Effects of Supplementation of Bacillus subtilis LS 1–2 Grown on Citrus-juice Waste and Corn-Soybean Meal Substrate on Performance and Gut Health of Weaning Pigs

The present experiment was conducted to investigate the effects of dietary supplementation with Bacillus subtilis LS 1-2 grown on citrus-juice waste and corn-soybean meal substrate on performance and gut health of weaning pigs. A total of 240 weaning pigs (Landrace x Yorkshire x Duroc) were randomly allotted to 4 treatments, each with 4 replicates of 15 pigs. Dietary treatments included basal diet without any antimicrobial (NC; negative control) or with 150 mg/kg apramycin (PC; positive control), 0.45% B. subtilis LS 1-2 grown on corn-soybean substrate (P1) and 0.45% B. subtilis LS 1-2 grown on citrus-juice waste substrate (P2). The experimental diets were fed in a meal form for 2 phases (d 0-14, phase I and d 14-28, phase II). Overall ADO, ADFI, FCR and ATTD of DM and GE (d 14, d 28) were better (P < 0.05) in pigs fed the PC, P1 and P2 diets than pigs fed the NC diet. Also, the ATTD of CP (d 14 and d 28) in pigs fed the PC and P2 diets was greater (P < 0.05) than pigs fed the NC diet. At d 28, pigs fed the PC diet had lower (P < 0.05) caecal total anaerobic bacteria, Clostridium spp. and coliforms than pigs fed the NC diet. In addition, pigs fed the P2 diet had lower (P < 0.05) caecal coliforms than pigs fed the NC diet. Pigs fed the PC, P1 and P2 diets had greater (P < 0.05) villus height and villus height: crypt depth than pigs fed the NC diet. In addition, growth performance, ATTD of nutrients, caecal microbial population and intestinal morphology of pigs fed P2 diet were not different (P > 0.05) from pigs fed the PC diet. These results indicate that B. subtilis LS 1-2 inclusion at 0.30% level had beneficial effects on weaning pigs growth performance, ATTD of nutrients, caecal microfiora and intestinal morphology. Additionally, citrus-juice waste can be used as substrate for growth of probiotic B. subtilis LS 1-2.