The effects of supplementation of Bacillus subtilis and Bacillus coagulans spores on the intestinal microflora and growth performance in rat

Background and Objectives: The intestinal microflora has an important role in the health status. Since probiotics can bal- ance the intestinal microflora, they have a lot of health beneficial effects. So the appropriate selection of probiotics can cause health-promoting effects. In this study, the combined effects of Bacillus subtilis and Bacillus coagulans on the intestinal microflora and growth performance in rats were investigated. Materials and Methods: 80 male rats were divided into the treatment (receiving 5×107 spores/ml of B. subtilis and 5×107 spores/ml of B. coagulans for three weeks in daily water) and control (tap water without probiotics) groups. The total aerobic and anaerobic microorganisms, lactic acid bacteria (LAB), coliforms and spores were weekly counted in the fecal samples. Additionally, the water and feed consumption, the weight gain and Feed Conversion Ratio (FCR) were calculated for each week. Results: The probiotics significantly increased the total aerobic, LAB and spore counts and caused significant reduction in the anaerobe and coliform counts. Following three weeks of probiotic administration, the number of anaerobic bacteria, and coliforms were reduced by up to 0.7 and 1.18 log and the number of aerobic bacteria, LAB and spores were increased by 1.29, 1.15 and 7.2 log respectively. Also, the results showed the feed consumption reduction, weight gain and FCR enhance- ment in the probiotic group (p < 0.05). Conclusion: Supplementation the spores of B. subtilis and B. coagulans improved the growth performance and was benefi- cial to the intestinal microbiota in rats.