Comparing the intestinal bacterial communies of sympatric wintering Hooded Crane (Grus monacha) and Domestic Goose(Anser anser domesticus)

Background:Gut microbiota play crucial roles in host health.Wild birds and domestic poultry often occupy sympatric habitats,which facilitate the mutual transmission of intestinal microbes.However,the distinct intestinal microbial communities between sympatric wild birds and poultry remain unknown.At present,the risk of interspecies transmission of pathogenic bacteria between wild and domestic host birds is also a research hotspot.Methods:This study compared the intestinal bacterial communities of the overwintering Hooded Crane(Grus monacha)and the Domestic Goose(Anser anser domesticus)at Shengjin Lake,China,using Illumina high-throughput sequencing technology(Mi-Seq platform).Results:Our results revealed that Firmicutes,Actinobacteria,Proteobacteria,Bacteroidetes and Chloroflexi were the dominant bacterial phyla in both hosts.The gut bacterial community composition differed significantly between sympatric Hooded Cranes and Domestic Geese.However,the hosts exhibited little variation in gut bacterial alphadiversity.The relative abundance of Firmicutes was significantly higher in the guts of the Hooded Cranes,while the relative abundances of Actinobacteria,Proteobacteria,Bacteroidete and Chloroflexi were significantly higher in guts of Domestic Geese.Moreover,a total of 132 potential pathogenic operational taxonomic units(OTUs)were detected in guts of Hooded Cranes and Domestic Geese,and 13 pathogenic OTUs(9.8%)were found in both host guts.Pathogenic bacterial community composition and diversity differed significantly between hosts.Conclusions:The results showed that the gut bacterial community composition differs significantly between sympatric Hooded Cranes and Domestic Geese.In addition,potential pathogens were detected in the guts of both Hooded Cranes and Domestic Geese,with 13 pathogenic OTUs overlapping between the two hosts,suggesting that more attention should be paid to wild birds and poultry that might increase the risk of disease transmission in conspecifics and other mixed species.

Effects of foraging site distances on the intestinal bacterial community compositions of the sympatric wintering Hooded Crane(Grus monacha)and Domestic Duck(Anas platyrhynchos domesticus)

Background:The composition of intestinal microflora in animals is affected by cross-species transmission.In a nature reserve,the foraging sites of waterbirds are relatively fixed,but frequently close to residential areas and can also be visited by domestic fowls.It is easy to result in the trans-species-flock dispersal of gut microbes between the wild birds and domestic fowls.The effects of the variable foraging site distances on the gut microbe structures of the waterbirds and the sympatric domestic fowls are currently unclear,and further research is required to evaluate the impacts of geographic location on cross-infection.Methods:Illumina high-throughput sequencing and bioinformatics analysis software were utilized to compare and analyze the composition of gut microbes from the fecal samples of Hooded Cranes(HC;Grus monacha)and two groups of Domestic Ducks(Anas platyrhynchos domesticus)that foraged at 1 km(ducks in near areas,D-N),and 4 km(ducks in far areas,D-F)away from the habitats of the Hooded Cranes at Shengjin Lake,China.Results:The results showed that there were significant differences in the alpha-diversity of the gut bacteria in the HC,D-N,and D-F samples under the interspecific distance factor.The dominant bacterial phyla,Cyanobacteria and Proteobacteria,showed correlations with distance for each host.The D-N group had more diverse intestinal flora than the D-F,as they were physically closer to the HC and had more indirect contact and cross-transmission of their gut microbes.More potentially pathogenic bacterial sequences,and Operational Taxonomic Units(OTUs)were found in the D-N than in HC and D-F.Conclusions:Hooded Cranes and the Domestic Duck populations at variable distances from the cranes showed significant differences in their intestinal bacteria and potentially pathogenic bacteria.The closer the foraging sites were,the easier the intestinal flora spread across species.The results provide a basis for determining the safe distance between wild birds and domestic fowls in a nature reserve.

Dramatic shifts in intestinal fungal community between wintering Hooded Crane and Domestic Goose

Background:The intestinal microbiota play remarkable roles in maintaining the health of their hosts.Recent studies focused on gut bacterial diversity in birds and poultry,with little information about the ecological functions of their gut fungal community.Methods:The high-throughput sequencing was applied to compare intestinal fungal community structure between Hooded Crane(Grus monacha)and Domestic Goose(Anser anser domesticus),and infer the potential pathogens of each species at Shengjin Lake of China.Results:Intestinal fungal alpha diversity was higher in Hooded Crane than Greylag Goose(Anser anser).Gut fungal community composition showed dramatic shifts between the two species.Hooded Cranes mainly eat Vallisneria natans and Potamogeton malaianus,while artificial hurl food(i.e.,paddy)was the main food resource for Domestic Geese,suggesting that the variations in fungal community might be induced by different diets between the two hosts.Two enriched genera(i.e.,Acremonium and Rhodotorula)which could increase host's digestion were detected in guts of Hooded Cranes.In addition,there were 42 pathogenic amplicon sequence variants(ASVs),17%of which shared in Hooded Crane and Greylag Goose.The Hooded Crane had higher gut fungal pathogenic diversity and abundance relative to Greylag Goose.Conclusions:The study demonstrated that divergence in intestinal fungal community structure might be induced by different diets between wintering Hooded Crane and Domestic Goose.Hooded Crane might rely more on their gut fungal taxa to acquire nutrients from indigestible food resources.Our study also implied that more research should focus on intestinal pathogens in wild birds and domestic poultry,as they might increase risk of disease in other animals,even human beings.The degree of cross infection in pathogens among wild birds and sympatric poultry should be clearly verified in future study.

Shifts in foraging behavior of wintering Hooded Cranes(Grus monacha) in three different habitats at Shengjin Lake, China

Background: Wetland loss and degradation result in a reduction in the availability and quality of food for wintering waterbirds. Birds normally modify their foraging behavior to adapt to variations in food availability. In this study, we compared shifts in foraging behavior of Hooded Cranes(Grus monacha) in three different habitats at Shengjin Lake, China to understand the response of these cranes to changes in habitat.Methods: We investigated the food density and foraging behavior of Hooded Cranes in Shengjin Lake National Nature Reserve from November 2014 to April 2015. We used regression equations to describe the changes in food density. A total of 397 behavioral observations were used in the analyses of their foraging efforts. We fitted a candidate set of generalized mixed linear models to analyze the relationship of foraging efforts and food density. We used a method of information theory to guide the selection of the model and Akaike's Information Criterion to calculate the value of each model. The relationship between food density, disturbances and foraging behavior was illustrated using a generalized linear model.Results: Along with the temporal variation and exploitation of food biomass, the food density varied widely among foraging sites. During the early winter period, foraging efforts were more pronounced in the paddy fields and meadows but not significantly different among the three habitats. The cranes spent more foraging effort in the paddy fields and meadows during the middle stage and in the meadows and mudflats during the late winter. The results of the generalized linear model showed that food density and disturbances had different effects on the rate of foraging success during the winter, while the effect of foraging effort was not significant. Furthermore, the rate of feeding success was markedly affected by disturbances in the paddy fields. The combined action of food density and disturbances had a significant effect on the rate of foraging success in the meadows, while the effect of foraging effort was also not significant in three habitats.Conclusions: Changes in foraging behavior were significant in three habitats, which were affected by food density and disturbances. The rate of foraging success increased in the habitat with low food density and low disturbances to increase the foraging efficiency in the lake. With abundant food and a high level of disturbance, the rate of foraging success decreased to ensure more secure access to food.