A study on the regulation of lipid accumulation in juvenile turbot (Scophthalmus maximus L.)

Abstract:

A 12-week feeding trial was conducted to investigate the effects of high plant protein diets with taurine and fish protein hydrolysate on the lipid accumulation of juvenile turbot (initial body weight 4.16±0.01 g). Three experimental diets were formulated. The control diet (C) contained 30% fishmeal. After half of the fish meal in the control diet was replaced by plant protein sources, 0.8% taurine was added to formulate the second diet (HT). 7% fish meal in diet HT was further replaced with fish protein hydrolysate to formulate the third diet (HTPH). The feeding trail was conducted in indoor flowing seawater system. Each diet was assigned to quadruplicate groups of 25 fish. The results showed that compared to groups C and HT, group HTPH significantly reduced the whole-body neutral lipid content and the hepatosmatic index. Compared to the control group, groups HT and HTPH significantly increased the whole-body moisture content, but significantly reduced the neutral and total lipid content in liver. Compared to the control group, the polar and total lipid was significantly reduced only in group HTPH. No significant difference was observed in gut lipid contents among dietary treatments. The contents of triglyceride and cholesterol in serum of group HTPH were significantly lower compared to the control group. Groups HT and HTPH tend to reduce the concentration of long chain polyunsaturated fatty acids, but increase the concentrations of C18:2n-6, C18:3n-6 and C18:3n-3. These results suggested that high plant protein diets supplemented with taurine reduced the lipid accumulation in turbot liver, and further use of fish protein hydrolysate reduced the neutral and total lipid content in whole body, liver, muscle, and serum of juvenile turbot.