Fructooligosaccharides (FOS) significantly increased the relative abundance of intestinal in mice with different genotypes.

Fructooligosaccharides (FOS) promote the proliferation of , especially in C57BL/6J mice. However, the response of intestinal microbes to FOS is influenced by host genotypes. Therefore, we compared the intestinal microbiota of four commonly used mice before and after FOS intervention, including C57BL/6J, BALB/c, Institute Cancer Research (ICR), and Kunming (KM) mice. The intestinal microbiota of the four genotypes exhibited similarities in composition but differences in relative abundance. was significantly increased to different degrees in the four genotypes of mice after FOS intervention, and and were also significantly increased in BALB/c and KM mice. and levels were unchanged or decreased. Within the genus , was the dominant species in the four genotypes of mice and proliferated significantly after FOS intervention, with dramatic proliferation in C57BL/6J mice (9.49%). Furthermore, eight strains of were screened from the feces of mice with four genotypes, and there was a great difference in the ability and manner of utilizing FOS among the strains. The strains from C57BL/6J mice exhibited the strongest utilization of 1-kestose (GF2), whereas other strains could utilize both GF2 and nistose (GF3) weakly. The gut microbial analysis of mice with different genotypes complemented our previous studies. The results provided the background strains of the different mouse genotypes and suggested a correlation between the utilization ability and the response of the strains to FOS. Further studies on the utilization ability of strains and competition in the intestine will contribute to the understanding of the mechanisms of the intestinal microbial response to diet.