南美白对虾幼虾饲料蛋白质的需要量

Protein requirements in compounded diets for Penaeus vannamei juveniles

以酪蛋白和明胶为主要蛋白源,配制成蛋白质质量分数分别为28%、33%、38%、43%和48%的5种精饲料,分别在盐度2和28的水体中,对南美白对虾(Penaeusvannamei)幼虾进行49d的饲养试验。虾苗平均体重为(0 011±0 001)g,每天投喂4次。结果表明,饲料系数、蛋白质效率均随饲料蛋白质含量的增加而减小,饲料蛋白质水平对南美白对虾幼虾肌肉游离氨基酸和肝胰腺胰蛋白酶的活性有显著的影响。在盐度2的水体中,26.7%饲料蛋白质水平最适宜;在盐度28的水体中,33.0%饲料蛋白质水平最适宜。说明在一定范围内,低蛋白高能量饲料可以取得更高的蛋白质利用率以及更好的对虾养殖效果。

The average body weight of the juvenile Penaeus vannamei was (0.011±0.001) g. The main protein source of the experimental diets was supplied by casein and gelatin and the diets protein levels were designed at 28%, 33%, 38%, 43% and 48%, and two experiment salinity levels were 2 and 28. The experiment period was 49 d, during which the water temperature was 27.0-31.5 ℃, DO 4.5-5.6 mg/L and pH 7.8-8.3. The final results show that the feed conversion ratios and protein efficiency ratios both decrease with the increasing levels of dietary protein. The effects of dietary protein level on trypsin activities and essential amino acids compositions in shrimp muscle were significant(P<0.05). The optimum level of dietary protein for P. vannamei juveniles is about 26.7% at salinity 2 with the weight gain of 9 844.27%, and at salinity 28 the optimum level of dietary protein is 33% at salinity 28 with the weight gain of 9 937.15%. The conclusion is that within certain range of dietary protein level, the diets with low protein level and high energy may get much high protein efficiency rate and good culture effects compared with high protein level diets.