配合饲料中不同蛋白质水平对日本沼虾生长的影响

Effects of dietary protein levels on growth of oriental river prawn Macrobrachium nipponense

采用鱼粉作为主要饲料蛋白源，利用酪蛋白来调节饲料的蛋白质含量，设置蛋白质水平为30％～46％的6种不同梯度的试验饲料，试验设3个重复，每个重复放养日本沼虾100尾，平均初重0．067g。每天投喂2次，试验共进行60d，研究配合饲料中不同的蛋白质水平对日本沼虾生长的影响并得出日本沼虾配合饲料中的最适蛋白质含量。结果表明：蛋白质水平为39．32％和41．67％的试验组的虾体增重和特定生长率均显著高于其它试验组（P〈0．05）；以增重率和特定生长率为衡量指标，采用二次方程回归分析法，得出日本沼虾配合饲料中蛋白质的最适含量约为41％～41．5％。饲料中不同蛋白质水平对日本沼虾虾体（全虾）的水分和粗蛋白质含量具有显著影响（P〈0．05），但对其成活率，粗脂肪含量和粗灰分含量均无显著影响（P〉0．05）。

A 60 day experiment was conducted to determine the optimal protein level in practical diet for oriental river prawn Macrobrachium nipponense. 6 isocalorie experimental diets were formulated with crude protein levels ranged from 30.17 g/kg to 45.45 g/ kg. The fishmeal and casein were used as main protein source, and the graded protein levels was regulated by casein. The triplicate feeding trials were conducted in tanks indoor, 100 prawns（initial mean weight： 0.067 g） were randomly stocked into each of eighteen 100L tanks at water temperature 26 ± 2 ℃ The prawns were fed to satiation twice a day （8：00 and 16：00 hours） during the experimental period. The results showed that the weight gain and specific growth rate of prawns fed a test diet with 39.32% and 41.67% crude protein on wet basis were significantly higher（ P 〈 0.05 ） than those of the other test groups. Based on quadratic model regression analysis of the weight gain and specific growth rate, it was found that the optimal protein requirement in practical feed was 41% -41.5%. The whole body moisture content of prawns fed diet 4 and diet 5 was significantly lower than those of fed diet 1, diet2, diet 3 or diet 6 ; and the body protein content of prawns fed diet 4 and diet 5 was significantly higher than those of fed diet 1, diet2, diet 3 or diet 6 ; but no significant difference was found on survival rate and the whole body lipid and ash content among all treatments（P 〉 0.05 ）.