Seasonally changing metabolism in Atlantic salmon (Salmo salar L.) II -: β-oxidation capacity and fatty acid composition in muscle tissues and plasma lipoproteins

With the aim of elucidating seasonally changing lipid metabolism in immature Atlantic salmon (Salmo salar L.) in sea water, one group was reared under simulated natural light, while one group was reared under continuous light. Fatty acid pro. le in plasma lipoproteins did not vary during the experiment, while beta-oxidation capacity increased during spring, concurrent with decreasing temperatures. Simultaneously, the relative level of monounsaturated fatty acids (MUFA) in muscle tissue decreased (42-36%). Muscle levels of saturated fatty acids were low during early spring (19%), but then increased slowly, and muscle levels of polyunsaturated fatty acids increased during spring (from 36% to 39%). It is suggested that increased spring growth and the concomitant energy demand was met by increased lipid oxidation, where MUFA were preferred as energy substrate.