Effect of feeding Atlantic salmon ( Salmo salar L.) a diet enriched with stearidonic acid from parr to smolt on growth and n -3 long-chain PUFA biosynthesis

• Published in: British Journal of Nutrition
• Main Authors: Codabaccus, MB, Bridle, AR, Nichols, PD, Carter, CG
• Format: Article in Journal/Newspaper
• Language: English
• Published: C A B I Publishing 2011
• Subjects: Agricultural and Veterinary Sciences; Fisheries Sciences; Aquaculture; Eta; Atlantic salmon; Salmo salar
• Online Access: https://doi.org/10.1017/S0007114510005714; http://ecite.utas.edu.au/72062

Vegetable oils (VO) have become the predominant substitute for fish oil (FO) in aquafeeds; however, the resultant lower content of n -3long-chain (≥C20) PUFA ( n -3 LC-PUFA) in fish has put their use under scrutiny. The need to investigate new oil sources exists. The presentstudy tested the hypothesis that in Atlantic salmon (Salmo salar L.), a high intake of stearidonic acid (SDA) from Echium oil (EO) wouldresult in increased n -3 LC-PUFA biosynthesis due to a lower requirement for Δ6 desaturase. Comparisons were made with fish fed on dietscontaining rapeseed oil (RO) and FO in freshwater for 112 d followed by 96 d in seawater. EO fish had higher whole-carcass SDA andeicosatetraenoic acid (ETA) in freshwater and prolonged feeding on the EO diet in seawater resulted in higher SDA, ETA, EPA anddocosapentaenoic acid (DPA) compared with RO fish. Fatty acid mass balance of freshwater fish indicated higher biosynthesis of ETAand EPA in EO fish compared with fish fed on the other diets and a twofold increase in n -3 LC-PUFA synthesis compared with ROfish. In seawater, n -3 biosynthetic activity was low, with higher biosynthesis of ETA in EO fish and appearance of all desaturated andelongated products along the n -3 pathway. SDA-enriched VO are more suitable substitutes than conventional VO from a human consumerperspective due to the resulting higher SDA content, higher total n -3 and improved n -3: n -6 ratio obtained in fish, although both VO werenot as effective as FO in maintaining EPA and DHA content in Atlantic salmon.