Tailoring of a cardioprotective muscle fatty acid composition of Atlantic salmon (Salmo salar) fed vegetable oils

A feeding experiment was performed to investigate the possibility of feeding vegetable oils to Atlantic salmon, followed by a wash-out period to maintain salmon fillet as a product highly beneficial for human health, due to the high levels of VLCn−3 PUFA and high n−3/n−6 ratio. Six groups of Atlantic salmon, initial weight 142 ± 1 g, were fed increasing dietary inclusion of rapeseed oil (RO) in a regression design and one group was fed a 50% olive oil (OO)/50% capelin oil (FO) diet for 42 weeks, followed by 25 weeks, of wash-out, when all groups were fed 100% FO. Muscle gross composition, lipid class and fatty acid composition and astaxanthin were measured at the start and after 22 and 42 weeks of feeding. Fillet fatty acid composition was analysed at the start and throughout the wash-out period of 25 weeks and 1788 day degrees. Growth, total lipid, astaxanthin content, and lipid class composition were not affected by dietary oil source. Muscle and fillet fatty acid composition were highly affected by dietary fatty acid composition. Through the wash-out period, the VLCn−3 PUFAs EPA and DHA was restored already after 1300 day degrees, whereas the wash-out of 18:2n−6, 18:1n−9 and 18:3n−3 was a slower process, requiring a minimum 1788 day degrees for reaching 100% FO levels. For reducing n−6 fatty acids and increasing VLCn−3 PUFA, a period of feeding with 100% FO was sufficient for the groups fed 25% RO, 50% RO and 50% OO prior to wash-out. Considering the recommended n−3/n−6 ratio and VLCn−3 PUFA intake for human consumption, fillets from fish fed 100% FO, 25% RO, 50% RO and 50% OO prior to wash-out, followed by 1788 day degrees of 100% FO diet, can be considered beneficial for human health promotion.