Individual and Group-Based Effects of In Vitro Fiber Interventions on the Fecal Microbiota

The development of microbiome-targeted strategies is limited by individual differences in gut microbiome composition and metabolic responses to interventions. In vitro models that can replicate this variation allow us to conduct pre-clinical studies and assess efficacy. This study describes the exposure of 16 individual fecal microbiota samples to 5 different fibers using an in vitro system for the anaerobic cultivation of bacteria. The individual microbiota differed in composition and metabolite profiles (short-chain fatty acids and branched-chain fatty acids) after incubation with the fibers. Furthermore, microbiota composition after fiber incubation was significantly different between subjects with good intestinal health and subjects with Inflammatory Bowel Disease (IBD). a-diversity was differently affected by dietary fibers; for example, exposure to psyllium resulted in increased diversity in the healthy group and in decreased diversity in the IBD group. Instead, the functional metabolic profile did not differ between the two groups. Finally, the combination of all fibers, tested on the microbiota from IBD subjects, resulted in stronger overall effects on both microbiota composition and metabolite production compared to the single fibers. These results confirm that incubation with dietary fiber results in different compositional and functional effects on individual microbiota and that in vitro models represent successful tools for studying individual fiber effects.

Automated summary

The development of microbiome-targeted strategies is hindered by individual variations in gut microbiome composition and metabolic responses. In vitro models have been used to replicate this variation, allowing for pre-clinical studies and efficacy assessment. This study exposed 16 individual fecal microbiota samples to different dietary fibers in an in vitro system, demonstrating differences in microbiota composition and metabolite profiles between subjects with different intestinal health and subjects with Inflammatory Bowel Disease (IBD) after fiber incubation. The combination of all fibers showed stronger effects on microbiota composition and metabolite production compared to single fibers when tested on IBD subjects' microbiota.