Lipid metabolism and tissue composition in Atlantic salmon (Salmo salar L.) - Effects of capelin oil, palm oil, and oleic acid-enriched sunflower oilas dietary lipid sources

Triplicate groups of Atlantic salmon (Salmo salar L.) were fed four diets c ontaining different oils as the sole lipid source, i.e., capelin oil, oleic acid-enriched sunflower oil, a 1:1 (w/w) mixture of capelin oil and oleic acid-enriched sunflower oil, and palm oil (PO). The beta-oxidation capacity , protein utilization, digestibility of dietary fatty acids and fatty acid composition of lipoproteins, plasma, liver, belly flap, red and white muscl e were measured. Further, the lipid class and protein levels in the lipopro teins were analyzed. The different dietary fatty acid compositions did not significantly affect protein utilization or beta-oxidation capacity in red muscle. The levels of total cholesterol, triacylglycerols, and protein in v ery low density lipoprotein (VLDL), low density lipoprotein (LDL), high den sity lipoprotein (HDL), and plasma were not significantly affected by the d ietary fatty acids. VLDL, LDL, and HDL fatty acid compositions were decreas ingly affected by dietary fatty acid composition. Dietary fatty acid compos ition significantly affected both the relative fatty acid composition and t he amount of fatty acids (mg fatty acid per g tissue, wet weight) in belly flap, liver, red and white muscle. Apparent digestibility of the fatty acid s, measured by adding yttrium oxide as inert marker, was significantly lowe r in fish fed the PO diet compared to the other three diets.