罗非鱼湖病毒对稀有鮈鲫(Gobiocypris rarus)的感染研究

Infection Study of Rare Minnow(Gobiocypris rarus) by Tilapia Lake Virus(TiLV-2017A)

罗非鱼湖病毒(TiLV)感染引起的罗非鱼湖病毒病(TiLVD)对全球的罗非鱼养殖业造成了严重威胁。TiLV不仅可感染罗非鱼及其变种,也可感染其他鱼类。稀有鮈鲫是一种优良的小型实验鱼,为探究TiLV对稀有鮈鲫的感染特性,用毒株 TiLV-2017A 对稀有鮈鲫进行腹腔注射感染,对感染后稀有鮈鲫的临床症状、病毒载量、组织病理和免疫基因的表达进行分析。结果表明:TiLV-2017A可感染稀有鮈鲫,死亡率约为10%,病毒载量在第13天达到峰值,为1.582×10;拷贝数·μL^(-1);对相关免疫基因进行检测,发现稀有鮈鲫白细胞介素-8(IL-8)、NK细胞增强因子(NF-κB)、白细胞介素-1β(IL-1β)、Mx蛋白(Mx)、Toll样受体3(TLR3)、髓样分化因子(MyD88)、α-干扰素(IFN-α)和 Toll 样受体 5(TLR5)等免疫相关基因在各组织中均有不同程度的上调,在肠中上调较为显著。H.E染色结果显示肝脏中肝细胞肿大、脾脏和肾脏中噬铁血黄素增加、鳃组织中鳃丝部分断裂等病理症状。

Tilapia lake virus disease caused by tilapia lake virus (TiLV) infection poses a serious threat to tilapia farming worldwide. The TiLV could infect not only tilapia and its variants, but also other fish species. In this study, the infection characteristics of TiLV on rare minnow, a suitable small experimental fish were investigated.The virus TiLV-2017A was injected intraperitoneally to infect rare minnow, then the clinical symptoms, viral load,histopathology and immune gene expression were analyzed. The results showed that TiLV-2017A could infect rare minnow with a mortality rate of 10%, and the viral load peaked at 1.582×10;copies·μL^(-1) at 13 d. Detection of relevant immune genes reveals increased expression of interleukin- 8 (IL- 8), nuclear factor- kappa B (NF- κB)interleukin- 1β (IL- 1β), Mx protein (Mx), Toll- like receptor 3 (TLR3), myeloid differentiation factor (MyD88)alpha-interferon (IFNα) and Toll-like receptor 5 (TLR5) in all the tissues, with most significant upregulation in the intestine. The results of H.E staining also displayed enlarged hepatocytes in the liver, increased iron phagocytosis in the spleen and kidney, and partially broken gill filaments in the gill tissue.