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Effects of dietary fatty acids on eicosanoid-generating capacity, fatty acid composition and chemotactic activity of rainbow trout (Oncorhynchus mykiss) leucocytes

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Abstract

Rainbow trout, Oncorhynchus mykiss, were maintained on isocalorific diets in which either sunflower, menhaden or Fosol oils were used as the dietary source of fatty acids. At intervals over a period of 6 months, head kidney leucocytes were isolated and used for the analysis of their fatty acid composition and eicosanoid-generating capacity. Major changes in fatty acid composition were apparent within 4 weeks on the diets, with fish fed sunflower oil diets showing a 2.1-fold increase in total n-6 fatty acids and a 2.3-fold decrease in n-3 fatty acids, compared with the original basal levels. By week 8 the fatty acid composition changes were greater in the sunflower-fed fish, but thereafter remained relatively stable to the end of the experiment at week 24. Leucocytes from the fish maintained for > 8 weeks on the sunflower oil containing diet produced significantly lower percentages of 5-series lipoxygenase products derived from eicosapentaenoic acid including 12-hydroxyeicosapentaenoic acid, leukotriene B5 and lipoxin A5 compared with those cells from fish fed either menhaden or Fosol based diets. Unlike the fatty acid composition, differences in lipoxygenase product profiles between the dietary groups increased throughout the experiment and by week 24 the arachidonic acid/eicosapentaenoic acid derived product ratios were approx. 14:1 in the sunflower oil-fed fish compared with approx. 1:1.5 in the menhaden oil-fed fish. A functional consequence of these differing ratios was seen in the ability of supernatants containing these products to cause the in vitro locomotion of trout neutrophils. Supernatants from sunflower oil-fed fish were less chemo-attractive than supernatants from menhaden or Fosol oil-fed fish.

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... inflammatory mechanisms underlying the relationship between dietary PUFA and cardiac lesions in Atlantic salmon (Bell et al., 1993). Similar studies combining leukocyte (Ashton et al., 1994;Bell et al., 1996) and astrocyte (Tocher et al., 1996) cultures assessed the effect of fatty acid diet on fish inflammatory responses, as modifications of dietary lipids affected the in vitro production of the leukotrienes LTB4 and LTB5 by isolated salmon kidney macrophages. A similar in vitro approach using cell cultures of T-and B-cells from peripheral blood leukocytes (Bly et al., 1990), and of long-term monocyte cell lines (Vallejo et al., 1992b) from the channel catfish (Ictalurus punctatus) was used to demonstrate the relationship between the lipid composition of leukocyte cell membranes, especially PUFA and cholesterol, and the thermal adaptation of fish leukocytes through the modification of membrane fluidity (Bly and Clem, 1992). ...
... In vitro assays References Permanent cell lines AS (Atlantic salmon, Salmo salar, heart, liver, kidney and spleen tissues) Cell viability and growth Ghioni et al., 1999 Metabolic transformation of Polyunsaturated fatty acids (PUFA) Tocher et al., 1995 Tocher andDick, 2001 SAF-1 (Gilthead sea bream, Sparus aurata, fin) " Ghioni, 1999 Ghioni et al., 2001 PLHC-1 (Topminnow, Poeciliopsis lucida, hepatocarcinoma) " Tocher et al., 1995 TF (Turbot, Scophthalmus maximus fin) " Tocher et al., 1995Ghioni et al., 1999 Channel catfish, Ictalurus punctatus, monocyte-like Antigen processing and presentation at different temperatures Tocher et al., 1996 Primary cultures Astroglial brain cells from Rainbow trout (Oncorhynchus mykiss) Metabolic transformation of PUFA Tocher and Wilson, 1990;Tocher and Sargent, 1990 Turbot (Scophthalmus maximus) Production of prostaglandins and leukotrienes Tocher et al., 1996 Isolated hepatocytes from S. salar Metabolic transformation of PUFA Tocher et al., 1997 Macrophage-enriched and leukocyte cultures from S. salar pronephros Production of prostaglandins and leukotrienes Leukocyte motility (chemotaxis) Ashton et al., 1994;Bell et al., 1996 successful cell culture systems for environmental toxicology (Babich and Borenfreund, 1991;Castaño and Tarazona, 1995;Castaño et al., 1996;Segner, 1998;Segner and Cravedi, 2001). Concerning fish health, there are numerous studies that have demonstrated the influence of different aquatic inorganic and organic pollutants on disease susceptibility in farmed fish (Zeeman and Brindley, 1981;Dunier and Siwicki, 1993;Zelikoff, 1993;Anderson and Zeeman, 1995;Bols et al., 2001), and the effects of aquatic toxicants in the fish's innate immune system have been reviewed recently by Bols et al. (2001). ...
Article
This review focuses on the application of cellculture and in vitro methods to addresssome of the key elements identified asstrategies for integrated health management inaquaculture, including the standardization andvalidation of diagnostic methods, thedevelopment of new safe therapeutants, and theimplementation of effective disease controlmethodologies. It is expected that anylong-term rise in seafood production willdepend on the future progress of aquaculture.However, the development of aquaculture faces anumber of problems, of which diseases –particularly the emergence of new pathogens –represent serious risks for the production ofaquatic animals, but also for the health offish farmers and of the consumers ofaquaculture products. The complex interactionsunderlying disease outbreak and progression maybe better studied using in vitro modelsthat use cell/tissue culture methods andexperimental systems, in which the interactionsbetween aggressors and the host can bedissected. Researchers have developed invitro assays for fish toxicological,pathological, and immunological studies, as thein vitro assays allow higher control ofthe conditions of the experiments. Thecombination of cell/tissue cultures and invitro assays reduces also the variability ofthe in vivo responses, which are due tothe unavoidable effects of stress and ofenvironmental influences, and to the disparategenetic backgrounds of farmed fish andshellfish species.
... They also found that fish fed PUFAs were more resistant to bacterial infections. Ashton, Clemens, Barrow, Secombes & Rowley (1994) found that leucocytes from rainbow trout fed a diet enriched with n-3 fatty acids had greater migration stimulating ability than those from trout fed n-6 fatty acid enriched diet. In gilthead sea bream, Sparus aurata L., it has been found that adequate levels of n-3 HUFA in diets are necessary for the maintenance of alternative complement activity (Montero, Tort, Izquierdo, Robaina & Vergara 1998). ...
... ish macrophages. The natural killer cell-like activity of rainbow trout leucocytes was also enhanced by dietary n-3 HUFA (Kiron, Gunji, Okamoto, Satoh, Ikeda & Watanabe 1993). Resistance to infection of Atlantic salmon was superior in fish fed a high ratio n-3/n-6 PUFA diet than fish fed a low ratio n-3/n-6 diet (Thompson, Tatner & Henderson 1996). Ashton et al. (1994) found that head kidney supernatants derived from rainbow trout fed a diet enriched with n-3 fatty acid had greater migration stimulating ability when compared with fish fed an n-6 fatty acid enriched diet. Dietary fatty acid composition also affects the humoural immune system. Waagboe, Hemre, Holm & Lie (1995) found a negative correlati ...
... Various mammalian processes and systems known to be affected via eicosanoids include vasodilation, constriction, and cell proliferation of the vascular system; regulation of acid and mucus secretion and blood flow within the gastrointestinal tract; maintenance of vascular tone and flow, particularly in terms of renal function; initiation and maintenance of pregnancy and parturition; inflammation and the immune response; protein metabolism; and oxidative stress (Christie 2006b, 2006c, 2006d). Eicosanoid synthesis has been relatively well researched in fishes (Ashton et al. 1994; Bell et al. 1994, 1996; Knight et al. 1995; Ghioni et al. 1997; Farndale et al. 1999); among fishes, dietary manipulations of the eicosanoid cascade have resulted in cardiac and immunological pathologies (Bell et al. 1993, 1996; Ashton et al. 1994). Eicosanoids have potentially far-reaching physiological consequences for the processes described above and may be involved in stress-related perturbations of homeostasis, particularly responses to physical stressors such as exertion. ...
... Various mammalian processes and systems known to be affected via eicosanoids include vasodilation, constriction, and cell proliferation of the vascular system; regulation of acid and mucus secretion and blood flow within the gastrointestinal tract; maintenance of vascular tone and flow, particularly in terms of renal function; initiation and maintenance of pregnancy and parturition; inflammation and the immune response; protein metabolism; and oxidative stress (Christie 2006b, 2006c, 2006d). Eicosanoid synthesis has been relatively well researched in fishes (Ashton et al. 1994; Bell et al. 1994, 1996; Knight et al. 1995; Ghioni et al. 1997; Farndale et al. 1999); among fishes, dietary manipulations of the eicosanoid cascade have resulted in cardiac and immunological pathologies (Bell et al. 1993, 1996; Ashton et al. 1994). Eicosanoids have potentially far-reaching physiological consequences for the processes described above and may be involved in stress-related perturbations of homeostasis, particularly responses to physical stressors such as exertion. ...
Article
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We evaluated the effect of dietary natural source vitamin E (NSVE) on hematology and tissue composition of sunshine bass (female white bass Morone chrysops × male striped bass M. saxatilis) at rest and under the physical stress of exertion. Experimental diets were formulated to contain 1, 2, 5, or 30 times the dietary vitamin E requirement of sunshine bass as met by NSVE (22 mg NSVE/kg of feed, supplemental). After an 8-week feeding trial, dietary treatment groups were subdivided for experimental exertion (forced swimming at 0.12 m/s): Control (no exercise), short-term exertion (30 min), and long-term exertion (180 min). Short-term exertion induced the greatest plasma cortisol concentrations and depressed hematocrit. Dietary NSVE and exertion treatments were observed to affect eicosanoid synthesis via significant effects on cytosolic phospholipase (cPLA2) activity in adipose tissue but not white muscle or hepatic tissue. At rest, increasing NSVE was associated with increased adipose cPLA2 activity, suggesting elevated liberation of arachidonic acid (20:4[n-6], where 20 is the number of carbon atoms, 4 is the number of double bonds, and 6 is the position of the first double bond from the methyl end) from this storage site; the ratio of 20:4(n-6) to eicosapentaenoic acid (20:5[n-3]) was accordingly reduced in adipose tissue. Resultant cardiac prostaglandin F2α (PGF2α) was also affected by dietary and exertion treatments; however, these results were not wholly congruent with alterations in cPLA2 activity. Levels of PGF2α decreased in association with the stress response but only among super-requirement NSVE groups. Across all dietary treatments, exertion resulted in increased glucose liberation and minor reductions in hepatic glycogen stores. Exertion was not observed to affect tissue fatty acid composition, whereas increasing dietary NSVE was associated with minor changes in tissue composition. We conclude that dietary NSVE has some regulatory influence over eicosanoid synthesis but the mechanism is apparently not restricted to cPLA2-mediated 20:4(n-6) release. Moreover, NSVE may affect response to stressor exposure or exertion; however, further research is needed to fully elucidate the physiological consequences of super-requirement NSVE supplementation.
... Some authors have reported negative effects of high dietary levels of n-3 PUFAs in channel catfish (Erdal et al., 1991;Li et al., 1994), whereas other reports show positive effects of n-3 fatty acids on the immune response of fish. For instance, high levels of dietary n-3 fatty acids increased activity of head kidney macrophages of channel catfish (Sheldon and Blazer, 1991) and rainbow trout (Ashton et al., 1994). In addition, inadequate levels of dietary n-3 PUFAs reduced antibody production and in vitro killing of bacteria by macrophages in rainbow trout (Kiron et al., 1995) and depleted alternative complement pathway activity in gilthead seabream (Montero et al., 1998). ...
... However, the inclusion of soybean oil or rapeseed oil in the diet during prolonged feeding periods (204 days) affected both humoral and cellular immunology in seabream (Experiment II). Extreme substitution levels may alter the production of compounds with relevant physiological activity, such as eicosanoids, resulting in imbalances of both AA-derived and EPA-derived eicosanoids (Ashton et al., 1994), which may act as inmunomodulators and affect fish resistance to diseases. As an example, the inclusion of 7% linseed oil in diets for catfish reduced fish survival to infection with Edwarsiella ictaluri at a temperature of 28 jC, as well as the ability of fish to produce antibodies . ...
Article
Full-text available
Commercial feeds for gilthead seabream are highly energetic, containing fish oil as the main lipid source. The steady production and raising prices of fish oil encourage the inclusion of vegetable oils in fish feeds. Fish oil could be at least partially substituted by vegetable oils in diets for marine species, being this substitution resulted in good feed utilization and maintenance of fish health, since imbalances in dietary fatty acids may alter the immunological status and stress resistance in fish. In order to evaluate the effect of vegetable oils on gilthead seabream health, fish were fed different isonitrogenous and isocaloric diets for 101 days (Experiment I) and 204 days (Experiment II). In Experiment I, diets were formulated to contain 60% of the fish oil used in the control diet (FO) as soybean oil (Diet 60SO), rapeseed oil (60RO), linseed oil (60LO) or a blend of those oils (Mix). In Experiment II, the same diets plus two which contained 80% of the fish oil as soybean oil (80SO) and linseed oil (80LO), respectively, were assayed. At the end of both experiments, basal levels of different immunological parameters were determined, including both humoral immunity (alternative complement pathway activity and serum lysozyme activity) and cellular immunity (circulating neutrophil activity and phagocytic index of head kidney macrophages). In addition, response to a confinement stress was assayed in terms of variations in plasma cortisol. The effect of dietary vegetable oils on fatty acid composition of head kidney macrophages and circulating red blood cells (RBC) was also studied. No effects of dietary vegetable oils were found in fish fed the experimental diets for a medium period. Feeding dietary vegetable oils for a long period did not affect lysozyme or neutrophil activity. However, in Experiment II, the inclusion of soybean oil reduced both serum alternative complement pathway activity (from 249 IU/ml (FO2) down to 153.8 IU/ml (60SO2)) and head kidney phagocytic 0044-8486/03/$-see front matter D
... A natural consequence of this is that increases in n-6 HUFA in PI following increased feeding of 18:2n-6 should cause major increases in the production of this series of eicosanoids. Indeed most available literature do point to this in salmonids while Norwegian Scientific Committee for Food Safety Vitenskapskomiteen for mattrygghet (VKM) 81 07/604 -final increases in n-3 HUFA or linseed oil (18:3n-3) will inhibit the production of n-6 eicosanoids (Ashton et al. 1994;Bell et al. 1996a;Balfry and Higgs 2001;Tocher et al. 2003b;Gjøen et al. 2004). The question then remains if increasing the n-6 PUFA in plant oil supplemented diets will enhance the immune response as seen in mammals and reduce the likelihood of infections. ...
... Lower haematocrit, higher thrombocyte counts, and increased resistance to erythrocyte fragility has been noted (Klinger et al. 1996). A possible functional disability was observed in rainbow trout when head kidney supernatants from sunflower oil fed fish were less chemoattractant to neutrophils compared to those fed fish oils (Ashton et al. 1994). In Atlantic salmon parr, exchanging fish oil to sunflower oil reduced the number of B cells (kidney and spleen) in vaccinated fish responding to A. salmonicida and made them more susceptible to disease when non-vaccinated fish were challenged with A. salmonicida and Vibrio anguillarum (Thompson et al. 1996). ...
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A thorough review of different aspects on the health implications of using vegetable feed ingredients, both protein and lipid alternatives to fishmeal and fish oil, plus possible additions of immunostimulants, also including a short chapter on undesirable components, the use of genetically modified plants, and how processing may affect feed quality and availability, are given in the different chapters of the present risk assessment. Discussed in particular are Atlantic salmon (Salmo salar), rainbow trout (Onchorhyncus mykiss), Atlantic halibut (Hippoglossus hippoglossus) and Atlantic cod (Gadus morhua). Deemed necessary, since literature on these species is scarce, some theoretical background in the assessment chapter (Chapter 4) includes studies on other species when relevant for the present terms of reference, and to better be able to conclude on possible health implications due to changes in diet ingredients. The answers to the present Terms of Reference are given in Chapter 5 (Risk characterization and conclusions). Chapter 6 presents future challenges that need focus in research to be able to have healthy farming of fish even when volumes increase.
... Some authors have reported negative effects of high dietary levels of n-3 PUFAs in channel catfish (Erdal et al., 1991;Li et al., 1994), whereas other reports show positive effects of n-3 fatty acids on the immune response of fish. For instance, high levels of dietary n-3 fatty acids increased activity of head kidney macrophages of channel catfish (Sheldon and Blazer, 1991) and rainbow trout (Ashton et al., 1994). In addition, inadequate levels of dietary n-3 PUFAs reduced antibody production and in vitro killing of bacteria by macrophages in rainbow trout (Kiron et al., 1995) and depleted alternative complement pathway activity in gilthead seabream (Montero et al., 1998). ...
... However, the inclusion of soybean oil or rapeseed oil in the diet during prolonged feeding periods (204 days) affected both humoral and cellular immunology in seabream (Experiment II). Extreme substitution levels may alter the production of compounds with relevant physiological activity, such as eicosanoids, resulting in imbalances of both AA-derived and EPA-derived eicosanoids (Ashton et al., 1994), which may act as inmunomodulators and affect fish resistance to diseases. As an example, the inclusion of 7% linseed oil in diets for catfish reduced fish survival to infection with Edwarsiella ictaluri at a temperature of 28 jC, as well as the ability of fish to produce antibodies . ...
Article
Commercial feeds for gilthead seabream are highly energetic, containing fish oil as the main lipid source. The steady production and raising prices of fish oil encourage the inclusion of vegetable oils in fish feeds. Fish oil could be at least partially substituted by vegetable oils in diets for marine species, being this substitution resulted in good feed utilization and maintenance of fish health, since imbalances in dietary fatty acids may alter the immunological status and stress resistance in fish.
... Dietary metabolism of polyunsaturated fatty acid was studied using Atlantic salmon cell line (AS) by Ghioni et al. (1999). Likewise, the effect of dietary fatty acids from sunflower, menhaden oils on eicosanoid production, fatty acid composition, and in vitro locomotion of neutrophils were studied using leucocytes derived from head kidney of Oncorhynchus mykiss, rainbow trout (Ashton et al. 1994). Morin et al. (2020) used rainbow trout hepatoma cells (RTH-149) as models to reveal the underlying mechanism of amino acid regulated pathways in rainbow trout. ...
Chapter
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Cell culture serves as a reliable and proficient tool in diverse research fields such as virology, physiology, toxicology, immunology, oncology, genetics, and pharmacology. These systems can be employed for pathogen detection, confirmation, and characterization especially of viruses. It is also applicable in the case of intracellular bacteria, myxosporean or microsporean parasites as well. Fish cell cultures have gained more popularity in recent years and have prominent roles in viral disease diagnosis. Since treatment options are limited for many viral diseases, early disease diagnosis and proactive management measures are key for successful fish health management. The ability to propagate fish viruses in vitro using cell cultures is imperative in advancing research on viruses and to facilitate disease management strategies such as vaccines and antiviral agents. Moreover, potential host range of pathogens via susceptibility to cell cultures, virus-host cell interactions, and virus localization studies using cell cultures provide a better understanding of the viral pathogenesis. Availability of suitable fish cell cultures for propagation of viruses and disease diagnosis is very limited, which is a major concern in this area. The wide array of applications exemplifies the versatility, cost-effectiveness, and high potential of fish cell cultures in various research fields. The recent swift growth observed in research employing cell cultures is definitely an outcome of the progress in this sector and also due to increasing ethical demands for reduction and replacement of animal use in research. In the near future, innovations in 3D cell culture and CRISPER-Cas9 genome editing will further enhance the research prospects of fish cell culture systems.
... Several fish cell lines have been used as in vitro models to study elongation and desaturation of different PUFA. These in vitro models were also useful for unveiling the pro-inflammatory mechanisms underlying the relationship between dietary PUFA and cardiac lesions in salmon [46], the effect of fatty acid diet on fish inflammatory responses [122,123]. To study fish nutrition and metabolism, cell lines provide a great interest near future, especially advanced methods, such as CRISPR/cas9 and that may certainly work with new feed formulations for the development of sustainable aquaculture. ...
Article
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Introduction Cell line derived from fish has been established as a promising tool for studying many key issues of aquaculture covering fish growth, disease, reproduction, genetics, and biotechnology. In addition, fish cell lines are very useful in vitro models for toxicological, pathological, and immunological studies. The easier maintenance of fish cell lines in flexible temperature regimes and hypoxic conditions make them preferable in vitro tools over mammalian cell lines. Great excitement has been observed in establishing and characterizing new fish cell lines representing diverse fish species and tissue types. The well-characterized and authenticated cell lines are of utmost essential as these represent cellular functions very similar to in vivo state of an organism otherwise it would affect the reproducibility of scientific research. Conclusion The fish cell lines have exhibited encouraging results in several key aspects of in vitro research in aquaculture including virology, nutrition and metabolism, production of vaccines, and transgenic fish production. The review paper reports the cell lines developed from fish, their characterization, and biobanking along with their potential applications and challenges in in vitro research.
... Similar effects were also observed in some fish species (Erdal et al. 1991;Li et al. 1994). However, positive effects of high n-3 FA intake on immune response have also been reported in other studies (Sheldon and Blazer 1991;Ashton et al. 1994;Balfry et al. 2006). The effects of long-chain unsaturated FAs on immune response of fish are inconclusive and should be examined. ...
Article
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The effect of varying dietary lipid and n-3 polyunsaturated fatty acids (PUFAs) on growth, feed efficiency, protein and energy utilization, carcass quality, and nonspecific immune functions was investigated in rainbow trout reared at two different water temperatures (7.5 and 15 C). Six diets were formulated to contain 47% digestible protein and 21 MJ/kg digestible energy. Three of the diets were formulated to contain increasing lipid levels (10, 16, and 18%) and three additional diets formulated to 18% lipid with different lipid sources. Varying dietary lipid and n-3 PUFA levels had little effect on growth and on protein and energy utilization. Diet composition only had limited effect on susceptibility of the flesh to rancidity and on the nonspecific immunity of the fish. Increasing lipid levels did not affect fish carcass or fillet proximate composition. Replacing half of fish oil with beef tallow resulted in lower n-3 PUFAs in fish fillet but did not affect nutrient digestibility or growth performance of fish even at 7.5 C. Increasing dietary n-3 levels using a fish oil concentrate resulted in significant enrichment of n-3 PUFAs and elevated n-3 : n-6 ratio of the whole body and carcass. Water temperature significantly affected apparent digestibility coefficient (ADC) of protein and energy but did not affect the ADC of lipid, nor did it affect nitrogen and energy retention efficiencies. The study suggests that highly saturated fats, such as beef tallow, can be used to partially replace fish oil without negative effect on digestibility and growth even at low water temperature. High dietary n-3 PUFAs levels can be used to enrich n-3 PUFAs of the flesh without negative effect on the immune response.
... Bransden et al. (2003) found significantly increased cumulative mortalities in Atlantic salmon fed diets containing sunflower oil and challenged with Vibrio anguillarum. Increased activity of head kidney macrophages has been associated with increased dietary n-3 fatty acids in channel catfish (Blazer 1991;Sheldon & Blazer 1991) and rainbow trout (Ashton et al. 1994). Moreover, Atlantic salmon fed diets with a high ratio of n-3/n-6 PUFA had increased B lymphocyte responses following experimental challenges with Aeromonas salmonicida and V. anguillarum (Thompson et al. 1996). ...
Article
Triplicate groups of European sea bass (Dicentrarchus labrax L.), of initial weight 90 g, were fed four practical-type diets in which the added oil was 1000 g kg−1 fish oil (FO) (control diet), 600 g kg−1 rapeseed oil (RO) and 400 g kg−1 FO, 600 g kg−1 linseed oil (LO) and 400 g kg−1 FO, and 600 g kg−1 olive oil (OO) and 400 g kg−1 FO for 34 weeks. After sampling, the remaining fish were switched to the 1000 g kg−1 FO diet for a further 14 weeks. Fatty acid composition of flesh total lipid was influenced by dietary fatty acid input but specific fatty acids were selectively retained or utilized. There was selective deposition and retention of docosahexaenoic acid (DHA; 22:6n-3). Eicosapentaenoic acid (EPA; 20:5n-3) and DHA were significantly reduced and linolenic (LNA; 18:3n-3), linoleic (LA; 18:2n-6) and oleic (OA; 18:1n-9) acids significantly increased in flesh lipids following the inclusion of 600 g kg−1 RO, LO and OO in the diets. No significant differences were found among different treatments on plasma concentrations of prostaglandin E2 and prostaglandin F2α. Evaluation of non-specific immune function, showed that the number of circulating leucocytes was significantly affected (P < 0.001), as was macrophage respiratory burst activity (P < 0.006) in fish fed vegetable oil diets. Accumulation of large amounts of lipid droplets were observed within the hepatocytes in relation to decreased levels of dietary n-3 HUFA, although no signs of cellular necrosis was evident. After feeding a FO finishing diet for 14 weeks, DHA and total n-3 HUFA levels were restored to values in control fish although EPA remained 18% higher in control than in the other treatments. This study suggests that vegetable oils such as RO, LO and OO can potentially be used as partial substitutes for dietary FO in European sea bass culture, during the grow out phase, without compromising growth rates but may alter some immune parameters.
... Homologues of PG are produced from n-6 and n-3 precursors (e.g., prostaglandin E 2 or PGE 2 from AA, and PGE 3 from EPA) that exert similar biological effects in fish and mammals. Arachidonic acid-derived PG are much more biologically active than EPA-derived PG in both mammals (Calder 1998) and fish (Ashton et al. 1994), and AA is preferred for prostaglandin synthesis, even though EPA is more abundant in fish tissues (Bell et al. 1997). In mammals, PG derived from n-6 fatty acids have been implicated in mediation of the adrenocorticotropic hormone (ACTH) response to psychological and physical stress (Bugajski et al. 1996). ...
Article
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Relationships between dietary lipid source, stress, and oxidative stress were examined in juvenile chinook salmon (Oncorhynchus tshawytscha). Four different experimental diets were used: menhaden oil (MHO; elevated 20:5n-3 and 22:6n-3), soybean oil (SBO; elevated 18:2n-6), linseed oil (LSO; elevated 18:3n-3), and a mixture of 55% linseed oil and 45% soybean oil (MIX; approximately equal levels of 18:2n-6 and 18:3n-3). Juvenile salmon (initial body weight of 16.0 g) were fed experimental diets for 12 weeks (early March to early June). At the end of feeding, fish subjected to a low-water stressor for 96 h had greater liver and brain lipid peroxidation compared to unstressed controls; peroxidation was not influenced by diet. Diet and stress affected plasma cortisol levels. Stressed fish fed SBO had the greatest cortisol concentrations, followed by MIX, MHO, and LSO (mean concentrations for the SBO and LSO diets differed significantly). The cortisol response to stress may have been influenced by the ratio of prostaglandin 1- and 2-series to prostaglandin 3-series precursor fatty acids provided by the different diets. The results of this study suggest a connection between the physiological response to stress, dietary lipid quality, and oxidative stress. This is the first evidence of such a relationship in fish. Abbreviations: AA - arachidonic acid; ACTH - adrenocorticotropin; BHT - butylated hydroxytoluene; BLPO - brain lipid peroxidation; dGLA - dihomo-γ-linolenic acid; DHA - docosahexanoic acid; EPA - eicosapentanoic acid; FER - feed efficiency ratio; FOX - ferrous oxidation-xylenol orange; GLA -γ-linolenic acid; LA - linoleic acid; LCO3 - long-chain n-3 polyunsaturated fatty acids; LLPO - liver lipid peroxidation; LN - linolenic acid; LPO - lipid peroxidation; LSO - linseed oil; MHO - menhaden oil; MIX - 55% linseed oil + 45% soybean oil; PC - plasma cortisol; PG - prostaglandin(s); PGE2- prostaglandin E2; PUFA - polyunsaturated fatty acid; SBO - soybean oil.
... Additionally, HUFA can in£uence the immune system through the production of eicosanoids, alteration of gene expression, lipid peroxidation or apoptosis (de Pablo, Puertollano & A Ł lvarez de Cienfuegos 2002). In ¢sh, HUFA have been shown to a¡ect the immune response in£uencing the cytotoxic, chemotactic (Ashton, Clements, Barrow, Secombes & Rowley 1994), phagocytic activities and the production of antibodies (Kiron et al.1995). Chim et al. (2001) also de-monstrated an increase in the agglutination titre of plasma and the haemocyte oxidative activity in the blue shrimp L. stylirostris fed a diet enriched with HUFA. ...
Article
Juveniles fed a diet containing a low or a high level of highly unsaturated fatty acids (HUFA) for 38 days were exposed to handling stress. In a first experiment, stress was applied daily for 30 days, after which the physiological and immunological variables were measured, whereas in a second experiment, stress was applied once and samples were obtained 1 and 24 h after the stressor event. Shrimp that were stressed for 30 days showed significantly lower survival, final weight and feed consumption compared with unstressed shrimp. The concentration of the high-density lipoprotein beta-glucan-binding protein was significantly higher in shrimp fed the high-HUFA diet. The glucose concentration in the haemolymph was significantly higher in long-term stressed shrimp compared to controls. The lactate level in the haemolymph was significantly lower in shrimp fed the high-HUFA diet. Lactate and glucose in the haemolymph increased in the 1-h stressed shrimp, but returned to normal levels in 24-h stressed shrimp. A negative effect of repeated-handling stress applied for 30 days was mainly observed on biological performance, whereas the single-stressor event had a more pronounced effect on shrimp physiological and immune responses measured 1 and 24 h after the stressor. A beneficial role of enrichment with HUFA on tolerance to handling stress was observed on immune response capacity.
... In rainbow trout, a deficiency of n-3 FAs adversely affected antibody production and macrophage killing ability (Kiron et al. 1995), decreased serum complement activity (Tort et al. 1996;Montero et al. 1998), and agglutinating antibody titers (Tort et al. 1996). Decreased activity of head kidney macrophage from channel catfish (Blazer et al. 1989;Sheldon and Blazer 1991) and rainbow trout (Ashton et al. 1994) was reported in fish fed diets containing low levels in n-3 FAs. Nile tilapia fed beef tallow diet, which is deficient in both n-6 and n-3 FAs, had significantly reduced serum protein, lysozyme, and natural hemolytic complement activity (Yildirim-Aksoy et al. 2007). ...
Article
The effects of dietary linoleic (LA) and linolenic acids (LN) on growth and immunity of all‐male hybrid tilapia, Oreochromis niloticus × Oreochromis aureus, were evaluated for 10 wk. Fish fed 0.12% LA + 0% LN had the lowest weight gain (WG) but was not significantly different from diets containing 0.5% LA or 0.40% LA + 1.0% LN. Fish fed 1% LA had the highest WG but did not differ from diets with 0.5% LA, 2.0% LA, 0.26% LA + 0.5% LN, 0.69% LA + 2.0% LN, or diets containing both LA and LN at 0.25, 0.5, and 1.0%. Feed intake, feed efficiency, and survival did not differ among treatments. Total body n‐6 fatty acids (FAs) increased with increasing dietary levels of n‐6. Total body n‐3 FAs also appeared to increase with increasing dietary n‐3 levels but peaked at 1% of diet. Dietary treatment had no effect on hematology, immune function, or survival to Streptococcus iniae. This study indicates that both LA and LN are dietary essential for growth of hybrid tilapia. Dietary LA alone can meet the essential FA requirement, and a level of 1.14% of diet is required for optimum growth.
... The stimulatory effect of dietary n-3 HUFA has also been demonstrated in various fish species. Macrophages from head kidney of rainbow trout fed a diet enriched with n-3 fatty acids had greater migration-stimulating ability than those originating from trout fed a diet enriched with n-6 fatty acids (Ashton et al. 1994). In channel catfish, Lim et al. (2006) reported that 10% fish oil was sufficient to stimulate macrophage chemotaxis and phagocytosis. ...
Article
Growth performance, immune responses and disease resistance were studied in juvenile channel catfish, Ictalurus punctatus, fed a commercial diet (35.3% crude protein and 5.6% lipid) supplemented with menhaden fish oil at levels of 0, 3, 6, and 9% for 15 wk. Dietary fish oil levels did not significantly influence growth performance of catfish. Fatty acid compositions of whole-body and liver reflected dietary fatty acid composition. No differences were found in hematological values, except that fish fed the 9% fish oil diet had significantly lower hematocrit. The resistance of erythrocytes to hemolysis in hypotonic solutions increased with increasing fish oil levels and the highest resistance was seen with the 9% fish oil diet. Fish fed 6 and 9% added fish oil diets had significantly higher serum protein levels than that of control fish. Serum lysozyme activity of fish fed 3 and 6% added fish oil diet was significantly higher than that of the control. Complement activity and chemotaxis ratio significantly decreased in fish fed diets with 6 or 9% added fish oil. The 3% added fish oil diet, however, had significantly highest natural hemolytic complement activity. Mortality from Edwardsiella ictaluri 14 d postchallenge and antibody titers to E. ictaluridid not differ among treatments.
... Studies with rainbow trout, Oncorhynchus mykiss, showed that a deficiency of n-3 fatty acids adversely affected antibody production and macrophage killing ability (Kiron et al. 1995) as well as decreasing serum complement activity (Tort et al. 1996;Montero et al. 1998) and agglutinating antibody titers (Tort et al. 1996). Decreased activity of head kidney macrophages from channel catfish (Blazer et al. 1989;Sheldon and Blazer 1991) and rainbow trout (Ashton et al. 1994) has also been demonstrated in fish fed diets containing low levels of n-3 fatty acids. Likewise, in the present study, tilapia fed the BT-diet which is deficient in both n-6 (0.31% of diet) and n-3 (0.26% of diet) had significantly reduced serum protein (except fish fed CO-diet), lysozyme and natural hemolytic complement activity. ...
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This experiment was conducted to determine the effect of dietary lipid sources on growth performance, body proximate composition, hematology, immune response and resistance of Nile tilapia, Oreochromis niloticus, to Streptococcus iniae infection. Six isocaloric (3.2 kcal/g) and isonitrogenous (34% crude protein) semi-purified diets were supplemented with 7% of various sources of lipid, namely, corn oil (CO), beef tallow (BT), menhaden fish oil (FO), linseed oil (LO), and equal combinations of FO+CO+BT or LO+CO+BT. Diets were fed to tilapia in quadruplicate aquaria to apparent satiation, twice daily for 12 weeks. Fish fed the BT-diet exhibited significantly lowest weight gain, diet intake, feed and protein efficiency ratios, apparent protein utilization, and survival. Whole-body protein and ash were significantly (P < 0.05) lowest and highest, respectively, for fish fed the beef tallow-diet, but the values of these parameters did not differ among fish fed other diets. No significant differences (P > 0.05) were found among hematological values, except for fish fed the FO-diet which had abnormally high red and white blood cell counts. Serum protein concentration, lysozyme activity, and natural hemolytic complement activity were significantly (P < 0.05) reduced in fish fed the BT-diet. The values of these parameters did not differ among fish fed other diets. Post-challenge antibody titer was not influenced by dietary lipid sources. Cumulative mortality 15 days post-challenge with S. iniae was significantly lower (P < 0.05) for fish fed the BT diet compared with those fed FO or FO+CO+BT diets. No significant differences were observed in fish fed other dietary lipid sources.
... The dietary EFA deficiencies have been reported to produce immunosuppression in different fish species (Kiron et al. 1995), including gilthead seabream (Montero et al. 1998). The reduction of EPA due to dietary deficiency produced an increase in AA/EPA ratio in both tissues, suggesting a possible effect of dietary fatty acid in fish immunity as both EPA and AA are substrates for cyclooxygenese and lipoxygenese and thus precursor of eicosanoids (Ashton et al. 1994). The effect of dietary fatty acid on eicosanoid production has been described for other species including Atlantic salmon (Bell et al. 1992) and turbot (Bell et al. 1994). ...
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The aim of the present study was to determine the combined effect of both stress and EFA deficiency on several biological and biochemical parameters. Fish were fed during 15 weeks two isocaloric and isoproteic diets: a control diet based on fish oil and formulated to meet the n-3 HUFA requirements for this species (1.5% of n-3 HUFA) and a deficient diet containing beef tallow and formulated to be deficient in n-3 HUFA. Each experimental diet was evaluated both at high and low stocking densities (10 and 3.2 kg m−3 of initial density, respectively). High stocking density produced a chronic stress situation with elevation of plasma cortisol levels. It also caused a reduction in hepatosomatic index and liver lipid contents, increasing the oleic acid/n-3 HUFA ratios in the polar lipids. Fish fed the EFA deficient diet at low stocking density showed common deficiency symptoms. High stocking density in fish fed the EFA deficient diet induced a higher degree of EFA deficiency symptoms leading to mortality, liver steatosis, liver lipid deposition, reduced muscle lipid and reduced n-3 HUFA contents, which particularly affected EPA, but not DHA, suggesting a preferential retention of the latter fatty acid, specially in the phosphoglycerides fraction.
... However, other reports show positive effects of n-3 fatty acids on the immune response of fish. High levels of dietary n-3 fatty acids in the diet increase the activity of head kidney macrophages of channel catfish (Sheldon and Blazer, 1991) or rainbow trout (Ashton et al., 1994). Inadequate levels of n-3 PUFAs in the diet reduce antibody production and in vitro killing of bacteria by macrophages in rainbow trout (Kiron et al., 1995) and deplete alternative complement pathway activity in gilthead seabream (Sparus aurata) (Montero et al., 1998). ...
... increase the phagocytic capacity of leukocytes (Kiron, Gunji, Okamoto, Satoh, Ikeda & Watanabe, 1993;Ashton, Clements, Barrow, Secombes & Rowley, 1994). In crustaceans, it has been shown that a low temperature has a deleterious effect on the structure and function of cell membranes, and that HUFAs allow an adaptation to slow temperature decreases by modifying the composition of the cell membrane, leading to an increase in its fluidity (Pruitt, 1990). ...
Article
The prawn Penaeus stylirostris (Stimpson), when fed for 28 days with n-3 highly unsaturated fatty acid (HUFA)-enriched feed pellets, demonstrated an enhanced resistance to variations in environmental parameters (a decrease in temperature and salinity over a 4-day period from 28 degreesC to 17 degreesC and from 35 parts per thousand to 10 parts per thousand respectively) and an improvement in their immune defence potential, i.e. increased agglutination titre of plasma and increased respiratory burst of haemocytes.
... However, this predicted effect is rarely clear as illustrated by the discrepancies in results between studies. Positive effects of high n−3 fatty acid intake on immune response have been reported in some studies (Ashton et al., 1994;Sheldon and Blazer, 1991). Balfry et al. (2006) observed that Atlantic salmon fed diet with FO containing higher n−3 fatty acid levels exhibited higher postvaccination levels of peripheral blood leukocyte respiratory burst activity and higher serum antibody titers against Listonella anguillarum, compared to fish fed diets with canola oil and poultry fat. ...
Article
This study examined the effect of dietary medium-chain triglycerides supplied by coconut oil on postprandial plasma metabolite profiles in rainbow trout. The fish (initial body weight 71.3 ± 0.3 g, 17 °C) were fed one of four practical diets containing either 5% fish oil (FO low-fat, FL), 15% fish oil (FO high-fat, FH), 5% coconut oil (CO low-fat, CL) or 15% coconut oil (CO high-fat, CH) for 3 weeks. At the end of the trial, the fish were weighed and plasma sampled to determine glucose, non-esterified fatty acids (NEFA), triglyceride (TG), cholesterol, high density lipoprotein-cholesterol (HDL-cholesterol), and myeloperoxidase (MPO) at 3, 6, 9, 12, 15 and 24 h after the last meal. Plasma total ketone bodies (KB) were determined at 6, 12 and 24 h after meal. Blood nitroblue tetrazolium (NBT) tests were also performed in samples withdrawn at 24 h after meal. Plasma glucose was higher in fish fed the low fat level diet than those fed high fat level, and peaked at postprandial 9–12 h. Fish fed CH showed higher plasma TG than CL at 3 h after meal, and there was no significant difference in plasma TG at the other time points. The peak of TG appeared 12 h after the meal. No clear pattern was found for cholesterol and HDL-cholesterol (HDL-C) in any of the groups. However, fish fed diet FH had the highest postprandial plasma HDL-cholesterol level and HDL-C/cholesterol ratio. The peak of NEFA was observed at 12–15 h after meal and plasma NEFA of fish fed CH was the highest. Plasma total KB decreased with postprandial time, and fish of FH groups had higher KB than that of CL group at 6 h. Besides, NBT in fish fed FH was significantly higher than that of CH, but there were no differences in MPO between groups. In summary, time-course changes in plasma profiles related to dietary fat level were as expected whereas those related to dietary fat source were relatively small.
... ish macrophages. The natural killer cell-like activity of rainbow trout leucocytes was also enhanced by dietary n-3 HUFA (Kiron, Gunji, Okamoto, Satoh, Ikeda & Watanabe 1993). Resistance to infection of Atlantic salmon was superior in fish fed a high ratio n-3/n-6 PUFA diet than fish fed a low ratio n-3/n-6 diet (Thompson, Tatner & Henderson 1996). Ashton et al. (1994) found that head kidney supernatants derived from rainbow trout fed a diet enriched with n-3 fatty acid had greater migration stimulating ability when compared with fish fed an n-6 fatty acid enriched diet. Dietary fatty acid composition also affects the humoural immune system. Waagboe, Hemre, Holm & Lie (1995) found a negative correlati ...
Article
An experiment was conducted to determine the effect of an essential fatty acid (EFA) deficient diet on growth, immune status and renal morphology of juvenile gilthead sea bream, using two diets: a control diet containing 2% (DW) of n-3 high unsaturated fatty acid (n-3 HUFA) and a diet formulated to be deficient in EFA for this species and containing 0.5% DW of n-3 HUFA (diet NFA). After 9 weeks of feeding the EFA-deficient diet fish showed a reduction in growth compared with the control group (107.48 +/- 9.14 and 123.14 +/-11.87 g final weight respectively). Fish fed the NFA diet showed a reduction in the erythrocyte volume together with increased erythrocyte fragility, haemoglobin content and red blood cell count in comparison with fish fed the control diet. EFA deficiency also reduced cellular immunity in terms of neutrophil activity and the number of circulating lymphocytes. The serum alternative complement pathway was markedly reduced in fish fed the EFA deficient diet. Fish fed the control diet showed glomeruli with a well-defined Bowman's space and normal renal tubes. However, up to 88% of fish fed the EFA-deficient diet showed alterations in renal morphology affecting at least 50% of the glomeruli, which showed extreme dilation of capillaries and occlusion of Bowsman's capsule. Mesangial proliferation and diffuse thickening of the capillary walls, as well as renal tube degeneration, were also observed.
... Fish oil is preferred in the diet of farmed animals and aquaculture due to the presence of LC omega-3 fatty acids, which has been reported to offer major benefits to animal health, including improved immunity against disease (Ashton et al. 1994), higher survival and growth, and reduced incidences of deformities (FAO 1986). It is highly digestible, which leads to increased growth and less wastage of food, and is also considered to increase feed appeal. ...
Chapter
In the recent past, there has been an increasing demand for fish oil in the pharmaceutical industry, due to the findings of the health benefits provided by omega-3 fatty acids, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Fish oils are unique in the variety of fatty acids of which they are composed, and are an excellent source of the highly unsaturated C20 and C22 omega-3 fatty acids of medical interest. In the past, fish oil was mainly used as an important ingredient in aquaculture feeds and was also used in feeds for livestock, such as poultry and swine. Due to increasing awareness on the potential health beneficial roles of omega-3 fatty acids in humans, there has been an increasing interest in the use of fish oils for human consumption. The nutritional and physical properties of fish oil have made hardened fish oils an attractive constituent in the human diet. A wide range of food products containing fish oils have been launched over the past decade. The instability of EPA and DHA and the fishy odor have become major problems in incorporating long-chain omega-3 oils into food products. There is an established market for dietary supplements, as well as a developing market for food ingredients produced from fish oils and concentrates of fish oil. Increasing scientific evidence in the health beneficial roles of fish oil has led to a tremendous growth in its use in the pharmaceutical industry and it is expected to play a dominant role in the future.
... Dietary fish oil levels up to 14%, however, had no effect on hematological parameters, serum protein, total immunoglobulin, lysozyme activity and antibody production against do E. ictaluri. Increased intracellular killing of the bacteria F. ictalu'ri by head kidney macrophages has been demonstrated in channel catfish fed on diets containing high levels of n-3 fatty acids (Blazer et at., 1989;Sheldon and Blazer, 1991), Macrophages from head-kidney of rainbow trout fed a diet enriched with n-3 fatty acids had greater migration stimulating ability than those from trout fed an n-6 fatty acid-enriched diet (Ashton et al., 1994). Thompson et at. ...
... In general, a diet high in n-6 PUFAs will produce relatively higher levels of the proinflammatory 2-series PGs and 4-series LTs and LXs derived from AA. Alternatively, a diet high in n-3 PUFAs will produce relatively higher levels of the anti-inflammatory 3-series PGs and 5-series LTs and LXs derived from EPA (Figure 11.1; Ashton et al. 1994). Therefore, the fatty acid composition of the diet influences the immune response because, to a large extent, it will determine which eicosanoid precursors are present in the cell membranes. ...
... Inadequate levels of n -3 PUFAs in the diet reduced the immunological response of the phagocytes and lymphocytes in the pike perch, Sander lucioperca (Kowalska et al. 2012). In contrast, high levels of dietary n -3 fatty acids in the diet increase the activity of head kidney macrophages of channel catfish (Sheldon and Blazer 1991) and rainbow trout (Ashton et al. 1994). Similarly, an inadequate balance of n -3 and n -6 dietary fatty acids has been shown to alter the synthesis of eicosanoids compounds directly involved in the immune response (Bell et al. 1993). ...
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This study was undertaken to assess the effects of feeding European seabass (Dicentrarchus labrax) canola oil-added diets on growth, health status and liver and intestine histomorphology. Seabass (56.18 ± 0.16 g initial body weight) were fed one of three fish meal-based diets with *48 % crude protein and *16.0 % lipid, combining fish oil (FO) and canola oil (CO) for 12 weeks. The diets contained: zero (control, CTRL), 45 (CO50) or 63 (CO70) g CO kg-1 assigned in triplicates to three dietary groups. The results indicated that neither dietary oil type (FO or CO) nor CO level adversely affected (P[0.05) the growth, feed utilization or major blood constituents’ composition as an indicator of the overall health status of fish. Despite the CO diets influence on head kidney macrophage activity being unappreciable (P[0.05), there was a reducing trend with an increase in CO level incorporation. The CO70 diet induced a minor fat infiltration in hepatocytes and leucocytes infiltration, hyperplasia of the basal nuclei and supranuclear vacuolization of the enterocytes of the distal intestine. The present observations suggest that it is possible to incorporate up to 63 g CO Kg-1 in the feed for European seabass juveniles without major negative effects on growth, health status or liver and intestinal histomorphology. Keywords European seabass � Dicentrarchus labrax � Canola oil � Growth � Haematology � Liver and intestine histology
... However, despite the crucial correlation between dietary lipid composition and fish immunity, the functional effects of dietary lipid on fish immune response are controversial. Positive effects of n-3 fatty acids on the immune response were found in O. mykiss (Kiron et al., 1995) and S. aurata (Montero et al., 2008), whereas negative effects of high levels of dietary n-3 PUFAs on immunity are found in I. punctatus (Fracalossi and Lovell, 1994) and O. mykiss (Ashton et al., 1994). In this study, although we found that partial inclusion (25%) of soybean oil in diet can enhance immunity, it still warrants further study to investigate the mechanism why inclusion of vegetable oil can improve fish immunity. ...
Article
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An 80 day feeding trial was conducted to evaluate the effects of dietary inclusion of soybean oil to replace fish oil in the diet on growth, muscle fatty acids and immune responses of Pelteobagrus vachelli. Isonitrogenous and isocaloric diets were formulated with four fish oil to soybean oil ratios at 8:0 (FO, control), 6:2 (MO1), 2:6 (MO2) and 0:8 (SO) in triplicate. Each diet was fed to juvenile darkbarbel catfish (1.0 ± 0.02 g) twice daily. No significant differences were found in weight gain, special growth rate, hepatosomatic index and intraperitoneal fat ratio among all the treatments. Incorporation of soybean oil significantly modified the fatty acid composition and n-3 and n-6 PUFAs ratio in muscle of fish. Fish fed MO1 showed significantly higher serum lysozyme activity, complement C3 and C4 contents and total IgM content than those fed other diets. These results indicate that partial replacement of fish oil with soybean oil does not compromise fish growth, but improve fish immunity. This study suggests that 25% fish oil replacement with soybean oil can be used in the practical diet of this fish.
... Generally, based on studies accepted that diets containing vegetable oil compare to fish oil diets, increase levels of mono unsaturated fatty acids and poly unsaturated fatty acids particularly n-6 series and decrease the level of totally n-3 poly unsaturated fatty acids (Lall, 2000). Evidence suggests that diverse fatty acid profile related to vegetable or fish oil can influence on immune function by changing the physiological process and eicosanoid and prostaglandin synthesis or even physiology of the cell membrane (Ashton et al, 1994). Previously shown that immune parameters related to humeral and cell immunity such as phagocytosis highly altered by level and profile of fatty acids, mainly due to change in membrane fluidity, intracellular signaling pathways and trans membrane receptors involved in complement activity ,Montero et al (2008). ...
Article
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To study the effects of dietary oil sources, L-carnitine and Ractopamine supplement on the meat filet composition, hematological and immunological parameter of rainbow trout, 288 fish (initial body weight 90 ± 5 g) were fed by 8 dietary treatments as a 2×2×2 factorial experimental design. Dietary treatments contained fish oil or soybean oil and two levels of L-Carnitine (0 or 1g.kg-1) and ractopamine (0 or 10 mg.kg-1) supplement and fish fed for 8 week feeding trials. At the end of experiment, fish filet composition (protein, fat and ash), liver fat and hematological parameter (hematocrit, red blood cell, white blood cell, hemoglobin, phagocytosis and etc.) and also concentration of immunoglobulin M (Ig M) in blood of fish were measured. Results showed that replacement of fish oil by soybean oil significantly increased crud protein percentage of fish filet, lipid content of liver and hematocrit, red blood cell count, hemoglobin, phagocytosis activity and phagocytosed particles in blood fish as comparison of fish oil dietary treatment (p<0.05). Dietary L-carnitine supplementation reduced heterophils and phagocytosed particles but no change other hematological parameter and filet fish composition (p<0.05). Ractopamine supplement significantly reduced hematocrit, monocyte and Ig M but increased phagocytosed particles (p<0.05) in blood fish. Addition of L-carnitine plus ractopamine to soybean oil diet reduced fat content of filet and increased it in fish liver. Also addition of L-carnitine or ractopamine to fish oil diet increased lymphocyte and reduced Ig M in fish blood. Data of the present experiment showed that immunological and hematological response of rainbow trout to L-carnitine and ractopamine supplement were affected by dietary oil sources.
... Les organes associés à la croissance (par exemple le foie, le pancréas, les reins, le tube digestif) ou la respiration (coeur) ont des taux métaboliques spécifiques à la masse très élevés par rapport au muscle squelettique ou aux tissus conjonctifs (Oikawa et Itazawa 1984, Elia 1992, Wang et al. 2001. AGLPI ou un déséquilibre entre les voies n-3 et n-6, pouvait affecter les fonctions immunitaires et ainsi induire une réponse inflammatoire ( Henderson et al. 1985, Sheldon Jr. et al. 1991, Lie et al. 1992, Ashton et al. 1994, Kiron et al. 1995, Bell et al. 1996, Ganga et al. 2005). Les AGLPI sont également impliqués dans la résistance au stress et aux maladies (pour revue, voir Sargent et al. 2002). ...
Thesis
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Une des questions cruciales dans le débat écologique actuel est de déterminer si la plasticité phénotypique pourra permettre aux espèces de répondre au rythme rapide des changements environnementaux en cours. L’objectif général de cette thèse était d’étudier les effets d’un appauvrissement en acide gras polyinsaturés du type n-3 (AGLPI) sur la plasticité de deux espèces, le bar européen (Dicentrarchus labrax) et le bar rayé (Morone saxatilis). L’effet combiné d’une augmentation de la température et d’une réduction en disponibilité des AGLPI n-3 nutritionnels chez les juvéniles de bar européen a entrainé une modification importante des acides gras neutres musculaires ainsi qu’un taux de croissance et une masse hépatique plus faibles. À température élevée, une croissance accrue a été observée avec les deux régimes, suggérant une absence de carence. En revanche, l’aliment n’a pas eu d’effets sur les facteurs transcriptionnels hépatiques liés à la régulation de la bioconversion des AG. Les juvéniles nourris avec le régime appauvri en AGLPI n-3 présentaient une vitesse critique de nage accrue en présence de contraintes hypoxiques et hypoosmotiques. Chez le bar rayé, le régime alimentaire modifie les profils en AG du muscle (fraction neutre) et du foie. Le régime pauvre en AGLPI n-3 a été associé à une augmentation de la masse cardiaque, sans effet sur la croissance en eau froide. Un niveau de stress plus élevé associé à des mortalités a été observé en eau douce. Ces résultats contribuent à une meilleure compréhension de l’impact des changements globaux sur les organismes aquatiques et ouvrent la voie à de nouvelles perspectives de recherche.
... Dietary fish oil levels up to 14%, however, had no effect on hematological parameters, serum protein, total immunoglobulin, lysozyme activity and antibody production against do E. ictaluri. Increased intracellular killing of the bacteria F. ictalu'ri by head kidney macrophages has been demonstrated in channel catfish fed on diets containing high levels of n-3 fatty acids (Blazer et at., 1989;Sheldon and Blazer, 1991), Macrophages from head-kidney of rainbow trout fed a diet enriched with n-3 fatty acids had greater migration stimulating ability than those from trout fed an n-6 fatty acid-enriched diet (Ashton et al., 1994). Thompson et at. ...
... However, other reports show positive effects of n-3 fatty acids on the immune response of fish. High levels of dietary n-3 fatty acids in the diet increase the activity of head kidney macrophages of channel catfish (Sheldon and Blazer, 1991) or rainbow trout (Ashton et al., 1994). Inadequate levels of n-3 PUFAs in the diet reduce antibody production and in vitro killing of bacteria by macrophages in rainbow trout (Kiron et al., 1995) and deplete alternative complement pathway activity in gilthead seabream (Sparus aurata) (Montero et al., 1998). ...
... Fish oil is preferred in the diet of farmed animals and aquaculture due to the presence of LC omega-3 fatty acids, which has been reported to offer major benefi ts to animal health, including improved immunity against disease (Ashton et al. 1994 ), higher survival and growth, and reduced incidences of deformities (FAO 1986 ). It is highly digestible, which leads to increased growth and less wastage of food, and is also considered to increase feed appeal. ...
... Fish oil is preferred in the diet of farmed animals and aquaculture due to the presence of LC omega-3 fatty acids, which has been reported to offer major benefi ts to animal health, including improved immunity against disease (Ashton et al. 1994 ), higher survival and growth, and reduced incidences of deformities (FAO 1986 ). It is highly digestible, which leads to increased growth and less wastage of food, and is also considered to increase feed appeal. ...
Chapter
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Fish oil is a virtually unique source of natural long-chain (LC) omega-3 fatty acids, comprising eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Fish oils account for about 2 % of the world’s consumption of fats and oils and are a by product of the fish meal industry. Traditionally, the industry focus was on marine oils from fish and also mammals, such as whales and seals. But, at present, greater attention is given to smaller fish with a relatively high fat content, such as anchovies, sardines, pilchards, menhaden, herring, and sand eels, as raw materials in the fish oil industry. Fish liver oil, on the other hand, is produced only from the liver of fish. It has therapeutic value and is an important source of vitamins A and D. Historically, marine oils have played an important role in human nutrition and there is an increasing demand for fish oil due to its medicinal properties. The major interest in marine oils in these fields is due to their high content of polyunsaturated fatty acids (PUFAs). In recent centuries, the food industry has used PUFAs as a source of fat, either fully or partially hydrogenated, in various foods as substitutes for fats, such as butterfat, lard, and tallow. There is an established market for dietary supplements, as well as a developing market for food ingredients produced from fish oils and concentrates of fish oil. Besides being used as food, fish is also increasingly in demand for use as feed. Nearly one-third of the world’s wild-caught fish are reduced to fish meal and fish oil, which are then used in feeds for livestock, like poultry and pigs, and in feeds for farmed carnivorous fish.
... Kuhn et al. (2017) suggested LXA 4 is preferentially produced in periparturient cows, perhaps as a mechanism to reduce the systemic inflammatory state observed after parturition. We found supplementing calves with n-3 FA in their first meal tended to increase LXA 4 concentrations, which is curious considering LXA 4 is derived from ARA. Supplementation with n-3 FA in rainbow trout and female rats decreases LXA 4 and other ARA-derived lipoxygenase products (Ashton et al., 1994;Poulsen et al., 2008), which was consistent with the idea that ARA and n-3 FA compete for lipoxygenase binding (Schmitz and Ecker, 2008). However, calves receive a greater n -6: n -3 FA ratio in the diet, and supplementing n-3 FA in a short period of time in the current study is likely not enough to alter n-6 FA phospholipid content, and thus their oxylipid products, in all tissues. ...
Article
Calves may experience increased oxidative stress at birth through activation of metabolic and respiratory processes. Reducing oxidative stress may enhance calf viability in early life. Our objective was to determine the dose response to fish and flaxseed oil when supplemented in colostrum on concentrations of plasma fatty acid (FA), FA metabolites, and index of oxidative stress during the critical first week of life in calves to understand how supplementing n-3 FA may decrease oxidative stress. We hypothesized that n-3 FA supplemented in colostrum in a linear dose-dependent fashion would associate with increased plasma n-3 FA concentrations and decreased oxidative stress. Twenty-four male and female Holstein calves were randomly assigned to receive 0, 30, 60, or 120 mL of a 1:1 fish to flaxseed oil supplement in colostrum. All calves received 2.8 L of previously frozen colostrum (≥22% Brix) with their respective treatment within 6 h after birth. Blood was sampled before first feeding after birth and on d 1, 2, 4, 7, and 14 d of age to assess oxidant status and plasma free PUFA, phospholipid FA, and oxylipid concentrations. Health indicators were observed daily. Indicators of general health and growth were unaffected by treatment. Supplemented calves exhibited greater concentrations of n-3 FA in plasma as free and phospholipid FA and some n-3 and n-6 FA-derived oxylipids in the first week of life in a linear fashion with increasing supplemental dose. Fish and flaxseed oil treatments did not alter oxidant status but overall decreased isoprostane concentrations in plasma, indicating oxidative stress was decreased. Together, these responses indicate that the fish and flaxseed oil supplement was antiinflammatory. In conclusion, supplementing colostrum with 30, 60, and 120 mL of a 1:1 mixture of fish and flaxseed oil linearly increased plasma concentrations of n-3 FA and metabolites and decreased biomarkers of oxidative stress, but did not alter oxidant status or affect health or growth. Our findings suggest neonatal calves may benefit from n-3 FA supplementation in colostrum to encourage a greater antiinflammatory state.
... In line with the results of the current study, high density dietary n-3 HUFA has been reported to result in a decreased response by the non-specific immune system in Atlantic salmon (Erdal et al., 1991;Waagbø et al., 1993a;Waagbø et al., 1993b). In contrast, positive effects of high n-3 fatty acid intake on immune response have been reported in some studies on rainbow trout (Ashton et al., 1994), channel catfish (Sheldon Jr. and Blazer, 1991), and Atlantic salmon (Balfry et al., 2006). However, it remains unclear as to why in some species diets improved immune responses, and in others it did not. ...
Article
Identifying and effectively utilizing suitable, novel, terrestrial oil sources either alone or as blends to replace fish oil (FO) is a prerequisite for improving the sustainability of global aquaculture. Therefore, the present study evaluates several novel terrestrial oil blends (TOBs), optimized for their fatty acid profile, as alternatives to FO in low fishmeal diets fed to rainbow trout (Oncorhynchus mykiss) and describes the subsequent effects on fish growth, fatty acid composition and health. Insect oil (IO), genetically modified canola oil (CO), palm oil (PO) and linseed oil (LO) were used for the formulation of three TOBs viz., TOB-1 (30%IO+36%CO + 34%LO), TOB-2 (40%PO + 20%CO + 40%LO) and TOB-3 (50%TOB-1 + 50%TOB-2). Formulas TOB-1 and TOB-2 considered the total fatty acid profile based upon the general FO fatty acid profile, published fatty acid research for rainbow trout, and the fatty acid requirements of rainbow trout. A low fishmeal based basal diet containing 44% crude protein was formulated, and FO, TOB-1, TOB-2 and TOB-3 were incorporated in the basal diet to prepare the experimental diet groups, Control, TOB-1, TOB-2 and TOB-3, respectively. All experimental diets were fed to triplicate groups of rainbow trout juveniles (initial weight 7.9 ± 0.02 g) for 9 weeks. Growth performance (final weight, percent weight gain and specific growth rate) in TOBs fed groups were equal to the FO-based control group. Fish fed the TOB-3 diet consumed more feed followed by the control and TOB-1 diet groups. Significantly lower feed intake was observed in the TOB-2 diet group. Feed conversion ratio and protein efficiency ratio were not significantly influenced by dietary oil sources. Fish fed the control group showed significantly higher hepatic lipid content compared to TOB groups, followed by TOB-2, TOB-3, and TOB-1, which was significantly lower in hepatic lipid content. Muscle lipid content and whole-body major nutrient compositions were not significantly influenced by the dietary oil sources. Fatty acid composition of muscle and liver reflected that of the diets. Maximum values for n3 LC-PUFAs (EPA and DHA), lauric acid (C12:0) and C18:3n-3 were observed in the FO, TOB-1 and TOB-2 groups, respectively. Except for C12:0, muscle saturated fatty acid contents were significantly lower in TOBs-based diet compared to the FO-based control diet fish. As expected, muscle C12:0 content was significantly higher in the TOB-1 group followed by the TOB-3 group. TOB-2 and control groups had significantly lower content of C12:0. The fillet total n-3 LC-PUFA was significantly higher in fish fed the control diet group followed by TOB-3 and TOB-2 groups, TOB-1 showed significantly lower content of total n-3 LC- PUFA. Hepatic delta-5 desaturase (Δ5fad), delta-6 desaturase (Δ 6fad) and fatty acid elongase-2 (Elovl-2) gene expressions were significantly influenced by dietary oil sources, where TOB-based groups showed higher Δ6fad and Elovl-2 expressions. Measured innate immunity and antioxidant markers were not affected by TOBs. Finally, we concluded that TOBs could serve as a substitute for FO in rainbow trout feed without negatively impacting growth and health performance. Moreover, fillet total n-3 LC-PUFA of TOB-fed fish also satisfies the suggested dietary requirement of total n-3 LC-PUFA relative to the suggested daily serving for humans.
... качества на рибното месо(Reinitz and Yu, 1981;Hardy et al., 1987; Arzel et al., 1994;Skonberg et al., 1994). Мазнините на дъгова пъстърва, хранена със слънчогледово масло като заместване на част от рибеното масло в дажбата, показват два пъти по-високи нива на всички ПНМК и 2,3 пъти намаляване на n-3 ПНМК, сравнено с първоначалното базово ниво(Ashton et al., 1994). Мускулатурата на риби хранени със слънчогледово масло съдържа два пъти по-висока концентрация на олеинова киселина, в сравнение с дажба, съдържаща херингово масло, посочва експеримент наSkonberg et al. (1994). ...
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The aim of this work was to determine the influence of linseed and sunflower oil supplementation in feed on the survival rate, weight gain, feed conversion, chemical composition, technological properties and fatty acid profile of the meat in rainbow trout (Oncorhynchus mykiss W.) and carp (Cyprinus carpio L.), cultivated in recirculating systems and cages. The results showed that the productive traits were positively influenced by the supplementation of 5% linseed or sunflower oil in the extruded feed for the rainbow trout and carp, cultivated in recirculating system. It decreased the feed convertion, increased the weight gain and had no effect on the survival rates of the fish. The same trend was observed at the inclusion of 1% linseed oil in the feed for the carp, cultivated in cages. The linseed and sunflower oil added in amount of 5% in the feed for rainbow trout, cultivated in recirculating system increased the nutritional value of the meat augmenting the protein content. In carp, cultivated in recirculating system the supplementation of the feed with the same levels of the vegetable oils also led to higher protein content and diminished the content of water, thus increasing the dry matter content as well. The same was observed after the supplementation of the feed with 1% linseed oil for the carp, cultivated in cages. No influence of the 5% supplementation with the vegetable oils was detected on the technological parameters (WHC and cooking loss) in both trout and carp. The linseed and sunflower oil added in amount of 5% to the feed for the rainbow trout, cultivated in recirculating system affected positively the fatty acid composition of the meat, increasing the linoleic, α-linolenic and n-3 polyunsaturated fatty acids, while decreasing the ratio n-6/n-3. No effect on the PUFA/ SFA ratio was observed. In carp, cultivated in recirculating system, the 5% linseed or suflower oil supplementation in the diet decreased the content of the myristic and palmitic acids as well as the total content of the saturated fatty acids. On the other hand the levels of linoleic, α-linolenic, eicosatrenoic, arachidonic, docosapentaenoic, UFA, PUFA and n-3 PUFA increased significantly. Positive influence on the ratios PUFA/ SFA and n-6/n-3 were also observed showing augmented values in the former and decreased in the latter. The same effect on the fatty acid composition of the meat was found in the carp, cultivated in cages in response to 1% linseed oil supplementation of the feed. Thermal treatment (roasting) affected positively the fatty acid profile of meat in the rainbow trout and carp, leading to considerable increase of the content of 20:5, 22:6, n-6 and n-3 polyunsaturated fatty acids, while at the same time the n-6/n-3 ration diminished. The supplementation of 5% vegetable oils to the extruded feed for rainbow trout cultivated in recirculating system augmented the economic efficiency coefficient, while in carp in the same rearing conditions, the inclusion of 5 % oils showed the lowest coefficient of economical efficiency in the group receiving sunflower oil, but considerably higher in the control and linseed oil group. The linseed oil in amount of 1% to the feed of the carp cultivated in cages increased the cost price with 0.59% for kilogram fish.
... Individual fatty acid percentages showed a profile that reflected the consumed diet, whereby the accumulation of LA, OA and LNA, and the decrease of DHA concentrations in commercial feed group were mainly responsible for the observed differences. These changes in fatty acid profiles agree with those of other authors working in wild mullet feeding on lost pellets from sea-cages ) as well as mullet and other species in laboratory conditions, where similar trends were found when feeding on diets rich in vegetable oils (Argyropoulou et al., 1992;Ashton et al., 1994;Mourente et al., 2007). Due to limitations of the sample size, we could not analyse the fatty acid profile of leucocytes, but other studies have demonstrated that tissues like flesh tend to reflect the fatty acid composition of the diet (Farndale et al., 1999;Kiron et al., 2011). ...
Article
We simulated in the laboratory the possible effects on fatty acids and immune status of wild fish arriving for the first time in the vicinity of a sea-cage fish farm, shifting their natural diet to commercial feed consumption, rich in fatty acids of vegetable origin. The flesh fatty acid profile of golden mullet specimens was altered after 2 weeks of commercial feed consumption, showing an increase in fatty acids of vegetable origin. The serum peroxidase and bactericidal activities, and head-kidney leucocyte phagocytic capacity, increased after eight weeks of the new diet, while the respiratory burst activity decreased. The extent of these changes cannot be considered large enough to regard them as compromising the health status of fish. More research is needed in order to elucidate whether the rapid assimilation of the dietary fatty acids could harm the immune status of fish when feeding for longer periods than two months.
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Atlantic salmon (Salmo salar) post-smolts were fed diets containing either Fosol (FO), a North Sea fish oil, sunflower oil (SO), linseed oil (LO) or Marinol K (MO), a southern hemisphere fish oil rich in 20:5(n-3) for 12 weeks. A macrophage-enriched leucocyte preparation was obtained from head kidney and the fatty acid compositions of the individual membrane phospholipids measured. In general phospholipids from SO- and LO-fed fish had increased 18:2(n-6), 20:2(n-6) and 20:3(n-6) compared to the fish oil treatments while LO-fed fish had lower 20:4(n-6) than any other dietary treatment. Fish fed LO also had increased 18:3(n-3), 18:4(n-3), 20:3(n-3) and 20:4(n-3). The 20:5(n-3) content of kidney macrophage-enriched leucocyte phospholipids was highest in MO-fed fish followed by FO- and LO-fed fish with the lowest level in fish fed SO. The overall effect on the ratio of eicosanoid precursors, 20:4/20:5, showed the highest value in SO-fed fish and the lowest in fish fed LO. Production of LTB5 by kidney macrophage-enriched leucocytes stimulated with A23187 was highest in MO-fed fish and lowest in those fed SO. Production of LTB4 was greatest in SO-fed fish and lowest in fish fed LO. Serum Ig levels were significantly affected by dietary treatment with highest values in fish fed FO and SO and lowest in fish fed MO and LO.
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The effects of high dietary docosahexaenoic acid (22:6n−3, DHA) and varying arachidonic acid (20:4n−6, AA) were tested on growth, survival and resistance to handling stress in 5–35 day old gilthead seabream larvae. Three enrichment treatments differing in their DHA/AA ratios were fed to rotifers (Brachionus rotundiformis) and Artemia nauplii. The high DHA (35.9% TFA) enrichment treatment (DHA-PL) contained no AA and included lipid from the heterotrophically grown DHA-rich dinoflagellate Crypthecodinium sp. A second enrichment treatment (AADHA), selected from an earlier screening study, supplemented the high DHA enrichment treatment with an AA-rich lipid (52% TFA) from the heterotrophically grown fungus Mortierella alpina. A third enrichment treatment (ALGA) was the commercial product Algamac 2000, which is devoid of AA, but includes approximately 12.9% of TFA as docosapentaenoic acid (DPA, 22:5n−6). Rotifers fed the DHA-PL, AADHA and ALGA treatments demonstrated a range of DHA/AA ratios (20.9, 5.6 and 10.1, respectively) as did the Artemia nauplii (25.8, 3.7 and 4.6, respectively).
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Under intensive culture conditions, fish are subject to increased stress owing to environmental (water quality and hypoxia) and health conditions (parasites and infectious diseases). All these factors have negative impacts on fish well-being and overall performance, with consequent economic losses. Though good management practices contribute to reduce stressor effects, stress susceptibility is always high under crowded conditions. Adequate nutrition is essential to avoid deficiency signs, maintain adequate animal performance and sustain normal health. Further, it is becoming evident that diets overfortified with specific nutrients [amino acids, essential fatty acids (FAs), vitamins or minerals] at levels above requirement may improve health condition and disease resistance. Diet supplements are also being evaluated for their antioxidant potential, as fish are potentially at risk of peroxidative attack because of the large quantities of highly unsaturated FAs in both fish tissues and diets. Functional constituents other than essential nutrients (such as probiotics, prebiotics and immunostimulants) are also currently being considered in fish nutrition aiming to improve fish growth and/or feed efficiency, health status, stress tolerance and resistance to diseases. Such products are becoming more and more important for reducing antibiotic utilization in aquafarms, as these have environmental impacts, may accumulate in animal tissues and increase bacterial resistance. This study reviews knowledge of the effect of diet nutrients on health, welfare and improvement of disease resistance in fish.
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Sweet smelt (Plecoglossus altivelis) were fed four different diets supplemented with either perilla oil rich in 18:3n-3 (CP), and perilla oil and Enteromorpha compressa meal (CPA), soybean oil rich in 18:2n-6 (CO), or soybean oil and algal meal (CA) for 4 weeks. The growth performance, fatty acid composition of muscle, plasma lipid peroxidation and blood components of the sweet smelt were then determined. The specific growth rate and feed efficiency in the fish fed the CPA diet were the highest, while the other groups showed similar results. The fatty acid composition of muscle in sweet smelt reflected the dietary lipids; 18:3n-3 was higher in the fish fed the CP and CPA diets, and 18:2n-6 was higher in the fish fed the CO and CA diets. The other fatty acid profiles presented almost no differences with respect to the diet composition. The fish fed the CA, CP and CPA diets contained significantly lower levels of triglyceride, thiobarbituric acid-reactive substances and hydroxyl radical in their plasma than that fed the CO diet. Phagocytic activity was the highest in the fish fed the CPA diet and higher in those of the fish fed the CP and CA diets compared to the CO diet group. The results from this study suggest that a dietary supplement of perilla oil together with E. compressa meal may improve the growth and health of cultured sweet smelt.
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Two species of shark found in the coastal waters Karachi (Pakistan) were studied, Eusphyra blochii (winghead snark) and Carcharhinus bleekeri (sandbar shark) for their liver oil fatty acid composition. Since liver has high lipid content and traditionally the liver oil of these species been used to relieve muscular pain and arthritis in Pakistan this study was conducted. The isolation, identification and characterization of these fatty acids were carried out by gas liquid chromatography (GLC) and a combination of the thin layer chromatography (TLC)-GLC technique. A large variation was observed between winghead shark liver oil and sandbar shark liver oil. Twenty-five individual fatty acids from the oil of marine fish were analysed. Among those studied, palmitic acid was a major saturated fatty acid while stearic acid was the other major constituent. Unsaturated monoenoic fatty acids e.g. oleic and palmitoleic acids, were major constituents and traces of dienoic and trienoic fatty acids were also found. In addition, medicinally important polyunsaturated fatty acids, such as eicosapentaenoic and docosahexaenoic acids, were also identified.
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Aquaculture contributes significantly to world food supplies and the rapid growth of this sector has brought forth the need to ensure that development is based on environmentally responsible practices, including those concerning feeds. The major players in the aquafeed industry are greatly aware of this and they attach importance to sustainability issues during feed development. There is consensus among the feed manufacturers and the farmers that quality feeds should not only ensure superior growth, but also return prime health. Therefore, the potential health promoting quality of each component is to be taken into account while formulating feeds.The role of dietary nutrients or additives on the functions of the immune system in fish has been investigated since the 1980s. Not all nutrients have received attention; most of the studies have been directed towards vitamins C, E and fatty acids (oils). Popular additives comprise yeast-derived products such as glucans and mannan oligosaccharides, besides probiotics. Several of these components have been examined for their ability to protect fish from stressors or diseases. The physiological outcomes attributed to these nutrients or additives are presumed to be translated to good health. More convincing evidences should be gathered before they are classified as ‘functional ingredients’. Aquafeeds of the future are expected to impart dual benefits of good growth and health to the farmed organism, and preventive health care through nutritional means is certainly a strategy to ensure sustainability in aquaculture.
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Rainbow trout (Oncorhynchus mykiss) macrophages generated lipoxin (LX) A4, LXA5, leukotriene (LT) B4, LTB5 and 12-hydroxyeicosatetraenoic acid (12-HETE) during the phagocytosis of zymosan and Escherichia coli, but not of the yeast Saccharomyces cerevisiae. Prostaglandin (PG) E2 was also detected in supernatants from macrophages incubated with either zymosan or calcium ionophore A23187. LXA4 (10(-8)-10(-6) M) and LTB4 (10(-9)-10(-7) M) provoked rapid and transient dose-dependent increases in intracellular calcium ([Ca]i) concentrations in leukocyte suspensions containing 40-60% macrophages. EC50 values were 14.9 and 1.2 nM, respectively. PGE2 and 12-HETE had no effect on [Ca]i at concentrations up to 30 microM. PGE2 and 12-HETE (10(-5)-10(-10) M) enhanced the in vitro phagocytosis of yeast test particles by trout macrophages, whereas LXA4 and LTB4 had no demonstrable effect on the responses of these cells at concentrations up to 10(-5) M. In conclusion, the processes involved in trout macrophage stimulation are complex but involve generation of both cyclooxygenase and lipoxygenase products. The increase in [Ca]i caused by LXA4 and LTB4 may form part of the chemotactic transduction mechanism that recruits granulocytes and macrophages to sites of inflammation. The effects of eicosanoids on phagocytosis appear to be independent of changes in [Ca]i.
Article
Recent uncontrolled work has suggested that dietary supplementation with fish oils high in eicosapentaenoic acid may improve psoriasis.1 We have investigated this in a double-blind, placebo-controlled trial. Twenty-nine patients (12 male, 17 female) with stable chronic plaque psoriasis, using only topical medicaments, were recruited into the trial. Patients were randomly allocated to receive either 10 capsules ‘MaxEPA’ daily, containing 1·8 g eicosapentaenoic acid (treatment group), or 10 identical capsules containing vegetable oil daily (control group), for a period of 12 weeks. Patients were allowed to continue their previous topical treatments, the quantity used being recorded at each visit. The percentage surface area affected, itching, erythema and scaling were assessed at 0, 4, 8 and 12 weeks. Tablet counts and erythrocyte membrane lipid measurements were performed to assess compliance. Twenty-five patients completed the trial, 12 in the treatment group and 13 in the control group. Two patients defaulted from each group. After 8 weeks, 11 out of 12 patients in the treatment group had a reduction in surface area affected, compared with seven of 13 controls (P < 0·05; x2 test). The mean surface area affected (± SEM) at 0 and 8 weeks was 11·3 ± 1·7% and 7·6 ± 1·4% in the treatment group, and 11·8 ± 1·6% and 10·3 ± 1·5% in the control group, respectively. Itching improved at 8 weeks in 10 of the treatment group compared with four of the control group (P < 0·01;x2 test). Erythema improved in 10 of the treatment group compared with four of the controls, but this was not statistically significant (P < 0·01;x2 test). There was no improvement in scaling in either group. This study confirms that dietary supplementation with fish oil is a useful adjunctive therapy in patients with psoriasis, particularly when itching is a prominent symptom.
Article
Diets containing either fish oil or sunflower oil, both of which supplied the minimum required level of n−3 fatty acids, were given to Atlantic salmon (Salmo salar) postsmolts for a period of 16 weeks. In fish fed sunflower oil, the phospholipids of gills showed increased 18∶2n−6 (2–13-fold), 20∶2n−6 (4.5–12-fold) and 20∶−6 (2–8-fold). In addition, phosphatidylethanolamine had increased 20∶4n−6 (1.5-fold). Changes of a similar magnitude were observed in the phospholipids of blood leucocytes except that, in addition, 20∶4n−6 was elevated in phosphatidylserine (1.7-fold) and phosphatidylinositol (1.4-fold). Both tissues showed a general decrease in phospholipid 20∶5n−3 (up to 3-fold), which caused an increase in 20∶4n−6/20∶5n−3 ratio (1.3–6-fold). The elongation and desaturation products of 20∶4n−6, 22∶4n−6 and 22∶5n−6 were not increased as a result of feeding sunflower oil. When isolated gill cells were stimulated with the calcium ionophore A23187, 12-hydroxy-8,10,14,17-eicosapentaenoic acid (12-HEPE) was the major lipoxygenase product from salmon given fish oil. 12-HEPE was significantly reduced in salmon given sunflower oil. When stimulated with A23187, the lipoxygenase products derived from whole blood of fish given sunflower oil showed decreased levels of leukotriene B5, 12-HEPE and 12-hydroxy-5,8,10,14-eicosatetraenoic acid.
Rainbow trout leucocytes contain high levels of neutral lipid (about 70% of total lipid on a wt% basis) consisting of mostly triacylglycerol, free sterols and sterol esters (25%, 15% and 52% of neutral lipid, respectively). The phospholipids, separated by thin-layer chromatography, consisted predominantly of phosphatidylcholine, phosphatidylethanolamine and phosphatidylserine, each present at about 30% of the total phospholipid. Radiolabelling of the leucocytes for 1 h with 1 μCi (approx. 6 μM) [1−14C]20:4(n−6), [1−14C]20:5(n−3) or [1−14C]22:6(n−3) each gave similar uptake values (approx. 1 · 105 cpm/107 leucocytes). The incorporation into total phospholipids was highest for 22:6(n−3) and lowest for 20:4(n−6). A higher percentage of radiolabel from [1−14C]22:6(n − 3) was found incorporated into phosphatidylcholine and phosphatidylethanolamine as compared to that from [1−14C]20:4(n − 6) and [1−14C]20:5(n−3), while the reverse situation was found with phosphatidylinositol and phosphatidylserine. The relative rates of incorporation into the different phospholipid classes for all three fatty acids were in the order phosphatidylinositol > sphingomyelin > diphosphatidylglycerol > phosphatidylcholine > phosphatidylethanolamine > phosphatidylserine. Calcium ionophore-challenge did not significantly alter the pattern of phospholipid radiolabel. Ionophore-challenge released large amounts of radiolabel, much of which was recovered after high-performance liquid chromatographic separation as free fatty acid/monohydroxy fatty acids, although only approx. 0.3% was recovered in leukotriene B4 and leukotriene B5 for the [1−14C]20:4(n−6) and [1−14C]20:5(n−3) labelled leucocytes, respectively. Other lipoxygenase products were also radiolabelled and tentatively identified as 20-carboxy-LTB4, 20-hydroxy-LTB4, 6-trans-LTB4, 6-trans-12-epi-LTB4, 6-trans-8-cis-12-epi-LTB4 and the corresponding LTB5 structures. No ‘6-series’ leukotrienes were produced from [1−14C]22:6(n−3), nor was there any evidence for the synthesis of ‘5-series’ leukotrienes via retroconversion of 22:6(n−3) to 20:5(n−3). This latter finding shows that, despite the preponderance of 22:6(n−3) in the membranes of trout leucocytes, this fatty acid is not a substrate for leukotriene generation.
Article
Juvenile Atlantic salmon (Salmo salar L.) were fed experimental diets containing megadoses of vitamin C1 and C2, respectively, and increasing amounts of omega-3 fatty acids for periods of 52 and 72 days. General resistance to infection was assessed after challenge with Vibrio salmonicida. Development of specific immune response after vaccination against Yersinia ruckeri was assessed as likelihood of survival after challenge and antibody level. Cell wall strength was assessed by the erythrocyte fragility test, and occurrence of morphological changes in various body organs was investigated. In the present study, no significant increase in general or specific resistance to infection was seen. Fish fed diets with megadoses of vitamin C2 had increased antibody levels and higher incidence of degenerative changes in skeletal muscle. Omega-3 fatty acids exerted an immunosuppressive action with both significantly lower likelihood of survival and lower antibody levels. An increased incidence of degenerative changes was also observed. On the other hand, increased levels of omega-3 fatty acids increased erythrocyte cell wall strength.
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The formulation and manufacture of fish feed, the principal cost factor in fish production, must be based on sound information regarding nutritional requirements if the process is to be economical. Assessing nutrient requirements from growth experiments depends on the availability of a suitable model of growth, the analysis used to identify required levels of nutrients, choice of response variables, and the feeding scheme used to deliver the target nutrient to the fish. The review examines specific elements critical in experiments designed to estimate nutrient requirements for vitamins, proteins, amino acids, essential fatty acids, and minerals. Also provided are formulations for semi-purified diets and examples of data interpretation.
1.1. Atlantic salmon post-smolts were fed practical-type diets containing linoleic acid at 10, 25 or 45% of total dietary fatty acids for a period of 20 weeks.2.2. As dietary linoleic acid was increased, individual phospholipids of heart contained increased levels of 18:2n-6, 20:2n-6, 20:3n-6 and 20:4n-6 and reduced levels of 20:5n-3. The ratio of n-3/n-6 polyunsaturated fatty acids in heart phospholipids decreased and the ratio of 20:4n-6/20:5n-3 increased.3.3. An increased production of thromboxane B2 occurred in isolated cardiac myocytes from fish given the highest dietary linoleic acid but the production of 6-keto prostaglandin F1α was not significantly affected, nor was the activity of heart sarcoplasmic reticulum Ca2+-Mg2+ ATPase (EC 3.6.1.4).
Article
Platelets enzymatically convert prostaglandin H3 (PGH3) into thromboxane A3. Both PGH2 and thromboxane A2 aggregate human platelet-rich plasma. In contrast, PGH3 and thromboxane A3 do not. PGH3 and thromboxane A3 increase platelet cyclic AMP in platelet-rich plasma and thereby: (i) inhibit aggregation by other agonists, (ii) block the ADP-induced release reaction, and (iii) suppress platelet phospholipase-A2 activity or events leading to its activation. PGI3 (Δ17-prostacyclin; synthesized from PGH3 by blood vessel enzyme) and PGI2 (prostacyclin) exert similar effects. Both compounds are potent coronary relaxants that also inhibit aggregation in human platelet-rich plasma and increase platelet adenylate cyclase activity. Radioactive eicosapentaenoate and arachidonate are readily and comparably acylated into platelet phospholipids. In addition, stimulation of prelabeled platelets with thrombin releases comparable amounts of eicosapentaenoate and arachidonate, respectively. Although eicosapentaenoic acid is a relatively poor substrate for platelet cyclooxygenase, it appears to have a high binding affinity and thereby inhibits arachidonic acid conversion by platelet cyclooxygenase and lipoxygenase. It is therefore possible that the triene prostaglandins are potential antithrombotic agents because their precursor fatty acids, as well as their transformation products, PGH3, thromboxane A3, and PGI3, are capable of interfering with aggregation of platelets in platelet-rich plasma.
Article
ALTHOUGH earlier studies1 2 3 suggested that dietary fish had some properties that could potentially prevent coronary artery disease, it was not until the epidemiologic studies of Bang et al.4 and Dyerberg et al.5 in the mid-1970s that the association became noteworthy. These researchers reviewed reports of a low prevalence of atherosclerosis among Eskimos in Greenland and subsequent documentation of an age-adjusted mortality from myocardial infarction among the Greenland Eskimos that was approximately 1/10th that among Danes6 or North Americans, despite a diet as high in fat and cholesterol as that of the Danes or Americans. The striking difference between the diets . . .
Article
Diets containing linoleic acid at 10, 25 and 45% of total dietary fatty acids were fed to three groups of post-smolt Atlantic salmon (Salmo salar) for 18 weeks. Incorporation of linoleic acid into membrane phospholipids of leucocytes and gills increased in response to dietary intake. In general, there was an increase in arachidonic acid and a decrease in eicosapentaenoic acid in the individual phospholipids of both cell types in response to increasing dietary linoleic acid. These changes in eicosanoid precursors were reflected in significantly increased plasma concentrations of 6-keto-PGF1 alpha and TXB2 in salmon given the highest dietary linoleic acid. In whole blood stimulated with the calcium ionophore A23187, LTB4, 12-HETE and TXB2 were significantly increased and 12-HEPE significantly decreased in response to increasing dietary linoleic acid. In isolated gill cells stimulated with A23187, 12-HEPE, 12-HETE, 14-HDHE and TXB2 were all decreased in response to increasing dietary linoleic acid, although the ratio of 12-HEPE/12-HETE was also decreased.
Article
A rainbow trout leucocyte-derived chemoattractant(s) was prepared and tested as a stimulant of leucocyte migration. It was used to optimize an in vitro leucocyte migration assay using a 48-well micro chemotaxis chamber. This assay has subsequently been used to test the chemoattractant activity of antigen extracts from the tegument of Diphyllobothrium dendriticum plerocercoids and conditioned medium obtained after in vitro maintenance of live plerocercoids. Leucocytes were found to have an increased directional motility (chemotactic response) to the host-derived chemoattractant(s) but a random increased motility (chemokinetic response) following stimulation/contact with parasite-derived antigens.
Article
Forty-nine patients with active rheumatoid arthritis completed a 24-week, prospective, double-blind, randomized study of dietary supplementation with 2 different dosages of fish oil and 1 dosage of olive oil. Clinical evaluations were performed at baseline and every 6 weeks thereafter, and immunologic variables were measured at baseline and after 24 weeks of study. The 3 groups of patients were matched for age, sex, disease severity, and use of disease-modifying antirheumatic drugs (DMARDs). Subjects continued receiving DMARDs and other background medications without change during the study. Twenty patients consumed daily dietary supplements of n3 fatty acids containing 27 mg/kg eicosapentaenoic acid (EPA) and 18 mg/kg docosahexaenoic acid (DHA) (low dose), 17 patients ingested 54 mg/kg EPA and 36 mg/kg DHA (high dose), and 12 patients ingested olive oil capsules containing 6.8 gm of oleic acid. Significant improvements from baseline in the number of tender joints were noted in the low-dose group at week 24 (P = 0.05) and in the high-dose group at week 18 (P = 0.04) and 24 (P = 0.02). Significant decreases from baseline in the number of swollen joints were noted in the low-dose group at weeks 12 (P = 0.003), 18 (P = 0.002), and 24 (P = 0.001) and in the high-dose group at weeks 12 (P = 0.0001), 18 (P = 0.008), and 24 (P = 0.02). A total of 5 of 45 clinical measures were significantly changed from baseline in the olive oil group, 8 of 45 in the low-dose fish oil group, and 21 of 45 in the high-dose fish oil group during the study (P = 0.0002). Neutrophil leukotriene B4 production decreased by 19% from baseline in the low-dose fish oil group (P = 0.0003) and 20% in the high-dose group (P = 0.03), while macrophage interleukin-1 production decreased by 38.5% in the olive oil group (P not significant), 40.6% in the low-dose group (P = 0.06), and 54.7% in the high-dose group (P = 0.0005). Tritiated thymidine incorporation in peripheral blood mononuclear cells after stimulation with concanavalin A increased significantly in all 3 groups after 24 weeks, compared with baseline values. We conclude that the clinical benefits of dietary supplementation with omega-3 fatty acids are more commonly observed in patients consuming higher dosages of fish oil for time intervals that are longer than those previously studied. Dietary supplementation with olive oil is also associated with certain changes in immune function, which require further investigation.
Article
Stimulation of whole blood from rainbow trout with the calcium ionophore, A23187 (20 microM), produced leukotrienes B4 and B5 at concentrations in the range 22-30 ng.ml-1 and 8-24 ng.ml-1, respectively. Their identification and quantification was achieved using reverse-phase high-performance liquid chromatography, combined capillary column gas chromatography-electron capture chemical ionization mass spectrometry and ultraviolet spectroscopy. A number of other lipoxygenase products were also detected, but only partially analysed. The fatty acid composition of the leucocytes, which are presumed to be the site of leukotriene synthesis, was determined by thin-layer and gas-liquid chromatography to enable a comparison of the relative levels of the polyunsaturated fatty acids, which act as substrates for the synthesis of these lipoxygenase products. Arachidonic (20:4(n - 6)), eicosapentaenoic (20:5(n - 3)) and docosahexaenoic (22:6(n - 3)) acids represented approx. 6, 5 and 40%, respectively, of the total fatty acid content.
Article
Since eicosanoids have been implicated in the pathogenesis of psoriasis, less potent eicosanoid mediators derived from fish oil might improve psoriasis. Using a double-blind, randomized, parallel design, 18 patients with stable, plaque psoriasis received capsules of either fish oil or identical-appearing placebo olive oil for 15 weeks, with concomitant sub-erythemal UVB in weeks 3 to 11. At the conclusion of phototherapy, and 4 weeks later, patients in the fish oil group had a greater decrease in the total body surface area of psoriasis and more improvement compared to patients in the olive oil group. The improvement in the fish oil group was statistically significantly greater for all parameters compared to the change in the olive oil group. The apparent safety and general health-promoting features of fish oil could provide an ideal adjunctive therapy for psoriasis.
Article
Arachidonic acid is released from membrane phospholipids upon cell stimulation (for example, by immune complexes and calcium ionophores) and converted to leukotrienes by a 5-lipoxygenase that also has leukotriene A4 synthetase activity. Leukotriene A4, an unstable epoxide, is hydrolyzed to leukotriene B4 or conjugated with glutathione to yield leukotriene C4 and its metabolites, leukotriene D4 and leukotriene E4. The leukotrienes participate in host defense reactions and pathophysiological conditions such as immediate hypersensitivity and inflammation. Recent studies also suggest a neuroendocrine role for leukotriene C4 in luteinizing hormone secretion. Lipoxins are formed by the action of 5- and 15-lipoxygenases on arachidonic acid. Lipoxin A causes contraction of guinea pig lung strips and dilation of the microvasculature. Both lipoxin A and B inhibit natural killer cell cytotoxicity. Thus, the multiple interaction of lipoxygenases generates compounds that can regulate specific cellular responses of importance in inflammation and immunity.
Article
Docosahexaenoic acid (DHA) or eicosapentaenoic acid (EPA) was facilely incorporated into phospholipids of mouse peritoneal macrophages following incubation with pure fatty acids complexed to bovine serum albumin. Following stimulation with calcium ionophore A23187, the DHA-enriched cells synthesized significantly smaller amounts of leukotriene C4 and leukotriene B4 compared to control or EPA-enriched cells. The EPA-enriched cells synthesized lower amounts of leukotriene C4 and leukotriene B4 compared to control cells. The stimulated macrophages utilized endogenously released arachidonic acid for leukotriene B4 and leukotriene C4 synthesis. Exogenous arachidonic acid increased the formation of 12-hydroxyeicosatetraenoic acid (12-HETE) and 15-HETE and macrophages enriched with DHA or EPA produced similar amounts of 12-HETE and 15-HETE compared to control cells. These studies demonstrated that the synthesis of leukotriene C4, leukotriene B4 and HETE in macrophages is differentially affected by DHA and EPA.
Article
1. Leukotriene (LT) B3 was prepared by total chemical synthesis and its identity was confirmed by nuclear magnetic resonance analysis and proton homonuclear plot of connectivities and chemical shift assignments. The effects of LTB3 on complement receptor enhancement, chemotaxis and lysozyme release in human neutrophils (PMN) were compared with those of LTB4 and LTB5. 2. LTB3 and LTB4 elicited a virtually identical dose- and time-dependent enhancement in complement receptors type 1 (CR1) and type 3 (CR3) and release of lysozyme. LTB5 was approximately 100 times less potent than LTB4 in enhancing CR1 and CR3, whereas it was 10000 times less potent than LTB4 in releasing lysozyme from human PMN. 3. LTB3 and LTB5 were respectively 5- and 100-fold less potent than LTB4 in eliciting chemotaxis. 4. These findings indicate that the pro-inflammatory potential of LTB3 and LTB4 are similar, whereas LTB5 is substantially less potent as an inflammatory mediator. 5. The finding that LTB5 is a weak and partial agonist relative to LTB3 and LTB4 could be due to the rigidity of the C-17–C-18 double bond in LTB5. This may interfere with the active site specificity of LTB5 to a substantial extent. 6. One approach to the development of antagonists to the LTB4 receptor may be to establish a rigid structure in the C-17–C-18 region of the LTB4 molecule.
Article
The effects of dietary fish-oil fatty acids on the function of the 5-lipoxygenase pathway of peripheral-blood polymorphonuclear leukocytes and monocytes were determined in seven normal subjects who supplemented their usual diet for six weeks with daily doses of triglycerides containing 3.2 g of eicosapentaenoic acid and 2.2 g of docosahexaenoic acid. The diet increased the eicosapentaenoic acid content in neutrophils and monocytes more than sevenfold, without changing the quantities of arachidonic acid and docosahexaenoic acid. When the neutrophils were activated, the release of [3H]arachidonic acid and its labeled metabolites was reduced by a mean of 37 per cent, and the maximum generation of three products of the 5-lipoxygenase pathway was reduced by more than 48 per cent. The ionophore-induced release of [3H]arachidonic acid and its labeled metabolites from monocytes in monolayers was reduced by a mean of 39 per cent, and the generation of leukotriene B4 by 58 per cent. The adherence of neutrophils to bovine endothelial-cell monolayers pretreated with leukotriene B4 was inhibited completely, and their average chemotactic response to leukotriene B4 was inhibited by 70 per cent, as compared with values determined before the diet was begun and six weeks after its discontinuation. We conclude that diets enriched with fish-oil-derived fatty acids may have antiinflammatory effects by inhibiting the 5-lipoxygenase pathway in neutrophils and monocytes and inhibiting the leukotriene B4-mediated functions of neutrophils.
Article
The incorporation of [1-14C]arachidonic acid and [1-14C]eicosapentaenoic acids into phospholipids was studied in peripheral blood neutrophils from plaice, a marine fish whose lipids are rich in (n-3) polyunsaturated fatty acids. The incorporation of both labelled fatty acids into phospholipids was approximately equal when presented individually, and at equal concentration, to the cells. Arachidonic acid was relatively preferred when both acids were present in the incubations. When incorporation was expressed per unit mass of phospholipid class, the order of incorporation was PI greater than PC greater than PE greater than PS greater than sphingomyelin for both fatty acids. However, the specificity for incorporation into PI was significantly greater with arachidonic acid. Eicosapentaenoic acid was incorporated into PC to a greater extent than arachidonic acid. The results are discussed in relation to the possible roles of arachidonic acid and eicosapentaenoic acid in polyunsaturated fatty acid metabolism in plaice neutrophils.
Article
Leukotriene B4 (LTB4) was found to induce enhanced migration of the eosinophilic G1 granulocyte of the dogfish Scyliorhinus canicula in the migration under agarose assay. Higher levels of LTB4, however, were required to produce this effect than with mammalian neutrophils under similar conditions. It is postulated that this may be due to the dogfish granulocytes possessing fewer receptors for LTB4 than their mammalian counterparts. The eosinophilic G3 granulocyte was also tested using the same assay but results were inconclusive. The effect of LTB4 on dogfish G1 and G3 granulocytes was also monitored with the bipolar shape formation (BSF) assay. LTB4 induced BSF in both granulocyte types, and this method appeared to be more sensitive than the migration under agarose assay. Whether the enhanced migration observed is a result of chemotaxis or chemokinesis is not determined. This present study represents the first known report of the function of LTB4 in a non-mammalian vertebrate.
Article
Experiments are described to define further the fatty acid requirements of rainbow trout (Salmo gairdneri). In all cases, feeding semipurified diets containing no polyunsaturated fatty acids resulted in poor growth and feed conversion. Linolenic acid was superior to linoleic in stimulating growth and improving feed conversion. The requirement of linolenic acid (ω3 fatty acids) for rainbow trout is 1% of the diet or approximately 2.7% of the dietary calories. Essential fatty acid deficiency symptoms that were cured or prevented by linolenic acid included fin erosion, heart myopathy, and a shock syndrome. It is concluded that linolenic acid has an essential role in rainbow trout similar to that assigned to linoleic acid in man and higher animals.