尼罗罗非鱼在淡水和海水中的生长及对蛋白质需求的比较

Growth and Optimal Protein Requirement of Tilapia Fed CaseinAs Sole Protein Sources in both Fresh Water and Sea Water

以酪蛋白为蛋白源,配制蛋白质含量为19 80%～40 50%的6种精饲料,采用室内循环水养殖系统,在饱食投喂和(27±1)℃水温条件下对吉富品系尼罗罗非鱼幼鱼进行8周的饲养实验,比较其在淡水和海水中的生长及蛋白质需求。结果显示:尼罗罗非鱼在淡水和海水中生长良好,存活率分别为100%和87%～100%;随着饲料蛋白质含量增加,实验鱼的平均终重、增重率和日增重率呈线性增加,饲料系数呈线性下降,蛋白质效率也呈下降趋势。在相同的饲料蛋白水平下,上述指标在淡水鱼和海水鱼之间均无显著差异蛋白质适宜需要量为28%～32%。

A 8-week feeding trail was simultaneously conducted in two sets of recirculating rearing systems to compare the growth and protein requirement of GIFT Nile tilapia juveniles in fresh water and sea water at (27±1)℃, respectively. The juveniles were fed six purified diets containing crude protein (casein) from 19.80% to 40.50%. The results showed that tilapia fed at satiation had a good growth and survival rates of 100% and 87% in both fresh water and sea water, respectively. There were almost linear increases in final body weight and daily body weight increment with the increase in dietary protein contents,while there was decrease in protein efficiency ratio. At the same crude protein level, however, there were no significant differences in growth, survival and protein efficiency ratio in fresh water and sea water. It is recommended that the optimal dietary protein contents be 28%～32% in either freshwater or seawater.