Correlation analysis of lactation and infant sex with intestinal bacterial diversity and gene function in infants

The human gut constitutes a very rich and complex microbial ecosystem. Early in life, the microbiota consisted mainly of actinobacteria and proteobacteria, which later became more diverse with the rise of firmicutes and Bacteroidetes. There are many factors that affect the diversity of gut bacteria in infants. Early colonization by gut bacteria can affect infant health and long-term health. Some substances secreted by intestinal microorganisms can inhibit the harm of pathogenic bacteria and their metabolites to the host, which is crucial for the formation of the immune system of offspring. In this study, we sought to determine the effects of lactation and infant sex on the developing gut bacterial diversity of healthy infants from birth to 4 months of age. Illumina-Miseq sequencing technology was used to analyze the V3-V4 variable region of fecal bacteria 16S rRNA gene from 24 infants in Hohhot, Inner Mongolia. The structure and diversity of the bacteria were compared and the gene function was predicted. The results showed that the diversity of intestinal bacteria in infants was significantly different between lactation periods, but not between genders (P<0.05). The bacterial diversity of the dominant family and genera in the intestinal tract of infants was the same. There are significant differences in intestinal bacteria between lactation and infant sex. Pathogenic microorganisms accounted for less. According to the gene function prediction by PICRUSt2 software, the main metabolic gene functions of bacteria are Global and overview maps, Amino acid metabolism, Amino acid metabolism and so on. In conclusion, the bacterial diversity and microbiota structure in the gut of infants are significantly different. In addition, with the prolongation of lactation, the dominant bacterial flora of infants changed, and the gene function changed accordingly. This study not only established a full understanding of the bacterial diversity in the gut of healthy infants in Hohhot, Inner Mongolia, but also provided a basis for the study of beneficial microorganisms.