Excess and deficient dietary lysine intake can have negative impacts on fish growth, emphasizing the importance of developing species‐specific formulations. A 50‐day feeding experiment was conducted to evaluate the optimal dietary l‐lysine demand for juvenile Nibea albiflora. Fish were fed six diets, in which the l‐lysine content was 13.1, 18.1, 23.1, 28.1, 33.1 and 38.1 g/kg dry diet (measured values). The 18.1–33.1 g/kg diets significantly enhanced weight gain and specific growth rate. Similarly, feed efficiency was highest in fish fed the 23.1 and 33.1 g/kg diets. The protein efficiency ratio of fish fed 13.1 g/kg diet was significantly lower than those of fish fed 23.1, 28.1 and 33.1 g/kg diets. The 28.1 g/kg diet resulted in higher whole‐body protein content than other diets. The expression level IGF‐I and IGF‐IR in liver and muscle significantly increased by proper dietary lysine, respectively. Based on a second‐order polynomial model of weight gain, the optimal demand of l‐lysine in the diet for juvenile N. albiflora is 24.85 g/kg diet. These results have practical implications for improving growth performance and feed utilization in juvenile N. albiflora.

中文翻译：

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日粮赖氨酸会影响黄大鼓黄花苜蓿的生长性能，全身组成和与生长相关的基因表达

饮食中赖氨酸摄入过多和不足会对鱼类的生长产生负面影响，强调开发特定物种配方的重要性。50天喂养试验，以评估最佳膳食升少年赖氨酸需求黄姑鱼。喂食6个日粮，其中所述升赖氨酸含量为干饲料日粮13.1 g，18.1、23.1、28.1、33.1和38.1 g / kg（测量值）。18.3–33.1 g / kg的饮食可显着增加体重增加和特定增长率。同样，饲喂23.1和33.1 g / kg日粮的鱼的饲料效率最高。饲喂13.1 g / kg日粮的鱼的蛋白质效率比显着低于饲喂23.1、28.1和33.1 g / kg日粮的鱼。28.1 g / kg的饮食比其他饮食产生更高的全身蛋白质含量。适当的饮食赖氨酸会分别显着提高肝脏和肌肉中的IGF-I和IGF-IR表达水平。基于体重增加的二阶多项式模型，幼年猪笼草日粮中l赖氨酸的最佳需求量是24.85 g / kg饮食。这些结果对提高幼龄N. albiflora的生长性能和饲料利用率具有实际意义。