Feng Dexiang, Yu Yangping, Liu Kaifang, Su Yi, Fan Tianyu, Guo Xusheng, Li Ming
School of Fisheries, Xinyang Agriculture and Forestry University, Xinyang, China.
School of Marine Sciences, Ningbo University, Ningbo, China.
Front Physiol. 2023 Jul 26;14:1247410. doi: 10.3389/fphys.2023.1247410. eCollection 2023.
The experiment was conducted to investigate the effects of dietary leucine on growth, antioxidant capacity, immune response, and inflammation in juvenile yellow catfish. Five diets were formulated to contain five dietary leucine levels: 12.00 (control), 19.00, 26.00, 33.00, and 40.00 g kg. Each diet was randomly assigned to triplicate groups of 30 juvenile fish (5.02 ± 0.15 g) twice daily to apparent satiation for 56 days. Weight gain rate, specific growth rate, and activities of liver superoxide dismutase, glutathione peroxidase, and serum lysozyme, as well as immunoglobulin M content, significantly increased with increase in dietary leucine levels up to 26.00 g kg, but those values decreased significantly with a further increase in dietary leucine. On the contrary, the lowest malondialdehyde content was found in 26.00 and 33.00 g kg leucine groups. The expression levels of and genes in muscle were significantly upregulated with increase in dietary leucine levels up to 26.00 g kg, but the expression of level showed the opposite trend. The lowest expression levels of and genes in the liver were found in 26.00 g kg leucine groups. The quadratic regression analysis on weight gain, specific growth rate, and feed conversion ratio against dietary leucine levels indicated that the optimal dietary leucine requirement was estimated to be 26.84-27.00 g kgof the dry diet.
本实验旨在研究饲料中亮氨酸对幼龄黄颡鱼生长、抗氧化能力、免疫反应和炎症的影响。配制了五种饲料，其亮氨酸水平分别为：12.00（对照）、19.00、26.00、33.00和40.00 g/kg。每种饲料随机分配到三个重复组，每组30尾幼鱼（5.02±0.15 g），每天投喂两次，直至明显饱足，持续56天。随着饲料亮氨酸水平增加至26.00 g/kg，增重率、特定生长率、肝脏超氧化物歧化酶、谷胱甘肽过氧化物酶活性、血清溶菌酶活性以及免疫球蛋白M含量均显著增加，但随着饲料亮氨酸水平进一步升高，这些指标显著下降。相反，丙二醛含量在亮氨酸水平为26.00和33.00 g/kg的组中最低。随着饲料亮氨酸水平增加至26.00 g/kg，肌肉中 和 基因的表达水平显著上调，但 水平的表达呈现相反趋势。肝脏中 和 基因的最低表达水平出现在亮氨酸水平为26.00 g/kg的组中。对增重、特定生长率和饲料转化率与饲料亮氨酸水平进行二次回归分析表明，干饲料中亮氨酸的最佳需求量估计为26.84 - 27.00 g/kg。
