摘要
在自然感染无乳链球菌(Streptococcus agalactiae)的罗非鱼(Oreochromis niloticus)成鱼、稚鱼和自然携带无乳链球菌的罗非鱼体内分别获得14株、4株和2株无乳链球菌。临床和组织病理学分析显示,罗非鱼成鱼出现无规则游动,脑、眼眶、鳃和鳍条充血,眼球突出、白浊,内脏器官肿大、充血,以肾小管玻璃样变性、脑膜炎和心外膜炎等组织病理学变化为特征;罗非鱼稚鱼体表无明显症状,但部分内脏器官呈现肿大、充血现象,以脾脏血管区出血、肾小管上皮细胞变性、脑组织炎症反应较轻为其主要组织病理学特征。此外,罗非鱼胃固有层内及稚鱼肝脏组织中有大量的嗜酸性粒细胞浸润,可观察到无乳链球菌在成鱼的脑、心脏以及稚鱼肝脏中增殖;自然携带无乳链球菌的罗非鱼临床症状和组织学病变均不明显。PCR检测发现,各无乳链球菌毒力基因谱相同,但自然感染无乳链球菌的罗非鱼成鱼、稚鱼和自然携带无乳链球菌的罗非鱼的病理学损伤差异显著。
We isolated 14,4 and 2 strains of Streptococcus agalactiae from naturally infected adult and juvenile tilapia as well as tilapia naturally carrying S.agalactiae,respectively.The clinical signs and anatomy changes of adult tilapia were as follows:erratic swimming,congestion of brain,eyeballs,gills and fins,exophthalmia,corneal opacity and swelling of visceral organs,which were characterized by histopathological changes with tubular hyaline degeneration,meningitis and epicarditis.The clinical symptoms of juvenile tilapia were not obvious,but some of the internal organs showed swelling and congestion,characterized by main histopathological features of hemorrhage of spleen vascular area,degenerated renal tubular epithelial cells and milder inflammatory response in brain tissue.In addition,eosinophil infiltration was found in the lamina propria of tilapia and in the liver of juvenile fish.It was observed that S.agalactiae proliferated in the brain and heart of adult fish and in the liver of juvenile tilapia,respectively.The clinical symptoms and histological lesions in tilapia carrying S.agalactiae were not obvious.The results of PCR detection show that all the S.agalactiae strains had the same virulence gene profiles,but there were significant differences in pathological damages among adult fish,juvenile fish and tilapia carrying S.agalactiae.
作者
谢云丹
冯娟
刘婵
邓益琴
王江勇
苏友禄
XIE Yundan;FENG Juan;LIU Chan;DENG Yiqin;WANG Jiangyong;SU Youlu(College of Fisheries,Tianjin Agricultural University,Tianjin 300384,China;Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization,Ministry of Agriculture and Rural Affairs,South China Sea Fisheries Research Institute,Chinese Academy of Fishery Sciences,Guangzhou 510300,China)
出处
《南方水产科学》
CAS
CSCD
北大核心
2019年第2期47-57,共11页
South China Fisheries Science
基金
国家自然科学基金项目(31502210)
"广东特支计划"科技青年拔尖人才项目(2016TQ03N275)
广州市珠江科技新星项目(201610010015)
关键词
罗非鱼
无乳链球菌
比较病理学
自然感染
毒力基因谱
tilapia
Streptococcus agalactiae
comparative pathology
naturally infection
virulence gene profile
