The long-term oral administration of a product derived from a probiotic, Clostridium butyricum induced no pathological effects in rats.

Recent studies have suggested that short chain fatty acids (SCFAs) exert a therapeutic effect on some human and experimental animal diseases. In our previous study, we showed that Clostridium butyricum produces high levels of SCFAs in the culture system used. In addition, an additive based on yogurt was effective in eliminating and masking the odor derived from these SCFAs in the product. Recently, we reported that the oral administration of a high concentration (50% w/w) of this product derived from Clostridium butyricum for 17 days caused no pathological abnormalities in rats. The aim of the present study was to investigate the effects of the prolonged oral administration of this product in rats. Male and female Wistar Hannover GALAS rats, 5 weeks old, were given a mixture of a standard diet plus the product derived from Clostridium butyricum (5% w/w) with 0.1% additive for 16 months (n=6). The control rats were allowed the same standard diet plus tap water (5% w/w) with 0.1% additive (n=6). After 16 months, a laparotomy was performed. A hemocyte count, and biochemical and electrolyte analyses were subsequently carried out. The esophagus, stomach, small intestine, large intestine and pancreas were investigated macroscopically and microscopically. The results showed that the rats grew normally for the duration of the experimental period. The body weights of the product-fed rats were comparable with those of the control-fed rats. There were no significant differences in the organ weight between the product- and control-fed rats, except for a significantly increased weight of the large intestine in the product-fed male rats. No pathological abnormalities were found in the hemocyte count, the biochemical and electrolyte analyses, or the macroscopic and microscopic findings.