仿刺参幼体烂胃病及其致病原鉴定

山东、辽宁两省在仿刺参（Apostichopus japonicus）苗种培育期间的5-7月，耳状幼体易发生一种以胃壁增厚、萎缩、溃烂为主要特征的“烂胃病”。从患烂胃病的耳状幼体中分离到1株细菌LW-1，人工回接感染实验证实其具有较强的致病性，并与自然发病症状相同。通过API半自动化鉴定和常规的生理生化试验的结果表明，LW-1具有弧菌属的特征，其表型特征与灿烂弧菌（Vibrio splendidus）相似。对该菌株16S rRNA基因序列分析和构建系统发生树。结果显示，菌株LW-1与灿烂弧菌的亲缘关系最近，相似率达到99．8％。菌株LW-1可鉴定为灿烂弧菌，并视为耳状幼体烂胃病的致病原之一。通过对多起仿刺参苗期烂胃病的调查研究表明，烂胃病病原也具有多样性和复杂性，并与投喂老化腐败的单胞藻饵料有关。

Stomach ulcer disease in auricularia of sea cucumber(Apostichopus japonicus) and its etiological identification

A high mortality occurred in reared auricularia of sea cucumber Apostichopus japonicus along the coastal area of Shandong and Liaoning Provinces from May to July in recent years.The syndrome was called stomach ulcer disease,which was characterized by hyperplasia,atrophy,and ulceration in the stomach tissues.The disease can cause high mortality of auricularia(up to 70%-90%),often resulting in failure of breeding practice.One dominant bacterium LW-1 was often isolated from the affected auricularia,and it was verified to be the pathogen causing the stomach ulcer disease through an artificial infection test.Traditional physiological and biochemical methods as well as semi-automatic identification through API system were applied in the bacterial classification.The result showed that LW-1 had the similiar characters as Vibrio sphendidus,having short rods with a single polar flagellum,forming yellow colony on TCBS agar.Further results from 16S rRNA sequence analysis showed that the sequence of bacterium LW-1 was highly identical to Vibrio splendidus,with 99.8% identity.Thus bacterium LW-1 was identified as V.splendidus,and regarded as one of the major pathogens causing stomach ulcer disease.In addition,this investigation also revealed that the causative pathogens are complicated and comprise more microbes associated with the disease condition,and the occurrence of the disease was associated with the unadvisable use of aging microalgae.This paper is the first report to reveal the causative agents and the pathogenisis of stomach ulcer disease.It is useful to provide information and techniques for healthy management in sea cucumber cultivation.Journal of Fishery Sciences of China,2006,13(6):908-916]