Fig. 1

Inter-individual variations in fibers-induced microbiota composition alterations. The in vitro microbiota MBRA system was inoculated with fecal slurry from 6 healthy donors and stabilized for 72 h, at which point fiber treatment was applied using cellulose, inulin, or psyllium. A, B Bacterial DNA was extracted and 16S rRNA qPCR-based bacterial density quantification. For each donor, the bacterial load is expressed as a relative value for inulin-treated (A) or psyllium-treated (B) chambers compared to cellulose-treated chambers. Extracted DNA was subjected to Illumina-based 16S rRNA gene sequencing and C–F Beta diversity evolution was computed through the QIIME2 pipeline using the Bray–Curtis (C, D) or the Unweighted Unifrac (E, F) distance matrix. For each donor, the evolution of microbiota composition is represented using distances expressed as relative values for inulin-treated (C, E) or psyllium-treated (D, F) chambers compared to cellulose-treated chambers. G, H Alpha diversity evolution computed through the QIIME2 pipeline using the Evenness index. For each donor, the evolution of microbiota richness is represented using the Evenness index expressed as a relative value for inulin-treated (G) or psyllium-treated (H) chambers compared to cellulose-treated chambers. Donor 1 and donor 2 are represented in bolded in all the data related to the use of the MBRA system, since they were subsequently used to perform fecal microbial transplantation. Data are the means ± S.E.M (N = 3). Significance was determined using 2-way group ANOVA corrected for multiple comparisons with the Bonferroni test (# indicates p < 0.05) compared to the control group (cellulose-treated chambers). Color of the # sign corresponds to the donor for which statistical significance is reached