The Effect of on Gut Microbial Changes and Functional Profiles of Metabolism in High-fat Diet-fed Rats Depending on Age and Sex.

Background/aims: A high-fat diet (HFD) causes dysbiosis and promotes inflammatory responses in the colon. This study aims to evaluate the effects of on HFD-induced gut microbial changes in rats.

Methods: Six-week-old Fischer-344 rats with both sexes were given a control or HFD during 8 weeks, and 1-to-100-fold diluted were administered by gavage. Fecal microbiota analyses were conducted using 16S ribosomal RNA metagenomic sequencing and predictive functional profiling of microbial communities in metabolism.

Results: A significant increase in and , which are butyric acid-producing bacterial families, was observed in the probiotics groups depending on sex. In contrast, , which increased through a HFD regardless of sex, and decreased in the probiotics groups. positively correlated with Claudin-1 expression in males ( < 0.001) and negatively correlated with the expression of Claudin-2 ( = 0.042), IL-1β ( = 0.037), and IL-6 ( = 0.044) in females. In terms of functional analyses, a HFD decreased the relative abundances of M00131 (carbohydrate metabolism module), M00579, and M00608 (energy metabolism), and increased those of M00307 (carbohydrate metabolism), regardless of sex. However, these changes recovered especially in male groups. Furthermore, M00131, M00579, and M00608 showed a positive correlation and M00307 showed a negative correlation with the relative abundance of ( < 0.001).

Conclusion: The beneficial effects of on HFD-induced gut dysbiosis in young male rats originate from the functional profiles of carbohydrate and energy metabolism.