天津地区中华绒螯蟹及养殖环境中二尖梅奇酵母流行情况调查  

Investigation on the prevalence of Metschnikowia bicuspidata in Eriocheir sinensis and culture environment in Tianjin area

作　　者：徐晓丽 郝爽[1] 李媛媛 郝俊 贾磊[1] 耿绪云[1] 张鹏 XU Xiao-li;HAO Shuang;LI Yuan-yuan;HAO Jun;JIA Lei;GENG Xu-yun;ZHANG Peng(Tianjin Fishery Research Institute,Tianjin 300221,China;Tianjin Agricultural University,Tianjin 300191,China;Agricultural Development Service Center of Beichen District,Tianjin 300400,China)

机构地区：[1]天津市水产研究所,天津300221 [2]天津农学院,天津300191 [3]天津市北辰区农业发展服务中心,天津300400

出　　处：《中国预防兽医学报》2023年第11期1127-1134,共8页Chinese Journal of Preventive Veterinary Medicine

基　　金：天津市科技计划项目(22YFZCSN00200、22ZYCGSN00310、21YFSNSN00090);天津市农业农村委天津市淡水养殖产业技术体系创新团队项目(ITTFRS2021000)。

摘　　要：为探究近年天津地区中华绒螯蟹(河蟹)“牛奶病”病原二尖梅奇酵母的感染情况及传播特点,本研究于2020年~2022年间,从天津地区稻蟹综合种养殖企业和育苗场采集各生长阶段河蟹样品(包括溞状幼体、大眼幼体、种蟹等)236批共8163只,环境样品51批共116份(包括养殖水体、底泥、稻田野杂鱼虾等)。将处理过的上述样品涂布孟加拉红固体平板,28℃培养48 h后观察菌落形态。采用PCR检测上述样品及疑似菌落中的二尖梅奇酵母并测序比对。结果显示,部分样品在固体平板上长出乳白色、边缘光滑、不透明的圆形菌落,镜检观察可见菌体长约3μm~7μm,呈大量多边出芽生殖的圆形或卵圆形。PCR结果显示部分样品出现339 bp的目的条带,测序后于NCBI数据库中比对结果显示,测序片段与二尖梅奇酵母相应基因序列高度一致。统计结果显示,河蟹样品总阳性率14.71%(1201/8163)、批次阳性率34.32%(81/236),养殖环境样品总阳性率12.07%(14/116)、批次阳性率13.73%(7/51)。根据PCR检测结果按月份统计2020年~2022年间河蟹二尖梅奇酵母的阳性率,分析该病原感染的季节流行规律;在该病原流行季节,按年份统计该病原的阳性率以分析该病原的流行趋势。对河蟹养殖环境经PCR检测该病原,并结合不同生长阶段河蟹及其环境样品的PCR检测结果,分析二尖梅奇酵母的传播途径,并分析该病原感染对河蟹养殖经济效益的影响。结果显示:3、4、5、6月份养殖河蟹的个体阳性率分别为26.22%(392/1495)、52.7%(293/556)、58.37%(408/699)和10.24%(43/420),批次阳性率分别为55.56%(25/45)、80.95%(17/21)、83.33%(25/30)和26.32%(5/19),其中4、5月份个体阳性率和批次阳性率均显著高于其他月份(P<0.05),7月~11月未检到该病原;对2020年~2022年每年3月~6月该病原感染河蟹的统计结果显示,2020年、2021年、2022年越冬后河蟹个体阳性率分别为37.17%(139/374)、43.69%In order to explore the infection situation and transmission characteristics of Metschnikowia bicuspidata leading to"milky disease"in Eriocheir sinensis in Tianjin in recent years,this study conducted research from integrated rice crab breeding enterprises and nurseries in Tianjin between 2020 and 2022.8163 crabs(include zoaeas,megalopas,broodstock crabs)and 116 culture environmental samples from major breeding zones(include water,sediment,wild fish and shrimp)were collected.The samples were spread on Bengal Red culture medium and cultured at 28℃for 48 hours to observe the colony morphology.PCR was used to detect M.bicuspidata in the above samples and suspected colonies,and sequenced for comparison.The results showed that milky-white,smooth-edged,opaque round colonies grew on the solid plates of some samples.Microscopic examination showed that the bacterial cells were about 3μm to 7μm long and were round or oval in shape with a large number of polygonal buddings.PCR results showed that 339bp target bands were present in some samples.After sequencing,they were compared in the NCBI database.The results showed that the sequenced fragments were highly consistent with the corresponding gene sequences of M.bicuspidata.The statistical results showed that the overall positive rate of crab samples was 14.71%(1201/8163),and the batch positive rate was 34.32%(81/236).The overall positive rate of culture environmental samples was 12.07%(14/116)and the batch positive rate was 13.73%(7/51).According to the results of PCR detection,the positive rate of M.bicuspidata was calculated by month from 2020 to 2022,and the seasonal prevalence of the infection was analyzed.During the epidemic season of the disease,the positive rate of the disease was counted by year to analyze the epidemic trend of the disease.PCR was also used to detect M.bicuspidata in the crab culture environment,and combined with the PCR results of crabs and their environmental samples at different growth stages,the transmission route of the disease was analyzed

关 键 词：中华绒螯蟹 二尖梅奇酵母 牛奶病 流行情况调查 

分 类 号：S945[农业科学—水产养殖]