Molecular analysis of the gut microbiome of diabetic rats supplemented with prebiotic, probiotic, and synbiotic foods

Beneficial symbionts residing in our gut have positive therapeutic effects on several metabolic disorders including diabetes. Oral administration of probiotic and prebiotic foods strengthens the beneficial symbiont populations in the gut and may prevent immune-mediated destruction of pancreatic β-cells. The present study was designed to elucidate the gut microbiome of diabetic rats supplemented with a Lactobacillus probiotic and a Saccharomyces cerevisiae (SC) cell wall prebiotic. Diabetes mellitus was induced in male Wistar rats with allaxon monohydrate (150 mg/kg). The rats were fed chow maintenance diet (control and diabetic control groups) or the same diet supplemented with a SC prebiotic (1 %), probiotic (multispecies Lactobacillus @10⁸ CFU), or synbiotic. On d30, DNA was extracted from colon digesta for 16S ribosomal RNA (rRNA) gene sequencing. Serum was obtained to estimate total oxidant and anti-oxidant concentrations. A distinct clustering pattern (Unifrac distances, analysis of similarities (ANOSIM) P = 0.0361) was observed for the different treatment groups, with the main distinction consisting of the separation between the control and the diabetic control groups. Distinct bacterial clades dominated different treatment groups, particularly for the control and the diabetic control groups, though several bacterial groups overlapped, demonstrating a core microbiota dominated mainly by Firmicutes and Bacteroides. A trend of dysbiosis, characterized by low species richness, was observed in the diabetic rats, albeit not statistically significant. Serum oxidant and anti-oxidant concentrations were not different (P > 0.05) among different treatment groups. No significant effects of supplementations of prebiotic, probiotic, and synbiotic were observed on species richness or clustering pattern of the microbiome.