Study On The Dynamic Changes Of Intestinal Microflora Structure In Lactating Cows And Calves

This experiment was to study lactating cows-calf intestinal microbial flora structure by its diversity,determine its dynamic changes of the structure of intestinal flora,and to explore different stages calf intestinal structure and function to guide its nutritional regulation in different stages,and for lactation cows-calf intestinal microbial flora structure dynamics provide theoretical basis for the research.Fresh rectal fecal samples were collected from 5 cows in early lactation and 6 healthy lactating calves(including a pair of twins)at different time points(1d,3d,6d,9d,12 d,24d,36 d,48d,60 d and 72D).In addition,16 s RNA high-throughput sequencing technology and bioinformatics analysis were used to compare the composition and diversity of intestinal microbes.The results showed as follows: 1.The composition of microflora at different time points in lactating cows at phylum level,firmicutes and Bacteroides were the dominant microflora,accounting for about 80% of the total abundance;2.At the genus level,rumenobacteriaceae(UCG-005),Rijcidaceae(RC9)and Rumenobacteriaceae(UCG-010)were the dominant flora,while other genera accounted for less.Based on the analysis of Beta diversity and significant difference between groups,the overall intestinal samples of cows showed significant aggregation,indicating that the intestinal microflora structure was similar.Although the structure of the same group of samples was different at different time points,there was no significant difference.2.Composition at phylum level at different time points of lactating calves,firmicutes,Proteobacteria and Bacteroides were the dominant flora,accounting for 98% of the total abundance.At the genus level,lactobacillus,Escolibacillus shigella and Rumenobacteriaceae_UCG-014 were the dominant strains,and Lactobacillus was the most dominant strain at 3,6,9,12,24,36 and 48 days of age.After 24 days of age,rumenobacteriaceae_UCG-014 increased with age.The intake of solid feed and roughage increased continuously,while the intake of breast milk decreased gradually,so that the proportion of bacteria that degraded fiber and starch increased,and the bacteria became stable bacteria in gastrointestinal tract.The intestinal microflora of calves showed continuous dynamic changes with the increase of age.3.During lactation,1261 OTUs were aggregated from 110 samples at different time points,and the total number of OTUS was 1256;The findings: On the level of the door,thick wall door,bacteria-the bacteroidetes door,door of soft wall of bacteria became the cow intestines advantage bacterium group,and in the calf intestinal advantage bacterium group structure for the thick wall door,bacteria-the bacteroidetes door,the door deformation bacteria,lactating cows-there is a same flora calf intestine,but with the increase of day age and growth and development,there are some bacteria disappeared,Some new bacteria colonized in the intestinal tract.In the genus level,rumen bacteria,riken bacteria families RC9 gradually become cows advantage of intestinal bacteria genera,such as the calf intestinal advantage all genera of lactic acid bacteria,e.coli bacteria genera-hayes bacteria genera,rumen bacteria_UCG-014,with the increase of age,appear similar to cow the intestinal flora of intestinal flora,gradually developed and become mature intestinal microflora.Conclusion: 1.The composition of intestinal flora of lactating cows is very similar at different time points,but there are differences among individuals.2.During the whole development process from birth to 72 days of age,the intestinal microflora structure of Suckling calves gradually tended to be similar,and the microflora structure similarity gradually increased with the increase of age,and finally became the same.3.Intestinal microbiota in lactating cows indirectly affect the colonization of intestinal microbiota after birth.In this study,16 s RNA sequencing was used to analyze the relationship between intestinal microflora of lactating cows and newborn calves,providing a solid theoretical basis for the study of nutrient digestion and absorption and intestinal health of ruminants.