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Algae for Aquaculture and Animal Feeds

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This article reviews the current state-of-the-art for algae use in aquaculture, plus recent developments in algal biomass as a micro- or bulk ingredient in formulated animal feeds (terrestrial livestock and aquaculture species). Microalgae provide an important direct or indirect feed source for early developmental stages of many farmed finfish, shellfish and invertebrate species. Hatcheries typically cultivate microalgae in-house, with commercial concentrates now also being used widely. Different strains of micro- and macroalgae vary in their efficacy within formulated animal feeds, although there is sufficient evidence of good nutritional properties to promote algal biomass as a source of micronutrients or as a bulk feedstuff. High costs of algal biomass compared to commodity feedstuffs currently confine their commercial use to niche animal feed applications; greater availability/lower price, via biofuels and biorefinery would enable more widespread use in future
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... On the other hand, algae production is widely maintained and regulated independently of aquaculture globally [1, 25,47]. In the world of aquaculture, several studies have been published acknowledging that microalgae are considered the "super food" for all aquatic animals [48]. In this context, the nutritional profiles (protein, lipid, and carbohydrate) of algae (microalgae and seaweed) in comparison with most commercially available aquafeed components are presented in Table 1. ...
... In this technology, microalgae, microbes, and zooplankton were abundant in rearing ponds where fish larvae were kept. This technology can be based on natural microalgal populations that are stimulated to flourish with the addition of fertilizer, or cultured microalgae strains can be inoculated to culture tanks if the system water has been pre-treated to exclude competing bacteria [48]. ...
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The aquaculture industry has rapidly increased in response to the increasing world population, with the appreciation that aquaculture products are beneficial for human health and nutrition. Globally, aquaculture organisms are mainly divided into two divisions, aquatic animals (finfish, crustaceans, and molluscs) and aquatic plants (microalgae and seaweed). Worldwide aquaculture production has reached more than 82 million tonnes (MTs) in 2018 with more than 450 cultured species. The development of economical, environmentally friendly, and large-scale feasible technologies to produce aquaculture organisms (even aquatic animals and/or aquatic plants) is an essential need of the world. Some aquaculture technologies are related to aquatic animals or aquatic plants, as well as some technologies have an integrated system. This integration between aquatic plants and aquatic animals could be performed during early larvae rearing, on-growing and/or mass production. In the context of the blue revolution, the current review focuses on the generations of integration between aquatic plants and aquatic animals, such as live feeds, biomass concentrates, water conditioners “green water technique”, aqua-feed additives, co-culturing technologies, and integrated multi-trophic aquaculture (IMTA). This review could shed light on the benefit of aquatic animals and plant integration, which could lead future low-cost, highly efficient, and sustainable aquaculture industry projects.
... Croaker, Pompano, Siganids, Barramundi Table 4. some groups of microalgae along with their use in aquaculture (Shields and Lupatsch, 2012;Khanjani et al., 2019) Application in aquaculture Microalgae ...
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Today, increase of world’s population and climate change has resulted in the reduction of fresh water resources and the increase of arid and semi-arid areas, and thus, it is necessary to find a new solution to increase the production of food resources. Aquaculture is one of the sources of food production, which can play a key role in fighting poverty and hunger. Sustainable aquaculture is strongly dependents on water quantity and quality, and also, optimal fish production can be determined by the physical, chemical and biological quality of water. Due to the current restrictions and the global increase in demand for aquatic products, unconventional waters (UWs) have been used in aquaculture. UWs include: recycled water, sewage, saline water, agricultural drains and water resulting from the process of sweetening and desalination of salty water. Today, these water resources have been used to grow all kinds of aquatic animals to provide food and protein. Considering the limited water resources in the world, the use of UWs is very effective and efficient in managing drought, and is considered as one of the ways to develop food production for humans. Due to its importance in areas facing water scarcity, the use of UWRs to supplement or replace the use of conventional fresh water sources has been considered. In this review study, the importance of UWs and their sources, aquaculture products and aquatics that can be cultivated with the help of UWs are discussed.
... have moderate protein and high polyphenols contents and a structural polysaccharides level of up to 70 % [8]. This high structural polysaccharides content may hamper its potential as an ingredient for fish feeds [21]. Ulva spp. ...
Article
Macroalgae are promising ingredients for aquafeeds, but their recalcitrant polysaccharide structure limits their wide use. To disrupt this structure, different physical (ultra-sounds, autoclave, microwaves), chemical (acid, alkaline), and biotechnological (solid-state fermentation, SSF; SSF followed by sequential hydrolysis, SSF-SH) treatments were carried out in Ulva rigida. The chemical composition, morphological microstructure, release of reducing sugars, soluble protein, and phenolic compounds were evaluated in the final products. All treatments increased U. rigida protein content, while lipid content increased after autoclave, ultra-sound, microwave, and SSF treatments. SSF-SH treatment was more effective in disrupting the cellulose and hemicellulose fractions, resulting in a higher reducing sugars release. The alkaline treatment was more efficient in reducing lignin content and increasing phenolic compounds, antioxidant activity, and soluble protein of U. rigida. The most promising products were then included at 5 % in diets for European seabass (Dicentrarchus labrax) juveniles. Crude, ultra-sound, alkaline, and SSF-SH-treated U. rigida reduced fish growth, while SSF-treated U. rigida resulted in similar growth as the positive control (fish meal-based diet). Feed intake was reduced in all experimental groups, but the feed efficiency of fish fed SSF-U. rigida diet and the protein efficiency ratio of fish fed crude, alkaline, and SSF-treated U. rigida were higher than the positive control. The highest total alkaline proteases activity was achieved with the crude U. rigida diet, while no differences were observed in fish fed the positive control, ultra-sound, and SSF diets. Overall, of the processing methods tested, the most efficient was SSF, which improved feed efficiency of European seabass juveniles fed U. rigida-including diet without affecting growth performance.
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Studies have shown that ancient cultures used microalgae as food for centuries. Currently, scientific reports highlight the value of nutritional composition of microalgae and their ability to accumulate polyunsaturated fatty acids at certain operational conditions. These characteristics are gaining increasing interest for the aquaculture industry which is searching for cost-effective replacements for fish meal and oil because these commodities are one of the most significant operational expenses and their dependency has become a bottleneck for their sustainable development of the aquaculture industry. This review is aimed at highlighting the use of microalgae as polyunsaturated fatty acid source in aquaculture feed formulations, despite their scarce production at industrial scale. Moreover, this document includes several approaches to improve microalgae production and to increase the content of polyunsaturated fatty acids with emphasis in the accumulation of DHA, EPA, and ARA. Furthermore, the document compiles several studies which prove microalgae-based aquafeeds for marine and freshwater species. Finally, the study explores the aspects that intervene in production kinetics and improvement strategies with possibilities for upscaling and facing main challenges of using microalgae in the commercial production of aquafeeds.
Chapter
Heading to the mid-twenty-first century, one of the greatest challenges will be to supply the approximately 9.7 billion human population in 2050 with high-quality food (Hua et al. 2019). Based on information in 2018, approximately 88% of fishery products were consumed by humans and this statistic tends to increase from year to year (FAO 2020). Fishery production is a main global food source that is related to the aquafeed market, both of which are experiencing continued growth (Shah et al. 2018). Fish meal is an essentially digestible feed ingredient that is used by aquatic farms because of its high content of proteins, lipids, minerals, vitamins, and small amounts of carbohydrates. Approximately 30 million tonnes of wild fish have been caught for producing fish meal (Olsen and Hasan 2012). The requirements and the restrictions related to obtaining wild-caught fish have created market uncertainty for producing fish meal, with prices increasing by nearly 300% in the last 10 years (Shah et al. 2018). Utilization of fish feeds for aquaculture is estimated to trend upward through 2025 while prospects of procuring wild-caught fish may be limited. Meanwhile, the prices of fish meal have been continuously rising (Tacon and Metian 2015). Therefore, in this chapter, we brief what is known about the various alternative protein feed sources together with antibiotic replacement and growth promoters which can potentially be used in order to approach aquatic sustainability.
Article
Background Algae are aquatic organisms rich in several biocompounds, and major ones are proteins and amino acids, carbohydrates and polysaccharides, lipids and fatty acids, pigments like chlorophyll, carotenoid, and phycocyanin, vitamins, minerals, and polyphenols that exhibit multiple beneficial effects on human health. These compounds are present in high concentrations in raw algal biomass, but some of them may not be available to exert their biological function in the human body, due to the inherent composition of algae cell wall. Scope and approach This review provides an overview of existing information of ongoing studies on the digestibility and bioavailability of algae derived compounds, while giving a glimpse of the studies that examine in vivo digestibility and bioaccessibility of microalgal biomass as feed supplementation for animals. Special attention is also given to the influence of cell wall disruption techniques on the bioaccessibility of algal bioactive compounds, showcasing carefully the in vitro bioaccessible nutrients of foods enriched with algal biomass. Key findings and conclusions Digestibility and bioaccessibility of major compounds varied greatly between algal species. Polysaccharides and fibers are undigestible by humans, binding carbohydrates assimilation. Combined disruption methods like bead milling or high pressure homogenization with enzymatic pretreatment, using cellulases prior to algal compound extraction, may help to increase the extractability and bioavailability of lipid and fatty acids, pigments and minerals, as well as enhancing even further protein and amino acid absorptions. Studies on in vivo dietary supplementation of algae in animals (sheep, chicken, mice, and fishes) showed good acceptability and digestibility of proteins and lipids. Traditional foods such as cookies, snack, bread, and yogurt enriched with maximum 5% of algal biomass allowed to carry on natural bioactive compounds of algae, extending the bioaccessibility and enlightening the positive impact of consuming algae-based food for human health promotion.
Chapter
Algae are heralded as a magnificent and potential source of biofuels, bioplastics, pigments, biofertilizers, as well as specific extravagant metabolites such as vitamins, therapeutic agents, animal feed, and nutraceuticals. Different bioprocessing techniques have been discovered with time to achieve integrated algal biorefinery. Howbeit more such bioprocessing models and different biorefinery routes need to be investigated. The concept of enlightening the value of product sustainability by practicing resource, recovery and recycling defines the circular bioeconomy. It has been perceived that the economical and environmental value of the biorefinery approach equally proves to be of utmost importance for the circular bioeconomy. While considering the algal biomass for the manufacturing of different products simultaneously, efforts need to be focused upon the circularity of the process involved starting from the source to its recovery and reuse, which eventually comprises of utilizing the waste drawn from the whole process for cherishing biorefinery in an economically friendly way. This chapter's objective defines to convey the recent know-how of the algal biorefinery by elaborating the eminence of biopolymers in accomplishing the same. Subsequently, various high-valued products derived from the refinery have been discussed and light has been shed on different bioprocessing systematic techniques used broadly in nexus with the algal biorefinery to acknowledge the felicitous aspects of circular bioeconomy.
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Aquafeed accounts for at least 75–90% of aquaculture’s operating costs. Traditional aquafeed ingredients such as fishmeal, fish oil, and soybean meal are unsustainable; further, their increasing cost necessities developing alternative feed ingredients. Microalgae-based aquafeed is not only environmentally friendly, but it can also be cost-effective with proper optimization. In addition, the nutrition profile of microalgae is similar to that of many fishes. The digestibility of a feed is one of the most important factors to consider in feed formulation. A highly digestible feed can lower production costs, reduce feed waste, and reduce the risk of eutrophication. This review discusses the digestibility of various nutrients such as protein, lipid, carbohydrate, amino acids, and fatty acids (including omega-3 fatty acids), dry matter, and energy of various microalgae in fish. Other commonly used aquafeed ingredients were also compared to microalgae in terms of nutrient and energy digestibility in fish. The intrinsic characteristics of microalgae, biomass pretreatment, and feed preparation methods are all discussed as factors that contribute to the nutrient and energy digestibility of microalgae in fish. Furthermore, methods for increasing the digestibility of microalgal biomass in fish are suggested. Finally, the review concludes with the challenges and prospects of using microalgae as a fish feed in terms of digestibility.
Article
The IPCC Special Report on Global Warming of 1.5 °C highlights the potential for dietary shifts to reduce greenhouse gas emissions from livestock. Reductions in the consumption of terrestrial animal protein require increases in the consumption of other food categories, to maintain food security, balanced dietary patterns, and protein intake. Aquaculture has long been suggested as one way to meet future food security needs, and marine and estuarine aquaculture in particular is associated with comparatively low greenhouse gas emissions. However, marine and freshwater aquaculture is affected by factors including harmful algal blooms (HABs), which have been increasingly documented around the world, correlated to increases in worldwide aquaculture. In this study, we applied a global multi-region input-output model to capture the direct effects as well as the indirect and induced effects HABs might pose to a global dietary transition from terrestrial livestock to increased seafood consumption from marine and estuarine aquaculture sources. We found that marine and estuarine aquaculture has a substantial potential to replace meat consumption from terrestrial livestock sources, as increases in CO2 emissions from aquaculture were more than offset by reductions in emissions from mainly cattle grazing and associated land clearing. HABs were found to have a minor monetary impact, but the impact on protein supply was found to be potentially sizeable. For example, in a future setting where 40% of terrestrial protein sources were replaced by aquaculture, a HAB-caused global loss of 5% would set in motion numerous supply-chain cascades, affecting industries auxiliary to aquaculture, indirectly and ultimately reducing protein intake by 10–20%. Such reductions have the potential for pushing parts of Sub-Saharan populations into protein-energy malnutrition. Nevertheless, there remains a significant potential for a dietary transition to increased aquaculture seafood to contribute to reductions in GHG.
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Microalgae have been found to have high prospects in wastewater treatment, particularly from agriculture. However, the uneconomical algal medium growth has become the major disadvantaged in algal industry. Multiple attempts includes the development of microalgae phycoremediation technology has been integrated into wastewater treatment to reduce the cost of expensive wastewater remediation. Utilising wastewater as a low-cost nutrient medium offers a synergistic effect of wastewater nutrient removal and co-production of valuable biomass simultaneously. This paper is mainly focused on potential, ability, strategy, application (i.e., palm oil wastewater), limitation and challenges of microalgae in agricultural wastewater treatment using phycoremediation. The understanding of cultivating microalgae using agriculture wastewater shall promote the utilisation of wastewater more sustainably in the future. The possible solutions in the application of microalgae for aquaculture and agriculture sector is also discussed in this review. Overall, the utilisation of wastewater in media cultivation for microalgae is restricted due to the expensive treatment and safety concern. However, this pitfall can be reduced in the future together with a further intensive scientific study, advanced technology, better management system and applying better standard protocol.
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Microalgae have high nutritional value and are used to feed adult and larval stages of bivalves, the larvae of some fish and crustaceans and zooplankton. However, microalgae production for aquaculture animal is very expensive. To overcome this, the use of preserved microalgae such as algae concentrate and dried algae, or algal substitutes has been developed. There are both advantages and disadvantages to this alternative food. For example, even though the cost production for algal substitute yeast-based diet is cheaper, their nutritional value is much lower compared to fresh microalgae. Moreover, there is no significant difference in nutritional value between preserved (concentrated or dried) and fresh microalgae; however, preserving microalgae for long periods will affect their nutritional value. In spite of this problem, preserved microalgae such as algal concentrate and dried algae seem to be more effective to feed bivalves than algal substitutes yeast based diet due to their availability and relatively high nutritional value. Furthermore, algae concentrates are more suitable to replace fresh algae than dried algae.
Chapter
The state of the art of microalgae biotechnology, particularly focusing on new culture techniques and actual and potential uses of microalgae in human and animal nutrition, in cosmetics and pharmaceutics, and for environmental applications, is described. Some examples of the world's largest commercial plants in the field are presented. For the future, it is possible to foresee a huge increase in the demand for cultured algae, in terms of both quantity and diversity. For example, aquaculture will require new animal species and, consequently, new microalgae to fulfil their nutritional needs will be necessary. The production of algae for high-value markets (aquaculture, food supplements, nutraceuticals, pharmaceuticals) will be developed through the search for, isolation and cultivation of new algal strains endowed with the activity of interest. Algal biomass might become an important source of biofuels, especially if its production will be carried out in low-cost photobioreactors and associated with wastewater treatment and greenhouse gas abatement.
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The present work aimed at studying the growth performance and feeding preference of Litopenaeus vannamei juveniles fed on diets supplemented or not with Spirulina meal. Litopenaeus vannamei juveniles (3.89 ± 0.25 g) were stocked for 72 days in 28 round 500‐L tanks at 44 shrimp/tank (77 juveniles/m2). The diets were supplemented with 0.5% of a commercial feed attractant (C25 and C50) or with Spirulina meal (S25 and S50). In C25/S25 and C50/S50 there were reductions of 25% and 50% in fishmeal inclusion level respectively. In a further study, two feeding trays with different diets were allowed to shrimp at the same moment and they were located in opposite walls of the tank. The feed remains in each feeding tray were collected and weighted to calculate the dry feed remains. The weekly growth rate of shrimp fed on S25 (0.89 ± 0.03 g) was not significantly different from those fed on C25 (0.89 ± 0.01 g). The attractiveness experiment showed that S25 was preferred significantly more by shrimp than C25. In conclusion, Spirulina meal added at 0.5% in a complete diet for L. vannamei juveniles, with 14% of Peruvian fishmeal, has proved itself as a nutritionally efficient feeding attractant.
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One of the major factors influencing marketability of sea urchins is their gonad colour. The effects of a prepared diet, algal diets, and rotational feeding of these diet treatments on the European sea urchin Paracentrotus lividus were studied to determine a diet that would provide optimal gonad colour and gonadal somatic index (GSI). P. lividus underwent six diet treatments: Ulva lactuca and Gracilaria conferta for 12 weeks (UG-12); prepared diet for 10 weeks followed by administration of Ulva and Gracilaria for 2 weeks (P-10); prepared diet for 8 weeks followed by Ulva and Gracilaria for 4 weeks (P-8); prepared diet for 6 weeks followed by Ulva and Gracilaria for 6 weeks (P-6); prepared diet for 12 weeks (P-12); and Ulva, Gracilaria and prepared diet for 12 weeks (UGP-12). The algae diet produced a dark orange colour but a low GSI. The pellet diet produced a good GSI but pale gonad colour. P. lividus fed the prepared diet for 8 weeks followed by 4 weeks of algal diet produced the optimal combination of desired gonad colour and GSI. The dominant carotenoid in the gonads was echinenone, which the sea urchin synthesises from h-carotene. The higher the echinenone level in the gonads, the more intense their colouration. The lack of echinenone found in the gut and its high accumulation in the gonad, in inverse proportion to the h-carotene profile, indicates bioconversion within the gonad or upon transfer from the gut to the gonad. D 2005 Elsevier B.V. All rights reserved.
Article
Dietary enrichments with the arachidonic acid (ARA)‐rich microalga, Parietochloris incisa, on the survival of guppy (Poecilia reticulata) fry were examined. Diets were applied via Artemia enrichment to fish from two commercial farms for 34 and 36 days of experimental period (trials 1 and 2, respectively). In trial 1, Artemia nauplii were enriched with dry biomass of whole algal cells at 0 (control), 0.1, 0.2 and 0.4 mg mL−1. Fry fed with Artemia enriched with 0.4 mg mL−1 demonstrated the lowest mortality rates (24% and 1% in farms 1 and 2, respectively) compared with controls (36% and 13% in farms 1 and 2, respectively). In trial 2, fry were fed with Artemia, enriched with whole algal cells (0.4 mg ml−1), algal hexane extract (HE; containing primarily ARA‐rich triacylglycerols and β‐carotene; 0.19 mg ml−1) or the extraction residue (0.28 mg ml−1). Acute stress (5 min air exposure) was applied after 18 days. The lowest mortality was recorded in the whole alga‐fed group (av. 26% and 2.6% in farms 1 and 2, respectively), with a slightly, but not significantly higher mortality in the HE‐fed group (av. 29% and 6.2% in farms 1 and 2, respectively). Elevated lysozyme was associated with the reduced mortality. Overall, the use of P. incisa as a dietary supplement for guppy fry during their first month of life enhanced their survival and stress resistance.
Article
Abstract The present study investigates the effects of dietary carotenoid sources on the coloration of the red porgy, Pagrus pagrus. Red porgies (131.9 ± 16.2 g; mean ± SD) were fed for 12 weeks on five different diets supplemented with red carotenoids (mainly astaxanthin esters) supplied from Haematococcus pluvialis algae and yellow carotenoids (mainly β-carotene, lutein, and zeaxanthin) supplied from Alfalfa, Medicago sativa L. and Spirulina, Spirulina pacifica. The carotenoid-supplemented diets did not have any marked effect on the growth rate, the feed conversion ratio, the daily feeding rate, or the hepatosomatic index of red porgy. The biochemical indices measured in plasma including cholesterol, total proteins, glucose, lactate, phospholipids, non-esterified fatty acids, triglycerides, and thyroid hormones did not differ significantly among groups. Diet did not affect significantly the melanophore-area coverage, the melanin skin concentration and skin lightness. Carotenoid-supplemented diets affected significantly the carotenoid deposition in the skin, the presence and distribution of erythorphores and xanthophores, and skin hue and chroma. Overall, data have shown the efficacy of Haematococcus algae in promoting a reddish coloration in red porgy.
Article
Microalgae are used in mariculture as live feeds for all growth stages of molluscs, for the larval stages of crustaceans and some fish species, and for Zooplankton used in mariculture food chains. In order to be nutritionally sufficient, microalgae must supply a balanced mixture of nutrients. We have studied the biochemical composition of about 40 species of microalgae from seven algal classes to define those that may be best adapted to the Australian conditions.Microalgae varied in their proportions of protein (6–52%), carbohydrate (5–23%) and lipid (7–23%). All species had similar amino acid composition, and were rich in the essential amino acids. Microalgal polysaccharides were variable in sugar composition, but most had high proportions of glucose (21–87%). Diatoms, prymnesiophytes, cryptomonads and eustigmatophytes were rich in one or both of the 20:5(n-3) and 22:6(n-3) polyunsaturated fatty acids important for marine fish larvae (5–35% total fatty acids), prasinophytes had low to moderate levels of one of the acids (4–10%) whereas chlorophytes were deficient in both acids (0–3%). All species had relatively high concentrations of ascorbic acid (1–16 mg g−1 dry weight) and riboflavin (20–40 μg g−1).The likely nutritional values of the microalgae, based on their biochemical composition, are discussed.