Abstract: In order to explore the effect of human milk N-glycome (HMN) and bovine milk N-glycome (BMN) on the intestinal flora in mice, glycosidase activity related to N-glycome in the fecal flora of C57BL/6J male mice was determined in vitro and the utilization of HMN and BMN by the fecal flora was simulated. The mice were randomly divided into control, HMN and BMN treatment groups. After 21 days of gavage, the contents of short chain fatty acids (SCFAs) in the cecum was detected, and 16S rDNA high-throughput sequencing was used to analyze the composition of intestinal microorganisms. The results showed that the activity of β-galactosidase, α-fucosidase and β-N-acetylglucosaminidase were detected in mouse fecal flora, and that HMN and BMN could be utilized by it. Compared with the control group, the intake of HMN increased the contents of total short-chain fatty acids (SCFAs) significantly (P < 0.05), while BMN did not (P > 0.05). The intake of HMN and BMN significantly changed the composition of intestinal microbes, a significant difference being observed between the two groups. At the phylum level, the intake of HMN reduced the relative abundance of Bacteroidetes and increased the relative abundance of Firmicutes, compared with the control group while the intake of BMN significantly reduced the relative abundance of Proteobacteria. And at the genus level, the relative abundance of Muribaculaceae_norank and Parasutterella were reduced in both HMN and BMN groups, whereas the relative abundance of Bacteroides and Enterococcus were increased compared with the control group. However, the relative abundance of Bacteroides and Enterococcus were not significantly different between the two groups. In addition, the relative abundance of Lactobacillus, Erysipelotrichaceae_Unclassified and Escherichia in the HMN group was higher than that in the control and BMN groups, while the relative abundance of Akkermansia in the BMN group was higher than that in the control and HMN groups. Generally, HMN and BMN could affect the structure and composition of mouse intestinal flora, which is important for understanding the function of N-glycome and applying it in the development of infant formula milk in the future.

Key words: human milk N-glycome; bovine milk N-glycome; glycosidase; gut microbiota; short chain fatty acids