吉富罗非鱼家系构建及抗病力检测

文章以吉富罗非鱼（GIFTstrainOreochromisniloticus）为研究对象，按照1雄配1雌原则进行家系配对，待家系鱼生长至50～60g·尾“时人工感染无乳链球菌（Streptococcusagalactiae）（菌株GD001）。通过对GD001菌株半数致死浓度测定及各家系感染死亡率的统计，研究了GD001无乳链球菌感染对各家系吉富罗非鱼抗病力的影响。结果表明，1）配对成功家系67个，经繁殖性能筛选后留种53个，家系留种率为79．1％；2）GD001菌株的半数致死浓度为4×108cfu·mL－1，感染后2～6d为死亡高峰期；3）GD001菌感染53个家系后有11个家系的成活率在90％以上，15个家系的成活率在70％～89％，19个家系的成活率在30％～69％，8个家系的成活率低于30％，表明不同家系对GD001菌株的抗病力存在着显著的差异（P〈0．05）。

Family establishment and disease resistance of different families of GIFT Nile tilapia Oreochromis niloticus

The families of GIFT strain Nile tilapia （ Oreochromis niloticus） were established by pair-mating and the juveniles （50～ 60 g） in each family were challenged by Streptococcus agalactiae （ GD001 strain）. According to the median lethal concentration （ LC50 ） and infection mortality rate of each family, we evaluated the disease resistance of GIFT strain Nile tilapia to the challenge of S. agalactiae GDO01 strain. The results show that： 1 ） 67 full-sibling families were successfully established, and 53 families （79. 1% ） were maintained based on their reproductive performance; 2） The LC50 of S. agalactiae GD001 strain to tilapia was 4 × 108 cfu·mL-1 ; 3 ） Among the 53 families, 11 families had survival rate of over 90%, 15 families （70%～89% ）, 19 families （30%～ 69% ） and 8 families （ less than 30% ）. It is suggested that the disease resistances of different GIFT families challenged with S. agalactiae were sig- nificantly different （ P 〈 0. 05 ）.