Effects of fructooligosaccharides and Lactobacillus reuteri on the composition and metabolism of gut microbiota in students

Fructooligosaccharides (FOSs) and Lactobacillus reuteri have shown great potential in treating gastrointestinal diseases by regulating gut microbiota and metabolites. However, the synergistic effect between these two remains unclear. In this study, an in vitro fermentation model was constructed to investigate the regulatory effects of FOSs and L. reuteri on the gut microbiota of healthy student populations. After 24 hours of fecal fermentation, the results indicated that the experimental group added with FOSs had increased relative abundances of Bifidobacterium and Lactobacillus, while it exhibited lower relative abundances of Escherichia-Shigella and Bacteroides. Conversely, the groups added with L. reuteri had higher relative abundances of Bacillus and unclassified_c_Bacilli. The results of microbial metabolism revealed that the addition of FOSs produced a large amount of acetic acid, but reduced the contents of propionic acid, butyric acid, isobutyric acid, and isovaleric acid, along with reducing the production of H2, H2S and NH3. In contrast, the addition of L. reuteri had no significant effect on metabolism. Compared to the single additions, the combination of FOSs and L. reuteri had its advantages and had a more balanced microbial structure and metabolic regulation similar to the addition of FOSs alone. Additionally, correlation analysis revealed a negative correlation between gas production and Bifidobacterium, Lactobacillus, and Bacillus, and a positive correlation with Escherichia-Shigella and Bacteroides. Moreover, the formation of acetic acid was positively correlated with Bifidobacterium and negatively correlated with Escherichia-Shigella. These findings demonstrated that the combination of FOSs and L. reuteri can effectively synergistically regulate the fecal microbiome of students. This study can provide a theoretical reference for the precise development of functional foods. However, the regulatory mechanisms need further in-depth investigation.