Towards the optimization of performance of Atlantic salmon reared at different water temperatures via the manipulation of dietary ARA/EPA ratio

• Main Authors: F Norambuena, A Rombenso, GM Turchini
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2016
• Subjects: Fisheries sciences not elsewhere classified; Zoology not elsewhere classified; 070401 Aquaculture; 830102 Aquaculture Fin Fish (excl. Tuna); School of Life and Environmental Sciences; Centre for Chemistry and Biotechnology; Faculty of Science Engineering and Built Environment; 3005 Fisheries sciences; Atlantic salmon; Salmo salar
• Online Access: http://hdl.handle.net/10536/DRO/DU:30074859; https://figshare.com/articles/journal_contribution/Towards_the_optimization_of_performance_of_Atlantic_salmon_reared_at_different_water_temperatures_via_the_manipulation_of_dietary_ARA_EPA_ratio/20902414

In recent years, aquaculture has been facing a series of new issues, including the necessary replacement of fish oil and fish meal because of their limited supply and sub-optimal water temperature conditions. Higher water temperatures are increasingly encountered as the result of climate change related phenomena and/or the practice of farming of species in areas with environmental characteristics outside their optimal physiological range, such as the case of Atlantic salmon (. Salmo salar) farming in Australia during the summer season. Previous studies in teleost fish have shown that when fish are exposed at higher environmental temperatures, fish had a preferential increased dietary intake for arachidonic acid (20:4n - 6, ARA). This observation suggests that, given the several metabolic roles of ARA, its dietary provision may play an important role in fish for adapting at sub-optimal high water temperatures. The objective of this study was therefore to evaluate the effects of different dietary ARA/EPA ratios in juvenile Atlantic salmon as affected by time of exposition to the diet and water temperatures, with particular focus to fish performance and possible resulting modifications of tissue fatty acid composition. The study showed that independently from dietary treatments, fish held at the higher temperatures had an increased ARA accumulation, primarily in the liver and this ARA accumulation increased over time. It was also shown that the combined dietary inclusion of ARA and EPA significantly improved fish performance, compared with diets either richer in ARA or EPA. A general trend toward higher content of n - 3 LC-PUFA at lower temperatures was also quite clear, especially in the liver. Therefore, and assuming that the trends in tissue fatty acid composition could be taken as a clue of the optimal fatty acid requirements of fish, the n - 6 requirement (and in particular ARA) clearly appears to be greater for Atlantic salmon raised at high water temperatures. Protein accumulation was higher in the diet with ...