Dependence of the Lipid and Unsaturated Fatty-Acid Compositions in Rainbow-Trout Skeletal Muscle on the Rearing Conditions and Physiological Status of Fish

Abstract

A final product of fish production, the skeletal muscle of fish, is a source of animal protein, phospholipids, and polyunsaturated fatty acids, which are essential for human consumption. The effects of rearing conditions (seasonal temperature and oxygen regimens) and physiological state (infectious status) on the lipid composition of the skeletal muscle of two-year-old rainbow trout Oncorhynchus mykiss grown in cages on a natural lake were studied. It was detected that the rate of body growth in trout juveniles decreased with increased water temperature, sporadic bacterial infection, and subsequent antimicrobial therapy. In addition, an excessive accumulation of reserve lipids (triacylglycerols) and increased saturation of the membrane lipids in fish muscle were shown. Dietary supplementation with an antioxidant additive including dihydroquercetin and arabinogalactan was used to mitigate the impact of exogenous factors and bacterial infection. It was shown that the lipid composition and unsaturated fatty-acid content were more stable with supplement-feeding of the fish tissue, which indicates better consumption characteristics and a balanced nutrient composition of the resulting fish product.