Parameters of Lipid Metabolism in Underyearlings of Atlantic Salmon Salmo salar Reared under Different Regimes of Photoperiod and Feeding Modes in Aquaculture in the Sourthern Region of Russia

A comparative study of the lipid and fatty acid composition of Atlantic salmon underyearlings reared under natural and continuous light in commercial aquaculture in the summer-autumn period in North Ossetia-Alania was carried out. A stable change in the main indicators of lipid metabolism in salmon underyearlings from September to November was found, aimed at preparing juveniles for smoltification. A change in key fatty acid indicators was detected: an increase in the content of PUFAs due to (n-3) PUFAs, and the “marine” type of PUFA – 22:6 (n-3), high values of the ratios (n-3)(n-6) PUFA, 18:3(n-3)/18:2 (n-6), 22:6(n-3)/ 18:3(n-3). It has been shown the stimulating effect of the combined and stable action of the continuous photoperiod and feeding in the summer-autumn period on the preparation for smoltification of Atlantic salmon fingerlings grown under aquaculture conditions.