【摘要】 从患有出血病症状的罗非鱼病灶部位分离筛选出一株高致病性菌(编号为BC-2),结合对菌落形态观察、生理生化实验及16SrDNA测序,确定该高致病菌为一种致罗非鱼死亡的蜡状芽孢杆菌.通过对健康鱼进行不同浓度致病菌的感染试验及定性数据机率的分析,可知其半数致死量(LD50)的对数值为7.534 8、感染的菌浓度为3.4×107 cfu·mL-1、置信限为95%.通过对患病鱼的不同组织器官的切片病理结构观察,可以发现鳃和肠是病变最明显的部位.更多还原

【Abstract】 A highly pathogenic bacterium(No.BC-2) was isolated from the infected hemorrhage tilapia.Combination of the colonial morphology observation,the biochemistry test and 16S rDNA sequencing,the highly pathogenic bacterium was determined as Bacillus cereus,which could cause tilapia dead.Then infective test was carried out to normal tilapias with different concentrations of the pathogen,and the qualitative probability data analysis results showed that the logarithmic concentration of LD50 was 7.534 8 with the confidence interval 95% when the infective concentration was 3.4×107 cfu·mL-1.After observing the pathological structure of different tissue and organ sections from infected tilapia,we found gill and intestine were the most evident lesion parts.更多还原