It needs adequate pre-processing to remove all undesirable features. The pre-processing technique can make or break a model and thus need a trial-and-error approach to find the best fit. As for spectral analysis and modelling, multicollinear nature of NIR spectra demands unsupervised analysis (PCA) to compact the features before application of supervised multivariate techniques such as LDA, PLS-DA, QDA etc. Machine learning approach of modelling has shown promising result in food authentication modelling and negates the need for unsupervised analysis before modelling.
... The histological analysis performed was a quantitative analysis. Measurements used a combination of parameters proposed by different authors [17,59,60]. Specifically, the histological analysis focused on the measurement of the length and width of the intestinal villus in the proximal and distal intestine and liver. ...
... As has been described, the poor results obtained with a total FM substitution may be due to the fact that plant protein sources induce intestinal inflammation [9,70]. This inflammatory response is characterized in salmonids by a shortening of mucosal folds and a widening of lamina propria [60] due to the infiltration of inflammatory cells identified as lymphocytes, macrophages, eosinophils and cells, granular neutrophils, and diffuse immunoglobulin M (IgM) [71]. However, the inclusion of plant protein sources does not produce such striking alterations in other species as seabream [72], and there is no available information about the effect on Mediterranean yellowtail, but it has been shown that high FM replacement (75%) can cause a decrease in enterocytes and villi size at intestine level [44]. ...
Fishmeal and fish oil substitution in aquafeeds might have adverse effects on fish growth and health, mainly in carnivorous species, such as Mediterranean yellowtail (Seriola dumerili). Mediterranean yellowtail shows great potential as an alternative aquaculture species due to its fast growth and high price on the market, but the need for high-quality protein and fatty acid content in its diets is limiting its production. In order to improve the sustainability of its production, this study was conducted with 360 fish of 35 g to evaluate the effects on fish growth and health. Six diets were used: one control diet without replacement, three with FM replacement (FM66, FM33, and FM0) (33%, 66%, and 100% FM replacement), and two with FO replacement (FO50 and FO0) (50% and 100% FO replacement). The substitution of FM was with vegetable (VM) (corn gluten) and animal (AM) (krill and meat meal) meals. The reductions in FM and FO of up to 33 and 0%, respectively, did not affect the growth and survival of S. dumerili at the intestinal morphology level, except for the anterior intestine regarding the lower villi length and width and the posterior intestine regarding the lower width of the lamina propria. On the other hand, the substitution of fish ingredients in the diet affects liver morphology, indicating alterations in the major diameter of hepatocytes or their nuclei. Finally, diet did not affect the gut microbiota with respect to the control, but significant differences were found in alpha and beta diversity when FO and FM microbiota were compared. A 66% FM replacement and total FO replacement would be possible without causing major alterations in the fish.
... While this has met with varying degrees of success, the most satisfactory responses have been gained using animal protein-based diets and those comprising blends of plant protein concentrates, and their combinations cf. [15][16][17][18][19][20][21][22][23]. Indeed, some longer-term studies support the concept that, with judicious selection and blending of various alternative proteins and oils, it may prove possible to completely replace FM/FO in salmon feeds [24][25][26][27][28][29][30]. ...
... In fact, previous studies reveal that shoppers will pay higher prices for salmon produced under sustainable conditions, provided account is taken of fish welfare, and that food safety is guaranteed [34][35][36]. For example, consumers are prepared to pay a 25.3% premium for organic salmon in the UK [37], 20% in Denmark [38], 15% in Norway [39],[11][12][13][14][15][16][17][18][19][20], and an 11% premium in France [41]. ...
The influence of feeding Atlantic salmon for 90 days on diets that excluded fishmeal (FM) and fish oil (FO) was examined for influence on various quality traits. In addition, the effect of adding krill meal (KM; 0%, 2.5%, and 5%), as a putative feed palatant was also examined. Total replacement of FM/FO had a limited effect on production characteristics, affecting percentage yields of headed and gutted control fish and their standard length (p < 0.05). Variances between dietary groups were observed for pigmentation, and plant protein-based KM-free-fed fish returned deeper hues across their belly, NQC (Norwegian Quality Cut), and back portions (p < 0.03). No differences were measured for relative fin condition. δ¹³C and δ¹⁵N concentrations were lower and higher, respectively (p < 0.05) for fish fed the FM/FO-based diet. δ¹³C:δ¹⁵N likewise differed between treatments with FM/FO-fed salmon expressing higher ratios. Fillet mechanical characteristics varied with fish fed on animal protein-based diets, without KM expressing higher springiness and resilience (p < 0.05). Fish fed plant-based diets were generally preferred by younger taste testers. The results from this trial illustrate that FM/FO can be completely removed from salmon diets without problematic effects on quality and palatability attributes.
... meal at an amount of no more than 20%, according to fish weight gain, assimilation of feed nutrients and intestinal morphology. Better rates of assimilation of proteins, fats, starch, and essential amino acids from feed were obtained when feeding with pea protein concentrate compared to soybean meal [61]. ...
... For example, replacing up to 25% of fishmeal with rice meal concentrate in the diet of Nile tilapia did not affect parameters of non-specific resistance, antioxidant activity, intestinal microbiota and resist-рибного борошна у кількості не більше 20%, відповідно до показників приросту маси риб, засвоєння поживних речовин корму та морфології кишечника. Отримано кращі показники засвоєння білків, жирів, крохмалю, незамінних амінокислот з корму при згодовуванні концентрату горохового білка порівняно із соєвим шротом [61]. ...
Purpose. Analysis of the state and prospects of the use of vegetable proteins of various methods of manufacture in carp feeding in view of their functional and technological characteristics as well as in accordance with their impact on fish productive parameters and the functional state of the fish body.
Findings. The world resources of animal and vegetable protein were characterized, a comparative analysis of nutrition, digestibility and functional characteristic data of feed components was carried out.
The protein needs of carp, the main object of aquaculture in Ukraine, were examined. It is noted that vegetable proteins are widely used in carp feeding, but there are a number of limiting factors for the complete replacement of animal proteins with vegetable ones. In particular, the main such factors are the content of anti-nutrients, low digestibility and unbalanced amino acid composition of feed components of plant origin.
Modern approaches to the introduction of plant proteins into the composition of feeds have been analyzed, which allows increasing the efficiency of their use in animal husbandry in general, and in fish farming in particular. The expediency of using plant proteins processed by a technical method, single-cell proteins obtained by fermentation, concentrates produced by the extraction method, hydrolysates obtained by enzymatic hydrolysis, as well as whey-purified protein isolates in feed production were characterized. The effect of their use in fish feeding on the physiological and biochemical parameters of the fish body is considered. It is noted that the composition and digestibility of vegetable proteins may differ depending on the source and processing method. A comparison of the economic feasibility of feeding vegetable and animal proteins to different types of fish was made. The expediency and prospects of using vegetable protein in the conditions of aquaculture in Ukraine and in the cultivation of carp are outlined.
Practical value. Modern approaches to the use of vegetable protein in fish feeding increase its biological value and availability of nutrients, which allows obtaining additional increases in the weight of fish, reduce production costs and improve the quality characteristics of the grown products.
... The utilization of pea meal in freshwater fish farming is not well-known and well-studied. Aside from Nile tilapia, limited data on pea meal-based protein diets identified its digestibility in shrimps (Davis et al., 2002;Bautista-Teruel et al., 2003;Cruz-Suarez, 2013), Atlantic salmon Salmo salar (Overland et al., 2009), milkfish (Borlongan et al., 2003), Asian sea bass Lates calcarifer (Ganzon-Naret, 2019) and rainbow trout Oncorhynchus mykiss (Burel et al., 2000;Thiessen et al., 2003). Moreover, there are limited studies on pea meal plant proteins as fishmeal replacement in the diets of Nile tilapia. ...
... In the current study, the whole-body proximate composition of Nile tilapia fed pea meal was unaffected. Similarly, previous studies on Atlantic salmon (S. salar) (Overland et al., 2009) and gilthead sea bream (Sparus aurata) (Pereira and Oliva-Teles, 2002;Sánchez-Lozano et al., 2009) fed dietary pea meal resulted in unaltered whole-body composition. This may be explained by the nutritional profile of the pea meal used. ...
One of the most widely cultivated species in the aquaculture sector is the Nile tilapia (Oreochromis niloticus). However, the rising price of fishmeal has a huge impact on its market value. Proteins derived from plants have been used to address the issue. In this study, systematic review and meta-analysis were used to quantitatively analyze the whole-body composition and growth of Nile tilapia fed pea meal. Based on the preferred reporting items for systematic reviews and meta-analysis methods, the literature review and paper selection were completed. Meta-analysis was performed on the data from peer-reviewed studies that met the inclusion screening requirements, namely: tilapia development stage, standard error reporting, feeding period, lack of nutritional supplements, and crude protein levels. The control diet outperformed the plant-based diets according to the result, in which growth and feed utilization characteristics were significantly different (P < 0.05). All except the final weight were significantly better (P < 0.05) in tilapia fed control compared to tilapia fed pea treatment. Additionally, the pooled estimate of whole-body composition of fish fed a diet based on pea meal was not substantially different from that of fish fed a diet based on fishmeal (P > 0.05). Due to large and statistically significant I2 values, the feeding interval, crude protein concentration, fish development stage, and dietary pea meal inclusions were all examined using meta-regression analysis to identify the sources of heterogeneity. Not all co-variates explained the heterogeneity except for the feeding period and crude protein % in some of the parameters. The minimum quantities of dietary pea meal needed for best Nile tilapia performance in terms of growth, feed utilization, and whole-body composition were found to be 4.9, 488.6, and 210.3 g kg−1, respectively.
... For the measurements and observations of the intestine, we used a combination of criteria reported by several authors [4,52,53]. Daprà et al. [54] and Øverland et al. [55] use the following parameters: serous layer (SL), muscular layer (ML), submucous layer (SML), villi length (VL), villi thickness (VT), and lamina propria (LP). Six measurements per section of each parameter were performed, and average values were determined. ...
... No significant differences were found in the LP, although the non-fishmeal diet (AA0) reached the lowest value of all. In several studies, the histological results show a circulatory disorder, with a marked infiltration of leukocytes and eosinophilic cells in the LP, when using diets with maximum replacement that imply an increase in the cellularity of the LP [53,55,77,78]. ...
Simple Summary
Aquaculture is currently directing its efforts towards the principles of sustainability, especially in the reduction in the use of fishmeal, which is why it faces a constant search for alternative sources. In the current work, it has been found that the use of two different feed additives, hydrolyzed porcine mucosa and nucleotide concentrate, in different percentages in a plant-based diet for gilthead seabream, improves growth and feed efficiency.
Abstract
The fishmeal replacement by vegetable meals or other alternative sources, without affecting fish performance and productivity, is one of the principal challenges in aquaculture. The use of hydrolyzed porcine mucosa (HPM) and nucleotide (NT) concentrates, as feed additives in gilthead seabream (Sparus aurata L.) non-fishmeal diets was assessed in order to determine the possible effects on growth, feed efficiency, protein digestion, and gut histology when these were included in a plant-based diet (HPM 1% and 2%, P1 and P2; NT 250 and 500 ppm, N250 and N500), in comparison with two control diets, AA0 (100% plant-protein-based diet) and FM100 (100% fishmeal-protein-based diet). Diets were assayed in triplicate and the growth assay lasted 134 days. Results showed a significant improvement in all groups in terms of final weight and specific growth rate in comparison with the AA0 group. An improvement in the feed conversion ratio and the protein efficiency ratio was also observed when the additives were included in lower percentages (P1 and N250) compared to the FM100 group. Significant differences were found in hepatosomatic index, villi thickness, and goblet cells. Thus, the inclusion of NT and HPM was tested as beneficial for the improvement of efficiency of plant feed in seabream.
... A significant amount of research has indicated the suitability of SPC as a protein source in feeds for many farmed fish species, and the results have demonstrated that different species have their own unique levels of tolerance towards SPC (Colburn et al., 2012;Escaffre et al., 2007;Kissil et al., 2000;Kokou et al., 2017;Metochis et al., 2016;Storebakken et al., 1998;Wang et al., 2017;Zhang et al., 2019;Zhang et al., 2012). Another potential alternative protein source is pea protein concentrate (PPC) Øverland et al., 2009;Penn et al., 2011;Zhang et al., 2012), which has higher protein (350-500 g kg − 1 ), and lower carbohydrate content compared to unprocessed peas (Øverland et al., 2009). ...
... Replacing 10-35% FM with SBM in diets for Atlantic salmon has gradually reduced leucine aminopeptidase activity in the DI (Chikwati et al., 2013;Krogdahl et al., 2003;Lilleeng et al., 2007;Marjara et al., 2012). The reduced BBM enzyme activities of maltase and leucine aminopeptidase in the distal intestinal mucosa with increasing dietary SBM levels was seen in salmon fed PPC (Øverland et al., 2009;Penn et al., 2011). The decreased leucine aminopeptidase activity in those studies mirrored the tissue dysfunctions resulting in SBMIE (Chikwati et al., 2013;Krogdahl et al., 2003). ...
This study investigated the effects of plant protein concentrates on the activity of digestive enzymes and microscopic structure of the intestine of juvenile lumpfish. The experiment was carried out using triplicate groups of lumpfish of 7 g average initial body weight, to 40 g average final weight, after 54 days. Four experimental diets were used; a fishmeal (FM) based control diet and three test diets with the plant protein concentrates; soy protein concentrate (SPC) and pea protein concentrate (PPC) (1:1 ratio) replacing FM in proportions of 25% (PP25), 50% (PP50) and 75% (PP75), respectively. Nested ANOVA showed several significant treatment differences in histomorphometry. Overall, fish fed test diets exhibited several changes such as shorter mucosal fold height (MFH) in the anterior intestine (AI), increased number of goblet cells (GCs) and width of lamina propria (WLP) in distal intestine (DI), compared to control. Principal component analysis (PCA) on histological indices showed that all three treatment groups (i.e. PP25, PP50 and PP75) had significantly altered overall intestinal architecture, compared to the control group. The observed enteritis was negatively related with the condition factor (CF). Regarding enzyme activities fewer changes were observed across diets. Fish fed the PP50 diet exhibited an increased activity of leucine aminopeptidase (LAP) in the pyloric caeca and a decrease on chymotrypsin (CHY) in the mid intestine (MI) compared to the control. Nevertheless, the overall changes captured by PCA on enzymes were associated only with condition factor (CF) and not with the diets. Overall, histological evaluation confirmed that lumpfish intestinal morphometry was significantly altered by plant protein ingredients at 25%, 50% and 75% levels, but replacing of FM up to 50% did not affected the growth and the enzyme activities up to 75% inclusion level.
... Они являются недорогими и легкодоступными источниками протеина, но их использование для питания плотоядных рыб ограничено высоким содержанием крахмала и сложных углеводов, а также широкого спектра антипитательных факторов, таких как ингибиторы протеазы, фитиновая кислота, сапонины и др. [4,13]. Тем не менее, аминокислотный профиль масличных шротов сходен с профилем рыбной муки (табл. ...
... Проводятся исследования по применению в аквакультуре и иных видов протеиновых концентратов. Одним из таких видов сырья является гороховый белковый концентрат [13,35]. F. P. Willora установил, что смесь соевого и горохового белкового концентрата может заменить до 50 % рыбной муки в рационе молоди пинагора (Cyclopterus lumpus) без какихлибо негативных последствий для ее роста и состава туши [40]. ...
Проблемой для предприятий аквакультуры является рост цен на традиционное сырье для приготовления кормов – рыбную муку и жир. Способом решения проблемы является их замена недорогими компонентами растительного происхождения. Целью исследования является обобщение и анализ научной информации по использованию в комбикормах для аквакультуры новых видов растительного сырья, технологиям их подготовки и применения, влиянию на качество корма. Выполнен отбор и систематический обзор научной литературы по теме исследования за период 2017-2022 гг. Основными видами растительного сырья для приготовления кормов в аквакультуре являются продукты переработки наземных сельскохозяйственных растений, такие как шроты масличных культур, белковые концентраты, глютен, отходы пищевой промышленности. Оптимальным вариантом для замены в рационах рыбьего жира в настоящее время являются растительные масла. Частичная или полная замена рыбной муки и жира новыми видами растительного сырья возможна и не приводит к ухудшению здоровья рыб и скорости их роста при включении этих компонентов в рацион в рекомендованных дозах. Такая замена является экономически выгодной. Но при применении растительного сырья есть и отрицательные эффекты, такие как наличие антипитательных факторов, ограничивающие его использование в аквакультуре. Разработка рецептов экономически эффективных кормов для рыб, в которых рыбная мука и жир полностью заменены растительными компонентами, является приоритетным направлением исследований, направленных на развитие интенсивной аквакультуры.
Rising prices of traditional feedstock for feed preparation (fish meal and oil) is a problem for aquaculture enterprises. Their replacement with inexpensive components of vegetable origin is the way for solving the problem. The aim of the study is to generalize and analyze scientific data on using new types of vegetable feedstock in aquaculture feeds, on technologies of their preparation and use, influence on feed quality. Selection and systematic review of scientific literature on the topic of the study for the period of 2017-2022 has been carried out. The derivatives of land agricultural plant products such as oilseed meal, protein concentrates, gluten and food industry wastes are the main types of vegetable feedstock for feed preparation in aquaculture. Currently, vegetable oils are the best variants for replacing fish oil in fish diets. Partial or complete replacement of fishmeal and oil with new types of vegetable feedstock is possible and does not lead to deterioration of fish health and growth rate when these components are included in the diet at recommended doses. Such a replacement is economically advantageous. But there are negative effects in the use of vegetable feedstock, such as the presence of anti-nutritional factors that limit its use in aquaculture. The development of recipes of cost-effective fish feeds in which fish meal and oil are completely replaced by vegetable components is a research priority for the development of intensive aquaculture.
... Они являются недорогими и легкодоступными источниками протеина, но их использование для питания плотоядных рыб ограничено высоким содержанием крахмала и сложных углеводов, а также широкого спектра антипитательных факторов, таких как ингибиторы протеазы, фитиновая кислота, сапонины и др. [4,13]. Тем не менее, аминокислотный профиль масличных шротов сходен с профилем рыбной муки (табл. ...
... Проводятся исследования по применению в аквакультуре и иных видов протеиновых концентратов. Одним из таких видов сырья является гороховый белковый концентрат [13,35]. F. P. Willora установил, что смесь соевого и горохового белкового концентрата может заменить до 50 % рыбной муки в рационе молоди пинагора (Cyclopterus lumpus) без какихлибо негативных последствий для ее роста и состава туши [40]. ...
Rising prices of traditional feedstock for feed preparation (fish meal and oil) is a problem for aquaculture enterprises. Their replacement with inexpensive components of vegetable origin is the way for solving the problem. The aim of the study is to generalize and analyze scientific data on using new types of vegetable feedstock in aquaculture feeds, on technologies of their preparation and use, influence on feed quality. Selection and systematic review of scientific literature on the topic of the study for the period of 2017-2022 has been carried out. The derivatives of land agricultural plant products such as oilseed meal, protein concentrates, gluten and food industry wastes are the main types of vegetable feedstock for feed preparation in aquaculture. Currently, vegetable oils are the best variants for replacing fish oil in fish diets. Partial or complete replacement of fishmeal and oil with new types of vegetable feedstock is possible and does not lead to deterioration of fish health and growth rate when these components are included in the diet at recommended doses. Such a replacement is economically advantageous. But there are negative effects in the use of vegetable feedstock, such as the presence of anti-nutritional factors that limit its use in aquaculture. The development of recipes of cost-effective fish feeds in which fish meal and oil are completely replaced by vegetable components is a research priority for the development of intensive aquaculture.
... In gilthead seabream, the nutritional properties of pea -namely the low protein content and imbalanced amino acid composition -allow its dietary inclusion as a partial replacement of fishmeal, reaching percentages up to 20% [27,28]. In addition, like soybean, pea seeds contain a source of Antinutritional Factors (ANF) such as tannins, lectins and protease inhibitors that constrain its use as a dietary ingredient [14,15,[29][30][31]. Pea digestibility can be improved by extrusion and de-hulling, which can also inactivate the ANF [24,32]. ...
... According to the digestive enzymatic patterns observed in this investigation, PPC did not cause apparent detrimental effects on the secretion of digestive enzymes. This finding confirmed what previously reported by Øverland et al. [31] in Atlantic salmon, where PPC was unable to affect protein digestibility compared to a FM reference diet. In the present study, in spite of high carbohydrate content of plant feed ingredients and particularly of field peas [14], PPC did not seem to affect amylase, whose secretion is rather stimulated by BPM in rationed fed O. mykiss. ...
Objective: In fish feeding formulation, high interest has recently been addressed to protein sources alternative to Fish Meal (FM); nevertheless, the response of digestive enzymes to dietary changes is not fully known. To fill this gap, a study was undertaken in rainbow trout (Oncorhynchus mykiss), to explore the effects on intestinal enzymes (tryp-sin, chymotrypsin, carboxypeptidases A and B, amylase) of three experimental diets, containing a plant protein source (pea protein concentrate-PPC), a microbial protein source (bacterial protein meal-BPM) or a mix of PPC and BPM (MIX), in partial (50%) replacement of FM. Methods: Two feeding regimes (apparent satiation or rationed feeding at 1.4% of the fish wet biomass) and three times (1, 3 and 24 hours) after ingestion were tested. Enzyme activities were measured using conventional biochemical methods for digestive enzymes determinations. Results: PPC administered to satiation lead to not significantly higher protein utilization than FM, as suggested by proteolytic enzymes trypsin, chymotrypsin, carboxy-peptidase A. In fish fed rationed regime, PPC induced car-boxypeptidase B peak and moderate trypsin increase. BPM stimulated trypsin in fish fed both feeding regimes and car-boxypeptidase A in those fed to satiation. MIX diet varied significantly trypsin, carboxypeptidase B and amylase, increasing carboxypeptidase A and decreasing chymotrypsin in fish fed to satiation.
... The relationships among different foods, feeding habits, and diet plans in crustaceans are crucial for increasing seed yield and deepening our understanding of these animals in captivity [8]. Midgut morphology is essential to differentiate nonfeeding and feeding larval stages [9], to realize histopathological studies [10] and to develop commercial diets for species of aquaculture interest [11]. Feeding habits are also reported to effect digestive tract structure and intestinal microorganisms [12]. ...
Feeding ethology and dietary preferences were studied in S. hydrodroma, a freshwater crab collected from Southern region of India. Oral appendage morphology, histological analysis of gut and stomach were also carried out accordingly. After offering a series of foodstuffs to isolated male and female crabs, the crabs were found to be herbivore-biased omnivore, under laboratory conditions. Male crabs preferred 54% of egg white and female crabs preferred 35% of commercial fish feed. Food ingestion behavior was carefully recorded and represented. Feeding behavior involved the use of mouth appendages, 1st and 2nd pereiopods. Particles were trapped by the dense setation of the 2nd and 3rd maxillipeds and ingested. Histology of gut and stomach reveals the presence of mucosa, goblet cells, gastric glands, gastric pits, lamina propria and its structural adaptations depend upon its unique environment and the feeding behavior.
... Fish obtain elements for the production of color from the food they consume, so diet affects color intensity (Nickell and Bromage 1998;Overland et al. 2009). Under natural conditions, fish obtain pigments from food like phytoplankton and zooplankton (Andersson, Van Nieuwerburgh, and Snoeijs 2003), and many studies have focused on improving diets to optimize fish color production under culture conditions (Torrissen and Christiansen 1995;Valente et al. 2006). ...
... Intriguingly, FI during the 'stimulus' phase was the same in V2 and M fish (Table 3) suggesting that the reduced growth was the result of less efficient nutrient utilisation and/or assimilation, an outcome reported previously in salmon fed diets with alternative plant-based ingredients (Overland et al., 2009;Pratoomyot et al., 2010;Refstie et al., 1998). In contrast, although not statistically significant, V1 fish consumed an average of 26% less feed daily (measured as % of BW) compared to M fish, indicating reduced intake of both diets (V s and M s ) as a reason for decreased growth compared to M fish. ...
New strategies are required to enhance the efficient assimilation and bioconversion of plant-based ingredients in Atlantic salmon (Salmo salar) diets, especially relating to the essential long-chain polyunsaturated fatty acids (LC-PUFA), eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3). Our study investigated nutritional programming and specifically evaluated the optimal duration of dietary ‘stimulus’ and whether it could be reduced compared to a previous study using a three- week ‘stimulus’. Fish were fed an experimental ‘stimulus’ vegetable-based diet (VS, 5 % marine meals [MM]/0 % fish oil [FO]) or a standard marine-based control (MS, 82 % MM/4 % FO) for either one (V1) or two weeks (V2 and M) from first exogenous feeding. All groups were then fed a standard marine based formulation, for an ‘intermediate’ grow-out phase to the end of 16 weeks post-first feeding, prior to a ‘challenge’ phase of six weeks when all fish were fed a vegetable-based diet (VC, 10 % MM/0 % FO). Compared to M, fish from both V1 and V2 groups were significantly smaller at the end of the ‘stimulus’ phase, but there were no statistical differences in overall growth, proximate or fatty acid compositions at the end of the trial. However, hepatosomatic and viscerosomatic indices were significantly lower in V1 compared to V2 fish and there was an overall trend of improved performance in V1 fish throughout the ‘intermediate’ and ‘challenge’ phases. During the ‘challenge’ phase, M fish displayed a greater net gain of DHA than V1 fish, whilst V2 was a net consumer of all n-3 LC-PUFA over the same period. Compared to M, n-3 LC-PUFA biosynthesis genes in pyloric caeca were downregulated in both experimental groups indicating possible post-transcriptional modification of this pathway in either V1 or V2, considering the differences in DHA retention levels between groups. Taken together, the results suggested that nutritional programming was not initiated by a one- or two- week ‘stimulus’. However, more studies are required to elucidate the mechanism behind enhanced performance of V1 fish.
... Changes in feed composition, especially those aimed at reducing the use of traditional ingredients, have in some cases been associated with negative effects on fish performance, feed utilization, and health (Montero and Izquierdo, 2010;Oliva-Teles, 2012;Torrecillas et al., 2017;Aragão et al., 2022). In particular, the integrity and functionality of the fish gut have been shown to be directly affected by changes in aquafeed, particularly in relation to reduced nutrient absorption, alterations in intestinal permeability and gut microbiota, and impaired gut-associated lymphoid tissue (GALT) immunological response (Øverland et al., 2009;Merrifield et al., 2011;Król et al., 2016;Torrecillas et al., 2017), which together faciliates the occurrence of inflammatory processes and disease outbreaks (Torrecillas et al., 2017;Aragão et al., 2022). ...
Optimizing growth and feed conversion ratios by improving gut function and health is critial to ensuring cost-effective production in aquaculture, especially in the current context of low fishmeal and low fish oil-based diets. However, the use of practical diets based on high levels of plant-based raw materials as an alternative to traditional marine ingredients has been associated with negative effects on fish performance, feed utilization, and health. Organic acids and their salts have been widely used as functional ingredients not only for their antimicrobial and immunomodulatory properties, but also for their potential to promote animal digestive capacity and gut health. The aim of the present study was to evaluate the effects of a mixture of formic acid and sodium formate (Amasil NA®, BASF, Germany-AMA diet) at a dietary level of 0.3%, on key performance indicators , gut morphology and disease resistance to Vibrio anguillarum in juvenile gilthead sea bream (Sparus aurata). The results of the present study showed that fish fed the AMA diet for 8 weeks, performed similar to fish fed the control diet in terms of growth but presented an optimization of 8% in the utilization of a low in fishmeal and high in plant proteins based diet. The AMA-diet also increased the folds length of gilthead sea bream anterior gut, increasing intestinal absorption area, and decreasing the submucosa width and goblet cell size in the posterior gut when included in a high dietary plant protein content diet. Furthermore, dietary supplementation with Amasil NA® at 0.3% increased gilthead sea bream disease resistance against V. anguillarum compared with fish fed the unsupplemented diet. These results highlight the potential of this combination of formic acid and sodium formate based product as a feed efficiency enhancer, and as a gut health promoter in gilthead sea bream plant protein-based diets.
... One hundred sections of the liver were examined using an Eclipse E400 Nikon light microscope from Izasa S.A. in Barcelona, Spain. To determine the effects of different feeds on the liver, the diameters of hepatocytes and nuclei were measured [51,52]. ...
Simple Summary
This study explores the use of organic ingredients as protein sources in the diet of juvenile organic seabass. Various diets, including organic options like insect meal, Iberian pig byproduct, and rainbow trout meal byproduct, were compared to a control diet using conventional fishmeal. The research found that the control diet produced the best growth rates, and histological analysis indicated certain differences. While organic ingredients promise to replace fishmeal in aquaculture diets, further investigation is needed to achieve a complete substitution.
Abstract
The use of organic ingredients as a source of protein in aquaculture diets has gained significant attention due to the growing demand for organic seafood products. This study aimed to evaluate the potential for the use of organic ingredients as protein sources in the diet of juvenile organic seabass (Dicentrarchus labrax). A total of 486 juvenile seabass with an average weight of 90 g were fed six diets containing varied organic proteins. The control group (CON) was fed a diet with conventional fishmeal from sustainable fisheries as the primary protein source. The other five groups were fed diets with different compositions: organic Iberian pig meal byproduct (IB diet), a combination of organic Iberian pig meal byproduct and insect meal (IB-IN diet), a mix of organic Iberian pig meal byproduct and organic rainbow trout meal byproduct (IB-TR diet), a blend of organic rainbow trout meal byproduct and insect meal (TR-IN), and a mixed diet containing all of these protein sources (MIX diet). Over a 125-day feeding trial, growth performance, feed utilisation, feed digestibility, and histological parameters were assessed. The results showed that the fish fed the control diet had the highest final weight and specific growth rate, followed by the fish fed the TR-IN and IB-TR diets. The IB-TR diet had the highest apparent digestibility coefficients (ADCs) for protein, while the TR-IN diet had the lowest. Histological analysis revealed that fish fed the control diet had the largest nucleus diameter and hepatocyte diameter. Use of IN seems to penalise performance in several ways. Fish fed diets containing insect meal grew less, and those diets had lower digestibility. Fish fed the TR and IB diets grew at rates near that of the control, and the feed had acceptable digestibility.
... Fishmeal traditionally has been the main protein source used in feeds (Luthada-Raswiswi et al. 2021) as its high protein content, amino acid profile and palatability make it suitable for piscivorous fish species (Rolland et al. 2015). However, due to the increased price of fishmeal and the inconsistency of global supply, plant proteins have gained significant interest (Burel et al. 2000;Carter and Hauler 2000;Chou et al. 2004;Hansen et al. 2007;Opstvedt et al. 2003;Øverland et al. 2009). Plant-based proteins are an interesting alternative due to their high availability, competitive pricing and nutritional profile (Gatlin et al. 2007;Hardy 2010) and have shown promise in several species (Lazzarotto et al. 2018;Egerton et al. 2020;Hartviksen et al. 2014;Taylor et al. 2019;Vera et al. 2020;Hansen and Hemre 2013;Kaushik et al. 2004;Torrecillas et al. 2017). ...
The effect of supplementation of a novel phytase (OptiPhos®; Huvepharma; 750 OTU) to high plant meal inclusion diets for Atlantic salmon (Salmo salar) was assessed. Diets were prepared without phytase, with phytase and with supplemental inorganic phosphorus (MCP). After 61 days significant increases in growth, FCR and protein efficiency were seen in diets supplemented with phytase and with MCP over the negative control (P < 0.05). Addition of phytase significantly increased digestibility of phytate and phosphorus (P) as well as retention over other diets (P < 0.05). Phytase addition significantly decreased faecal P losses while increasing metabolic loss over the negative control (P < 0.05). Addition of MCP showed significant increases in metabolic P loss (P < 0.05). In conclusion, the addition of phytase (OptiPhos®; Huvepharma) resulted in performance improvements comparable to inorganic P dosing, while significantly improving the reduction of effluent wastes from plant meal-based diets.
... Coho salmon (Oncorhynchus kisutch), an anadromous migratory species, is widely distributed in the North Pacific Ocean, and has become one of the cold-water fish species with the most potential in China. It is famous for its high contents of unsaturated fatty acids (HUFAs) and protein, which has effects in preventing cardiac-cerebral vascular disease and diabetes in human beings [33]. In traditional aquaculture, fish meal and fish oil are the main components of farming salmonids feed; however, with the development of the global aquaculture industry, the shortage resources, the rising price, and other factors, it is necessary to develop diets with low or FM-free products. ...
Simple Summary
As an excellent but most expensive source of protein, fish meal (FM) is commonly used in 30–60% of the aquafeed for salmon fish species including coho salmon. However, the high cost and unstable supply of FM led it no longer to be considered as a sustainable protein source for aquafeeds. Accordingly, alternative protein sources with low cost and high availability have become a research hotspot in aquafeed for carnivorous species. Poultry by-product meal (PBPM), one of the rendered animal protein sources, can be used as protein substitute of FM in aquafeed due to its economical availability and high protein content and growth promotion effects in comparison to plant proteins. Until now, little information has been available on evaluating the effects of replacing FM by animal proteins including PBPM for coho salmon. In this study, the effects of PBPM instead of FM on growth, muscle composition, and tissue biochemical indexes of coho salmon were investigated. The results showed that the growth performance, feed utilization, muscle composition, serum biochemical indices, and liver antioxidant enzyme activities of coho salmon were negatively affected by high dietary inclusion level of PBPMs, and the optimum substitution level was evaluated based on the specific growth rate (SGR).
Abstract
The present study evaluated the effects of partially substituting fish meal (FM) with poultry by-product meal (PBPM) on the growth, muscle composition, and tissue biochemical parameters of coho salmon (Oncorhynchus kisutch) post-smolts. Five isonitrogenous (7.45% nitrogen) and isoenergetic (18.61 MJ/kg gross energy) experimental diets were made by substituting 0%, 10%, 20%, 40%, and 60% FM protein with PBPM protein, which were designated accordingly as PBPM0 (the control), PBPM10, PBPM20, PBPM40, and PBPM60, respectively. Each diet was fed to triplicates of ten post-smolts (initial individual body weight, 180.13 ± 1.32 g) in three floating cages three times daily (6:50, 11:50, and 16:50) to apparent satiation for 84 days. Both specific growth rate (SGR) and protein efficiency ratio did not differ significantly (p > 0.05) among the control, PBPM10, and PBPM20 groups, which were remarkably (p < 0.05) higher than those of the PBPM40 and PBPM60 groups. Feed conversion ratio varied inversely with SGR. The PBPM replacement had no remarkable effects on the morphological indices and proximal muscle components. The control and PBPM10 groups led to significantly higher muscle contents of leucine, lysine, and methionine than groups of higher PBPM inclusion. The groups of PBPM40 and PBPM60 obtained significantly (p < 0.05) higher serum alanine aminotransferase and aspartate aminotransferase activities than the control and low PBPM inclusion groups. The control group had significantly higher albumin and total cholesterol contents than the groups with PBPM inclusion. The control group had significantly higher triglycerides content than the PBPM60 group. The PBPM60 group had significantly lower contents of high-density lipoprotein, low-density lipoprotein, and total protein than the control and PBPM10 groups. The high PBPM replacement level up to 40% and 60% had adverse effects on hepatic malondialdehyde levels. The catalase and superoxide dismutase activities were not affected by low PBPM inclusion, but significantly decreased in high-PBPM-inclusion groups. Based on broken-line regression analysis of SGR and PER, the optimum dietary PBPM replacing level was evaluated to be 16.63–17.50% of FM protein for coho salmon post-smolts.
... Since leaching of dissolved material typically occurs shortly after defecation (Shomorin et al., 2019), the presented ADC represents the particle portion of the feces after leaching. The ADC in various feed trials on Atlantic salmon is variable and generally similar to or lower than the used digestibility values (Storebakken et al., 1998;Glencross et al., 2004;Kraugerud et al., 2007;Øverland et al., 2009). ...
Commercial salmonid farming is typically performed in open-water net cages where interactions between the environment and production unit might be widespread and not easily predicted or controlled. Integrated multi-trophic aquaculture (IMTA) has been suggested to mitigate some of the environmental impacts. Based on empirical data, the assimilation of particulate waste from a commercial fish farm was modeled by two approaches to salmon/blue mussel IMTA: a system with mussels at the surface next to the fish farm and an alternative setup with mussels submerged under the farm. According to the model, 15% of the feed was defecated and assumed available to the mussels and the submerged mussel farm could assimilate 14.6% of the feces. Sensitivity analysis showed that the current speed, the mussel filtration rate, and the proportion of the material that settles slowly had an impact on this assimilation estimate, which could be significantly higher. However, the model did not include assimilation limitations due to particle size, which may contribute significantly to the submerged farm. The mussel farm at the surface mainly received small slow settling particles, and according to the model, only 0.4% of the fish farm waste was assimilated. The maximum obtainable assimilation was 5.5%. The fraction of slowly settling waste had the most pronounced influence on waste assimilation in the mussel farm at the surface. This is also among the most uncertain parameters, since the relative portion of different settling velocities of fish feces is highly variable, and more information on the size distribution of waste is needed.
... Intestine health-no effects: No histological changes were observed in the DI of Atlantic salmon fed extruded whole field peas at an inclusion level of 20% [45]. A study showed that PPC could replace 20% of the FM protein in the feed for Atlantic salmon without adverse effects on intestine health; no changes in the size of the intestine and no significant differences in the histology of the DI among dietary groups were detected [61]. These results were recently confirmed by [62], where in fish fed a PPC diet at an inclusion level of 4%, there were no signs of DI enteritis. ...
Simple Summary
The Atlantic salmon industry is expected to grow globally by 2–3% by the year 2030. The main protein source used in salmon feeds is fishmeal, which is produced from wild-caught marine fish, whose natural stocks are at risk of depletion. It is of major importance, therefore, to select alternative feed ingredients that present an adequate protein profile, guarantee a good health status and growth performance of Atlantic salmon, and at the same time are environmentally sustainable.
Abstract
The availability and cost of fishmeal constitute a bottleneck in Atlantic salmon production expansion. Fishmeal is produced from wild fish species and constitutes the major feed ingredient in carnivorous species such as the Atlantic salmon. These natural stocks are at risk of depletion and it is therefore of major importance to find alternative protein sources that meet the nutritional requirements of the Atlantic salmon, without compromising the animals’ health. Terrestrial animal by-products have been used in aquaculture feed, but their use is limited by the lack of several essential amino acids and consumer acceptance. In the case of plant ingredients, it is necessary to take into account both their concentration and the extraction methodologies, since, if not dosed correctly, they can cause macro- and microscopic alterations of the structure of the gastrointestinal tract and can also negatively modulate the microbiota composition. These alterations may compromise the digestive functions, growth of the animal, and, ultimately, its well-being. An updated revision of alternative protein sources is provided, with the respective impact on the intestine health in terms of both morphology and microbiota composition. Such information may constitute the premise for the choice and development of Atlantic salmon feeds that guarantee fish health and growth performance without having a significant impact on the surrounding environment, both in terms of depletion of the fish’s natural stocks and in terms of pressure on the terrestrial agriculture. The sustainability of aquaculture should be a priority when choosing next-generation ingredients.
... respectively). In contrast to pea protein concentrates, which can easily replace FM in salmon and seabream diets [29,50,51], whole peas are not subjected to pre-treatment before being used in fish feeds. Whole plant ingredients have a high fiber content, which is considered to be an antinutritional factor [52]. ...
This trial aimed to assess the growth performance of trout (Oncorhynchus mykiss) fed novel formulations, evaluate fish welfare status, and determine flesh quality as part of the evaluation of sustainable feeds. A control diet containing fish meal and soy products (CTRL) was compared to: a diet with processed animal proteins (PAP); a diet without PAP (NoPAP); a PAP diet lower in protein (PAP−); and a NoPAP diet higher in protein (NoPAP+). Groups of 50 fish, weighing 58.84 ± 1.39 g (IBW), were allocated to 20 tanks and fed with formulated diets ad libitum over 91 days. Better growth performance was observed after the experiment in fish fed the NoPAP+ diet when compared to other diets. Protein retention was higher in CTRL diets than in PAP and PAP− diets. Protein and phosphorous digestibility were lower in fish fed PAP− diet. Diets did not influence the texture analysis. However, sensory analysis revealed higher acceptance for fish fed the NoPAP diet when compared to the PAP diet. Lysozyme was higher in the NoPAP diet than in other treatments. In addition, long-term predictions using FEEDNETICSTM software suggest some of these alternative formulations may be economically sustainable. Overall, these results support the hypothesis that the new formulations are viable options for trout farming.
... However, turbot is strictly carnivorous during its life cycle [10] and has a high demand for protein (55%) [11] and, depending on the alternative protein sources used, significant effects on growth, feed performance and organismic parameters were observed at replacement levels of more than 30-35% for juvenile turbot [12][13][14][15]. However, effects in organs, tissues, transcriptome, and metabolome can be detected even before the performance indicators are affected [16][17][18][19]. Among the 'omics' approaches, metabolomic studies are attracting increasing interest in aquaculture research in order to gain a deeper understanding of how feed ingredients affect performance indicators through changes in the physiological process [20]. ...
Circular economy driven feed ingredients and emerging protein sources, such as insects and microbial meals, has the potential to partially replace fishmeal in diets of high-trophic fish. Even though growth and feed performance are often unaffected at low inclusion levels, the metabolic effects are unknown. This study examined the metabolic response of juvenile turbot (Scophthalmus maximus) to diets with graded fishmeal replacement with plant, animal, and emerging protein sources (PLANT, PAP, and MIX) in comparison to a commercial-like diet (CTRL). A ¹H-nuclear magnetic resonance (NMR) spectroscopy was used to assess the metabolic profiles of muscle and liver tissue after feeding the fish the experimental diets for 16 weeks. The comparative approach revealed a decrease in metabolites that are associated with energy deficiency in both tissues of fish fed with fishmeal-reduced diets compared to the commercial-like diet (CTRL). Since growth and feeding performance were unaffected, the observed metabolic response suggests that the balanced feed formulations, especially at lower fishmeal replacement levels, have the potential for industry application.
... A similar growth response, but poor feed efficiency, in experimental feed containing high BSG can be explained by the less palatability of the diets when the feed contains a high level of BSG (Eyo and Ezechie, 2004). It has also been reported that different starch and protein sources affected the physical quality of extruded fish diets which can in turn affect its palatability and acceptability (Øverland et al. 2009;Sørensen et al., 2010). Another plausible explanation to the growth differentials among the treatment groups may be the imbalance in the digestible energy of the test diets (Eyo, 2004), since energy of the test diets were observed to decrease with increase in the level of BSG in the diets. ...
The response of catfish fed brewer's spent grain (BSG) based diets was evaluated in the diet of Clarias gariepinus using growth performance, nutrient utilization and apparent digestibility coefficient as indices. Seven iso-nitrogenous diets were formulated with BSG replacing 0,10, 20, 30, 40, 50 and 100% of corn in the diets. A relatively good growth performance and nutrient utilization by Clarias gariepinus fed the test diets were observed. However, the results showed significant difference (p<0.05) in weight gain, SGR, FCR and RGR between treatments, with 0%BSG (control) performing best. There was significant (p<0.05) reduction in apparent digestibility of nutrients with increasing levels of BSG meal in the test diets. The apparent digestibility coefficient for organic matter, protein, lipid, fiber and NFE of the control diet (0% BSG) were highest when compared to the rest of the test diets. However, the digestibility values for protein and lipid in diet A (0% BSG) and diet B (10% BSG) were statistically comparable.
... Numerous studies have described peas as potential dietary protein ingredient in marine fishes and crustaceans such as European sea bass, Dicentrarchus labrax [10]; blue shrimp, Litopenaeus stylirostris [11]; juvenile pacific white shrimp, Litopenaeus vannamei [12]; milkfish, Chanos-chanos Forsskal [13]; juvenile tiger shrimp, Penaeus monodon [14] and in Atlantic salmon, Salmo salar [15]. Francis et al. [18] and Sharma et al. [17] reported the use of grain legumes as feed ingredients is limited due to the presence of trypsin inhibitors (TIA), phytic acid, tannins and saponins which decrease the nutritive value of the legumes, thus reducing food intake and nutrient utilization in animals. ...
... The effects of replacing the feed fish meal protein by plant protein on the growth of fish have been studied for several species including Atlantic cod (Hansen et al., 2007;Colburn et al., 2012), Atlantic salmon (Carter and Hauler, 2000;Refstie et al., 2001;Øverland et al., 2009;Penn et al., 2011), European seabass (Gouveia and Davies, 2000;Kaushik et al., 2004), Gilthead Seabream (Kissil et al., 2000), Yellowtail (Watanabe et al., 1998), Milkfish (Borlongan, Eusebio, & Welsh, 2003), Rainbow Trout (Refstie et al., 2000;Thiessen et al., 2003;Zhang et al., 2012), freshwater Crayfish (Fuertes et al, 2013), and ...
Norway is the largest producer of Atlantic salmon (Salmo salar) in the world and there is a need for new tools to overcome the salmon lice challenge the industry is facing. The interest for using biological treatments like cleaner fishes is a new environmental friendly trend that supports the sustainability goal of the industry. Lumpfish (Cyclopterus lumpus) is a promising salmon lice grazer with better performances compared to wrasse fish species which are less temperature tolerant. However, the knowledge regarding the nutrition of the lumpfish is more or less none existing. The aim of the study was therefore to investigate the performance of the fish when replacing fish meal in the diet with soy and pea protein concentrate (SPC & PPC) at different inclusion levels (0%, 25%, 50% and 75%). Lumpfish (n = 2000 per tank), with mean weight of 4 g were purchased from a commercial lumpfish farmer (Mørkvedbukta AS) and allocated randomly in twelve tanks with triplicate treatments. Biometrical data such as body weight, standard length, width and height were measured at week 0, 2.5, 5, and 7.5. In addition, proximate composition and histological analysis to study the growth and development of the muscle were at each sample point during the experiment.
At the start of the experiment, weight of the fish (mean ± SEM) was 7.29 ± 0.13 g (post acclimatization) and there was no mortality during the experimental period, indicating that the fish were in good health. All biometric parameters measured throughout the experiment did not show any changes with diets (P > 0.05). Similarly, plasticity of skeletal fast white muscle fibre was not significantly affected with plant protein inclusion (P > 0.05), and hyperplasia was documented to be the dominant mechanism of muscle growth during the experimental period. Proximate composition of the fish did neither vary between diets (P > 0.05). It is therefore concluded that, fish meal in the diet of juvenile lumpfish can be replaced with 75% of SPC & PPC without compromising the growth performance, muscle cellularity and proximate composition.
... Tissues were processed and embedded in paraffin following standard histological procedures (Øverland et al., 2009;Sørensen et al., 2011) at the histology laboratory of Nord University, Bodø, Norway. The skin tissues (approximately 2 cm) were sliced transversely into 3 equal parts and decalcified with 10% formic acid (25 blocks per L) for 5 h, prior to processing. ...
We investigated the ability of lactic acid bacteria, when added individually or in combination in feeds, to prevent soybean meal-induced enteritis in Atlantic salmon. A control diet, designed to induce enteritis, was formulated with marine ingredients and 20% soybean meal. Three more diets were produced by coating the control diet with two bacteria, either singly (Lactobacillus plantarum; L. fermentum) or in combination. The fish were fed the abovementioned diets for 38 days. We performed histological assessments and evaluated the expression of selected mucin and antimicrobial peptide genes in the dorsal skin, gills, and distal intestine. Digesta were also collected to study the short chain fatty acids. Feeding bacteria, individually or in combination, altered the short chain fatty acids−acetoacetic acid, lactic acid, succinic acid, propionic acid−and the total fatty acids in the digesta significantly. Of all the determined short chain fatty acids, the concentration of acetoacetic acid was the highest, and the fish fed the combination of the two bacteria had the significantly highest value. Succinic acid was also significantly higher in fish fed the combination compared to the control group and the L. fermentum group. Total fatty acids were significantly higher in fish fed the combination than those fed L. fermentum. Compared to the control and probiotic combination-fed fish, those fed L. plantarum had higher defensin1 expression in the skin. We also observed significantly higher number of gill mucous cells in the fish fed the blend compared to the control group. Lamina propria width was significantly reduced in fish fed the blend. Supra nuclear vacuoles were higher in fish fed the single species or the blend, compared to the control group. Thus, adding the probiotics to a soybean meal diet can elevate the digesta short chain fatty acids and intestine supranuclear vacuoles, and reduce the lamina propria width, which probably indicate prevention of enteritis.
... Materials from natural sources, including keratin in protein hydrolysates and peptides, have been investigated for their role as bioactive agents in modulating body functions. Wool keratin contains approximately 10% cysteine (w/w of total protein), higher than other animal byproducts, including casein and whey (Oosthuyse & Millen, 2016), beef, lamb and poultry meat and offal (Brown, 1989;Taheri et al., 2013), seafood (Brown, 1989;Hansen et al., 2010), legumes, and cereals (Kalman, 2014;Øverland et al., 2009;Rafii et al., 2018;Ulrich & Jakel, 2003). l-cysteine exhibits anti-inflammatory, immune-boosting, and antioxidant properties and several vital physiological roles (e.g., skeletal muscle functions and cellular redox homeostasis; Asano et al., 2018;McPherson & Hardy, 2011;Seidel et al., 2019). ...
The growing global population and lifestyle changes have increased the demand for specialized diets that require protein and other essential nutrients for humans. Recent technological advances have enabled the use of food bioresources treated as waste as additional sources of alternative proteins. Sheep wool is an inexpensive and readily available bioresource containing 95%–98% protein, making it an outstanding potential source of protein for food and biotechnological applications. The strong structure of wool and its indigestibility are the main hurdles to achieving its potential as an edible protein. Although various methods have been investigated for the hydrolysis of wool into keratin, only a few of these, such as sulfitolysis, oxidation, and enzymatic processes, have the potential to generate edible keratin. In vitro and in vivo cytotoxicity studies reported no cytotoxicity effects of extracted keratin, suggesting its potential for use as a high‐value protein ingredient that supports normal body functions. Keratin has a high cysteine content that can support healthy epithelia, glutathione synthesis, antioxidant functions, and skeletal muscle functions. With the recent spike in new keratin extraction methods, extensive long‐term investigations that examine prolonged exposure of keratin generated from these techniques in animal and human subjects are required to ascertain its safety. Food applications of wool could improve the ecological footprint of sheep farming and unlock the potential of a sustainable protein source that meets demands for ethical production of animal protein.
... Intestinal inflammation (focal or diffuse expansion of the submucosa by leukocytic infiltrates) is included in this category. Enteritis characterized by a widening of the lamina propria infiltrated by a mixed population of inflammatory cells identified as lymphocytes, macrophages, eosinophilic and granular cells, are reported in teleosts as Atlantic salmon, rainbow trout and common carp fed a diet based on partial replacement of fish meal by soybean, attributing this alteration to soya saponins (Uran et al., 2008(Uran et al., , 2009Øverland et al., 2009 consequently to the inclusion of soybean meal in the diet. In addition, ESB seems to be less sensitive to certain soy-anti-nutritional factors, which induce intestinal disturbances in salmonids (Tibaldi et al., 2006;Bonaldo et al., 2008;Bonvini et al., 2018). ...
Gilthead seabream (GSB - Sparus aurata) and European seabass (ESB - Dicentrarchus labrax) are two of the most farmed fish species in EU. However, production of sea bream/bass in the EU has remained stagnant for the last decade and the Mediterranean EU aquaculture faces significant sustainability challenges. In consideration of this, and as it is largely recognized that the success of marine aquaculture strictly depends on the production of good quality larvae/juveniles, in this paper the authors put forward an original standardized tool for the histological assessment of GSB and ESB larva/juveniles. This tool promptly allows to highlight problems in marine fish larval batches because of managerial practices, suggesting to fish farmers which direction take to resolve them. A Multiparametric Semi-quantitative Scoring System (scoring range 1–5) has been originally developed for larval/juvenile histological evaluation and it includes 18 descriptors related to 6 organ districts. The values of each descriptor can be summarized in two indexes: the CHI (Cumulative Histological Index), giving general information about the quality of a fish batch in that precise moment and the OCV (Organ condition value) showing the general condition of each organ and by the individual descriptors. The paper purposes are to describe the MSSS, the criteria established for the score attribution and to supply some indications for the use of the tool.
... Knowledge on the morphology of the midgut tract is important to differentiate non-feeding from feeding larval stages (Lovett and Felder, 1989;Nakamura and Seki, 1990), to realize histopathological studies (Kaushik and Kumar, 1998;Martin et al., 2004), and to develop commercial diets for species of aquaculture interest (Fontagn e et al., 1998;Bonaldo et al., 2006;Øverland et al., 2009). In decapods, the epithelium of the midgut tract has two cell types: digestive cells with columnar shape involved in secretory and absorptive activities; and small regenerative cells with oval shape probably involved in cell division and differentiation (Sonakowska et al., 2015(Sonakowska et al., , 2016. ...
The midgut tract of decapods is a digestive organ involved in the synthesis of peritrophic membrane, food transport, absorption of nutrients, and osmoregulation. The midgut tract has been described in detail in adult decapods, but little information is available regarding the morphology and ultrastructure of the midgut tract in larval stages. The present study describes the midgut tract and the midgut–hindgut junction of the larvae of the common spider crab Maja brachydactyla Balss, 1922 using techniques that included dissection, light microscopy, and electron microscopy. The study is mainly focused on the stages of zoea I and megalopa. The results obtained in this study show that the larval midgut tract is a short and simple tube positioned anteriorly, between the stomach and the hindgut tract. During larval development, the maximum length of the midgut tract increases significantly, but no differences were found on either the maximum diameter or the morphological traits of the organ. The midgut tract is active at least ca. 12 h after hatching, as suggested by the presence of the peritrophic membrane in the lumen, the presence of abundant electro-dense vesicles in the cell apex, and the release of the vesicle content on the organ lumen. The midgut–hindgut junction forms an abrupt transition between the midgut tract and the hindgut tract in which epithelial cells with mixed features of midgut and hindgut do not occur.
... ;Iqbal, Khalil, Ateeq, & Khan, 2006;Millar, Gallagher, Burke, McCarthy, & Barry-Ryan, 2019;Overland et al., 2009;Pownall, Udenigwe, & Aluko, 2010; ...
The effect of replacing 20% pork meat in cooked sausages by Pea Protein Isolate (PPI), pea Low Moisture Extrudates (LME), and pea High Moisture Extrudate (HME) on the nutritional, techno-functional and sensorial properties of emulsified cooked sausages was investigated. All hybrid sausages contained all essential amino acids in sufficient amounts. Interestingly, extrusion significantly reduced the Anti-Nutritional Factors (ANF) trypsin and chymotrypsin inhibitors, and the allergenic pea Pis s2 (convicilin) content. Inclusion of (texturized) pea proteins into hybrid meat sausages resulted in weaker networks, and thus (significant) softer bite, and significant color changes. The expert taste panel did not note any significant differences between the hybrid sausage with PPI and its reference for all sensorial attributes.
Industrial relevance
Producing meat substitutes with powdered or extruded plant-based protein products, such as PPI, LME, and HME, can result in several limitations concerning textural, nutritional and sensorial features. To avoid these hurdles, hybrid meat products, where a fraction of the meat is replaced by alternative proteins, may bring a solution.
This work demonstrated that 20% of pork meat can be replaced by pea products PPI, LME or HME in emulsified cooked sausages without any implications towards the amino acid profile. Moreover, using extruded pea products could even significantly reduce ANF trypsin and chymotrypsin inhibitors and the allergenic pea convicilin contents. This knowledge plays a crucial role for product development, as this demonstrates that hybrid meats can be produced with great nutritional qualities. The challenges identified were that the hybrid sausage exhibited a weaker network with softer texture, and the inclusion of extruded proteins led to large cavities with jelly-like excretion. This demonstrates the importance of selecting suitable (forms of) plant proteins for the production of hybrid meats with great techno-functional and organoleptic properties.
With the rapidly increasing trend of cage fish farming in freshwater, practices to enhance fish farming sustainability are increasing. We estimated how different levels of phytase enzyme (0, 500, 1000, 2000, 4000 FTU kg⁻¹) affects the growth performance and nutrient load of tilapia (5.2 ± 0.1 g) reared in 15 cages for 180 days. The experimental design followed a completely randomized approach, with three replicates. The most significant increase in growth was observed in the groups that were given a diet supplemented with phytase at 4000 FTU kg⁻¹ of feed. These groups reached a slaughter size of 420.2 ± 6.6 g and experienced weight gain approximately three times greater than the control group (final weight: 146.8 ± 4.8 g). The phosphorus and nitrogen load for groups that were given diets with a phytase supplement of 4000 FTU kg⁻¹ of feed were 54% and 32% lower, respectively, compared to the control group and other diets that were supplemented with phytase. Hence, it is advisable to add phytase at a concentration of 4000 FTU kg⁻¹ feed in order to improve the growth performance and increase the availability of nutrients, while also minimizing waste in the cage culture of tilapia.
The global shrimp processing industry generates substantial amounts of solid waste (head, abdominal exoskeleton, and tail), with a considerable part currently being disposed of in landfills. It holds significant potential as an alternative ingredient in aquaculture feed due to its relatively high crude protein content, balanced amino acid profile, and presence of bioactive compounds. However, one of the main challenges with shrimp processing waste is its rapid spoilage. Consequently, shrimp solid processing waste must undergo further refinement to produce shrimp‐derived products suitable as aquaculture feed ingredients, such as meal, hydrolysate, or silage. This literature review describes the nutritional value, applications, challenges, and prospects of these shrimp‐derived products in aquaculture feed. Among the investigated shrimp‐derived products, shrimp hydrolysate has the highest nutritional value considering the high crude protein content, balanced amino acid profile, low chitin content, and low ash content. However, producing shrimp hydrolysate requires extensive processing, which can be costly, limiting its applications to high‐value aquaculture species. On the other hand, shrimp meal and shrimp silage, which require less energy‐intensive processing, may be more suitable for lower‐value aquaculture species that naturally consume feeds high in ash and chitin. The prospects for using shrimp‐derived products in aquafeed are promising, with advances in processing technologies showing potential to reduce costs, improve nutritional value, and enhance product quality and safety. Ultimately, shrimp‐derived products could replace current aquafeed ingredients while simultaneously utilizing current shrimp solid waste streams, provided that quality and safety measures are carefully considered.
a iFFO-the Marine ingredients Organisation, london, uK; b institute of Aquaculture, university of stirling, stirling, uK; c iFFO-the Marine ingredients Organisation, Beijing, china; d texas Agriculture & Medicine university, college station, texas, usA; e universidad de las Palmas de Gran canaria, spain; f norwegian university of life sciences, Aas, norway; g ciiMAR and icBAs, university of Porto, Porto, Portugal ABSTRACT A variety of new feed ingredients are emerging in the aquaculture feed sector. While the technology readiness of these options varies across and within the new ingredient classes, it remains important to consider them in terms of the overall feed ingredient spectrum. In this review, the use of marine, grain, terrestrial animal by-product and a range of novel (e.g., bacterial and yeast) resources being considered as potential protein feedstuffs for use in aquafeeds is explored. In comparing the nutritional attributes of each of the ingredient classes, an assessment framework is applied based on understanding the critical knowledge required to be able to accommodate any ingredient in a formulation process. To further examine each of the different ingredient classes a Strength-Weakness-Opportunity-and-Threats (SWOT) analysis is applied, to enable some consideration of what future potential may exist across the spectrum and what risks and opportunities they may bring. It is noted that all ingredients have strengths and weaknesses, and that there is no such thing as the perfect ingredient. By better appreciating the positives and negatives of each ingredient, it becomes possible to increase adaptability in responding to the various opportunities for their use in feeds.
This study explored and evaluated the addition of the probiotic Bacillus pumilus Rf8 to Coho salmon (Oncorhynchus kisutch) feed. A total of 360 juvenile Coho salmon with an initial body weight of 130.45 ± 1.11 g were randomly divided into four treatment groups, with three replicates per group and 30 fish per replicate. Different concentrations of B. pumilus were added to the feed of the four treatment groups: 0 (control group), 2 × 10⁶, 4 × 10⁸, and 8 × 10¹⁰ cfu/g. The experiment lasted 70 days. Growth performance parameters, nutritional metabolism, immune-related serum biochemical indicators, enzyme activity, gene expression, and muscle composition were evaluated. Furthermore, intestinal histology and intestinal flora were assessed.
The findings indicated that relative to the control group, B. pumilus Rf8 notably enhanced the growth performance, protein and fat metabolism, and immune status of the fish, effectively bolstering the structure and function of the intestinal microbiota. The “4 × 10⁸ cfu/g concentration” group demonstrated a substantial advantage in juvenile fish. The B. pumilus strains identified in this study exhibit promising potential as probiotic feed supplements in Coho salmon aquaculture.
The price of fishmeal (FM) has been increasing continuously due to the expansion of the gap between its stable production and rising demand. Therefore, plant protein sources are widely applied in the aquaculture industry to accomplish the protein requirement of farmed fish species. However, the massive number of results produced under various experimental conditions appended challenges for comprehensive summarization and comparison of the effects of plant protein sources on carnivorous fish species. Thus, a systemic review and meta‐analysis were conducted to compare the impacts of various plant protein sources on growth, feed utilization efficiencies, blood lipid, and liver health of representative carnivorous species. Supported by the data from 256 articles, our results indicated that Atlantic salmon, African catfish, Black seabass, and Hybrid striped bass were better at utilizing plant protein sources than Grouper and Japanese seabass. Cottonseed and lupin proteins were promising protein alternatives, while rapeseed showed significant growth suppression effects for these carnivorous fish species. Besides, deep processing methods such as fermentation and enzymolysis alleviated undesirable consequences effectively when less than half of FM was replaced by plant protein sources. Moreover, the optimal plant protein sources are discussed for each fish species. Overall, this article depicts the impact patterns of major plant protein sources on carnivorous farmed fish species and lays a solid foundation for further investigation on mechanisms for improving plant protein utilization.
During the past 20 years, there has been a growing concern about how best to replace fish meals with more sustainable, cost-effective, and environment-friendly ingredients. A global crisis of high feed prices, expansion of the aquaculture sector, and the increasing proportion of farmed fish have run into a decrease in the supply of fishmeal products. Therefore, scientists have redoubled efforts to discover alternatives and more renewable ingredients for aquafeeds worldwide. The goal has been to protect ecosystems and increase economic viability based on enhanced efficiency of production facility outputs and nutritional efficiency. A key challenge though is sourcing sustainable, renewable protein ingredients. This chapter reviews the advances, novel ingredients, and new techniques that serve the mission for the future of aquafeed research on alternatives for fishmeal to achieve global aquaculture sustainability, with a focus on partial or full replacement of fishmeal, especially in the feed of tilapia.
This edited book presents the emerging sustainable innovations in all areas of aquaculture in Africa with a view to create an opportunity whereby scientific outputs and recommendations can be endorsed for improved aquaculture outputs towards poverty alleviation and food security on the continent.
Food insecurity and poverty are some of the challenges faced on the African continent. These challenges are further exacerbated by the growing human population and the impacts of climate change. Today, aquaculture has become one of the fastest food producing sectors in the world, with the potential to contribute significantly to food security and poverty alleviation in developing countries. In Africa, aquaculture is at an infant stage, however, many African countries have recognized the potential roles of aquaculture in food security, poverty alleviation and conservation of aquatic resources through their commitment to achieve the United Nation Sustainable Development Goals.
The book reviews and synthesize research work from these thematic areas across Africa and provide a unique perspective on the emerging aquaculture innovations and illustrate how aquaculture practices could be feasible and cost effective while promoting social and environmental sustainability. The book also draws from global discussions on sustainable aquaculture practices and provides recommendations on what is feasible for Africa. This book is a great tool for the university students, scholars, aquaculture farmers, investors, and policymakers to understand the scientific based sustainable aquaculture innovations from an African perspective.
This book is focused on SDG 2 and SDG 14.
This edited book presents the emerging sustainable innovations in all areas of aquaculture in Africa with a view to create an opportunity whereby scientific outputs and recommendations can be endorsed for improved aquaculture outputs towards poverty alleviation and food security on the continent.
Food insecurity and poverty are some of the challenges faced on the African continent. These challenges are further exacerbated by the growing human population and the impacts of climate change. Today, aquaculture has become one of the fastest food producing sectors in the world, with the potential to contribute significantly to food security and poverty alleviation in developing countries. In Africa, aquaculture is at an infant stage, however, many African countries have recognized the potential roles of aquaculture in food security, poverty alleviation and conservation of aquatic resources through their commitment to achieve the United Nation Sustainable Development Goals.
The book reviews and synthesize research work from these thematic areas across Africa and provide a unique perspective on the emerging aquaculture innovations and illustrate how aquaculture practices could be feasible and cost effective while promoting social and environmental sustainability. The book also draws from global discussions on sustainable aquaculture practices and provides recommendations on what is feasible for Africa. This book is a great tool for the university students, scholars, aquaculture farmers, investors, and policymakers to understand the scientific based sustainable aquaculture innovations from an African perspective.
This book is focused on SDG 2 and SDG 14.
As a result of globalization, the quantity and generation rate of solid waste in Africa have increased tremendously. This calls for the need to salvage the situation before it gets out of hand. Most African countries dump waste in landfills where there is overflow and burnt, causing severe health and safety concerns. Therefore, instead of taking this waste to landfills, it is significant to reuse it to culture animal feed. From waste to feed might be an alternative feed ingredient to boost the African aquaculture industry. On the other hand, it enables sustainable aquaculture production with less reliance on fish meals. As a result, the aquaculture industry must ramp up its quest for alternative components made from renewable natural resources. Microbial and insect protein have been considered long-term components, owing to their ability to convert non-food lignocellulosic biomass into significant protein resources. This chapter outlined the importance of microbial and insect meals to aquatic animals and the steps involved in turning wastes into proteins. Furthermore, we discuss their nutritional capacity, growth promoters, and the immunoregulatory functions of these resources in aquaculture. However, several advancements in aquaculture nutrition and considerations for the future development of sustainable and safe aquaculture production are also discussed.KeywordsAquaculture industryAquatic productsFish meal replacementWasteMicrobial resourcesInsect
Insects have been proposed as an alternative source of nutrients to conventional foods, mainly protein sources because they have excellent nutritional quality and are sustainable. However, there are multiple barriers to mass consumption of insects, primarily the rejection and neophobia they provoke in individuals from Western cultures. Several studies have indicated that the acceptance of insects as food ingredients could be improved “if insects did not look like insects.” Therefore, the focus of current research is to transform commodity-type ingredients such as insect flour and oil through various technologies applied in the food industry such as protein concentration, encapsulation, hydrolysis, fermentation, deodorization, to develop food ingredients with better sensory and technological properties are better accepted by people as a part of their diet. Interestingly, some food ingredients obtained from insects also have functional properties that could increase interest in consumption. These aspects will be reviewed in this chapter for further consideration of insects as food ingredients of the future.
Food processing industries generate copious amounts of by-products and wastes, which contribute to various environmental problems. Valorization of these by-products is a potential solution in offsetting current issues and creating a more sustainable food system. This chapter provides a unique perspective on novel processing methods used for the valorization of brewer's spent grain (BSG), the most abundant processing by-product from the brewing industry. The major components of BSG are fiber and proteins, but it also contains lipids, minerals, and phenolic compounds. During the past two decades, tremendous efforts have been made to valorize BSG into different value-added products including food and aquaculture feed ingredients, biogas, biofuels, and functional materials using various processing techniques at lab scales. Nevertheless, challenges associated with the BSG valorization should be taken into consideration in the future including the development of integrated process to fully utilize BSG to produce multiple products, verification of the scalability of the process developed at lab scales, and evaluation of the environmental impact of the processes to valorize BSG.
The identification and implementation of raw materials to replace fish meal (FM) or its major alternative, soybean meal (SBM), among other factors, is crucial for the sustainable growth of aquaculture. Narbonne vetch (Vicia narbonensis) meal (NVM) has previously been identified as a promising alternative raw material locally produced in Europe to replace SBM. Previous work has showed that 33% replacement of SBM by NVM treated with a commercially available phytase (Rovabio® PHY) does not compromise fish growth performance in a 63-day trial. Here, a deeper characterization of the potential use of NVM to replace SBM was performed to unveil any potential undesired physiological impact in rainbow trout (Oncorhynchus mykiss) juveniles with an initial weight of 38.04 ± 0.07 g. After a 63-day feeding trial, high (66%) SBM replacement by NVM (even when treated with Rovabio® PHY) had a negative impact on rainbow trout: decreasing the activity of alkaline proteases, trypsin, chymotrypsin, and α-amylase; inducing cell shrinkage in hepatocytes; and reducing plasma triglycerides and hepatic vitamin E (VE) levels. No biochemical alterations were observed in blood plasma glucose, cholesterol or redox enzymes, regardless of the % of SBM replacement and/or Rovabio® PHY treatment. In fish fed diets with 33% replacement of SBM by NVM (regardless of being treated with Rovabio® PHY or not), only a reduced content of plasma triglycerides, and a slight modification in the position of the nucleus in enterocytes (more intermediate) from the proximal intestine, were reported. Altered metabolism of both carbohydrates and VE was also confirmed at transcriptional level, possibly being related to the presence of non-starch polysaccharides (NSPs) in NVM. The present study identifies future strategies to improve the use of NVM as an alternative raw material to replace SBM, allowing greater sustainability, and a lower carbon footprint in European aquafeeds to be achieved.
Simple Summary
In this study, we investigated Bacillus subtilis 9b effects in Totoaba macdonaldi fed with 30% and 60% of soy protein concentrate substitution. We found that B. subtilis 9b supplementation improved feed intake, weight gain, and internal organs condition of T. macdonaldi fed with 30% substitution. Animals fed with 60% of SPC substitution and B. subtilis doubled their weight and presented 20% more survival than its control diet without B. subtilis 9b probiotic strain. B. subtilis 9b was able to modulate T. macdonaldi intestinal microbiota and increase its resistance to Vibrio harveyi pathogenic strain.
Abstract
T. macdonaldi is a carnivorous species endemic to the Gulf of California. Indiscriminate exploitation has put totoaba at risk, inducing the development of aquaculture procedures to grow it without affecting the wild population. However, aquafeeds increasing cost and low yields obtained with commercial feeds have motivated researchers to look for more nutritious and cheaper alternatives. Soybean (SB) is the most popular alternative to fishmeal (FM); however, antinutritional factors limit its use in carnivorous species. In this study, we analyzed B. subtilis 9b probiotic capacity to improve growth performance and health status of T. macdonaldi fed with formulations containing 30% and 60% substitution of fish meal with soy protein concentrate (SPC). In addition, we investigated its effect on internal organs condition, their capacity to modulate the intestinal microbiota, and to boost the immunological response of T. macdonaldi against V. harveyi infections. In this sense, we found that T. macdonaldi fed with SPC30Pro diet supplemented with B. subtilis 9b strain and 30% SPC produced better results than SPC30C control diet without B. subtilis and DCML commercial diet. Additionally, animals fed with SPC60Pro diet supplemented with B. subtilis 9b strain and 60% SPC doubled their weight and produced 20% more survival than SPC60C control diet without B. subtilis. Thus, B. subtilis 9b improved T. macdonaldi growth performance, health status, modulated intestinal microbiota, and increased animal’s resistance to V. harveyi infections, placing this bacterium as an excellent candidate to produce functional feeds with high levels of SPC.
Fatty acid-binding proteins (FABPs) belong to the multigene family with 14–16 kDa molecular mass and have the function of binding long-chain fatty acids in both vertebrates and invertebrates. The intestinal fatty acid-binding protein (I-FABP) is a small cytosolic protein and plays a critical character in intracellular fatty acid trafficking and metabolism in fish gut. In this chapter, the nucleotide sequence and expression level of I-FABP gene in Trachinotus ovatus larvae are discussed. The full-length cDNA of I-FABP spanned 815 bp and a 399 bp open reading frame encoding 132 amino acids. In the process of ontogenetic development, the expression of 18 DPH is the highest. The expression level of I-FABP gene is the highest in the intestine on 18 DPH, followed by eyes. On 18 DPH, the expression of I-FABP genes was significantly affected by environmental temperature and nutrition enhancement. Monitoring of I-FABP gene expression level could serve as a potential indicator, used in assessing nutrient supply and functional development of the digestive system in fish larvae.KeywordsFatty acid-binding proteinsGolden pompano Trachinotus ovatusGene expressionOntogenyNutrition enhancement
This study analyzed the expression of growth‐related genes of olive flounder, Paralichthys olivaceus, fed a low‐fish meal (FM) diet to investigate the replacement of the FM diet in the field. The expression of growth hormone (GH)/insulin‐like growth factor (IGF) axis genes in the brain/pituitary/liver and plasma hormone concentrations were measured. A basal experimental diet was formulated using 63% FM and 12% soybean meal as the primary protein sources, and then two other diets were made by replacing 20% and 30% of the FM with soy protein concentrate, tankage meal, and poultry by‐products meal. Each diet was fed to duplicate groups of juvenile flounder (150 ± 3.0 g) twice a day. After 20 weeks, the plasma growth‐related hormone concentrations were similar between the control and FM20 groups. Moreover, GH/IGF axis gene mRNA expression in the brain/pituitary/liver was similar between the control and FM20 groups. Immunoblotting of muscle and liver showed the same pattern. This study showed the utility of replacing 20% of the FM diet and supports the possibility of field application.
Nowadays, both pelleted feed (PF) and extruded feed (EF) have been widely adopted in the aquaculture industry. However, limited information is available comparing their utilization efficiencies and meanwhile interpreting the underlying mechanisms. This study aimed to compare the utilization efficiencies of both PF and EF by blunt snout bream (Megalobrama amblycephala) based on growth performance, digestive capacities, and endocrine functions. Two feeds with identical formulas were prepared and named PF and EF. Fish were randomly distributed into two groups, including one that fed the PF continuously, and one that offered the EF continuously. The whole feeding trail lasted 8 weeks. The results showed that the protein efficiency (PER), retention of nitrogen and energy (NRE and ERE), viscera index (VSI), apparent digestibility of dry matter, protein, carbohydrate, and gross energy, whole-body crude protein and energy contents, intestinal enzymatic activities of protease, amylase, and Na⁺,K⁺-ATPase, intestinal villi length, crypt depth, muscular layer thickness, and the transcriptions of leptin (LEP) and cholecystokinin (CCK) of the EF group were all significantly higher than those of the PF group, while the opposite was true for feed intake and feed conversion ratio. These findings suggested that compared with PF, EF could improve the feed utilization and nutrient retention of blunt snout bream by enhancing the intestinal digestive and absorptive functions but reduce the feed intake through the stimulation of both LEP and CCK.
The chapter provides an overview of nutrients, nutrient requirements of major farmed fish species, nutrient bioavailability, feed additives, evaluation of feed ingredients and feed, and basic concepts essential for feed formulations. Many biochemical and physiological processes transform feed components into body elements that are required for sustaining the life, growth, health, and productivity of aquatic animals. A brief description of the utilization of energy-producing nutrients (protein, lipid, carbohydrate) followed by vitamins and minerals are emphasized. An understanding of these basic nutrition concepts is essential for formulating rations and developing feeding practices for enhancing the efficiency of food production while protecting the environment and maintaining the nutritional value of fish-derived food products. In recent years, major shifts from the use of fish meals to planting ingredients have resulted in more focus on their nutrient bioavailability and evaluation of several alternated sources of protein and lipid. Current methods used in feed formulations are reviewed and future challenges are outlined.
This study aimed to evaluate the effects of glutamine supplementation to soybean meal (SBM) diet in hybrid sturgeon (25.00 ± 1.00 g). Three diets, including fishmeal (FM) diet, SBM diet, and SBMG diet (glutamine addition to SBM diet), were formulated to feed sturgeons for 8 weeks. Growth parameters and muscular crude lipid content were reduced by SBM substitution, and were further increased in SBMG-diet group. In liver morphology detection, moderate lipid droplets accumulation in hepatocytes found in fish fed SBM diet were partially retrieved by glutamine addition. Hepatic gas chromatography–mass spectrometry analysis detected 156 up-regulated metabolites and 15 related KEGG pathways affected by SBM replacement. Glutamine addition resulted in 102 down-regulated metabolites, together with 9 KEGG pathways enriched. In liver transcriptome sequencing analysis, 1074 and 1564 differentially expressed unigenes (DEGs) were detected by SBM/FM and SBMG/SBM pairwise comparisons, respectively. The least number of DEGs (143) was present in pairwise comparison of SBMG /FM. Our results indicated that glutamine addition attenuated the SBM-based negative effect including growth retardation, and muscle proximate composition alteration. Glutamine supplementation alleviated the liver damage caused by SBM substitution possibly through down regulating the elevated levels of metabolites or gene as well as related metabolic pathways.
Condensed tannins of eight cowpea [Vigna unguiculata (L.) Walp.] cultivara determined by the protein precipitation method were localized in the seed coat and concentrated in the cooking broth. They were positively correlated with seed coat color (r = +0.64**), which varied from white to light brown, dark red, and black. Cooking increased in vitro digestibility by 6-8% significantly. The digestibility of the cooked seeds with cooking broth was significantly different from that without the cooking broth. Replacing the cooking broth of the cooked white seeds with the broth of the cooked light brown and black seeds resulted in a decrease of 1.4% in digestibility. Replacing the cooking broth of the cooked light brown and black seeds with that of the white resulted in an increase in digestibility of 3 and 4%, respectively. The change in the relative nutritive value determined by Tetrahymena pyriformis W upon interchange of broth was greater (5-31%). Significant negative correlations were observed between condensed tannins and protein digestibility (r =-0.87**) and relative nutritive value (r =-0.96**). Polyvinylpolypyrrolidone when added to homogenized cooked seeds at 4 and 6 mg/mL increased protein digestibility by 3.7 %. Isolated cowpea condensed tannins and commercial tannic acid decreased the digestibility of raw white cowpea and casein by 3.6 and 5.1% and 2.6 and 4.2%, respectively.
Duplicate tanks of c.280 g Atlantic salmon (Salmo salar L.) were fed for 60 days on diets in which fishmeal was substituted with graded levels of extracted soybean meal (SBM) comprising 0%, 10%, 15%, 20%, 25% or 35% of total protein. The effects on feed intake, growth, feed conversion, apparent digestibility and utilization of macronutrients and energy, pathohistological response of the distal intestine (DI), activities of digestive enzymes in the mid and distal intestinal mucosa, and faecal trypsin and plasma insulin concentrations were studied. A negative, dose-dependent effect of SBM was observed on nearly all performance parameters with a notable exception of feed intake. The lowest SBM inclusion level of 10% resulted in moderate pathohistological changes in the DI. Each subsequent increase in SBM level increased the number of fish displaying severe changes. In contrast to the mid-intestine (MI), all enzyme activities in the distal intestinal mucosa decreased dose-dependently with increasing SBM inclusion. Faecal trypsin increased up to an SBM inclusion level of 20% and then levelled off. Plasma insulin increased from 0% to 15% SBM inclusion and then decreased. The results suggest that caution should be exercised in the use of even low levels of extracted SBM in salmon feeds.
The utilisation of dietary carbohydrates and their effects on fish metabolism are reviewed. Details on how dietary carbohydrates affect growth, feed utilisation and deposition of nutrients are discussed. Variations in plasma glucose concentrations emphasizing results from glucose tolerance tests, and the impact of adaptation diets are interpreted in the context of secondary carbohydrate metabolism. Our focus then shifts to selected aspects of hormonal regulation of carbohydrate metabolism and dietary carbohydrates and their variable effects on glycogen and glucose turnover. We analyse the interaction of carbohydrates with other nutrients, especially protein and protein sparing, and de novo synthesis of lipids, and finish by discussing the correlation of dietary carbohydrates with fish health.
This review summarizes information regarding digestion and absorption of carbohydrates in cultivated fish. Relevant results of studies of digestive enzymes, e.g. amylase, chitinase, cellulase and brush border disaccharidases are presented. Fish amylases appear to be molecularly closely related and to have characteristics comparable to mammalian amylases. Whether chitinases and cellulases are endogenous enzymes of some fish species is still a matter of speculation, although recent molecular evidence, at least for chitinase seems to settle the issue in favour of endogenous sources. Feed and intestinal microbes may be the source of polysaccharidases in fish feeding on nutrients-containing non-starch polysaccharides. Knowledge regarding monosaccharide transport in fish intestine as interpreted from studies of brush border membrane vesicles, everted sleeves of fish intestinal sections and molecular biology is discussed. Glucose transporters of the intestinal brush border show characteristics similar to those found in mammals. A tabulatory presentation of experimental details and results reported in the literature regarding starch digestibility is included as a basis for discussion. Although numerous investigations on digestion of starch and other carbohydrates in fish have been published, the existing information is highly fragmentary. As yet, it is impossible to derive a cohesive picture on the integrated process of carbohydrate hydrolysis and absorption and interaction with diet composition for any of the fish species under cultivation. The physiological mechanisms behind the species differences are not known.
The replacement of fish meal protein with soybean meal (SB) or protein concentrates made from narrow-leafed lupin (LP) or field peas (PP) was investigated in extruded feeds for Atlantic salmon. Salmon (47 g) were fed for 63 days on extruded feeds containing each of the plant meals to replace 25% and 33% of the fish meal protein and performance compared against a nutritionally balanced control and a commercial salmon feed formulation (extruded under the same conditions). There were no significant differences in weight gain between the control and feeds containing the plant proteins. The commercial feed produced significantly higher weight gain than the control feed and LP at both replacement levels. Feed consumption was significantly higher for LP at 33%, but there were no other significant differences between the other feeds. Feed efficiency ratio (FER) and productive protein value (PPV) were highest for PP and SB and not affected by inclusion level, whereas they were significantly lower for LP at 33% inclusion. The weight gain and feed efficiency ratio data showed that soybean meal and pea protein concentrate had the best potential for replacing at least 33% of the fish meal protein in extruded salmon feeds and that lupin protein concentrate was less well utilised at the higher inclusion level. These results support the use of processed plant meals as important replacement protein sources for fish meal in extruded feeds for Atlantic salmon.
The study was conducted to examine if cellulose affected physical characteristics of extruded feed and nutrient digestibilities in rainbow trout. Five diets with cellulose inclusion levels ranging from 0 to 150 g kg− 1 were produced with a target apparent bulk density of 520 g l− 1 and fed to triplicate groups of fish (average weight 0.45 kg) twice a day for 31 days. Production parameters during feed production and physical pellet quality were recorded. During the feed production specific mechanical energy (SME) was around 32 watt hour (Wh) kg− 1 for all of the five extruded diets. Pellet expansion decreased linearly with cellulose inclusion, while pellet hardness and durability increased in a non-linear manner. There was a non-linear increase in water hydration capacity and a decrease in protein dispersibility index in response to increasing dietary cellulose level. No significant effects of cellulose inclusion were found on digestibility of main nutrients. The faecal excretion of sodium increased significantly with increased cellulose inclusion. In conclusion, digestion of main nutrients in rainbow trout was not affected by cellulose inclusion, but cellulose inclusion increased pellet durability and hardness.
Recently, pea has developed into a major protein crop in Western Canada. In the search for new food protein resources, small commercial facilities in Canada have engaged in manufacturing protein concentrates from pea by air classification or wet milling techniques. However, the major products from these processes are either crude or refined pea starches. Pea starch has been utilized almost exclusively for industrial application. A major factor, which has an adverse effect on the widespread utilization of pea starch in food industry, it its high extent of retrogradation. This review summarizes the present knowledge on composition, structure and physiochemical properties of smooth and wrinkled seeded pea starches with a view to providing suggestions for needed research to improve the utilization of pea starches in the food industry.
Groups of fresh- and seawater-adapted Atlantic salmon (Salmo salar L.) and rainbow trout (Oncorhynchus mykiss) were fed diets with (SBM diet) or without (control diet) extracted soybean meal (30% of protein substituted with SBM) for 3 weeks. Average fish size per group ranged from 597 to 1763 g. One tank or net pen per species, dietary group and water salinity was used. In vitro nutrient transport (D-glucose, the L-amino acids aspartate, lysine, methionine, phenylalanine and proline, and the dipeptide glycyl-sarcosine) was measured using intact tissue (everted sleeve method) from the different postgastric intestinal regions. The dimensions of the different intestinal regions were also measured for each treatment group. Results indicate that SBM causes decreased carrier-mediated transport and increased permeability of distal intestinal epithelium for the nutrients, and the capacity of this region to absorb nutrient was diminished. Salinity may also affect the relative contribution of carrier-mediated and independent uptake to total nutrient absorption.
The formation, composition, fine structure, physical and chemical properties, production and consumption, and applications of silk fibres are described and discussed in this chapter which cites 185 references.
Four processed soybean products were evaluated as protein sources for Atlantic salmon: solvent-extracted soybean meal (SBM44), dehulled and solvent-extracted soybean meal (SBM50), dehulled full-fat soybean meal (FFSBM) and soybean concentrate (SBC). The soybean products replaced high-quality fish meal at levels corresponding to 0, 14, 28, 42 and 56% soybean protein of total protein.Dietary inclusion of SBC, at the expense of fish meal, did not affect weight gain, carcass lipids, fecal excretion of nutrients or fecal dry matter content significantly. The nutritive value of the SBC protein appeared comparable to that of the fish meal. The three other soybean products impaired performance increasingly with increasing levels of inclusion, indicating lower nutritive value than for the fish meal. The favourable results seen with SBC indicated a great potential of soybean to become an important protein source for Atlantic salmon through improved processing.
Quantitative data are presented on nutrient leaching from fish feces remaining in water for varying periods. Rainbow trout (Salmo gairdneri) were fed a multicomponent diet and feces produced were collected from the trough sediment with a fine-mesh net after 1, 4, 8, and 16 h. Removal of fecal samples from the lowest 2.5 cm of the intestine followed by 1 h water immersion gave digestibility coefficients comparable to those of feces netted from trough sediment at 1-h intervals. This relation suggested that absorption of nutrients was completed before the materials moved into the lower 2.5 cm of intestine. Most leaching of nutrients from feces occurred during the first hour in water. Storage of feces in trough water for 1 h increased digestibility estimates for dry matter, protein, and lipid by 11.5, 10.0, and 3.7 percentage points, respectively. A gradual increase in leaching of nutrients continued up to 4 h, but little or no leaching occurred between 4 and 16 h after defecation.In a second experiment, four methods of fecal collection were compared after rainbow trout were fed pelleted herring meal. Collection of the lowermost fecal pellet by intestinal dissection or anal suction gave equivalent digestibility coefficient values for dry matter, crude protein, and crude lipid. Netting of fecal sediment up to 1 h after defecation gave values for dry matter and protein that were elevated by about 5%, whereas samples collected by the stripping technique gave values 5% lower than those for samples collected by intestinal dissection and anal suction.
Several soybean products were evaluated as protein sources for rainbow trout reared in fresh water: solvent-extracted soybean meal (SBM44), dehulled and solvent-extracted soybean meal (SBM50), dehulled full-fat soybean meal (FFSBM) and soybean concentrate (SBC). The soybean products replaced high-quality fish meal at levels corresponding to 0, 14, 28, 42 and 56% soybean protein of total protein. Effects of inclusion of soybean products were evaluated using regression analysis. SBC and SBM50 did not affect weight gain significantly (p
Atlantic salmon (average weight: 199 g, group size: 55) and rainbow trout (average weight: 565 g, group size: 25) of the same age, kept in freshwater (FW) or full-strength seawater (SW), were fed diets containing 7% (LCH) or 23% (HCH) precooked maize starch, replacing dietary protein. The fish were fed ad libitum in triplicate groups. Feed intake was monitored.The species appeared quite similar regarding thermal growth coefficient (TGC); 3.09% and 3.14% for the salmon and the trout, respectively, and retention of digestible protein; 45.9% and 43.9%, and energy; 45.7% and 46.9%, respectively. Rainbow trout showed higher digestibilities than Atlantic salmon, most pronounced with the HCH diet. Digestibilities were negatively affected by starch level in Atlantic salmon, less severe in rainbow trout. Hepatosomatic index was higher in rainbow trout than Atlantic salmon when fed the HCH diet. Liver lipid, liver glycogen, plasma glucose and plasma insulin were higher in rainbow trout than in Atlantic salmon at both starch levels. The difference was greatest with the HCH diet. In Atlantic salmon, the HCH diet elevated only liver glycogen. Specific activities of maltase and iso-maltase were substantially higher in the rainbow trout than in the Atlantic salmon.In seawater, Atlantic salmon showed higher TGC than in FW. Rainbow trout seemed unaffected by salinity. Salinity did not affect body composition significantly, except for ash, which was higher in SW than in FW in both species. Digestibility of protein, starch, freeze dry matter and energy was higher in FW than in SW. For starch digestibility, this was true for Atlantic salmon only. Retention of protein, but not energy, was higher in SW than FW. No significant effects of water salinity were observed with regards to condition factor, dress-out percentage, HSI, liver lipid, liver glycogen, plasma glucose or plasma insulin.The high starch diet reduced TGC in both species with no significant effect on FCR or body composition. Negative effects of starch level were observed on digestibility of macronutrients and energy in Atlantic salmon, but not in rainbow trout. Retention of digestible energy was not significantly affected by starch level, indicating that starch energy can replace protein energy. The results clearly showed stimulating effects of dietary starch on mucosal maltase, sucrase and lactase activities in both Atlantic salmon and rainbow trout, contrary to results of previous research. The response in leucine aminopeptidase showed adaptation according to protein level.
Trivalent oxides of yttrium and rare earth metals were evaluated as inert markers in apparent digestibility studies with salmonids in four experiments. In Experiment 1, 100 mg kg−1 of each of 15 oxides (Dy2O3, Er2O3, Eu2O3, Gd2O3, Ho2O3, La2O3, Lu2O3, Nd2O3, Pr2O3, Sc2O3, Sm2O3, Tb(III and IV) oxide, Tm2O3, Y2O3 and Yb2O3) were included in a feed fed to rainbow trout. The ratio between each marker and Yb2O3 in stripped faeces was used as an indicator of recovery. Only Er2O3, Ho2O3 and Tm2O3 had lower recoveries than the other markers. Experiment 2 compared the excretion rates of Cr2O3 and of the selected alternative markers (La2O3, Y2O3 and Yb2O3). A feed with 7.5 g kg−1 of Cr2O3 and 750 mg kg−1 of each of the other markers was fed to Atlantic salmon for a period of 1 week. Thereafter, the fish were fed with a marker-free feed, and gastro-intestinal evacuation was evaluated by comparing the marker ratios in the feed and in the faeces sieved from the outlet water of the tanks. The results did not reveal any systematic differences in evacuation among the various markers. Experiment 3 compared in vitro solubility of Cr2O3, Dy2O3, La2O3, Y2O3 and Yb2O3 in weak acid (HCl, pH 3 as in stomach contents of Atlantic salmon), weak acid neutralised with NaOH, and in water. Cr2O3 was not dissolved. Only 1.3% of Yb2O3, 22% of Y2O3, 31% of Dy2O3, and 96% of La2O3 was soluble in weak acid, but more than 99% of the dissolved markers precipitated when neutralised, and none of the markers were soluble in water. Experiment 4 compared the estimates of apparent digestibility coefficients (ADCs) of nitrogen and fat in rainbow trout when using Cr2O3, La2O3, Y2O3 and Yb2O3 as markers. The feed contained 10 g kg−1 Cr2O3 and 100 mg kg−1 of each of the other markers. Markers in feeds and stripped faeces were dissolved for the analysis with both HCl:HNO3 and H3PO4:MnSO4. Except for Cr2O3, the markers gave similar ADCs within each acid solubilisation procedure. The ADCs of fat were similar with both procedures, but the ADCs of nitrogen were 0.2% lower with HCl:HNO3 than with H3PO4. Cr2O3 was incompletely dissolved in HCl:HNO3, resulting in low ADCs. With H3PO4, no differences were seen among the ADCs obtained with Cr2O3 and the other markers. In conclusion, trivalent metal oxides, such as La2O3, Y2O3 and Yb2O3, can substitute Cr2O3 in digestibility studies with salmonids, and can be used at lower concentrations without affecting accuracy.
Methods of feed digestibility determination in fish were reviewed. The indicator method, using chromic oxide, was judged most suitable, but the best method of sampling faeces was uncertain. Rainbow trout (Salmo gairdneri, Richardson) were fed an experimental diet containing 1% chromic oxide. Faeces were collected by two stripping methods, and gut contents were obtained by dissection from five zones of the alimentary canal. Analyses of feed, faeces, and gut contents were made, and digestibility of protein, fat, carbohydrate, ash and gross energy calculated. It was concluded that absorption occurs in all parts of the alimentary tract, and that it is important to limit the stripping of faeces for analysis in digestibility studies to the hindmost part of rectum, i.e. from the ventral fin to anus.
The study was designed to investigate effects of processing of soybean meal on physical quality of extruded fish feed. Three diets were produced; one fish meal (FM) based control diet, and two diets with 40% amino acids from FM replaced by defatted, toasted soybean meal (SBM) or defatted, untoasted soybean meal (white flakes, WF). The diets were extruded under steady state standardized conditions. The WF diet was also extruded with an alternative screw-configuration and reduced screw revolution (RPM) generating a specific mechanical energy (SME) during the production similar to the FM and SBM diets. The WF feed from the first and second production is thus denoted as the WF1 diet and the WF2 diet, respectively.Partial replacement of FM with either SBM or WF improved the physical quality of feed in terms of breaking force and durability, bulk density was elevated and radial expansion reduced. Inclusion of WF increased the motor load, die pressure and SME of the WF1 diet compared to the FM and SBM diets, resulting in significantly longer pellets and higher bulk density. Extrusion of the WF2 diet with a less shearing screw configuration in combination with reduced screw rotation gave SME comparable to the energy consumption used during the production of the FM and SBM diets. The new processing conditions caused a significant reduction in length and diameter, and hence increased bulk density. Breaking force corrected for the diameter of the pellet was significantly higher for the WF2 diet produced with lower shear and screw rotation compared to the other three feeds produced under the same extruder conditions. The overall conclusion from the experiment was that durability and breaking force of extruded fish feed was significantly improved by inclusion of soy, regardless of previous heat treatment of this feed ingredient.
A total of 115 samples representing 38 different feedstuffs was analysed for carbohydrates and lignin. The samples were analysed for low-molecular weight (LMW) sugars by high-performance liquid chromatography, starch, fructan and mixed linked β(1 → 3;1 → 4)-D-glucan by colorimetry, total, soluble and insoluble non-starch polysaccharides (NSP) by gas-liquid chromatography and lignin by gravimetry. For all but alfalfa meal, almost quantitative recovery of carbohydrates and lignin was obtained with a deviation between calculated and analysed values of less than 2 g kg−1 dry matter. The correlation between calculated and analysed values was 0.985 (P < 0.0001).The concentration (g kg−1 dry matter) of LMW-sugars varied from 5 g kg−1 and up to 137 g kg−1 with the lowest values found in cereal substitutes, whole grain cereals and by-products while the protein concentrates in general had the highest content of LMW-sugars (57–137 g kg−1). Starch was the main polysaccharide in whole grain cereals where it varied from 468 g kg−1 in oats to 690 g kg−1 in maize, in cereal by-products (93–902 g kg−1) and in tapioca (768 g kg−1). In contrast, the concentration of starch was low in all protein concentrates but peas and faba beans. The lowest levels of NSP and lignin were found in maize flour (NSP, 21 g kg−1; lignin, 4 g kg−1) and the highest levels in oat hull meal (NSP, 503 g kg−1; lignin, 148 g kg−1). There was also a significant variation in NSP and lignin in protein concentrates with the NSP value varying from 189 g kg−1 in faba beans to 451 g kg−1 in white lupins and with lignin varying from 12 g kg−1 in white lupins to 133 g kg−1 in sunflower cake. Grass meal, alfalfa meal and sugar beet fibre had in general high concentrations of NSP and lignin with values in grass and alfalfa meals of NSP: 329–426 g kg−1 and lignin: 128–169 g kg−1 and in sugar beet fibre 779 g kg−1 and 35 g kg−1, respectively.
Total tract digestibility in Atlantic salmon and ileal digestibility in chicken were assessed from diets with different soyabean products (hulled, toasted, extracted, SBM; reduced oligosaccharide content, ROM; ethanol-extracted protein concentrate, SPC; isolated protein, ISP). The concentration of dietary fibre was highest in SBM and ROM, while it was low in ISP. In vitro viscosity was also higher in SBM than in the other soyabean products. The diets for the salmon and chickens were based on the same feed ingredients, with the exception that fish meal provided half the crude protein in the salmon diets. For each species, the diets were isonitrogenous, contained similar amounts of fat (fish oil), and were balanced with dextrin, thus substituting soyabean non-starch polysaccharides (NSP) and other non-proteinous components by dextrin.In the salmon, total tract digestibility of nitrogen and dry matter were lower (p
The functional properties of the protein and starch fractions of a model feed system had a greater effect on pellet quality (durability and hardness) of mixed pelleted feed than the method of conditioning. Maximum pellet durability (93%) was obtained with mixtures containing raw soya protein and pre-gelatinised tapioca starch and minimum durability with mixtures containing denatured soya protein and native tapioca starch. Improvements due to the inclusion of raw protein were greater than those from inclusion of pre-gelatinised starch. Hardness and durability of pellets were found to be related logarithmically. Specific output (kg kWh−1) and output rate (kg h−1) increased with increase in pre-gelatinised starch content, indicating a lubricating action by the pre-gelatinised starch during pellet compression. Implications of these findings on the known behaviour of certain feed ingredients are discussed.
The nutritive value of two white- and one dark-flowered cultivar of pea was determined in eight growing pigs weighing 31-55 kg. Each diet was given to two animals according to a replicated 4 × 4 Latin Square design. The apparent digestibility coefficients of organic matter, neutral detergent fibre, crude fibre and energy were significantly lower (P < 0.05) for the dark-flowered cultivar than for the white-flowered cultivars. All pea cultivars differed significantly with respect to the digestibility of crude protein, whereas the dark-flowered cultivar had considerably lower digestibility coefficients than the other cultivars. The mean content of metabolizable energy in the dark-flowered cultivar was only 13.6 MJ kg-1 of dry matter, which was 1.5-2.1 MJ less than the contents of the two white-flowered cultivars. The differences in nutritive value between the white- and the dark-flowered cultivars of pea can be explained by a higher content of tannins and other "anti-nutritional factors" in the latter cultivar, which results in low digestibility of nutrients and energy and consequently, a lower content of metabolizable energy in the feed. The apparent digestibility coefficient of nutrients and energy and the metabolizable energy content of the diets increased with increasing weight and age of the animals. This is probably due to increased fermentation activity in the caecum-colon, as the efficiency of N retention and NPU were not influenced by changes in live weight.
A simple and inexpensive method for determining daily feed intake of groups of fish in tanks is described. The method is based on the collection of waste feed from the effluent water and consists of an effective drainage system and a wire mesh collector. This technique is dependent upon the use of feed with good physical stability. The daily feed intake of fish in a tank is calculated by the difference between the amount fed and the amount of waste feed collected (corrected for leaching losses). The system can be combined with any type of feeding method in which sinking pellets are used. It allows accurate intake measurements for research purposes or can be used in commercial operations for adjusting feeding level without knowledge about biomass in the tank or water temperature. Use of the method has revealed large variations in daily feed intake of groups of Atlantic salmon fed continuously.
The study was designed to investigate disulfide bond (SS) digestibility, the effect of extrusion on dietary SS content, and the relationship between dietary SS content and nitrogen (N) and SS digestibility. Three high-quality fish meal-based diets were produced; one control diet (FM) and two diets with 40% of amino acids from fish meal replaced by defatted, toasted soybean meal (SBM) or untoasted soybean meal (white flakes; WF). The diets were given both extruded (EX) and unextruded (UEX) to mink (Mustela vison).Dietary SS content ranged between 23.3 and 32.7nmolmg−1 crude protein, and was not affected by extrusion at 120°C and 28% moisture in the FM diet, while it was moderately increased by extrusion of the SBM- and WF-diets. Coefficients of SS digestibility, being about 0.80, were higher than coefficients of free thiol (SH) digestibility in all diets. Coefficients of N and thiol digestibility in the WF UEX diet were much lower than in the other diets, probably due to high activity of protease inhibitors. No effect of dietary SS content on N or SS digestibility could be seen. The results indicate that other factors, such as lumen environment, feed passage rate and SS accessibility, are more important deciding factors than dietary SS content for SS and N digestibility.
Microscopy andin vitrodigestibility methods were used to obtain information about the putative inhibitory effect of guar gum, an endospermic seed extract, on the rate of digestion of wheat bread starch. Guar seed endosperm was examined by bright field microscopy after staining with toluidine blue or ruthenium red, by epifluorescence microscopy after labelling with two fluorescein-labelled lectins specific for α-D-galactose andD-mannose residues, respectively, and by scanning electron microscopy (SEM). These methods showed that guar galactomannan, the main component of guar gum, was located both within the plant cell walls and as amorphous deposits within the cell vacuole. SEM examination showed that the latter persisted in the milled guar flour. Examination of wheat bread containing guar gum by SEM and by fluorescence microscopy using the labelled lectins revealed that the starch granules and surrounding bread matrix were coated with a layer of galactomannan mucilage. After guar bread was ingested by pigs, the close association of galactomannan with the wheat starch persisted during the early post-prandial period (0–90 min), but this was greatly reduced at later post-prandial times (≥180 min). Thein vitrohydrolysis of starch in guar bread was found to be attenuated significantly compared with normal wheat bread. The results are consistent, therefore, with the concept that guar galactomannan acts as a physical ‘barrier’ toalpha-amylase–starch interactions and/or subsequent release of hydrolysed products (e.g. maltose). Such a process, in addition to the effect of guar gum on digesta viscosity, may be significant in reducing the rise in post-prandial glycaemia caused by guar gum in humans.
Juvenile gilthead sea bream with a mean initial body weight of 5 g were fed for 12 weeks with experimental diets containing 10% and 20% fishmeal protein (sole protein source in the control diet) replaced by processed pea seed meals. The processed pea seed meals were dehulled, defibred, extruded and microground pea seed meal (PSM1) or whole pea treated by infrared radiation and ground (PSM2). Apparent digestibility coefficients of the experimental diets were determined in a separate trial. At the end of the growth trial there were no significant differences in growth performance, feed utilization or whole-body composition among experimental groups. There were no differences in apparent protein digestibility among experimental groups (except for fish fed PSM1 at the lowest inclusion level). Both dry matter and energy digestibility of the diets, including PSM2 and with the highest inclusion level of PSM1, were significantly lower than those of the control diet. The results of this study suggest that pea seed meal may replace up to 20% fishmeal protein in diets for gilthead sea bream juveniles without affecting fish performance. Further studies should focus on technological treatments to increase utilization of pea seed meal carbohydrate, as both apparent dry matter and energy digestibility were affected by dietary inclusion level and by pea seed meal processing method.
Enhancement of fish feed extrusion-technology and improvements of technical pellet quality requires knowledge about causal connections amongst variables of processing condition and raw materials, and how these connections can be elucidated by measurements. Weibull analysis of feed pellet tensile strengths may represent one possible measurement tool for this purpose; this analysis is evaluated here and compared with the Holmen durability test. Diets added pre-treated red yeast Xanthophyllomyces dendrorhous (Basidiomycetes) that differ in the degree of enzymatic cell wall digestion (45, 70 and 97% CWD) were extruded at two temperatures, 100 and 140 • C. Pellet expan-sion ratio (32%) was independent of both temperature and yeast CWD. Bulk density and sinking velocity corroborated accordingly, with only marginal difference in density (640 kg m −3) and no effect of the independent variables on sinking velocity (10.7 ms −1). Average Holmen durability was significant higher (P<0.01) for pellets extruded at 100 • C (97.2%) than at 140 • C (96.4%), and the difference increased disproportional for testing times of 90 and 120 s. Tensile stresses at failure were Weibull distributed with values for the modulus m in the range 4.3–6.6, and the scale parameter σ 0 in the range 360–430 kPa. Inclusions of yeast cells with digested cell walls (97% CWD) improved ten-sile strengths significantly, and the positive effect was evident at both extrusion temperatures. Pellets Abbreviations: CWD, cell wall digestion; SME, specific mechanical energy extruded at the highest temperature showed significant lower strength. Weibull analysis suggests that the effect of temperature is caused by differences in anisotropy in these feeds.
The development of a pathological condition in the distal intestine of Atlantic salmon, Salmo salar L., induced by dietary soybean meal, was studied in a 6-week feeding experiment. The fully developed condition, as observed after 3 weeks on the experimental diets, was characterized by: (1) a shortening of heights of the mucosal foldings; (2) a loss of the normal supranuclear vacuolization of the absorptive cells in the intestinal epithelium; (3) a widening of the central stroma within the mucosal foldings, with increased amounts of connective tissue; and (4) a profound infiltration of inflammatory cells in the lamina propria. The first signs of morphological changes were observed after 2 days on a diet containing a solvent extracted soybean meal, and within 7 days, all the above mentioned signs were observed. When the fish were subsequently transferred to a control diet, the mucosal folds were rebuilt from the base, resulting in an apparently functional epithelium after 3 weeks. Starved fish also exhibited characteristic changes of the mucosa, including a finely granular cytoplasm replacing the supranuclear vacuoles seen in the epithelial cells of normal fish. In addition, a pattern of irregularly spaced indentations developed in the epithelium of the simple folds. The condition induced by dietary soybean meal was classified as a no n-infectious subacute enteritis, and a pathogenesis involving immunological mechanisms is suggested.
A digestibility experiment and subsequent 84-day feeding experiment evaluated the use of pea and canola meal products in diets for rainbow trout. The effect of milling and heat treatment on nutrient, dry matter and energy digestibility of raw/whole peas, raw/dehulled peas, extruded/dehulled peas and autoclaved air-classified pea protein was determined. Digestibility of the protein component was uniformly high for all pea ingredients (90.9–94.6%), regardless of the processing treatment. Autoclaving or extrusion increased starch digestibility by 41–75% (P ≤ 0.05), which consequently increased energy and dry matter digestibility of whole and dehulled peas. Autoclaved air-classified pea protein had superior protein (94.6%), energy (87.0%) and dry matter (84.0%) digestibility (P ≤ 0.05). It was demonstrated that inclusion of 25% dehulled peas, 20% air-classified pea protein or 20% canola meal fines was feasible in trout diets allowing for replacement of soya bean meal. The data showed no difference (P ≥ 0.05) in feed intake, final weight and specific growth rate (SGR) measurements, and feed utilization was not compromised with inclusion of pea or canola meal products as the primary plant ingredient. It was concluded that dehulled peas, air-classified pea protein and canola meal fines are suitable ingredients for use in trout diet formulation at a level of 20%.
The microstructure of extruded pellets (EP) for fish under various extrusion cooking temperatures was studied by using a twin-shaft extruder. As the extrusion cooking temperature increased, the expansion rate increased and the bulk density of EP decreased. The liquefaction of the material started because of the increase in inner material temperature, the decrease in inner material pressure, and the decrease in main motor amperage. Thus, the microstructure of EP changed depending on the extrusion cooking conditions, that is, the extrusion cooking temperature effected greatly the liquefaction of the material. Generally, when the extrusion cooking temperature increased, the expansion rate increased, but a suitable temperature was found for a maximum expansion rate. The microstructure of the EP was caused by the liquefaction of the material and the microstructure effects on the function of EP. For example, the water holding capacity was affected by the inner bubble structure of an EP. These functions affect the character of the feed. EP produced under suitable conditions can have additional functions for feed.
A feeding experiment was conducted to evaluate the supplemental effect of bile salts to a defatted soybean meal-based non-fish meal diet for rainbow trout Oncorhynchus mykiss. A fish meal-based diet (FM) and two non-fish meal diets with and without bovine bile salts (SC + B and SC, respectively) were fed to fish (13 g initial weight) for 10 weeks. Fish fed diet SC showed inferior growth and feed efficiency, while bile salt supplementation improved the parameters to the same levels as fish fed diet FM. Crude fat and starch digestibility of diet SC-fed fish decreased after the 10-week feeding trial compared to the data obtained with fish that had no experience of the diet. Total biliary bile salt content and intestinal maltase activity of fish fed diet SC were the lowest among treatments, while these parameters were improved by bile salt supplementation. Morphological changes occurred in the distal intestine and liver of the diet SC group, although the histological features of fish fed diet SC + B were similar to those of fish fed diet FM. These results suggest that bile salt supplementation to a soybean meal-based diet improves the nutrient utilization by normalizing digestive processes in rainbow trout.
Continued growth and intensification of aquaculture production depends upon the development of sustainable protein sources to replace fish meal in aquafeeds. This document reviews various plant feedstuffs, which currently are or potentially may be incorporated into aquafeeds to support the sustainable production of various fish species in aquaculture. The plant feedstuffs considered include oilseeds, legumes and cereal grains, which traditionally have been used as protein or energy concentrates as well as novel products developed through various processing technologies. The nutritional composition of these various feedstuffs are considered along with the presence of any bioactive compounds that may positively or negatively affect the target organism. Lipid composition of these feedstuffs is not specifically considered although it is recognized that incorporating lipid supplements in aquafeeds to achieve proper fatty acid profiles to meet the metabolic requirements of fish and maximize human health benefits are important aspects. Specific strategies and techniques to optimize the nutritional composition of plant feedstuffs and limit potentially adverse effects of bioactive compounds are also described. Such information will provide a foundation for developing strategic research plans for increasing the use of plant feedstuffs in aquaculture to reduce dependence of animal feedstuffs and thereby enhance the sustainability of aquaculture.
The use of plant-derived materials such as legume seeds, different types of oilseed cake, leaf meals, leaf protein concentrates, and root tuber meals as fish feed ingredients is limited by the presence of a wide variety of antinutritional substances. Important among these are protease inhibitors, phytates, glucosinolates, saponins tannins, lectins, oligosaccharides and non-starch polysaccharides, phytoestrogens, alkaloids, antigenic compounds, gossypols, cyanogens, mimosine, cyclopropenoid fatty acids, canavanine, antivitamins, and phorbol esters. The effects of these substances on finfish are reviewed. Evidently, little unanimity exists between the results of different studies as to the specific effects of antinutrients, since most studies have been conducted using an ingredient rich in one particular factor and the observed effects have been attributed to this factor without considering other antinutrients present in the ingredient, or interactions between them. Tentatively, protease inhibitors, phytates, antigenic compounds, and alkaloids, at levels usually present in fish diets containing commercially available plant-derived protein sources, are unlikely to affect fish growth performance. In contrast, glucosinolates, saponins, tannins, soluble non-starch polysaccharides, gossypol, and phorbol esters, are more important from a practical point of view. The effectiveness of common processing techniques such as dry and wet heating, solvent extraction and enzyme treatment in removing the deleterious effects of antinutrients from feed materials is discussed. More insights into the nutritional, physiological and ecological effects of antinutrients on fish need to be accumulated through studies using purified individual antinutrients and their mixtures in proportions similar to those in alternative nutritional sources in fish feeds. Such studies would provide data useful for designing optimum inclusion levels of plant-derived materials and treatment methods that would neutralise the negative effects of the antinutritional factors.
Duplicate groups of Atlantic salmon (Salmo salar), kept in saltwater, were fed fish meal based cold-pelleted diets where graded levels of native or extruded non-starch polysaccharides (NSP) from soybeans replaced cellulose, at a total NSP level of 100 g kg− 1 for 28 days. The study also included a diet where defatted soybean meal (SBM) constituted the NSP at a level of 100 g kg− 1 and a reference diet without NSP supplementation.The SBM diet resulted in a significant reduction in faecal dry matter content, apparent digestibilities of starch and organic material, and growth, and an increased faecal output of several elements (K, Na, Zn), compared to all the other diets. Morphological changes were only seen in the intestine of the fish fed the SBM, i.e. the diets holding purified soy-NSP did not induce enteritis. When compared to the diet without NSP, cellulose addition increased faecal dry matter, while inclusion of native soy-NSP reduced it. Dry matter in faeces and apparent digestibility of crude protein decreased in a linear manner, while the digestibility of starch and faecal output of K and Na increased linearly when native soy-NSP replaced graded levels of cellulose from 0 to 100 g kg− 1 feed. When diets with 75 or 100 g kg− 1 of native NSP and extruded soy-NSP were compared, fish fed native soy-NSP had reduced faecal dry matter, higher digestibility of starch, and increased faecal output of Cu, Fe, and K. Dry matter in faeces and faecal output of Cu was lower for the highest inclusion level, while digestibility of starch and faecal output of Mn and K were higher.In conclusion, soy-NSP was inert compared to the fish meal reference, with respect to nutrient digestibilities and intestinal pathologies, but affected faecal mineral excretion in Atlantic salmon.
Starch is a predominant component of wheat grain. It plays an important role in appearance, structure and quality of food products. Starch consists of two kinds of glucose polymers (amylose and amylopectin) with the ratio of amylose/amylopectin ranging between 25–28 and 72–75%, respectively. The isoforms of granule-bound starch synthase (GBSS) are responsible for the biosynthesis of amylose fraction, whereas amylopectin synthesis is more complicated with concerted activities of the soluble starch synthase together with branching and de-branching enzymes. Recently, waxy (amylose-free) and high-amylose wheats produced through the development of new physicochemical and biological techniques provide the unique starch functional properties. The starches of these wheats have the specific structures and unique characteristics that are believed to enhance the quality of food products. In this review, we will focus on recent advances in the studies of the characteristics of waxy and high-amylose wheat flours and starches and their application for food processing. In addition, we also propose further research ideas for clearer understanding of their characteristics and for their effective utilization.
A feeding trial and subsequent digestibility trial were performed on juvenile European sea bass. The diet formulation allowed for the incorporation of up to 30% of a highly processed commercial pea seed meal as a replacement for both fish meal and the non-protein energy component of the diet (mainly starch). After 11 weeks, it was observed that a positive but non-significant trend existed for both growth and feed utilization with increasing incorporation of pea seed meal in the diets. There were, however, other nutritional parameters such as protein efficiency ratio (PER) and nitrogen deposition that increased according to graded levels of pea seed meal indicating that a high inclusion of this ingredient was beneficial to protein assimilation. Digestibility coefficients for protein, lipid and carbohydrates were not appreciably affected by the inclusion of this ingredient which was also reflected with respect to the overall carcass composition of sea bass at the end of the study.
Starch from cultivars of black bean, pinto bean, smooth pea, lentil and wrinkled pea starches were isolated and their composition, physicochemical properties and susceptibility towards porcine pancreatic α-amylase determined. The yield of starch ranged from 16.4 to 34.1% on a whole seed basis. The shape of the granules varied from round to oval to irregular. Bound and total lipids ranged from 0.26 to 0.80% and 0.35 to 0.84%, respectively. The total amylose content ranged from 30.5 to 78.4%, of which 10.3 to 12.2% was complexed by native starch lipids. The X-ray diffraction pattern was of the ‘B’ type in wrinkled pea starch and of the ‘C’ type in other starches. The relative crystallinity and the ‘B’ polymorphic content ranged from 17.7 to 33.4% and 27.1 to 92.2%, respectively. The starches differed in the degree of swelling, extent of amylose leaching, gelatinization temperatures and gelatinization enthalpy. The above differences were more pronounced between cultivars of black bean and lentil. The results showed that starch chain interactions within the amorphous domains were more pronounced in wrinkled pea starch. All starches exhibited a biphasic hydrolysis pattern, a relatively rapid rate at the initial stage followed by a progressively decreased rate thereafter. Wrinkled pea starch exhibited a much higher initial velocity than the other starches. Cultivars of black bean and lentil showed significant differences in their initial velocities. However, differences in initial velocity between cultivars of smooth pea and pinto bean were not significant. Black bean, lentil and wrinkled pea starches showed a plateau at 93, 85 and 65% hydrolysis, respectively. The time taken for the appearance of the plateau was identical for black bean cultivars, but was different for cultivars of lentil. Pinto bean and smooth pea cultivars showed no plateau. At the end of the assay period (120 h), cultivars of each legume species were hydrolyzed to the same extent, and the extent of hydrolysis among the legume species followed the order: black bean>lentil>smooth pea>pinto bean>wrinkled pea. The X-ray pattern and the ‘B’ polymorphic content of all starches remained unchanged on hydrolysis. However, the relative crystallinity increased in wrinkled pea, but remained unchanged in the other starches. On hydrolysis, the apparent amylose content decreased in all starches. The extent of this decrease was most pronounced in wrinkled pea. In all starches, the enthalpy of gelatinization decreased, and the gelatinization transition temperatures increased slightly on hydrolysis. This study showed that the rate and extent of hydrolysis was influenced by structural organization of the starch chains within the native granule, and by the extent of interaction between hydrolyzed amylose chains.
Ten different plant protein and/or starch sources were studied in a 5-week experiment with triplicate groups of 0.7-kg Atlantic salmon in seawater, pre-adapted to a diet with fish meal, faba beans, sunflower cake, and wheat gluten as sources of protein and starch. The experimental ingredients were corn gluten, defatted soybean, defatted sunflower, dehulled lupin, defatted double-low rapeseed, whole field pea, whole and dehulled faba bean, whole wheat and naked oat, tested one at a time (14–24% inclusion). The diets were balanced by addition of pure wheat starch and/or pure cellulose, to obtain equal macro nutrient compositions. The control diet consisted of fish meal, wheat starch, cellulose and fish oil. The results showed reduced faecal dry matter content in fish fed the soybean diet and to a lesser extent in those fed the sunflower, lupin and rapeseed diets. Diets containing lupin and rapeseed resulted in a moderate increase in the viscosity of the digesta, while diets with wheat and oat increased viscosity of digesta more. Apparent digestibility of lipid decreased linearly with increasing dietary cellulose level. A significant reduction in the digestibility of crude protein was seen for the soybean, sunflower, rapeseed and oat diets, reflecting reduced digestibilities of most amino acids. The salmon fed the corn gluten, lupin, pea, bean and wheat diets had protein digestibilities comparable to the control group. The digestibility of phosphorus was highest for salmon fed the rapeseed diet and lowest for fish fed the oat diet. Faecal excretion of sodium was highly elevated for salmon fed the soybean diet, and moderately elevated for fish fed the corn gluten and sunflower diets. Faecal excretion of zinc was elevated in the fish fed the oat diet. None of these observations were significantly related to the dietary concentration of phytic acid. A histological examination of the stomach, mid- and distal intestine of all groups showed no other irregularities than enteritis in the distal intestine of salmon fed soybean meal. The present study demonstrated a potential for several plant ingredients, such as field pea and faba bean, partly replacing high-quality fish meal in diets for Atlantic salmon, based on nutrient digestibilities and absence of pathologies in the stomach and intestine.
An experiment was carried out to study the nutritional value of solvent extracted, toasted soybean meal (SBM) and solvent extracted, untoasted soy “white flakes” (WF) partly replacing high-quality fish meal (FM) in extruded diets for rainbow trout. Particularly, we wanted to find out if feed extrusion provides sufficient heat to reduce the soybean trypsin inhibitor activity (TIA) to a tolerable level in diets for trout. Three diets were produced: a control diet with 490 g FM kg− 1 (FM diet), a diet with 290 g FM and 250 g SBM kg− 1 (SBM diet), and a diet with 290 g FM and 250 g WF kg− 1 (WF diet). Each diet was fed to three groups of trout for 63 days. The TIA levels in the SBM and WF diets after extrusion were 0.6 and 2.1 mg (g dry matter)− 1, respectively. Feed intake was lower (P < 0.05) in trout fed the SBM and WF diets than in those fed the FM diet, resulting in reduced growth and poorer feed conversion. The diets did not significantly affect whole-body content of dry matter, protein and fat, or carcass yield, total gut weight, or weight of pyloric, mid and distal intestine. Trout fed the WF diet had higher stomach weight than trout fed the FM diet. Liver weight, plasma cholesterol and triacylglycerol were lower in trout fed the SBM and WF diets than in those fed the FM diet. Apparent digestibility of nitrogen was lower for the WF diet than for the FM diet and intermediate for the SBM diet. The SBM and WF diets caused lower digestibility of fat and most amino acids and lower nitrogen retention than the FM diet. Moderate morphological abnormalities were found in the distal intestine of trout fed the SBM and WF diets. Bile acid concentration in chyme was lower in fish fed the SBM and WF diets than in fish fed the FM diet, except for the proximal pyloric region and the posterior distal intestine. Trypsin activity in chyme of the distal intestine was higher and leucine amino peptidase activity in intestinal wall tissue was lower in trout fed the SBM and WF diets than in trout fed the FM diet. In conclusion, both SBM and WF had a negative influence on growth and feed conversion compared with the FM diet. Extrusion did not influence soy-related challenges such as reduced fat digestibility, and morphological and enzymatic changes. However, extrusion was sufficient to lower TIA in the diets to an acceptable level for rainbow trout.
The endogenous and exogenous factors reported to affect the proximate composition of cultured fishes, with emphasis on salmonids, are examined. Methods of reporting and comparing proximate composition are discussed. Examination of measurements presented in a number of published papers, using allometric analysis, indicates that comparison of proximate compositions on a dry weight basis and failure to include fish size as a covariate have, in many cases, led to erroneous conclusions concerning the effects of environmental and dietary factors on the proximate composition of cultured fishes. Available evidence indicates that the protein content of growing salmonids is determined solely by fish size (is endogenously controlled), that lipid level is effected by both endogenous and exogenous factors, that ash content is homeostatically controlled, and that whole body moisture is inversely related to body lipid. The implications of the present findings to nutrition studies and the potential for modification of carcass composition in cultured fish are discussed.
An 84-day feeding and digestibility trial was conducted to evaluate the use of a pea seed derived meal in experimental diets for European sea bass fingerlings of initial weight 10 g. It was demonstrated that up to 40% pea seed meal inclusion was feasible in diets allowing for a 12% reduction in fish meal content and a 25% substitution of carbohydrate content without appreciable loss in growth performance of juvenile sea bass or diet utilization. The data showed no difference in final weight and specific growth rate measurements, and feed utilization was not compromised by the supplementation of the reference fish meal basal diet with pea seed meal. The diets were formulated to be essentially isonitrogenous and isocaloric and the results of the digestibility trial confirmed that the availability of the protein and energy was consistent between the different dietary treatments. However, carbohydrate digestibility was markedly affected by the nature of the pea seed meal starch matrix and contributed to a significant reduction in digestible energy. It was also evident that this affected carcass composition with respect to energy deposition (lipid content), but not overall growth of fish in the relatively short duration of this trial.
An improved method is described for the measurement of total, soluble and insoluble dietary fibre as non-starch polysaccharides (NSP). An established procedure is modified to allow more rapid removal of starch and hydrolysis of NSP. In its present form the procedure is simpler and more robust than those previously published. In the modified method starch is removed enzymically within 50 min and NSP is precipitated with ethanol and then hydrolysed by treatment with sulfuric acid for 2 h. The constituent sugars can in turn be measured by gas-liquid chromatography, high-performance liquid chromatography or more rapidly by colorimetry. The improved procedure described here for the removal of starch and hydrolysis of NSP applies to all three techniques, but only the method for measurement of sugars by gas-liquid chromatography is described here in full.
The trypsin inhibitors present in a crude extract of unheated soybean flour were selectively removed by passage through a column of Sepharose bound trypsin. This inhibitor free extract was fed to rats at a level of 10% protein and evaluated with respect to protein efficiency ratio (PER), weight of the pancreas, and protein digestibility. A comparison was made with the original extract from which the inhibitor had not been removed, both in its native and heated states. From the results obtained it could be concluded that approximately 40% of the growth depressing as well as 40% of the pancreatic hypertrophic effect of the original unheated extract could be accounted for by the trypsin inhibitors. No differences in the digestibility of the protein in vivo were observed as a consequence of the removal of the inhibitor or by heat treatment. In vitro digestion studies, however, showed that the trypsin inhibitors accounted for only about 40% of the increased resistance of the protein of the original extract to attack by trypsin. It is believed that the reduced PER and pancreatic hypertrophy that persist in the absence of the trypsin inhibitor is primarily due to the refractory nature of native protein to attack by trypsin unless denatured by heat treatment.
The relationship between pasta texture and physicostructural characteristics was determined in relation to potential starch degradation and subsequent glucose release. Pastas with added soluble and insoluble dietary fiber ingredients were evaluated in relation to biochemical composition, cooking properties, and textural characteristics. Results show that both the type and amount of added fiber influence the overall quality of both raw and cooked pasta. Glucose release may be significantly reduced by the addition of soluble dietary fiber.
Amylase has a lower activity in carnivorous fish species, particularly in Atlantic salmon. We report the first cloning of a salmonid alpha-amylase cDNA from Atlantic salmon, a major species in aquaculture. By amino acid alignment of several species, we identified a seven amino acid deletion in one of the large loops of the enzyme in relatively close proximity to the active site, that could impair substrate binding. We also found the signal peptide to be less hydrophobic compared to other species. This may affect import into ER during protein synthesis. Active site residues were shown to be conserved. Amylase mRNA expression was shown in pancreatic tissue, liver, and in the heart. Using blocked p-nitrophenyl-maltoheptaoside as a substrate, we measured a low amylase activity in Atlantic salmon intestinal content, which was about half of the activity measured in Atlantic cod, whereas activity measured in rainbow trout was fourteen times higher. Amylase activities in all three species showed similar degree of reduction in hydrolytic activity in a dose-response trial with a wheat amylase inhibitor preparation. This indicates similar specific activity per amylase molecule.
Atlantic salmon develop subacute enteritis in the distal intestine (DI) when fed diets containing soybean meal (SBM) at high levels, a condition accompanied by increased trypsin activity in the DI intestinal content compared to fish fed conventional fishmeal (FM) based diets. To further investigate the responses of Atlantic salmon to dietary SBM, we measured trypsin activity in intestinal contents, quantified pancreatic trypsin mRNA expression, surveyed trypsin mRNA expression in selected tissues and characterized active forms of trypsin in the intestinal wall and brain. Enzyme measurements showed that trypsin activity in the intestinal content of SBM fed fish was lower in the proximal segments of the intestine, but higher in the DI compared to FM fed fish. The difference in enzyme activity was not reflected in a differential expression of pancreatic trypsin mRNA between fish fed the different diets (FM or SBM). Trypsin mRNA was expressed in 18 different tissues (esophagus, stomach, pancreas, pyloric tissue, midintestine, distal intestine, liver, head kidney, kidney, heart, spleen, thymus, brain, eye, gills, gonads, muscle and skin) but was most prominently expressed in tissues of the gastrointestinal (GI) tract and brain. We report for the first time an upregulation of trypsin-like activity in the DI wall using an in-gel trypsin activity assay, as well as modulated activity in the brain of fish fed SBM. The increased activity in the DI wall may contribute to disease severity and higher trypsin activity in the intestinal content.
Soybean meal improves the physical quality of extruded fish feed Soy products as fat and protein sources in fish feeds for intensive aquaculture
- M Sørensen
- N Stjepanovic
- O H Romarheim
- T Krekling
- T T Storebakken
- S Refstie
- B Ruyter
Sørensen, M., Stjepanovic, N., Romarheim, O.H., Krekling, T., Storebakken, T., in press. Soybean meal improves the physical quality of extruded fish feed. Anim. Feed Sci. Technol. Storebakken, T., Refstie, S., Ruyter, B., 2000. Soy products as fat and protein sources in fish feeds for intensive aquaculture. In: Drackley, J.K. (Ed.), Soy in Animal Nutrition. Federation of Animal Science Societies, Savoi, IL, USA, pp. 127–170.