Effects of dietary choline on growth performance, lipid deposition and hepatic lipid transport of grouper (Epinephelus coioides)

摘要

The number of 360 individuals with an average initial weight of 87.8 +/- 0.04 g was fed six diets containing graded levels of choline at 8.1 (control group), 602.5, 1119.0, 1511.5, 1970.0 and 4029.0 mg choline kg(-1) diet, respectively, to investigate the effects of dietary choline on growth performance, lipid deposition and hepatic lipid transport for grouper, Epinephelus coioides. Dietary methionine was estimated to be 10.02 g kg(-1), less than the requirement (13.10 g kg(-1)). The results of 10-week study period indicated that the best values of specific growth rate (SGR), feed conversion rate (FCR) and protein efficiency rate (PER) all occurred in 1119.0 mg choline kg(-1) diet (P 0.05). The survival range increased from 8.1 to 1511.5 mg choline kg(-1) diet and then plateaued. Dietary choline supplementation significantly decreased the liver lipid content of grouper (P 0.05), but the lipid content of the muscle tended to be increased firstly and then decreased (P 0.05). Liver choline concentration reached a plateau in 1511.5 mg choline kg(-1) diet and then levelled off (P 0.05). Serum high density lipoprotein-cholesterol (HDL-C) and total cholesterol (TCHO) levels were firstly decreased and then increased with dietary choline supplementation. A reversed tendency, however, was found in triglyceride. Broken-line regression analysis of SGR and liver choline content indicated that choline requirement of grouper was 1093.7 and 1579.7 mg kg(-1) diet, respectively.