Abstract: Objective To explore the influence of butyric acid bacteria on harmful gas emissions in KM mice. Methods Eighty KM mice were randomly divided into four groups (group I, II, III and IV) with equal number of females and males in each group. The mice in group II, III and IV were fed with butyric acid bacteria at the dose of 500 mg/kg、1000 mg/kg、1500 mg/kg by gavage for 21 d, respectively, and group I as control. The concentration of ammonia and hydrogen sulfide were monitored every day, and the growth performance, the activity of urease in faeces in each group were tested at 21 d. Result Compared to the control group, the average daily weight gain of group III and group IV were improved. On day 7 of gavage, the ammonia emission of group III and IV were significantly lower than that of group I and group II (P<0.05), while the H₂S emission were not edfected. The urease activities of group III and IV were lower than group I and II, but not significantly (P>0.05). Conclusion The butyric acid bacteria may improve the production performance and reduce the ammonia emission of mice.

Key words: Butyric acid bacteria, Mice, Harmful gas, Urease