The morbidity and mortality peak of farmed Procambarus clarkii occurs around May every year,a phenomenon known as"Black May"disease(BMD).Increasing evidence shows that the intestinal flora is closely related to host health.We analyzed and compared the microbiota of healthy and BMD-affected P.clarkii intestines.The results show that there was no significant difference in bacterial α-diversity(richness P=0.59;evenness P=0.43;and diversity P=0.052)between the diseased group and the control group.Four dominant phyla in the intestines of crayfish in the control group,namely Tenericutes(30.86％),Bacteroidetes(29.99％),Firmicutes(22.23％),and Proteobacteria(15.23％),were identified.However,a striking shift in the microbial composition were found in the intestines of P.clarkii with BMD.Bacteroidetes was a dominant phylum in healthy P.clarkii,whereas the prevalence was low in diseased P.clarkii(1.87％).By contrast,the prevalence of Proteobacteria was significantly higher(P＜0.05)in P.clarkii with BMD than in P.clarkii without BMD.Candidatus Bacilloplasma,Bacteroides,Vibrio,and Aeromonas showed significant differences(P＜0.05)at the genus level.Tax4Fun function prediction indicated that the relative abundance of genes involved in energy metabolism in the intestinal flora of P.clarkii with BMD was significantly reduced(P＜0.05).Therefore,BMD can change the composition of the intestinal microbiota of P.clarkii.This study contributes to the understanding of the relationship between intestinal flora and host especially in aquatic animals.

Jie GONG;Guoqing SHEN;Mengru ZHU;Ming ZHAN;Changjun XI;Yan SHUI;Zenghong XU;Huaishun SHEN

Wuxi Fisheries College,Nanjing Agricultural University,Nanjing 210095,China;Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization,Ministry of Agriculture,Freshwater Fisheries Research Center,Chinese Academy of Fishery Sciences,Wuxi 214081,China

海洋湖沼学报（英文版）

[1]Jie GONG;Guoqing SHEN;Mengru ZHU;Ming ZHAN;Changjun XI;Yan SHUI;Zenghong XU;Huaishun SHEN-.16S rRNA gene sequencing analysis on changes in the intestinal flora of Procambarus clarkii with"Black May"disease)[J].海洋湖沼学报（英文版）,2022(05):2068-2079

Bacilloplasma

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