Comparative Study On The Intestinal Bacterial Communities Of Hooded Crane (Grus Monacha) And Bean Goose (Anser Fabalis) At Shengjin Lake

The diversity of gut microbes is influenced by many aspects including the host internal factors and external environmental factors,what really matters is that trans-species spread of intestinal bacteria caused by direct or indirect contact with mixed-species wintering waterbird flocks.Hooded crane(Grus monacha)and bean goose(Anser fabalis)are mixed colony foraging at Shengjin Lake.As the mixing time lengthens,the contact degree of hooded crane and bean goose is increasing at Shengjin Lake.In this study,Illumina high-throughput sequencing was used to analyze the intestinal bacteria of these two species during different wintering periods at Shengjin Lake.We tested whether mixed time enhances the trans-species spread of gut bacteria.The main results of the study are as follows:1.There were differences and some similarities in the gut bacteria between the hooded crane and the bean goose.Firmicutes,Proteobacteria,Actinobacteria and Bacteroidetes were the dominant phyla.Bacilli,Betaproteobacteria,Alphaproteobacteria,Gammaproteobacteria,Actinobacteria and Clostridia were the dominant bacterial classes in hooded crane and bean goose.There was no significant difference in the dominant taxa of the two species except for Actinobacteria(P=0.049).Analysis of similarity proved that there was a significant difference in intestinal bacterial community structure between hooded crane and bean goose(ANOSIM:R=0.259,P=0.001).The bacterial operational taxonomic unit(OTU)types and Alpha-diversity(OTU richness,Shannon index,Phylogenetic diversity,Chao1 index)in hooded crane were significantly higher than that in bean goose(P<0.001),suggests that richer gut bacteria were present in hooded crane.2.At each wintering period,the intestinal bacteria communities between hooded crane and bean goose showed significant species differences.Alpha-diversity and microbial structure displayed significant separation between the two species(P<0.001),and hooded crane has a richer gut microbiome than the bean goose in every period,although the number of bacterial types shared increased with increasing mixed time.3.With the advance of wintering period,the gut bacteria of hooded crane and bean goose showed the same variation pattern during the wintering period.For the same species,with the lengthening of mixed time,the number of OTU in the host intestine augmented,and the common OTU and structural similarity of microflora in the middle and late periods were more than in the early and middle periods.Alpha-diversity was increased throughout the wintering period.Studies on specific bacteria in the early period showed that gut bacteria in the two species were influenced by each other,but bean goose may have a greater influence on hooded crane.4.A total of 63 potential pathogens were found,of which the two species shared a large proportion.Whether different species in the same wintering period or same species in different wintering periods have different intestinal pathogenic bacterial compositions.Our study also suggests that gut microbiota can inhibit pathogen colonization,as hooded crane had more pathogenic OTU than bean goose(hooded crane: 223,bean goose: 165)with a lesser sequence number and lower proportion of pathogens(hooded crane: 0.793%,bean goose: 1.134%).The research results revealed the intestinal bacteria communities characteristics of two sympatric waterbirds and illustrates the trans-species spread potential.It is of great significance to understand the dynamic changes of intestinal microbiome and interaction between intestinal bacteria of birds,and guiding significance for the protecting wild waterbirds and disease prevention.