Preparation of a Freeze-dried Powder of Clostridium butyricum and Its in vivo Safety Evaluation
This experiment involved scaling up the cultivation of Clostridium butyricum BLCC1-0022 in a bioreactor to obtain a freeze-dried powder of Clostridium butyricum,followed by an assessment of its toxicity in vivo through acute oral toxicity testing in mice.The results showed that Clostridium butyricum BLCC1-0022,when cultured in a 500 L bioreactor,reached the stationary phases at 18 hours with a mini-mum pH of 5.15.The viable cell count in the fermentation broth was 2.89 × 108 CFU/mL,with a spore yield of 96%.The freeze-dried bacterial powder obtained from the entire fermentation broth had a viable bacterial count of 4.1×1010 CFU/mL(CFU/g).Compared to the control group,the low dose(5 × 108 CFU),medium dose(5 × 109 and 5×1010 CFU),and high-dose(5×1011 CFU)groups of mice administered Clostridium butyricum showed no significant differences in growth performance and blood parameters(P>0.05).Furthermore,no bacterial translocation occurred,and there was no pathological damage to the heart,liver,or spleen tissues of the mice.In conclusion,Clostridium butyricum BLCC1-0022 did not in-duce toxic reactions in the internal organs,blood,or growth performance of the mice,indicating a high level of in vivo safety.