梭子蟹假丝酵母菌病初步研究

Preliminary study on Candida oleophila disease in Portunus trituberculatus

2002-2003年,舟山市暂养梭子蟹连续发生被称为'乳化病'的暴发性疾病,并导致大量死亡.发病主要集中在每年10月至翌年2月低水温期的海捕暂养梭子蟹,病蟹蟹体消瘦,肌肉萎缩,横切步足,在断口处有乳白色的液体流出,打开蟹盖,盖内可见大量乳白色液体.从乳白色液体内能镜检出大量酵母菌样微生物,菌体大小为(2.3～7.8) μm×(1.3～6.5) μm,多数呈卵圆形,细胞大多单个或成对排列,多边芽殖.同时,显微组织病理观察可见病蟹肌肉、心脏、肝胰脏以及鳃等部位也可发现相同菌体.该菌可生长在TCBS上形成白色菌落,在孟加拉红上形成红色菌落,经菌体形态、培养特性及生理生化反应,鉴定为假丝酵母菌属酵母菌(Candida oleophila).人工感染试验发现,其对健康梭子蟹具有致病性,出现与自然病蟹相同的症状,并在人工感染病蟹中分离出相同菌株,表明假丝酵母菌属酵母菌是该病的病原.

An epidemic disease named“muscle emulsification disease” consecutively happened in cultured swimming crab Portuns trituberculatus during the years 2003 - 2004 in Zhousan, Zhejiang Province. This disease, with the symptoms of muscle shrink and emulsification, mainly occurred on temporarily cultured swimming crab in low water temperature from Oct. to Feb., caused serious loss. A great deal of yeast-like organism was observed from the milky emulsion in the leg, and with lid open, milky liquid was seen. as well as in muscle,heart, hepatopancreas from the disease crab. These yeast-like organism were isolated and cultured with TCBS agar and identified as Candida oleophila. Artificial challenge test showed that the isolated yeast could cause emulsification disease of health swimming crab, when injected or dipped with the cultured yeast, with the similar symptom as the naturally infected crab. oleophila was re-isolated from the artificial infected crab. The results showed that Candida oleophila was the pathogen of the muscle emulsification disease of swimming crab in Zhejiang Province in recent years.