Effects of dietary lysolecithin (LPC) on growth, apparent digestibility of nutrient and lipid metabolism in juvenile turbot Scophthalmus maximus L.

Abstract

An 8-week trial was conducted to investigate graded levels of dietary LPC on growth, apparent digestibility (ADs) of nutrients and lipid metabolism in juvenile turbot Scophthalmus maximus L. Five experimental diets were formulated which contain 11% crude fat with graded amounts of LPC (0, 1000, 2500, 4000, 5500 mg/kg diet). The fish fed diet with 11% crude lipid and 0 LPC was used as the negative control group (C-), meanwhile the fish fed diet with 12% crude fat and 0 LPC was used as the positive control group (C+). Each diet was fed to triplicate groups of turbot (initial body weight of 41 g) for 56d. Weight gain rate and specific growth rate of the fish fed LPC supplemented diets were significantly higher than the control groups, and the growth performance of the C-group was significantly lower than the others. The viscerosomatic index (VSI) was significantly decreased and the gall bladder somatic index (GSI) was significantly increased by dietary LPC. Crude lipid contents of muscle were elevated by dietary LPC. Apparent digestibility of energy was decreased by dietary LPC, but protein and lipid were not affected. Both total cholesterol (T-CHO) and high density lipoprotein cholesterol (HDL-C) were up-regulated, meanwhile neither alanine aminotransferase (ALT) nor total protein (TP) were down-regulated by dietary LPC. Enzymes involved in lipid metabolism (total lipase, hepatic lipase, lipoprotein lipase, fatty acids synthase, and lipase) were all elevated by dietary LPC. In conclusion, the lipid requirements of turbot were decreased by dietary LPC and the lipid utilization coefficient was enhanced. Based on SAS NLIN regression, dietary 870.37 mg/kg LPC was appropriate for turbot juvenile. Keywords: Turbot, Lysolecithin (LPC), Growth performance, Lipid metabolism