凡纳滨对虾亲虾持续性死亡病因的初步研究

Preliminary Study on Pathogeny Associated with Sustained Death in Parent Shrimp of Litopenaeus vannamei

2014年夏季,广西发生一起凡纳滨对虾(Litopenaeus vannamei)亲虾持续死亡病例,患病亲虾部分个体肝胰腺明显萎缩,腹节肌肉轻微白浊,个体呈黄鳃。采用TCBS选择培养基从病虾和亲虾池水中分离细菌,对各分离菌株16S rRNA基因序列进行扩增、测序,运用DNAStar软件进行序列分析;利用石蜡组织切片技术对病虾肝胰腺、鳃丝、肌肉、肠等器官组织进行病理分析。结果从病虾中分离到5株优势菌,均鉴定为巴西弧菌(Vibrio brasiliensis);从亲虾池水中分离到2株巴西弧菌,1株副溶血弧菌(Vibrio parahaemolyticus),1株哈氏弧菌(Vibrio harveyi)。推测此次亲虾发病是由于投喂了弧菌数量超标的牡蛎及鱿鱼,巴西弧菌可能为致病菌。组织病理观察发现患病亲虾多个器官组织均发生不同程度的病变,且肝胰腺呈现显著的弧菌病病理变化。

In summer of 2014,sustained death occured in parent shrimp of Litopenaeus vanname in Guangxi. The hepatopancreas of infected shrimps turned atrophic,the muscles of uromere turned whitish,and the gill turned yellow. The bacteria were isolated from the infected shrimps and the pond water by TCBS. The 16 SrRNA were amplified,sequenced and analyzed by DNAStar. Then,the hepatopancreas,gill filaments,muscles and guts were researched on histopathological changes. The results showed that five strains isolated from the infected shrimps were identified as V. brasiliensis. Moreover two V. brasiliensis strains,one V. harveyi strain and one V. parahaemolyticus strain were isolated from the pond water. Presumably feeding by oyster and sleeve-fish with overproof amount of vibrios might be the pathogeny,and the V. brasiliensis might be the pathogen. The histopathology research showed that there were some changes in many organs and tissues,and the hepatopancreas showed obvious histopathological changes caused by vibrio.