Microbial Diversity Analysis Of Cultured Chinese Mitten Carb(Eriocheir Sinensis) And Its Environment In Shanghai Suburb

Chinese mitten crab(Eriocheir sinensis),an omnivorous aquatic animal,is an important economic product of aquaculture in China.Microorganisms inside and outside the organism play an important role in the growth and development of organisms as well as other important life activities.However,there are few studies about the microbial diversity in Eriocheir sinensis and breeding environment so far.To understand the microbial diversity in Eriocheir sinensis,and further provide a new idea for the research of high-quality breading of Eriocheir sinensis aquaculture,we collected a series of samples in the aquaculture base around Shanghai,including: intestines and gills of Eriocheir sinensis,and samples of feeding water,sediment and aquatic weeds in the breeding environment.Then,use nucleic acid extraction,genomic DNA library construction,Next-generation sequencing and other technologies to obtain metagenomic data in all samples respectively,and performed bioinformatics analysis of the sequenced data.The results are follows: 1.Analysis of microbial diversity of Eriocheir sinensis in 8 breeding plants in suburbs of Shanghai:The predominant strains in the gill of Eriocheilae sinensis in 8 aquatic farms in the suburbs of Shanghai are Proteobacteria,Actinomyces,Bacteroides,Firmicutes and Saccharibacteria.The predominant species in the intestinal tract are Proteobacteria,Firmicutes,Tenericutes and Bacteroidetes.In some ponds,Actinomycetes and Saccharibacteria are also observed.Compared with gills,there are fewer organisms of Flexobacteria in the intestinal.PCA and inter-group differences showed that there were common microorganisms and different microorganisms in Eriocheir sinensis in different environments,the microbial structure of the gill was more affected by the environment than that of the intestinal tract.2.Effects of cyanobacteria bloom on microbial diversity of Eriocheir sinensisBoth the cyanobacteria group and the control group contained Bacteroidetes and Proteobacteria in their intestines and gills,however,Actinomycetes only existed in their gills,but not in intestines.In the cyanobacteria group,a large area of the intestinal tract contained the species of Tenericutes,while in the control group,the species of Tenericutes only in the gill and most of the contents were not high.The intestines all contained certain amounts of Firmicutes,which were also present in some control samples.VEEN figure showed that the total number of OTU in the intestinal tract,gill and environment samples of cyanobacteria bloom group and control group was 355,321 and 222,respectively.The NMDS diagram shows that the structure distance of the intestinal flora of river crabs in different environments is very short,with more parts overlapping,while the microbial composition of the gills is relatively independent,with only a small part close.This was also confirmed by inter-group difference detection,which showed that there were more species with differences in gills than in intestines.3.Effects of different feeds on microbial diversity of Eriocheir sinensisComparing the above experiments,the dominant species of intestinal and gill microbes in animal feed pond and feed pond showed no significant difference at the level of phylum,and different feeds had little effect on intestinal and gill in the detection of inter-group differences.According to the analysis of VEEN diagram,the total OTU of intestinal tract and gill are 402 and 295 respectively,and the total is one-third more than the gills.The NMDS charts show that the microorganisms in gill is more diverse than which in the intestine.We were speculated that one group was pellet feed fed,and the other group was fed by pellet feed with seawater feed fish,little difference in feed composition,which didn't impact microbial structure.