摘要
【目的】确诊北京地区某养殖场金鱼发生烂鳃病的病原。【方法】采集具有临床症状的濒死金鱼,制作鳃组织的水浸片进行寄生虫和真菌观察,取肝脏、肾脏、脾脏、鳃组织开展金鱼造血器官坏死病病毒(GFHNV)检测。同时,从鳃上分离病原菌,分析病原菌的形态特征、理化特性、分类地位及药物敏感性等特性;采取鳃组织划痕浸泡和未划痕浸泡方式开展病原菌的人工感染试验。【结果】自然发病鱼鳃丝上有少量车轮虫寄生,未观察到真菌菌丝,GFHNV核酸检测呈阴性。从鳃组织分离到大量假根状菌落,该菌株为革兰染色阴性长杆菌,菌体大小(0.5~0.7)μm×(4~8)μm,氧化酶、过氧化氢酶阳性,降解明胶和硫酸软骨素,产生硫化氢,不发酵葡萄糖等糖醇类,基于16S rDNA序列构建的进化树与柱状黄杆菌聚为一枝,确认分离菌为柱状黄杆菌(Flavobacterium columnare),基因型Ⅰ型。划痕浸泡的各组金鱼均出现死亡,症状与自然发病鱼相似,划痕对照组和未划痕浸泡组均未出现死亡,经计算该菌对金鱼的半数致死量(LD 50)为8.8×10^(6) CFU,为弱毒株。该菌对恩诺沙星、盐酸多西环素和磺胺类药物敏感,而对试验的其他抗菌药物不敏感。【结论】本研究分离的柱状黄杆菌弱毒株可造成鳃组织破损金鱼的死亡,结合实践生产中许多金鱼感染少量车轮虫造成鳃组织破损但未出现发病死亡的病例,确定这起慢性、低死亡率的金鱼烂鳃病是由车轮虫和柱状黄杆菌弱毒株混合感染所致,而继发感染的柱状黄杆菌弱毒株是造成金鱼死亡的主要原因。
【Objective】The experiment was aimed to confirm the pathogen of gill rot disease in a goldfish farm in Beijing.【Method】The moribund goldfishes with clinical symptoms were collected,and wet mount of gill tissue were prepared for observing parasites and fungal hypha.Liver,kidney,spleen and gill tissues were collected to detect Goldfish hematopoietic necrosis virus(GFHNV).At the same time,the pathogenic bacteria were isolated from the gill,and the morphological characteristics,physical and chemical characteristics,taxonomic status and drug sensitivity of the pathogenic bacteria were analyzed.The experiments of artificial infection of pathogenic bacteria were carried out by the methods of gill tissue scratch soaking and non-scratch soaking.【Result】There was a small amount of trichomyces parasitica on the gill filaments of naturally occurring fish,no fungal hypha was observed,and GFHNV nucleic acid test was negative.A large number of rhizoid colonies were isolated from gill tissue.The strain was Gram-negative longobacterium,with a body size of(0.5-0.7)μm×(4-8)μm.It was positive for oxidase and catalase,degraded gelatin and chondroitin sulfate,produced hydrogen sulfide,and did not fermentation glucose and other sugar alcohols.The phylogenetic tree constructed based on 16S rDNA sequence was polymerized with Flavobacterium columnare.The isolated bacteria was identified as Flavobacterium columnare,genotypeⅠ.All groups of goldfish soaked in scratches experienced death,and the symptoms were similar to those of the naturally infected fish.No death occurred in scratch control group and non-scratch soaking group.The calculated median lethal dose(LD 50)of the bacteria to the goldfish was 8.8×10^(6) CFU,which was a mild strain.The bacterium was sensitive to enrofloxacin,doxycycline hydrochloride and sulfonamides,but not to the other antimicrobials tested.【Conclusion】The weakly virulent strains of Flavobacterium columnare isolated in this study could cause gill tissue damage and death in goldfish.Based on pra
作者
王小亮
曹欢
王姝
张文
王静波
吕晓楠
王澎
徐立蒲
WANG Xiaoliang;CAO Huan;WANG Shu;ZHANG Wen;WANG Jingbo;LYU Xiaonan;WANG Peng;XU Lipu(Beijing Aquatic Product Technology Promotion Department,Beijing 100176,China)
出处
《中国畜牧兽医》
CAS
CSCD
北大核心
2023年第11期4612-4620,共9页
China Animal Husbandry & Veterinary Medicine
基金
现代农业产业技术体系北京市渔业创新团队项目(BAIC07-2023-09)
综合保障项目(北京市水产技术推广站业务运转)。
关键词
金鱼
烂鳃病
柱状黄杆菌
药物敏感性
goldfish
gill rot disease
Flavobacterium columnare
drug sensitivity
