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The aims of this review are to describe the role of 'blue‐food production' (animals, plants and algae harvested from freshwater and marine environments) within a circular bioeconomy, discuss how such a framework can help the sustainability and resilience of aquaculture and to summarise key examples of novel nutrient sources that are emerging in the field of fed‐aquaculture species. Aquaculture now provides >50% of the global seafood supply, a share that is expected to increase to at least 60% within the next decade. Aquaculture is an important tool for reducing resource consumption in global protein production and increasing resilience to climate change and other global disruptions (i.e. pandemics, geo‐political instability). Importantly, blue foods also provide essential nutrition for a growing human population. Blue foods are helping to help the global goal of 'zero hunger' (United Nation's Sustainable Development Goal 2) while reducing the dependency on finite natural resources but further refinement and new solutions are needed to make the industry more 'circular' and sustainable, particularly with respect to sourcing raw materials for aquafeeds. This review describes the feed resources that are available or may be created within a circular bioeconomy framework, their role within the framework and in aquaculture and ultimately, how these resources contribute to de‐risking and establishing a resilient aquaculture production chain. [ABSTRACT FROM AUTHOR]

Nile tilapia (Oreochromis niloticus) offers an affordable food source to many low‐income consumers. However, farmed tilapia has drawn much criticism over the low omega‐3 (n‐3) and high omega‐6 (n‐6) lipid levels. Subsequently, it has been questioned whether it is truly healthy food. This study fed tilapia with a specialized "finishing" diet with the inclusion of commercial Thraustochytrids protist biomass and oil before the harvestable fish size. The fish are fed with two different dietary regimes over 6 weeks. One is a commercially available tilapia feed used as a reference. The second diet is composed of an exclusive oil source from Thraustochytrids protist (HI‐n3). The results show that HI‐ n3 has significantly increased the fillet n‐3 content by 400% in comparison to commercial diet (COM) after Week 6 of feeding. Specifically, docosahexaenoic acid (DHA, n‐3) content is the attributing fatty acid for the n‐3 increase. This is particularly evident when DHA is expressed as a percentage of total lipid content. The n‐3:n‐6 ratio increased in tilapia fed with the HI‐n3 diet attributed to the DHA accumulation. The investigation shows that it is possible to favorably "lipid tailor" tilapia before harvest. Practical applications: The practical application of this technique is to enrich farmed tilapia with a high dietary omega‐3 (n‐3) Thraustochytrids protist oil source for a short‐term period before harvesting. It is an objective that the fillet product would be more functional in its nutritional content by supplying more than just high‐quality protein for consumers. This would have paramount implications for low‐income consumers, where high n‐3 oil foods are not readily available or affordable (e.g., landlocked nations). Furthermore, tilapia is widely consumed in China and Southeast Asian countries but is also promoted as a high nutritional value food source in the western hemisphere. This investigation advocates the ability to change the image of this fish species by a simple dietary manipulation. In an era of elevated intake of omega 6 (n‐6) fatty acids food sources, n‐3 rich fish is a vital balance to counter this negative trend in human health. [ABSTRACT FROM AUTHOR]

Background. Stable isotope analysis of single amino acids (AA) is usually applied in food web studies for tracing biosynthetic origins of AA carbon backbones and establishing trophic positions of consumers, but the method is also showing promise for characterizing quantity and quality of dietary lipids and carbohydrates. Methods. To investigate whether changes in high- and low-digestible carbohydrates affect "13C values of glycolytic AA, i.e., AA carbon backbones sourced from the glycolytic pathway, we compared Atlantic salmon (Salmo salar) from a feeding experiment with and without dietary inclusion of the red macroalga Palmaria palmata. The Control and experimental diets had similar relative proportions of macronutrients, but their ingredients differed; in the experimental treatment, 15% Palmaria inclusion substituted proteins from fishmeal and carbohydrates from corn starch. Results. We found that 13C values of the glycolytic AA were highly sensitive to substitution of corn starch with Palmaria. The "13C offsets of glycolytic AA between salmon and their diets were significantly greater in the Palmaria inclusion than Control treatment. This greater offset can be attributed to the different utilization of high- vs. low-digestible carbohydrate sources, i.e., corn starch vs. Palmaria, in the two treatments, and metabolic routing of dietary lipids. In addition, similar "13C values of essential AA between treatments indicate similar nutrient assimilation efficiency for all terrestrial (pea protein concentrate and wheat gluten meal) and marine (fishmeal and red alga) derived protein sources. These results show that "13CAA analysis is a promising tool for improving our understanding of how carnivorous fish utilize macronutrient and route metabolic intermediates to tissue. [ABSTRACT FROM AUTHOR]

Supplementation of salmon (Salmo salar) diets withUlva rigida(UR; 0, 5, 10, and 15% UR) or synthetic astaxanthin (positive control, PC) for 19-weeks preslaughter on quality indices of fresh (raw) salmon fillets was examined. Susceptibility of salmon fillets/homogenates to oxidative stress conditions (cooking/iron-ascorbate induced oxidation) was also measured. In salmon fillets stored in modified atmosphere packs (MAP; 60% N2:40% CO2) for up to 15 days at 4ºC,U. rigidaincreased surface “−a*” greenness and “b*” yellowness values in a dose-dependent manner resulting in a final yellow/orange flesh color. Proximate composition, pH, and lipid oxidation (fresh, cooked, and fillet homogenates) were unaffected by dietary addition ofU. rigida. On Day 12, 5% UR psychrotrophic bacterial growth was lower than controls. Salmon fed 5% UR did not influence “eating quality” sensory descriptors (texture, odor, oxidation flavor, and overall acceptability) in cooked salmon fillets compared to 0% UR. Higher levels of dietaryU. rigida(10 and 15% UR) were negatively correlated with color and overall acceptability descriptors. Results indicated that dietaryU. rigida, at a level of 5%, may prove to be a functional ingredient in salmon feed to enhance salmon fillet quality. [ABSTRACT FROM PUBLISHER]

Bacteria fromthe Vibriogenus are autochthonous to aquatic environments and ubiquitous in aquaculture production systems. Many Vibrio species are non-pathogenic and can be commonly found in healthy farmed aquatic animals. However, some Vibrio species and strains are pathogenic leading to a variety of 'vibriosis' diseases. These diseases can have a significant negative impact on animal production, including farmed crustaceans such as shrimps, lobsters, and crabs. As such, vibriosis can pose a threat to meeting growing food demand and global food security. Preventive management is essential to avoid the onset of vibriosis. This includes a robust health management plan, the use of prophylaxis and treatment measures, and enhancing animal health through nutrition. Furthermore, the use of probiotics, prebiotics, synbiotics, quorum sensing disruption, green water, biofloc, bacteriophages, and immune priming could also play a role in preventing and controlling a vibriosis outbreak. This review aims to inform and update the reader about the current state of knowledge about Vibrio and associated vibriosis in farmed crustaceans (i.e. shrimp, lobster, and crabs). Furthermore, the review will identify potential knowledge gaps in the literature, which serves as a basis for future research priorities., (Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Stable isotope analysis of single amino acids (AA) is usually applied in food web studies for tracing biosynthetic origins of AA carbon backbones and establishing trophic positions of consumers, but the method is also showing promise for characterizing quantity and quality of dietary lipids and carbohydrates., Methods: To investigate whether changes in high- and low-digestible carbohydrates affect δ 13 C values of glycolytic AA, i.e., AA carbon backbones sourced from the glycolytic pathway, we compared Atlantic salmon ( Salmo salar ) from a feeding experiment with and without dietary inclusion of the red macroalga Palmaria palmata . The Control and experimental diets had similar relative proportions of macronutrients, but their ingredients differed; in the experimental treatment, 15% Palmaria inclusion substituted proteins from fishmeal and carbohydrates from corn starch., Results: We found that 13 C values of the glycolytic AA were highly sensitive to substitution of corn starch with Palmaria . The δ 13 C offsets of glycolytic AA between salmon and their diets were significantly greater in the Palmaria inclusion than Control treatment. This greater offset can be attributed to the different utilization of high- vs. low-digestible carbohydrate sources, i.e., corn starch vs. Palmaria , in the two treatments, and metabolic routing of dietary lipids. In addition, similar δ 13 C values of essential AA between treatments indicate similar nutrient assimilation efficiency for all terrestrial (pea protein concentrate and wheat gluten meal) and marine (fishmeal and red alga) derived protein sources. These results show that δ 13 C AA analysis is a promising tool for improving our understanding of how carnivorous fish utilize macronutrient and route metabolic intermediates to tissue., Competing Interests: The authors declare there are no competing interests., (©2019 Wang et al.)

The rapid expansion of the aquaculture industry with carnivorous fish such as salmon has been accompanied by an equally rapid development in alternative feed ingredients. This has outpaced the ability of prevailing authentication method to trace the diet and origins of salmon products at the retail end. To close this gap, we developed a new profiling tool based on amino acid δ 13 C fingerprints. With this tool, we discriminated with high-accuracy among wild-caught, organically, and conventionally farmed salmon groups, as well as salmon fed alternative diets such as insects and macroalgae. Substitution of fishmeal with macroalgae was detected at 5% difference level. The δ 13 C fingerprints of essential amino acids appear particularly well suited for tracing protein sources, and the non-essentials for tracing lipid origins (terrestrial vs. aquatic). In an industry constantly developing new feed proteins and functional additives, our method is a promising tool for tracing salmon and other seafood products., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background: The use of Palmaria palmata (PP) as a natural ingredient in farmed Atlantic salmon diets was investigated. The effect of salmon diet supplementation with P. palmata (0, 5, 10 and 15%) or synthetic astaxanthin (positive control, PC) for 16 weeks pre-slaughter on quality indices of fresh salmon fillets was examined. The susceptibility of salmon fillets/homogenates to oxidative stress conditions was also measured., Results: In salmon fillets stored in modified atmosphere packs (60% N2 /40% CO2 ) for up to 15 days at 4 °C, P. palmata increased surface -a* (greenness) and b* (yellowness) values in a dose-dependent manner, resulting in a final yellow/orange flesh colour. In general, the dietary addition of P. palmata had no effect on pH, lipid oxidation (fresh, cooked and fillet homogenates) and microbiological status. 'Eating quality' sensory descriptors (texture, odour and oxidation flavour) in cooked salmon fillets were not influenced by dietary P. palmata. Salmon fed 5% PP showed increased overall acceptability compared with those fed PC and 0% PP., Conclusion: Dietary P. palmata was ineffective at providing red coloration in salmon fillets, but pigment deposition enhanced fillets with a yellow/orange colour. Carotenoids from P. palmata may prove to be a natural pigment alternative to canthaxanthin in salmon feeds., (© 2014 Society of Chemical Industry.)