Effect of Ulva meal supplement to diet on the lipid metabolism of red sea bream.

Abstract

A diet supplemented with 5% Ulva pertusa meal was fed to red sea bream Pagrus major. Growth was not affected, but hepatosomatic index and intraperitoneal fat body (IPF) ratio de-creased slightly. Plasma nonesterified fatty acids (NEFA) and amino nitrogen changed signi-ficantly. The lipid levels of the dorsal muscle and liver were not affected apparently but the lipid class composition in the liver changed remarkably. Highly unsaturated fatty acids accumulated selectively in triglycerides of the Ulva meal fed fish. As to similarity of fatty acid composition, triglycerides of the liver and IPF were low between the two dietary groups. Fish were subsequently starved for 21 days. Increase in plasma NEFA and decrease in amino nitrogen found in the experimental group suggested that the Ulva meal activated lipid mobilization and suppressed protein breakdown. Starvation resulted in the utilization of highly unsaturated fatty acids in the Ulva meal fed fish, but fatty acids of the control group were uniformly consumed. Ulva meal was demonstrated to be capable of regulating lipid accumulation and mobilization in red sea bream.