Effect of dietary cottonseed meal on growth performance, physiological response, and gossypol accumulation in preadult grass carp, Ctenopharyngodon idellus

• Published in: 中国海洋湖沼学报：英文版 no. 5; pp. 992 - 1003
• Main Author: 刘昊昆 严全根 韩冬 金俊琰 朱晓呜 杨云霞 解绶启
• Format: Journal Article
• Language: English
• Published: 2016
• ISSN: 0254-4059; 1993-5005

Cottonseed meal （CM） was used at up to 36.95% content in the diet （replacing 60% of dietary fish meal protein） without any negative effects on growth performance of pre-adult grass carp （initial body weight, 761 g） under outdoor conditions. A culture trial was conducted in net cages installed in a large concrete pond. Seven isonitrogenous and isoenergetic diets containing a gradient of CM concentrations （0, 12.2%, 24.4%, 36.6%, 48.8%, 54.8%, and 61.0%） as replacement for dietary fish meal protein （0, 20%, 40%, 60%, 80%, 90%, and 100%） were formulated. Dietary non-resistant starch （from maize） was inverse to dietary CM. Growth performance and feed utilization of fish fed the diets containing CM replacing 0-40% fishmeal protein were not affected after the 6-week feeding trial. Accumulation of hepatopancreatic total gossypol in the hepatopancreas was significantly correlated with free gossypol content in the diets （HTG=88.6＋ 1.5 × DFG, R^2=0.89, P〈0.05 ）. Intestinal a-amylase and y-glutamyl transpeptidase activities rose along with increasing dietary CM level. The structure of the mid-intestinal tissues and the ultrastructure of the enterocyte microvilli were normal when dietary CM was 〈36.6% （60% protein replacement）. Increasing dietary CM content increased serum alanine aminotransferase levels but decreased serum alkaline phosphatase, cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, and albumin （P〈0.05）.