养殖黄颡鱼腹水症病原研究

Pathogenic Bacteria Causing Ascites Disease of Cultured Yellow Catfish(Pelteobagrus fulvidraco)

对近年来黄颡鱼养殖过程中暴发的腹水症的病原进行了研究。病鱼症状主要为游动迟缓,体表、肝脏充血,积有腹水,后期伴有皮肤溃烂等,采用光镜及透射电镜超薄切片观察,生理生化指标鉴定及16SrDNA同源性分析及系统发育树构建等方法,对从多处组织中分离获得的病原菌进行了鉴定:其形态特征及生理生化指标符合迟钝爱德华氏菌特点,GenBank中同源序列检索结果显示,该菌与迟钝爱德华氏菌的16SrDNA序列同源性高达99%,系统进化树中与迟钝爱德华氏菌自然聚为一支。

In recent years,a great number of yellow catfish （Pelteobagrus fulvidraco）were sick and finally died,in the fishery ponds of Jiangsu province, with the distinctness symptom of belly tumidity, blood in the liver and body surface,no food intake,and soliquoid. In this paper,a dominant bacterial was purified from the ascites,liver, gill and canker skin of the sick yellow fish from several farms. With the help of light microscope,TEM, biochemical characteristics of the bacterial, and the molecular systematic （phylogenetic tree based on 16S rDNA sequences）, the bacterial was identified. It was concluded that the bacterial isolated from the sick yellow fish above, was Edwardsiella tarda, which induced the serious Hemorrhagic Sapticemia disease in the fishery ponds in Jiangsu before, with the homology of 99%, and together with Edwardsiella tarda in phylogenetic tree,what＇s more,with the same biochemical characteristics as Edwardsiella tarda. It was the first report about the prevalence of Edwardsiella tarda in yellow catfish.