Molecular exploration of fecal microbiome in quinoa-supplemented obese mice

Diet affects gut microorganisms and dietary interventions can help treat obesity and overweight. Our aim was to investigate the effect of quinoa supplementation on fecal microbial ecology of obese diabetic mice. Obese db/db mice were fed commercial diets with and without quinoa supplementation for eight weeks; non-obese mice consuming non-supplemented diet served as lean-control. Fecal bacterial communities were analyzed using marker gene sequencing of 16S rRNA genes. Over 300 000 good-quality sequences were studied and assigned to 5774 different bacterial species (Operational Taxonomic Units at 97% similarity). Significant differences in bacterial abundances were found among the treatment groups, including some associated specifically with quinoa consumption. Analysis of weighted UniFrac distances revealed a distinctive clustering of lean microbial communities independently from obese-control and quinoa-supplemented mice (Analysis of Similarities, P < 0.01). Predicted functional profiles showed significant differences in 38 metabolic functions but most were due to a difference between lean samples compared to both obese-control and quinoa. Quinoa supplementation was associated with lower butyrate and succinic acid concentrations in cecum that were not necessarily more similar to those concentrations in lean mice. This study provides insight into the complex interactions between nutritional supplements and the gut microbiota thus informing future molecular analysis of the health benefits.