梭子蟹酵母菌人工感染实验和组织病理学初步研究

Studies on pathological lesion of Portunus trituberculatus artificially infected by candida oleophila

近年,浙江省舟山市暂养梭子蟹(Portunus trituberculatus)连续暴发“乳化病”,发病蟹均分离到一种酵母菌。本实验以该株酵母菌通过肌肉注射方式,对三疣梭子蟹、红星棱子蟹、日本鲟3 个品种的健康蟹进行了人工感染实验,以验证其致病性。结果发现,该菌株能感染试验蟹类,并出现与自然发病蟹类似的症状。从感染蟹的体液、肝胰腺、心脏等部位分离到了酵母菌,但未分离到细菌,也未发现寄生虫。酵母菌在病蟹的肝胰腺、鳃、心脏中大量侵袭,并引起这些组织发生以坏死为主的变质性病变,其病理特征主要表现为:细胞肿胀、变性、坏死,某些细胞的细胞核固缩、碎裂或崩解。初步确认该酵母菌是引发梭子蟹“乳化病”的病原。

Recently, Emulsification disease of Portunus trituberculatus has become a serious disease in crab culture industry, and resulted in a gigantic economic loss in the aquaculture industry of Portunus trituberculatus. A pathogen of yeast has been isolated from diseased crab. In this study health crabs were inoculated with this strain by the intramuscular route. During the infection experiment, the symptom of sick crab was the same as that of the nature sick one. The yeast can be isolated from muscle, heart, hepatopancreas of the infected crab but neither bacterium nor parasite has been found. Microscopically, there were pathological changes in different degrees in the gills, heart, and hepatopancreas of diseased crabs, and the pathological characteristics mainly appeared as cells swelling, necrosis, karyopyknosis or karyorhexis. Budding of yeasts presented here and there within the hemolymph vessels throughout the whole body. The result indicated that this strain was the pathogenic organism of Emulsification disease. The infection of this yeast is fatal to the crab, and most major organs and tissues appear to be invaded.