This study aimed to estimate the ideal profile of essential amino acids (EAAs) for Nile tilapia (Oreochromis niloticus) in the finishing growth phase. A total of 264 fish (initial average weight of 625 g) were distributed among randomly arranged 33 fibre tanks of 1000‐L water capacity each, connected to a water recirculation system. The 60‐day experiment consisted of 11 treatments with three replicates each and fish were fed three times a day. The treatments consisted of a control diet (CD), 45% of which was composed of crystalline amino acids along with purified ingredients and the remaining 55% was contributed by the conventional ingredients meeting the nutritional requirements, and other 10 EAA‐deficient test diets (DD) which were deficient from 33%–41% in each evaluated AA. The essential amino acid ratios were calculated from the relationship between body nitrogen retention and the amount of amino acid deleted from the test diet. This study found the following ideal profile of essential amino acids expressed in relation to lysine (100%); arginine (80.73%), phenylalanine (69.73%), histidine (34.15%), isoleucine (51.24%), leucine (66.01%), methionine (41.49%), threonine (88.96%), tryptophan (23.07%) and valine (72.63%).

中文翻译：

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尼罗罗非鱼（Oreochromis niloticus）处于生长后期的必需氨基酸的理想特征

这项研究旨在估计尼罗罗非鱼（Oreochromis niloticus）的必需氨基酸（EAA）的理想概况）处于最终成长阶段。总共264条鱼（初始平均重量为625 g）被分配到随机排列的33个纤维箱中，每个水箱的水容量为1000-L，并与水循环系统相连。60天的实验由11种处理组成，每个处理重复3次，每天喂鱼3次。这些治疗包括对照饮食（CD），其中45％由结晶氨基酸和纯化成分组成，其余55％由满足营养要求的常规成分和其他10种缺乏EAA的测试饮食贡献（ DD）在每个评估的AA中从33％–41％不足。根据人体氮素保留量与从试验饮食中删除的氨基酸量之间的关系计算出必需氨基酸的比例。这项研究发现，相对于赖氨酸（100％）表达的必需氨基酸具有以下理想特征：精氨酸（80.73％），苯丙氨酸（69.73％），组氨酸（34.15％），异亮氨酸（51.24％），亮氨酸（66.01％），蛋氨酸（41.49％），苏氨酸（88.96％），色氨酸（23.07％）和缬氨酸（ 72.63％）。