title: Improving the growth performance and cholesterol metabolism of rainbow trout (Oncorhynchus mykiss) fed soyabean meal-based diets using dietary cholesterol supplementation.
abstract: A 9-week feeding trial was conducted to evaluate the effects of dietary cholesterol supplementation at different levels (0, 0·3, 0·6, 0·9, 1·2 and 1·5 %) on growth and cholesterol metabolism of rainbow trout (Oncorhynchus mykiss) fed soyabean meal (SBM)-based diets. Daily growth coefficient (DGC) steadily increased when the supplemental cholesterol was increased by up to 1·2 %, but declined upon further addition. The total cholesterol (TC), HDL-cholesterol (HDL-C) and LDL-cholesterol (LDL-C) levels in plasma generally increased when the supplemental cholesterol was increased by up to 1·2 %. Thereafter, the TC level reached a plateau, the LDL-C level showed a marked decline, whereas the HDL-C level continued to increase. Dietary cholesterol supplementation generally increased the total lipid and cholesterol levels in liver; the total lipid and TAG levels in muscle; the TC, free cholesterol, cholesteryl ester and total bile acid levels in intestinal contents; and the triiodothyronine and Ca levels in plasma. However, significant differences were mainly observed with high levels of supplemental cholesterol (0·9-1·5 %). Low levels of supplemental cholesterol (0·3-0·9 %) decreased hepatic 3-hydroxy-3-methyl-glutaryl-CoA reductase and cholesterol 7α-hydroxylase activities, but high levels of supplemental cholesterol (1·5 %) increased hepatic acyl-CoA:cholesterol acyl transferase and cholesterol 7α-hydroxylase activities. These results suggest that rainbow trout fed SBM-based diets have a certain 'cholesterol-buffering capacity', which in turn suggests the possibility of the inhibition of exogenous cholesterol absorption and/or inadequate endogenous production of cholesterol in trout fed SBM-based diets. DGC increased steadily with increasing supplemental cholesterol level up to 1·2 %, and the growth-promoting effects might be related to the alleviation of the negative effects caused by a soyabean diet and/or make up for the deficiency of endogenous cholesterol in rainbow trout.
authors.affiliation: College of Animal Science and Technology, Yunnan Agricultural University, Kunming 650201, People's Republic of China.
authors.forename: Junming
authors.initials: J
authors.lastname: Deng
authors.forename: Baoliang
authors.initials: B
authors.lastname: Bi
authors.forename: Bin
authors.initials: B
authors.lastname: Kang
authors.forename: Lingfu
authors.initials: L
authors.lastname: Kong
authors.forename: Qiuju
authors.initials: Q
authors.lastname: Wang
authors.forename: Xi
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001647:Bile Acids and Salts / Q000378:metabolism; D002118:Calcium / Q000097:blood; D002784:Cholesterol / Q000097:blood*; D002791:Cholesterol, Dietary / Q000097:blood / Q000494:pharmacology*; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D004032:Diet; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D007413:Intestinal Mucosa / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism; D017686:Oncorhynchus mykiss / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D013025:Glycine max; D014280:Triglycerides / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
chemical_list: D001647:Bile Acids and Salts; D002791:Cholesterol, Dietary; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D014280:Triglycerides; D014284:Triiodothyronine; D002784:Cholesterol; D002118:Calcium