饲料蛋白能量比对草鱼幼鱼生长性能、蛋白利用和体成分的影响

以鱼粉和豆粕为蛋白源,鱼油和豆油等比例混合油为脂肪源,采用4×4因子实验来确定草鱼(Ctenopharyngodon idellus)幼鱼饲料中的合适蛋白能量比(P/E),其中饲料蛋白水平分别为20%、25%、30%、35%,能量水平为12.5、13.7、15、16.2 k J/g,饲料蛋白能量比的范围为12.1~27.3 mg/k J,共16组饲料,每组设3个重复,连续投喂初体质量(16.85±0.29)g的草鱼幼鱼10周,研究饲料蛋白能量比对草鱼幼鱼生长性能、蛋白利用和体成分的影响。结果表明:(1)最高末体质量和特定生长率出现在P/E为18.3 mg/k J组,而P/E为16.0 mg/k J组的饲料系数最高,蛋白质效率和蛋白沉积率最高组分别为P/E 12.10 mg/k J组和15.20 mg/k J组。(2)P/E为27.30 mg/k J组的能量沉积率和总氮排泄率最大。(3)在同一饲料蛋白水平下,鱼体的脂肪含量随饲料能量水平升高而升高;在同一饲料能量水平下,鱼体的蛋白含量随饲料蛋白含量升高而升高。对生长、蛋白利用、体成分的实验结果进行综合分析,草鱼幼鱼饲料的最适蛋白含量为30%,最适P/E为19.5 mg/k J。

Effect of dietary protein-energy ratios on growth performance,protein efficiency and body composition of juvenile Ctenopharyngodon idellus

A growth experiment for 10 weeks was conducted to determine the optimal dietary protein -energy ratio (P/E) for juvenile Ctenopharyngodon idellus (initial body weight 16.85 ±0.29 g).Sixteen diets were formulated, containing four protein levels (20%, 25%, 30%, 35%), each with four energy levels (12.5, 13.7, 15, 16.2 kJ/g).P/E ra-tios of the diets ranged from 12.1 to 27.3 mg/kJ.Each diet was randomly assigned to triplicate groups of 20 fish in 250-L tanks.The results showed that: (1)The specific growth rate(SGR) and the final body weight were both significantly bet -ter in fish fed the diet with P /E ratio of 18.3 mg/kJ than other groups, and protein efficiency ratio (PER) and protein pro-ductive value (PPV) were significantly higher in fish fed the diets with P /E ratio of 12.10 mg/kJ and 15.20 mg/kJ than other groups, respectively.Fish fed the diets with P /E ratio of 16.0 mg/kJ had the highest feed conversion ratio .(2)
The highest energy retention (ER) and total nitrogenous excretion rate were in the group with P /E ratio of 27.30 mg/kJ. (3) At the same dietary protein level, the whole body lipid content increased with dietary energy level increasing .At the same energy level, the body protein content increased with dietary protein level .These results suggested that the diet con -taining 30% protein and P /E of 19.5 mg/kJ was optimal for juvenile Ctenopharyngodon idellus.