This study was carried out to evaluate the effects of water temperature (WT) and dietary protein levels on growth, body composition and blood biochemistry of GIFT tilapia (Oreochromis niloticus; initial average body weight: 38.75 ± 0.61g, n = 20). The fish were fed with six diets contained graded levels of protein (209.6, 251.0, 302.4, 354.3, 401.9 and 456.8 g/kg) and raised in each of WT (22°C, 28°C and 34°C) for 8 weeks. Results showed that the growth, feed utilization and protein efficiency were significantly increased with the increase of dietary protein level and followed by the latter platform at each WT. The fish raised at 28 and 34°C showed similar growth performance, and their values were significantly higher than the fish raised at 22°C (p < 0.05). The lipid contents in whole body were decreases with the increase of dietary protein level at each WT. However, the whole‐body protein, ash and moisture contents were not affected by dietary protein level or WT (p > 0.05). The values of serum biochemical indices (ALP, ALT, AST and TCHO) were all decreased with the increase of dietary protein. The optimal dietary protein requirement for GIFT tilapia to achieve maximal growth performance is 374.4, 301.7 and 304.9 g protein/kg diet at 22, 28 and 34°C, respectively.

中文翻译：

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水温和日粮蛋白水平对少年GIFT罗非鱼（Oreochromis niloticus）生长，身体成分和血液生化的影响

这项研究旨在评估水温和膳食蛋白水平对GIFT罗非鱼（Oreochromis niloticus；初始平均体重：38.75±0.61g，n  = 20）的生长，身体成分和血液生化的影响。用六种日粮饲喂鱼，其中六种日粮分别含有蛋白质的分级水平（209.6、251.0、302.4、354.3、401.9和456.8 g / kg），并在WT（22°C，28°C和34°C）中分别饲养8周。结果表明，随着日粮蛋白质水平的提高，其生长，饲料利用率和蛋白质效率均显着提高，随后在每个WT处均以后者为平台。在28和34°C饲养的鱼表现出相似的生长性能，其值显着高于在22°C饲养的鱼（p<0.05）。随着各WT日粮蛋白质水平的提高，体内脂质含量降低。但是，人体蛋白质，灰分和水分含量不受日粮蛋白质水平或野生型影响（p > 0.05）。血清生化指标（ALP，ALT，AST和TCHO）均随饮食蛋白质的增加而降低。要实现最大的生长性能，GIFT罗非鱼的最佳饮食蛋白质需求分别是22、28和34°C下374.4、301.7和304.9 g蛋白质/ kg饮食。