Studies on nutrition of red sea bream. XII. Effect of .OMEGA.3 fatty acid supplement in a corn oil diet on fatty acid composition of fish.

Abstract

Red sea bream fingerlings were kept on a corn oil diet, supplemented with 1% 18:3 ω3 and/or 2% ω3 polyunsaturated fatty acids (PUFA), and on a pollack residual oil diet. After a 45-day feeding trial, the general composition and the fatty acid composition of liver and muscle were determined. Fish fed on diets containing PUFA had higher contents of liver glycogen and muscle lipid than the fish fed the diet with or without the 18:3 ω3 supplement. Fatty acid analysis of liver phospholipid showed that the dietary 18:3 ω3 was converted into 22:5 ω3 and 22:6 ω3. Liver phospholipid of fish fed on diets with PUFA showed markedly higher level of 18:1 > fatty acids and lower levels of 20 < ω3 and 20 < ω6 fatty acids than those of fish fed the diets with 18:3 ω3, A relationship was recognized between the improve-ment of feed efficiency and the change in levels of 18:1 > fatty acids and 20<ω6 fatty acids in the liver phospholipid.