摘要
海盘虫Haliotrema sp.病是双斑东方鲀Takifugu bimaculatus养殖生产上主要致死性病害之一,为深入了解该病,本研究中从2016年6月—2019年6月对池塘养殖的双斑东方鲀海盘虫病发病情况进行调查,利用形态学观察、几丁质结构特征分析和分子生物学技术对病原虫体进行鉴定与分析,并观察病鱼鳃组织病理变化。结果表明:该病春末夏初和秋季易发,发病时病鱼主要症状为缓游于水面,食欲减退或不摄食;体色苍白,体形消瘦,尾鳍、臀鳍缺损,鳃丝上有大量海盘虫虫体,鳃片黏液多,肝脏、脾脏充血;病原虫体经形态学观察和几丁质结构特征分析,鉴定为双裂海盘虫H.bilobatus,双斑东方鲀为其宿主新记录;对该虫体18S rDNA和28S rDNA(C1~D2区)基因片段扩增测序分析显示,其18S rDNA序列(1282 bp)与栉齿刺尾鲷海盘虫H.ctenochaeti、丝蝴蝶鱼海盘虫H.aurigae等序列相似,一致性达97.68%~98.30%,其28S rDNA序列(886 bp)(C1~D2区)与镰茎海盘虫H.sicklocirrus序列最相似,但一致性仅达90.28%;基于18S rDNA和28S rDNA序列构建的系统发育树均显示,双裂海盘虫单为独立分支,为NCBI基因数据库未登记海盘虫属虫种;鳃组织病理学观察发现,虫体寄生导致双斑东方鲀鳃丝机械损伤、鳃上皮组织增生或脱落,甚至引起鳃组织病变、出血,重度感染会引发鳃小片坏死、崩解,大量黏液浸润鳃丝,从而使病鱼呼吸困难而死亡。研究表明,双裂海盘虫为福建池塘养殖双斑东方鲀海盘虫病的感染病原,该病春末夏初和秋季易流行。
The incidence of haliotremasis was investigated in twin-spot puffer Takifugu bimaculatus cultured in ponds along the coastal area of Fujian Province from June 2016 to June 2019,and the morphology and chitin structure feature of parasite Haliotrema sp.were observed and analyzed by molecular biology.The haliotremasis was found to occur in late spring,early summer,and autumn,in both juvenile and adult fish.The clinical symptoms included slow swimming in upper layer,anorexia,pale body color,weight loss,caudal and anal fin defect,and hemorrhagic liver and spleen.There were a large number of worms on the mucus covering the gill lamellae and gill filaments,which was identified as Haliotrema bilobatus based on the morphological observation and structural characteristics of chitin.This is the first report that H.bilobatus caused haliotremasis in twin-spot puffer.The 18S rDNA(1282 bp)and 28S rDNA gene sequence(C1-D2)region(886 bp)and sequence alignment analysis showed that H.bilobatus had the similar 18S rDNA gene to that of H.ctenochaeti,H.angelopterum,H.aurigae,H.leporinus,H.scyphovagina,and H.macracantha(with the identity of 97.68%-98.30%),with the most close to H.sicklocirrus(only identity of 90.28%)in 28S rDNA gene.Phylogenetic trees constructed based on 18S rDNA and 28S rDNA genes revealed that H.bilobatus is in an independent branch.The histopathological observation of gill tissue showed that H.bilobatus caused the damage of gill filaments,resulting in the proliferation or shedding of gill epithelial tissues.In the case of severe infection,the gill fragments were necrotic,disintegrated,and infiltrated with a large amount of mucus,interfering oxygen exchange across the gill surface and causing fish to die due to hypoxia.The findings indicate that H.bilobatus is a pathogen causing haliotremasis usually in late spring,early summer,or fall in twin-spot puffer cultured in ponds in Fujian Province.
作者
吴建绍
陆振
杨求华
朱志煌
周宸
葛辉
WU Jianshao;LU Zhen;YANG Qiuhua;ZHU Zhihuang;ZHOU Chen;GE Hui(Fisheries Research Institute of Fujian Province, Xiamen 361013, China;Zhejiang Provincial Mariculture Research Institute, Wenzhou 325005, China)
出处
《大连海洋大学学报》
CAS
CSCD
北大核心
2022年第1期10-18,共9页
Journal of Dalian Ocean University
基金
福建省属公益类科研院所基本科研专项(2015R1003-15,2020R1013005)
福建省种业创新与产业化工程项目(2017FJSCZY03)。
关键词
双斑东方鲀
海盘虫病
双裂海盘虫
形态学特征
分子生物学
病理观察
Takifugu bimaculatus
haliotremasis
Haliotrema bilobatus
morphological observation
molecular biology
histopathological observation