Impact of synbiotic diets including inulin, Bacillus coagulans and Lactobacillus plantarum on intestinal microbiota of rat exposed to cadmium and mercury

The aim of this study was to investigate the efficacy of two probiotics and a prebiotic (inulin) on intestinal microbiota of rats exposed to cadmium and mercury. Fifty-four male Wistar rats were randomly divided into nine groups. All groups except control group were fed standard rat chow with 5% inulin and treated as follows: i) control (standard diet), ii) Lactobacillus plantarum- treated group (1×109 CFU/day), iii) Bacillus coagulans-treated group (1×109 spores/day), iv) cadmium-treated group (200 μg/rat/day), v) L. plantarum and cadmium-treated group, vi) B. coagulans and cadmium-treated group, vii) mercury-treated group (10 μg/rat/day), viii) L. plantarum and mercurytreated group, ix) B. coagulans and mercurytreated group. Cadmium, mercury and probiotics were daily gavaged to individual rats for 42 days. Treatment effects on intestinal microbiota composition of rats were determined. Data showed that cadmium and mercury accumulation in rat intestine affected the gastrointestinal tract and had a reduction effect on all microbial counts (total aerobic bacteria, total anaerobic bacteria, total Lactic acid bacteria, L. plantarum and B. coagulans counts) compared to the control group. It was also observed that application of synbiotics in synbiotic and heavy metals-treated groups had a significant effect and increased the number of fecal bacteria compared to the heavy metals groups. Based on our study, it can be concluded that L. plantarum and B. coagulans along with prebiotic inulin play a role in protection against cadmium and mercury inhibitory effect and have the potential to be a beneficial supplement in rats’ diets.