Effect of Bacillus subtilis C-3102 Spores as a Probiotic Feed Supplement on Growth Performance, Nutrient Digestibility, Diarrhea Score, Intestinal Microbiota, and Excreta Odor Contents in Weanling Piglets

SIMPLE SUMMARY: The weanling period is a vital stage for piglets. Due to lack of a complete digestive system and an immune system, a series of stress problems develop, such as diarrhea. As a kind of microecological additive with high stability and rapid proliferation, Bacillus subtilis is suitable for piglets’ diets as an additive. The objective of our study was to determine and confirm the effect of Bacillus subtilis C-3102 spores as a probiotic feed supplement on growth performance, nutrient digestibility, fecal score, intestinal microbiota, and excreta odor contents in weanling piglets. Taken together, our results suggest that dietary supplementation with Bacillus subtilis C-3102 spores could benefit the body weight, average daily gain, and gain-to-feed ratio of weanling piglets and improve the ATTD of dry matter, crude protein, and energy. ABSTRACT: It has been well-documented that the dietary supplementation of Bacillus subtilis could improve piglet performance. The present study was conducted to investigate the effect of Bacillus subtilis C-3102 spores as a probiotic feed supplement on growth performance, nutrient digestibility, fecal score, intestinal microbiota, and excreta odor contents in weanling piglets. A total of 150 crossed ((Yorkshire × Landrace) × Duroc) weanling piglets (28-days-old), with an average initial body weight of 7.53 ± 1.23 kg, were divided into two treatment groups according to sex and initial body weight (BW) for a 6-week experiment. In each group, fifteen replicate pens consisting of five piglets per pen (three gilts and two barrows) were used in a randomized complete block design. Treatments consisted of (1) CON, a basal diet; (2) BSC, a diet of CON + 300 g Bacillus subtilis (B. subtilis) C-3102 spores per ton of feed. Supplementation with the B. subtilis C-3102 spores in the diet increased the BW, average daily gain (ADG), and gain-to-feed ratio (G:F) throughout the whole trial (p < 0.05). Weanling piglets that were fed B. subtilis C-3102 spores had increased dry matter (DM), crude protein (CP), and energy (E) digestibility compared to the CON group (p < 0.05). Lower diarrhea scores were observed in the B. subtilis C-3102 spores group on Day 7 (p < 0.05). Taken together, our results suggest that dietary supplementation with B. subtilis C-3102 spores could benefit the BW, ADG, and G:F of weanling piglets and improve the apparent total tract digestibility (ATTD) of the DM, CP, and E.