不同杂交罗非鱼F_1代耐寒性能的研究

Cold Tolerances of F_1 Tilapia Hybrids

以3种品系尼罗罗非鱼的雌鱼作为母本,奥利亚罗非鱼的雄鱼作为父本进行杂交配对,研究杂交罗非鱼F1代的耐寒能力。应用室内人工降温方法,测定了杂交子代死亡率、累积存活率和半致死低温（LT50）等耐寒指标。结果显示,3种杂交罗非鱼的耐寒能力各不相同,埃奥鱼、湘奥鱼和吉奥鱼半致死低温分别为：8.63℃、8.23℃、7.60℃。当水温降到9.6℃时,埃奥鱼首先开始死亡,其死亡低温范围为9.6-7.5℃;湘奥鱼的死亡低温范围为9.4-6.7℃;吉奥鱼的死亡低温范围为8.9-6.3℃。通过对3种杂交罗非鱼的LT5）进行单因素方差分析,结果表明3种杂交罗非鱼中,吉奥鱼的耐寒能力相对较强,其LT50与埃奥鱼、湘奥鱼相比差异显著（P〈0.05）,而其他2种杂交罗非鱼的LT50相比差异不显著（P〉0.05）。

The tolerances of 3F1 tilapia hybrids of Oreochromis niloticus（♀）×Oreochromis aureus（♂）to cold temperatures were studied.By artificially lowering the tank water temperature,the death rate,semi-lethal low temperature（LT50）,and cumulative survival rate of the fish were monitored to determine the abilities of the F1 tilapia hybridsto survive in cold temperatures.There were significant differences in their cold tolerances among the 3F1 hybrids.Aiao began to die soon after the water temperature was reduced to 9.6℃,ranging from 9.6℃to 7.5℃.For Xiang′ao,the lethal temperature ranged from 9.4℃to 6.7℃;and,it was 8.9℃to 6.3℃for Jiao tilapia.LT50 of Aiaowas 8.63℃;that of Xiang′ao,8.23℃;and,that of Jiao,7.60℃.It appeared that Jiao was a significantly more hardy tilapiathan either Aiao or Xiang′ao（P0.05）.