Partial substitution of fish meal with vegetable protein sources in a diet for sea bass: effects on lipogenesis.

Abstract

Three isoproteic (49.4%) and isolipidic (17.0%) diets were prepared: A control diet FM, in which protein was derived from fish meal and two experimental diets in which 70% of the fish meal protein was substituted with wheat gluten meal (WGM) or wheat gluten meal plus soybean meal (WGMsb), respectively, were fed on three hundred and fifteen sea bass (initial weight = 23.9±0.1 g), randomly divided into nine homogenous groups. The animals were reared in a closed recirculation system at 23.9◦C and were fed ad libitum twice a day for 96 days. The epatosomatic, viscerosomatic and mesenteric fat indices, and the body chemical composition were determined: fatty levels of the muscles, liver and the mesenteric fat. The hepatic activity of glucose-6-phosphate deidrogenase, malic enzyme, and ATP citrate lyase were detected. The zootechnical performances and the body composition of sea bass were not affected by a diet in which wheat gluten meal alone, or a combination of this and soybean meal, was used as partial replacement of protein usually derived from fish meal. The lipid distribution was modified in a different manner to that of the control fish, and there were also quantifiable changes in the acidic composition of muscle. The values of lipogenic specific enzymatic activity seem to be weakly correlated with the adiposity of sea bass fed with the different diets.