Effect of oral administration of Bacillus coagulans B37 and Bacillus pumilus B9 strains on fecal coliforms, Lactobacillus and Bacillus spp. in rat animal model

Abstract

Aim: To investigate the effect of oral administration of two Bacillus strains on fecal coliforms, Lactobacillus and Bacillusspp. in rat animal model. Materials and Methods: An in vivo experiment was conducted for 49-day period on 36 adult male albino Wister ratsdivided equally into to four groups. After 7-day adaptation period, one group (T1) was fed on sterile skim milk along withbasal diet for the next 28 days. Second (T2) and (T3) groups received spore biomass of Bacillus coagulans B37 and Bacilluspumilus B9, respectively, suspended in sterilized skim milk at 8-9 log colony-forming units/ml plus basal diet for 28 days, while control group (T4) was supplied with clean water along with basal diet. There was a 14-day post-treatment period. A total of 288 fecal samples (8 fecal collections per rat) were collected at every 7-day interval starting from 0 to 49 days andsubjected to the enumeration of the counts of coliforms and lactobacilli and Bacillus spores using respective agar media. In vitro acid and bile tolerance tests on both the strains were performed. Results: The rats those (T2 and T3) received either B. coagulans B37 or B. pumilus B9 spore along with non-fermentedskim milk showed decrease (p<0.01) in fecal coliform counts and increase (p<0.05) in both fecal lactobacilli and Bacillusspore counts as compared to the control group (T4) and the group fed only skim milk (T1). In vitro study indicated that boththe strains were found to survive at pH 2.0 and 3.0 even up to 3 h and tolerate bile up to 2.0% concentration even after 12 hof exposure. Conclusions: This study revealed that oral administration of either B. coagulans B37 or B. pumilus B9 strains mightbe useful in reducing coliform counts accompanied by concurrent increase in lactobacilli counts in the intestinal florain rats.