Lipid Profile of the Young Atlantic Salmon Salmo salar L. in the Letnyaya Zolotitsa River (Arkhangelsk Oblast, White Sea Basin)

Abstract

The lipid status of juvenile Atlantic salmon Salmo salar L. at the age of 0+, 1+, 2+, and 3+ was studied in the Letnyaya Zolotitsa River (the White Sea basin) in August 2015. The young-of-the-year juveniles have a relatively low lipid status on total lipids, especially reserve triacylglycerols, compared with elder juveniles (1+ to 3+). The proportion of long-chain polyunsaturated fatty acids (22:6n-3, 20:5n-3 and 20:4n-6) decreases with age (especially in 3+ individuals), but the proportion of reserve triacylglycerols and monounsaturated fatty acids (16:1n-7, 18:1n-9, and 18:1n-7) increases. The age-related changes in the ratio of reserve and structural lipids were analyzed. A low content of fatty acids typical for marine fishes (22:6n-3, 20:5n-3, and 20:4n-6) found in the 3+ juveniles, a reduced degree of their conversion from dietary fatty acids (18:2n-6 and 18:3n-3), and the lack of energy-rich triacylglycerols and monounsaturated fatty acids indicates that the young specimens are not ready for the transition to the marine environment. These indicators of the lipid status of juvenile salmon can be used as additional biochemical indicators of metabolic processes associated with the fish migration to another habitat.