文献类型：期刊文献

英文题名：Optimal dietary methionine requirement for Juvenile Cobia (Rachycentron canadum)

作者：Zhou Q.-C.; Wu Z.-H.; Tan B.-P.; Chi S.-Y.; Yang Q.-H.

机构：[1]Laboratory of Aquatic Economic Animal Nutrition and Feed, College of Fisheries, Guangdong Ocean University, Zhanjiang, 524025, China;[2]College of Fisheries, Ocean University of China, Qingdao, 266003, China

年份：2006

卷号：258

期号：1-4

起止页码：551

外文期刊名：Aquaculture

收录：Scopus(收录号：2-s2.0-33746980227)

语种：英文

外文关键词：Feed utilization; Growth; Juvenile cobia (Rachycentron canadum); Methionine requirement

外文摘要：An 8-week feeding experiment was conducted to quantify the dietary methionine requirement of juvenile cobia (initial weight of 11.61 ± 0.16?g, mean ± SD) reared in indoor flow-through and aerated aquaria. Six amino acid test diets (44% CP and 16% lipid), using fish meal and wheat gluten as intact protein sources supplemented with crystalline amino acids, were formulated to contain graded levels of methionine (0.61%, 0.83%, 1.05%, 1.30%, 1.48% and 1.68% of dry diet, respectively) at a constant dietary cystine level of 0.67%. Each diet was randomly assigned to three aquaria. Growth performance and feed utilization were significantly influenced by the dietary methionine levels (P < 0.05). Maximum weight gain, specific growth rate and protein efficiency ratio occurred at 1.05% dietary methionine (P < 0.05). The hepatosomatic index, viscerosomatic index and condition factor were not significantly affected by dietary methionine levels (P > 0.05). There were no significant differences in protein, lipid, ash and moisture contents in whole body or muscle, also red blood cell count and plasma protein content for fish fed graded methionine levels of diets; however, hemoglobin, hematocrit, leukocyte, plasma glucose and triacylglycerol concentrations showed significant differences among these treatments (P < 0.05). Methionine concentration in plasma significantly increased with an increase of dietary methionine (P < 0.05). Quadratic regression analysis of specific growth rate against dietary methionine levels indicated that the optimal dietary methionine requirement for maximum growth and feed utilization of juvenile cobia is 1.19% of dry diet in the presence of 0.67% cystine (corresponding to 2.64% of dietary protein on a dry weight basis). ? 2006 Elsevier B.V. All rights reserved.