杂交鳢(乌鳢♂×斑鳢♀)及其亲本对2种病原菌的抗感染能力比较

Comparison on Anti-infection of Hybrid Snakehead(Channa argus ♂× Channa maculate ♀) and Its Parents to Two Pathogenic Bacteria

[目的]分析评价杂交鳢及亲本对病原菌的抗病力水平。[方法]通过人工感染试验方法,开展了杂交鳢(乌鳢♂×斑鳢♀)及其亲本对两种病原菌的抗感染试验。[结果]以嗜水气单胞菌为试验菌株、菌液浓度9×108 cfu/ml(100、10-1、10-2、10-3 4个稀释度)、注射剂量0.5 ml时,3 d内杂交鳢LD50平均值介于乌鳢与斑鳢间,且差异均不显著;以诺卡氏菌为试验菌株、菌液浓度7×109 cfu/ml(100、10-1、10-2、10-3 4个稀释度)、注射剂量0.5 ml时,30 d内杂交鳢LD50平均值介于斑鳢与乌鳢间,且差异也均不显著。[结论]高浓度感染时,嗜水气单胞菌、诺卡氏菌对3种鳢鱼均有极强的致病性,108 cfu/ml菌液浓度时,3种鳢鱼死亡率达100%;不过低浓度感染时致死率明显减弱,且不同品种对病原菌的耐受力有些差异。

[Objective ] The study aimed to analyze and evaluation the anti-infective level of to the pathogenic bacteria.[Method] The test of anti-infection to 2 pathogenic bacteria was conducted on the hybrid snakehead and its parents through the artificial infection test method.[Results]When Aeromonas hydrophila was the tested strain,the bacterium fluid was 9×108 cfu/ml in which there were 4 dilution grade of 100,10-1,10-2 and 10-3,the injection dosage was 0.5 ml/fish,the median lethal dose（LD50） on the hybrid snakehead was between C.argus and C.maculate,and no significant difference was found among the strains.When Nocardia seriolea was the tested strain,the bacterium fluid was 7×109 cfu/ml in which there were 4 dilution grade of 100,10-1,10-2 and 10-3,the injection dosage was 0.5 ml/fish,the median lethal dose（LD50） on hybrid snakehead was between C.maculate and C.argus,and no significant difference was found among the strains.[Conclusion] When the bacterium fluid was at high levels of infection,both A.hydrophila and Nocardia seriolea were highly pathogenic to 3 kinds of the snakehead fish.When the bacterium fluid was 108 cfu/ml,the mortality rate of the snakehead fish was 100%.When the fluid was at low level of infection,the mortality rate was significantly weakened.The different varieties had some different tolerance to the pathogenic bacteria.