文献类型：期刊文献

英文题名：Dietary threonine requirements of juvenile Pacific white shrimp, Litopenaeus vannamei

作者：Zhou, Qi-Cun[1];Wang, Yong-Li[2];Wang, Hua-Lang[3];Tan, Bei-Ping[2]

机构：[1]Ningbo Univ, Sch Marine Sci, Ningbo 315211, Zhejiang, Peoples R China;[2]Guangdong Ocean Univ, Coll Fisheries, Zhanjiang 524025, Peoples R China;[3]Guangdong Evergreen Grp Corp, Aqua Feed Res & Dev Ctr, Zhanjiang 524094, Peoples R China

年份：2013

卷号：392

起止页码：142

外文期刊名：AQUACULTURE

收录：SCI-EXPANDED(收录号：WOS:000317567200020)、、Scopus(收录号：2-s2.0-84874941535)、WOS

基金：This study was funded by fundamental research grants from the Special Public Service Sectors of the Ministry of Agriculture (Grant No: 201003020) and the Agricultural Research Projects in the Department of Ningbo Science and Technology (Grant No: 2011C10006). This research was also sponsored by the K. C. Wong Magna Fund and K. C. Wong Education Foundation at Ningbo University.

语种：英文

外文关键词：Pacific white shrimp; Threonine; Growth performance; Enzyme activity

外文摘要：An 8-week feeding trial was conducted to determine the dietary threonine requirement of juvenile Pacific white shrimp, Litopenaeus vannamei. Six isonitrogenous and isolipidic practical diets (43% crude protein and 7.5% crude lipid) were formulated to contain graded dietary threonine levels ranging from 1.07% to 2.30% (dry weight). In all of the diets, the nitrogen content of the amino acids was kept the same by replacing threonine with a non-essential amino acid mixture. Each diet was randomly assigned to triplicate groups of 40 juvenile shrimp (approximately 0.53 g) that were fed 4 times daily to apparent satiation. The results indicated that significant difference was observed in the weight gain among all treatments. Maximum weight gain was obtained at 1.67% dietary threonine; however, weight gain did not significantly increase with further dietary threonine increases. The survival of the shrimps showed no significant differences among all treatments. Feed efficiency, protein efficiency ratio and protein productive value were also significantly influenced by the dietary threonine levels, and the trends were similar to those of growth performance. There were no significant differences among dry matter, crude protein, crude lipid or ash content in the whole body and muscle composition. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), superoxide dismutase (SOD) and phenoloxidase (PO) activities in hemolymph were significantly affected by dietary threonine levels. Shrimp fed the diet containing 2.30% threonine had higher AST and ALT values than those fed the other diets; however, the highest SOD and PO activities were observed at 2.05% dietary threonine. The optimal dietary threonine requirement, estimated by a broken-line model based on SGR, was 1.51% of the dry diet (corresponding to 3.53% of dietary protein on a dry-weight basis). Considering the threonine leaching loss in seawater within 30 min (duration of feeding each time), the threonine requirement for L. vannamei is 1.18% of dry diet (2.81% of the dietary protein). (C) 2013 Elsevier B. V. All rights reserved.