3种不同遗传型罗非鱼的耐盐性和生长性能的比较

Comparison of Salinity Tolerance and Growth Performance among Tilapia with Three Genetic Types

比较了尼罗罗非鱼、尼罗罗非鱼♀×萨罗罗非鱼♂F2(尼萨F2)以及尼罗罗非鱼♀×(尼罗罗非鱼♀×萨罗罗非鱼♂)F1♂(回交一代)3种不同遗传型罗非鱼群体鱼苗耐盐性能、鱼种与成鱼阶段的生长性能差异。急性致死试验结果显示,尼萨F2平均存活时间、50%存活时间、96h半致死浓度显著高于回交一代和尼罗罗非鱼(P<0.05),回交一代平均存活时间显著高于尼罗罗非鱼,50%存活时间和96h半致死浓度略高于尼罗罗非鱼(P>0.05);慢性致死试验结果显示,尼萨F2、回交一代、尼罗罗非鱼的50%死亡盐度分别为73±5.66、71.67±4.5、58.33±3.68,尼萨F2和回交一代半致死盐度显著大于尼罗罗非鱼(P<0.05)。苗种阶段,盐度为0和15时,尼罗罗非鱼日均质量增加率显著大于尼萨F2和回交一代(P<0.05),回交一代大于尼萨F2(P>0.05);盐度为20及25时,尼萨F2日均质量增加率显著大于回交一代和尼罗罗非鱼。成鱼阶段,盐度为0时,尼罗罗非鱼日均质量增加率大于回交一代和尼萨F2(P>0.05);盐度为15、20和25时,尼萨F2日均质量增加率显著大于回交一代和尼罗罗非鱼(P<0.05)。研究结果为耐盐罗非鱼杂交育种提供了基础资料。

The salinity tolerance of fry and growth rate of juveniles and adults were compared among tilapia with three genetic background （Oreochromis niloticus , O. niloticus ♀× Sarotherodon rnelanotheron ♂ F2 and O. niloticus♀- × （0. niloticus♀- × S. melanotheron ♂ F1）♂. The acute salinity tolerance test showed that the hybrids O. niloticus ♀× S. melanotheron ♂ F2 had significantly higher mean survival time （MST）, median survival time （ST50） and median lethal salinity-96h （MLS-96） than the hydrids O. niloticus and backcrossing BC1did （P〈0. 05）. There were higher MST, ST50 and MLS-96 in baekcrossing BC1 than those in the tilapis O. niloticus. Chronic salinity tolerance test revealed that the hybrid O. niloticus ♀×S. melanotheron ♂ F2 had MLS-X of 73±5.66, the hybrid backerossing BC1 58.33±3.68, and tilapia O. niloticus 71. 67 ± 4. 5, the hackcrossing BC1 being significantly higher than tilapia O. niloticus （P〈0. 05）, and lower than the hybrid O. niloticus♀× S. melanotheron ♂ F2 （P〉0. 05）. The juvenile O. niloticus had significantly higher daily weight gain than the hybrid O. niloticus ♀ × S. rnelanotheron ♂ F2 and backcrossing BC1 did under 0 and 15 salinities （P〈0.05）. However, the hybrid O. niloticus ♀× S. melanotheron ♂ F2 showed higher daily weight gain than tilapia O. niloticus and backcrossing BC1 at a salinity of 20 and 25 （P〈0.05）. The adult tilapia O. niloticus had higher daily weight than backerossing BC2 and the hybrid O. niloticus ♀ × S. melanotheron ♂ F2 did at a salinity of O. At a salinity of 15, 20 and 25, however, the hybrid O. niloticus♀× S. melanotheron ♂ F2 showed greater daily weight gain than backcrossing BC1 and O. niloticus did. These findings provide some basic data for hybridization breeding of tilapia with high salinity tolerance.