Effects Of Host On Gut Microbiome:Comparative Studies On Three Species Of Microtinae

Gut microbiota are closely related to nutritional metabolism,energy transfer,immune regulation and other activities of the host,and affected by host living environment and the host own factors.In extreme environments,such as high altitude and hypoxia,gut microbiota could help host adapt to environments.Presently,studies on gut microbiota of extreme environment animals mainly focused on microbiota composition,but it is difficult to distinguish the effects of environment and host on the structure of gut microbiota.Neodon fuscus,Lasiopodomys mandarinus and L.brandtii belong to the microtinae.Among them,N.fuscus which lives in high altitude environment with hypoxia,low pressure and strong ultraviolet radiation,L.mandarinus which lives in underground environment with hypoxia,darkness and high carbon dioxide,and L.brandtii are distributed on the ground in low-altitude areas.As adapting to different living environments in the wild,they are good animal models to study the relationship between gut microbiota and host.In order to study the effects of host factors on gut microbiota,wild N.fuscus,L.mandarinus and L.brandtii are raised in lab,and their fecal samples were collected after 6 month treatment.Then 16S/ITS r DNA high throughput sequencing are used to analyze the composition gut microbiota.After diversity analyse,taxonomy classification and function prediction,the differences of gut microbiota between N.fuscus and L.brandtii under lab conditions were analyzed,and the structure and composition of gut microbiota between L.mandarinus and L.brandtii feeding lab and wild conditions were compared.The main results are as follows:1.Sequencing,assembly and clustering of the gut microbiota of three volesA total of 5037848 high-quality sequences were obtained from the gut bacteria of lab feeding N.fuscus,L.mandrinus and L.brandtii,with unique OTU numbers of362,303 and 291,respectively,and 2451621 high-quality sequences of gut fungi were obtained,with unique OTU numbers of 62,70 and 91,respectively.Meanwhile,2522654 high-quality gut bacteria sequences of wild L.mandrinus and L.brandtii were obtained,with unique OTU numbers of 160 and 367,respectively.2.Comparative study on gut microbiota of N.fuscus and L.brandtiiUnder lab condition,the diversity of gut bacteria and fungi in N.fuscus and L.brandtii were the same between genders,but there were significant differences between the two voles.The abundance of Proteobacteria associated with lignin digestion and short chain fatty acid producter Prevotella in gut microbiota of N.fuscus was obviously higher than that of L.brandtii,which was as same as reported gut microbiota characteristics of high-altitude animals,indicating that these flora might be affected by the host.The value of Firmicutes/Bacteroidetes related to energy acquisition is reported higher in plateau animals,however,it was lower in N.fuscus compared with that in L.brandtii,indicating that this value may also be affected by the environment.3.Comparative study on gut microbiota of L.mandarinus and L.brandtiiIn wild environments,there were significant differences in gut bacterial richness and diversity between L.mandarinus and L.brandtii.The abundance of Firmicutes,Spirochaetes,Ruminococcus,Treponema,Desulfovibrio,Clostrdium and Oscillospira in L.mandrinus was lower than that of L.brandtii.And the abundance of Bacteroidetes and Lactobacillus of L.mandrinus was remarkably higher than that of L.brandtii.In lab environments,the abundances of Firmicutes,Spirochaetes,Ruminococcus,Treponema in the gut of L.mandrinus keptlower than that of L.brandtii.Instead,the abundance of Desulfovibrio turned higher than that of L.brandtii.The results showed that the Firmicutes,Spirochaetes,Ruminococcus and Treponema which are related to food degradation might be notebaly affected by host.On the contrary,the microbiota of Desulfovibrio,Clostrdium,Treponema,Clostrdium,Bacteroidetes,and Lactobacillus are related to anaerobic metabolism or immunity may be mainly affected by environment.Conclusion:The host of the three voles has a greater impact on the intestinal microbes that are closely related to the metabolism of high-fiber foods and energy supply,such as Proteobacteria that digests lignin,Spirochaetes and Ruminococcus that degrade cellulose,and Prevotella that produce short-chain fatty acids in gut.After feeding in the same environment,the gut microbiota of voles still maintain some characteristic flora in the wild environment,reflecting that the host plays an important role in regulating the structure of gut microbiota.This study initially revealed that the gut microbiota related to food digestion and energy metabolism are greatly affected by the host,and they could be used as the main bacterial species to indicate the type of animal food habits.