An extended feeding history with a stearidonic acid enriched diet from parr to smolt increases n-3 long-chain polyunsaturated fatty acids biosyntheses in white muscle and liver of atlantic salmon ( Salmo salar L.)

• Published in: Aquaculture
• Main Authors: Codabaccus, MB, Bridle, AR, Nichols, PD, Carter, CG
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier Science Bv 2011
• Subjects: Agricultural and Veterinary Sciences; Fisheries Sciences; Aquaculture; Atlantic salmon; Salmo salar
• Online Access: https://doi.org/10.1016/j.aquaculture.2011.09.014; http://ecite.utas.edu.au/74395

Vegetable oils (VO) are globally accepted alternatives for fish oil (FO) in aquafeeds. The lack of n-3 long-chain(≥C20) polyunsaturated fatty acids (n-3 LC-PUFA) in VO is a major constraint. Echium oil (EO), rich in stearidonicacid (SDA), has the potential to increase endogeneous n-3 LC-PUFA biosynthesis. We tested whetherfeeding Atlantic salmon an EO-based diet in both freshwater and seawater would increase n-3 LC-PUFA levelsby comparing the fatty acid (FA) profiles in liver and white muscle to fish fed FO and rapeseed oil (RO)-baseddiets. The gene expression of n-3 LC-PUFA biosynthetic enzymes was measured to demonstrate the underlyingmechanism of n-3 LC-PUFA biosynthesis. After prolonged feeding with EO diet from freshwater to seawaterphases, EO fish had higher n-3 LC-PUFA levels in both liver and white muscle compared to RO fish. However,FO fish had the highest n-3 LC-PUFA levels in examined tissues. Δ6 Desaturase gene expression in liver andwhite muscle was up-regulated in RO fish only, liver Δ5 desaturase gene expression was reduced in seawaterand liver FA elongase gene expression was regulated by an interaction between dietary oil and environment.This study showed that feeding Atlantic salmon from parr to smolt using an SDA enriched diet increases n-3LC-PUFA biosynthesis in liver and white muscle through increased supply of the n-3 LC-PUFA precursorSDA. The down regulation of Δ5 desaturase gene expression in the liver of seawater fish may explain environmentaldifferences in n-3 LC-PUFA biosynthesis