Effects of Bacillus subtilis C-3102 on growth performance, nutrient digestibility, ammonia gas emission and fecal microbiota of grower-finisher pigs

Abstract

Importance of the work: Bacillus subtilis C-3102 can be used as a probiotic feed additive to improve the production performance of grower-finisher pigs.
Objectives: To evaluate the effects of B. subtilis C-3102 on the growth performance, nutrient digestibility and fecal microbiota of grower-finisher pigs.
Materials & Methods: In total, 72 crossbred pigs (mean weight ± SD; 30.73 ± 3.24 kg) were allocated to two groups. Each group received basal feed with or without B. subtilis C-3102 (310⁵ colony forming units/g feed) over the feeding period.
Results: The final body weight (p < 0.05) and average daily gain (p < 0.05) were higher and the feed conversion ratio (p < 0.05) was lower in the probiotic group than the control. Dry matter digestibility was higher in the probiotic group (p < 0.05) at the end of the grower period. Lower slurry pH (p < 0.05) was observed in the probiotic group. Fecal bacterial culture showed that with time, Escherichia coli and Clostridium perfringens numbers increased (p < 0.05) and that the probiotic group had lower E. coli numbers than the control group throughout the study (p < 0.05). Molecular-based analysis further elucidated different fecal microbial compositions between the groups (p < 0.05) and that the microbiota of the finisher pigs were more diverse than for the grower pigs (p < 0.05).
Main finding: The supplementation of B. subtilis C-3102 in feed was effective in improving the growth performance of grower-finisher pigs and the modification of gut microbiota was likely to be one of the mechanisms of such improvement.