Enhancement Of Gut Microbial Succession In Mice In Environment Contaminated With Herbivore Feces

The relationship between intestinal flora and human health has been paid more and more attention.In the process of infant development,the natural succession of intestinal flora is one of the important conditions for the healthy development of infant,and the richness and diversity of intestinal flora is an important sign of the normal succession of intestinal flora.Environmental microorganism is one of the main sources of intestinal microflora.It is generally believed that the richness and diversity of microorganisms in human living environment has a major impact on the formation and development of the richness and diversity of intestinal microflora in human body,especially in infants,and is crucial for the further maturity of the immune system.With the advancement of urbanization and the change of modern people's life style,the living environment in the city has become cleaner.At the same time,human beings are also gradually away from the rich microorganisms in the nature,which have a profound impact on the development and maturity of human immune system.The incidence rate city is far lower than that of city children,and the diversity of intestinal flora of city dwellers and Native Americans living in South American forest tribes has shown that the diversity of urban intestinal flora is significantly lower than that of Aboriginal residents,and some of the original flora is located in the city.People's intestines have disappeared.These phenomena suggest that it is of great significance to explore whether microorganisms in human living environment have a practical impact on the richness and diversity of human intestinal flora and the level of immunity.The purpose of this study is to establish a living environment containing feces of large herbivores,simulate the living state of slight pollution of feces of large herbivores in farms,and evaluate the impact of environment on the diversity of intestinal flora in healthy mice,so as to provide evidence for determining the correlation of environment on the diversity of intestinal flora,and explore whether the intestinal tract of mice has the selectivity and year for colonization of alien flora Age related.This study may provide a new way to improve the diversity of intestinal flora in children and adults.Objectives Constructing an environment that simulates a natural farm,and to explore whether the mildly large herbivore animal fecal in the environment affects the diversity of the gut microbiota.By establishing animal models and sequencing analysis,there is a difference in the ability to accept the foreign flora in mice of different ages.Methods 1.Mix the required bedding(30g/cage)with the quantitative bovine,horse,and sheep feces(each 0.5g/cage)before feeding the mice,and place them in the incubator for 2 days.2.Adult mice and weaned mice were housed separately and randomly divided into 4 groups(n=6): Control group,6D was a 6-day feeding group,12 D was a 12-day feeding group,and 30 D was a 30-day feeding group.After one week of adaptive feeding,adult mice and weaned mice were separately reared,and the feces were taken every two days and the body weight was measured.The bedding was changed every 6 days,and the groups were sacrificed on the 6th,12 th,and 30 th days respectively.Blood,small intestine and colon tissues were taken for histological,molecular biology and immunological tests.3.The diversity and richness of the intestinal flora of each group were analyzed by 16 s DNA sequencing to identify the different bacteria.The histopathologocal observation of the small intestine and colon tissues of each group were performed by H&E staining;Immunofluorescence,IHC and Western-blotting technique was used to detect the distribution and expression of tight junction proteins in the small intestine and colon tissues of mice,and to analyze the changes of intestinal mechanical barrier.The effect of mildly polluted environment on the immune system of mice was analyzed by ELISA.Results 1.The results of DGGE and 16 s showed that the intestinal flora of the 6D group was significantly changed in the adult mice and the weaned mice.After long-term feeding,the intestinal flora became stable,but the intestinal flora diversity of the weaned mice was more similar with the environment.Bacteroidetes decreased in the long-term treatment group of the two groups of mice,while Firmicutes decrease in the short-term treatment group and increased in the long-term treatment group.Lactobacilaceae showed only a slight decrease in weaned mice,while other bacilli decreased.2.The mildly polluted environment did not cause significant changes in body weight in the two groups of mice.3.It can be observed by staining that both adult and weaned mice experienced shortterm intestinal barrier damage,but returned to normal after long-term treatment.4.From the various indexes of serum,the short-term inflammatory reaction occurred in both groups in the short-term treatment group.After long-term treatment,the inflammation index decreased to be close to the Control group.Conclusions 1.The environment containing the feces of large herbivores can affect the intestinal flora diversity.2.The influence of external environment on the intestinal flora diversity of weaned mice is higher than that of adult mice,and it may take longer for adult mice to significantly change the intestinal flora diversity and richness.3.The process of receiving foreign bacteria in mice was accompanied by short-term stress inflammatory response,and the intensity of the inflammatory response in weaned mice was higher than that in adult mice.