Impact of isoflavones and Lactobacillus acidophilus on the fecal microbiology status in healthy female rats

Background. Isoflavones and probiotics are promising agents with preventive and therapeutic effects on bone health. However, their mechanism of action is not fully understood. The combined effect of probiotics and isoflavones on the composition of gut microbiota is yet to be investigated. Thus, this study aimed to determine whether the inclusion of isoflavones and probiotics in the diet had an effect on the content of Lactobacillus spp. in the feces of female rats.
Materials and methods. This study included 50 female Wistar rats aged 3 months old. The rats were randomly assigned to six groups. The control group (K) received a standard diet (AIN 93M), while the other five groups received a standard diet supplemented with the following: tempeh flour at an amount of 250 g/kg of diet (TP); soy flour at 250 g/kg (RS); daidzein and genistein at 10 and 100 mg/kg (DG), respectively; Lactobacillus acidophilus at 1010 CFU/day (LA); or daidzein, genistein, and L. acidophilus (DGLA). At the beginning of the experiment and after 8 weeks, fecal samples were collected from the examined rats and the content of Lactobacillus spp. in feces was determined.
Results. A comparison of Lactobacillus spp. content in fecal samples before and after the intervention showed a significant increase in bacteria in K, DG, and DGLA groups. A significant decrease in Lactobacillus spp. content was observed in the RS group compared to other groups after 8 weeks of intervention.
Conclusion. Isoflavones may improve the gut Lactobacillus status in healthy rats, while raw soybean decreases the content of these bacteria.