暗纹东方魨幼鱼对蛋白质的最适需要量

Optimum protein requirement of juvenile Takifugu obscurus

以白鱼粉为蛋白源设计了6个不同蛋白质水平(35%,40%,45%,50%,55%,60%)的等能饲料,采用室内水泥池养殖,在水温为24～26℃条件下对暗纹东方幼鱼进行了12周的生长实验以确定其最适蛋白质需要量。增重率和饲料效率随着蛋白质水平的增加而上升,50%试验组的鱼体增重显著高于35%、40%和45%试验组(P<0.05),蛋白质含量高于50%以后增重不再有显著变化(P>0.05)。蛋白质效率总体上随着蛋白质水平的增加趋于降低,但在35%、40%和50%试验组之间无显著差异(P>0.05)。采用折线模型测算出暗纹东方幼鱼获得最大增长和对饲料利用最佳时的蛋白质水平分别大约是49%和46%,据此估算出暗纹东方幼鱼的最适蛋白质含量为46%～49%,这一结果同红鳍东方的最适蛋白质需要量基本一致。

It is important to study the nutrition requirement of Takifugu obscurus because the puffer is a precious and potential species for intensive aquaculture. A 12-week growth experiment was conducted in indoor concrete ponds to determine the optimum protein level for the growth of juvenile T. obscurus, at the temperature of 24-26℃. White fish meal was used as the sole protein source to formulate isocaloric experimental diets at six protein levels (35%, 40%, 45%, 50%, 55%, 60%). Weight gain and feed efficiency of fish improved with increasing dietary protein level up to 50% and reached a plateau above this level. Weight gain of fish fed 50% protein diet was significantly higher (P<0.05) than that of fish fed 35%, 40% and 45% protein diet, but not significantly different from that of fish fed 55% and 60% protein diet (P>0.05). The protein efficiency ratio tended to decrease with increasing dietary protein level, but there is no significant difference among the diets containing 35%, 40% and 50% protein levels (P>0.05). Dietary protein requirement using broken-line model was estimated at approximately 49% and 46% for maximum growth and maximum protein utilization, respectively. Therefore, it is suggested that the optimum dietary protein level for juvenile T. obscurus should be 46%-49%. The result is similar to that of tiger puffer T. rubripes.