Influence of Different Lighting and Feeding Regimes on the Expression of the Fadsd5, Fadsd6, Elovl2, and Elovl5a Desaturase and Elongase Genes in the Liver of Juvenile Atlantic Salmon Salmo salar L. under Aquaculture Conditions

The relative level of gene expression of enzymes, like desaturases and elongases (fadsd5, fadsd6, elovl2, elovl5a, and elovl4), which play a key role in the biosynthesis of long-chain polyunsaturated fatty acids, was studied in the liver of juvenile Atlantic salmon Salmo salar Linnaeus, 1758, reared under different lighting and feeding regimes in aquaculture conditions. The level of the fadsd5 desaturase gene expression was higher in Atlantic salmon smolts (0+) reared under regime of round-the-clock lighting and feeding compared to smolts from the experimental group with a natural photoperiod and daylight feeding. Changes in the level of gene expression (elovl2, elovl5a, and fadsd5) in juvenile Salmo salar reflect adaptive processes at the molecular genetic level during the growth and development of fish and in response to changes in environmental conditions. The obtained results make it possible to assess the capability/requirements for the biosynthesis of PUFAs in juvenile salmon during its growth and development.