Effects of Dietary Protein and Energy Levels on Growth, Feed utilization and Body Composition of Skin Carp Hemibarbus labeo

Abstract

A 12-week feeding trial was conducted to assess the effects of dietary protein and energy levels on the growth, feed utilization, and body composition of skin carp Hemibarbus labeo. Ten experimental diets with five levels of crude protein (CP) and two levels of crude lipid (CL) were designated as 32%, 36%, 40%, 44%, 48% and 18 MJ/kg,19.5MJ/kg, respectively. Final body weight (FBW) and weight gain rate (WGR) increased, whereas the feed intake (FI) and feed conversion ratio (FCR) decreased, with increasing dietary protein level from 32% to 48%. Fish fed the diets containing 44% CP and CL providing 19.5MJ/kg exhibited higher FBW and WGR, but lower FI and FCR. At the end of the feeding trial, the intraperitoneal fat ratio (IPFR) decreased with the increase of CP levels. Significant differences (P<0.05) were found in the carcass composition of fish fed different levels of CP and CL. No noticeable trend was observed for moisture and ash in the carcass. The optimum CP and CL level were found to be 44% and 19.5MJ/kg respectively for skin carp reared in net cages.