| As well as terrestrial animal,the gut of aquatic animal is also a complex ecosystem that always harbors a diverse bacterial community,thereby affecting the survival rate and quality of aquaculture.During the evolution of both the gut microbiota and the host,the gut microbial community has become an integral component of the host.The composition of gut microbiota may affect the host biology,and it plays a crucial role in health since it is involved in nutrition,pathogenesis,and immunology.Therefore,the study of intestinal flora in aquatic animals is of important theoretical significance,it can provide a scientific basis for the economic health breeding and disease prevention of aquatic animal.In this study,we chose Chinese mitten crab(Eriocheir sinensis)as experimental subject,using IlluminaMiSeq platform for high-throughput sequencing and bioinformatics software to explore the effects of gender difference and size difference on the composition of intestinal bacteria in Chinese mitten crab,and investigate the difference of the intestinal bacteria in Chinese mitten crab from three different breeding patterns.Specific results are as follows:First experiment,effects of gender and size on the composition of intestinal microflora in Chinese mitten crab.1.The gut flora of Eriocheir sinensis from West YangCheng Lake could belong to 5 phylums,9 classes and 21 genera.Tenericutes,Proteobacteria,Bacteroidetes and Firmicutes constituted the main structure of Chinese mitten crab intestinal flora.Tenericutes and Mollicutes were the first dominant intestinal phylums and classes in Yang Cheng Lake mitten crab.Mycoplasmataceae_norank and Candidatus_Hepatoplasma were the common dominant species of A,B and C three groups of samples.2.Alpha diversity analysis showed that the intestinal flora richness of male crabs was higher than female crabs,diversity contrast,the small size of male crab flora richness and diversity were higher than those of large-sized male crab;Statistical analysis showed that each group of index difference between Alpha diversity was not significant(P>0.05),gender and size factors did not cause significant impact on the richness and diversity of gut flora in Chinese mitten crab.3.Venn diagram,PC A nalysis results show that A,B and C three groups of samples consisting of overlapping and similarity greater;Heatmap analysis indicates that the intestinal microflora of male crabs were similar to female crabs,and there are some differences of microbial community structure between different size male crabs.4.LEfSe analysis found no significant abundance differences of flora exist in different specifications male crab intestine,the characteristics of flora in large-sized male crabs were mainly from Bacteroides and Proteobacteria,and Bacteroides mainly included Cytophagia;Proteobacteria mainly included Cytophagaceae and Rhodobacteraceae.the characteristics of flora in small-sized male crabs was Kocuria of Actinobacteria.Second experiment,comparative investigate of intestinal flora in Chinese mitten crab from three different breeding patterns.1.Through annotations and Statistics,all sequences were assigned to 7 phylums,11 classes,and 23 genera.At genus level,the dominant genus of pond-rised crabs were Candidatus_Hepatoplasma(33.51±31.62%),Mycoplasmataceae_norank(18.14±13.65%)and Bacteroides(10.67±10.73%);the dominant genus of enclosure-rised crabs were Mycoplasmataceae_norank(39.78±15.32%)and Candidatus_Hepatoplasma(17.34±13.60%);the dominant genus of eco-culture crabs were Prolixibacter(19.75±9.25%),Mycoplasmataceae_norank(14.84±5.56%)、Bacteroides(13.32±9.94%)and Alphaproteobacteria_unclassified(10.26±2.94%).2.Alpha diversity analysis showed that Chinese mitten intestinal flora richness and diversity of different breeding patterns are different,the performance of a sample group of ecological farming flora richness and diversity of the highest,followed by the pond group,fence culture lowest group.But statistical analysis shows that Alpha diversity index difference between the groups was not significant(P>0.05),namely the richness of the Chinese mitten crab breeding patterns under different intestinal flora diversity and the difference was not significant.3.We usied biometric methods for further analysis.Between purse seines and eco-culture groups,we found 0,2,and 4 species of significant difference(P<0.05)at three biological level(phylum,classe and genus)respectively;between pond culture and eco-culture groups,we found 2,4,and 5 species of significant differences(P<0.05)at three biological level(phylum,classe and genus)respectively;Between purse seines and pond culture groups,we found that they have only one genus of significant difference(P<0.05).This showed that the difference of intestinal microflora struction between pond and purse seines culture groups is small,and the difference of intestinal flora struction between eco-culture and the two other groups is large.This suggests that culture mode can impact the intestinal flora structure of Chinese mitten crabs,so we guess that the structure of intestinal microflora in Chinese mitten crabs is linked to food and culture water. |
