Common Bean (Phaseolus vulgaris L.) Flour Can Improve the Gut Microbiota Composition and Function in Mice Fed a High-Fat Diet

To evaluate the effects of whole flour and protein hydrolysate from common bean on gut health in mice fed a High-Fat Diet. BALB/c adults mice (n = 48) where divided in 4 groups (n = 12 each): normal control (NC standard diet AIN-93M); High-Fat Diet (HFD) only; HFD plus bean flour (HFBF) and HFD plus bean protein hydrolysate (HFPH; 700 mg/kg of body/day). After 9 weeks, the animals were euthanized. Cecum weight was measured and cecum content was collected. Cecum content was used to analyze moisture by gravimetric method, lipids by extraction in Soxhlet apparatus, short chain fatty acids (SCFA) by HPLC and DNA extraction and sequencing of the gut microbiota. Total genomic DNA was extracted from fecal samples and loaded using the Illumina MiSeq platform at Argonne National Laboratory. Data were analyzed by ANOVA and post-hoc of Newman-Kews. Nonparametric and independent samples were submitted to Kruskal-Wallis with a Dunn's multiple comparison test (P < 0.05). HFBF increased cecum weight (+69%), moisture (+104.6%) and lipids (+11.5%) in the feces compared to HFD group (P < 0.05), and the Beta diversity was different from HFD. Acetic acid concentration decreased (−37.7%) in cecal content of HFBF group compared to HFD group (P < 0.05), and propionic and butyric acids cecal concentration did not differ (P > 0.05) among experimental groups. The abundance of Bacteroidetes increased and the Firmicutes/Bacteroidetes ratio decreased in the HFBF compared to control groups. The operational taxonomic units (OTUs) enriched by HFBF were mainly assigned to Muribaculaceae family, which show high potential to improve gut health. The functional analysis of the microbiota shown beneficial changes in the host's genetic capacity, especially in the metabolic pathways involved with glucose metabolism. KEGG metabolic pathways involved with starch and sucrose metabolism, as well as the galactose metabolism were enriched in the HFBF group compared to the HFD group (P < 0.05). The intake of common bean flour modulates the microbiota composition and abundance of SCFA-producing bacteria, and attenuates the effects of HFD, showing potential to improve gut microbiota composition and function of mice. CNPq, CAPES, Fapemig and Fulbright (Brazil).