| Gut microbiota is a large microbial community,which plays an important role in feed conversion,digestion and absorption,and maintenance of intestinal physiological balance for livestock and poultry.More and more evidence suggest that by regulating the gut microbial structure may keep health in pig production,which has a very broad application prospect to improve the production efficiency safely,effectively and green.In this context,the commercial DLY(Duroc × Landrace × Yorkshire)sow(n=29)were taken as study subject,and the microbial structure and composition of the whole intestinal segment including duodenum,jejunum and ileum in the small intestine,cecum,colon and rectum in the large intestine at birth day(d0),nursery stage(d33),growing stage(d90),and fattening to marketing stage(d180)were analyzed based on 16 S rRNA sequencing technique.The main results are as follows:(1)The Alpha diversity based on Shannon index and Observed Features index showed an increasing trend of community diversity and community with the growth stages from birth to marketing.The microbial diversity and abundance in the large intestine were higher than that in the small intestines.Specifically,the microbial diversity and abundance of jejunum was the lowest,and that of colon was the highest.The Beta diversity based on Bray-Curtis and Jaccard showed that the microbial composition and community structure of the six intestinal segments was very similar at birth,and then they showed obvious time and space specificity.And it was showed obvious separation of large and small intestine.(2)At phylum level,nine phyla were observed among all test pigs,which Proteobacteria,Firmicutes,and Bacteroides were the dominant phyla.At the genus level,Romboutsia and Lactobacillus were the dominant bacteria in small intestine,which were related to protein and polysaccharide metabolism.Prevotella were the dominant bacteria in large intestine,which are involved in dietary fiber digestion.The different microbial composition in each intestinal segment may be compatible with intestinal function.(3)Further,the shared gut microbiota for each developmental stage at different intestinal segments showed that nursery stage has more similar bacterial genera,which are involved in valine,leucine and isoleucine biosynthesis,pentose acid pathway,peptidoglycan biosynthesis,etc based on PICRUSt2 analysis.While the shared gut microbiota for each intestinal segment at different developmental stage showed that duodenum and cecum have more similar bacterial genera,which may be related to the biosynthesis of ansamycin,fatty acid biosynthesis,D-alanine metabolism,pyruvate metabolism and other functions.These results suggest that these functions may play an important role in promoting intestinal growth and development.(4)Further analysis microbial biomarkers for each gut microbiota for different developmental stages found that: 16,60,81 and 68 species microbial biomarkers were found at birth,nursery,growing and fattening stages,mainly involved in D-arginine and Dornithine metabolism,D-alanine metabolism,lysine biosynthesis,linoleic acid metabolism and other functions.There were 97,49,53,78,103 and 91 species microbial biomarkers found in duodenum,jejunum,ileum,colon and rectum.These differences were mainly reflected in the synthesis and degradation of ketone bodies,biotin metabolism,terpenoid skeleton biosynthesis and other nutrient absorption and immune-related functions.These results indicate that intestinal digestion,absorption and immune function of pigs are continuously improved along with the growth and development of pigs.It is speculated that dietary change and immune regulation are one of the important factors affecting the evolution of microflora.In conclusion,the dynamic changes of intestinal microorganisms in pigs from birth to marketing were studied based on 16 S rRNA gene sequencing technology in the study.To provide a scientific and rational strategy for evaluating the gut microbes related to pig health,and to provide a theoretical basis for guiding disease prevention,nutrition regulation and feeding management at different stages in production management. |
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