PSXVI-3 Supplemental effects of Bacillus sp. in prevention of post-weaning diarrhea caused by enterotoxigenic F18+ Escherichia coli in nursery pigs

Abstract

Abstract This study investigated the effects of Bacillus sp. on intestinal health and prevention of diarrhea by F18+ Escherichia coli (ETEC) in nursery pigs. Forty-eight weaned pigs (7.9 ± 0.5 kg BW) were allotted to 4 treatments with 12 replicates (NC: no-challenge; PC: challenge/no-treat; BMD: challenge/bacitracin; BAC: challenge/Bacillus sp. at 109 CFU/kg feed). All pigs were fed diets for 28 d. At d 7, challenged groups were orally inoculated with ETEC (1.8 × 1010 CFU) and NC group received sterile solution. Growth performance was analyzed weekly and pigs were euthanized on d 28 to measure intestinal health. Data were analyzed using SAS 9.4. There were no difference on growth performance among treatments during pre-challenge period. From d 7 to 14, PC tended to reduce (P = 0.067) ADG (352 to 440 g/d), whereas no effect was observed during the overall period. The PC increased (P < 0.05) fecal score at d 7 (post-challenge) (4.1 to 3.3) and d 8 (4.1 to 3.3), whereas BMD decreased (P < 0.05) it at d 9 (4.3 to 3.5) and d 11 (3.8 to 3.3). The PC increased (P < 0.05) MDA (0.56 to 0.30 μmol/mg protein) and tended to increase TNFα (P = 0.084; 0.89 to 1.04 pg/mg protein), whereas BMD and BAC reduced (P < 0.05) MDA (0.56 to 0.31, 0.29 μmol/mg protein) and TNFα (1.04 to 0.81, 0.77 pg/mg protein) in jejunal mucosa. The PC reduced (P < 0.05) α-diversity (Chao1: 32.3 to 19.4), whereas BAC increased it (Chao1: 19.4 to 30.7) whereas BMD increased (P < 0.05) it (Shannon: 1.85 to 2.44; Simpson: 0.55 to 0.70) of jejunal mucosa-associated microbiota. In conclusion, ETEC challenge caused diarrhea, increased immune response, and oxidative stress by disrupting mucosa-associated microbiota. The BMD and BAC reduced jejunal immune response and oxidative stress by restoring mucosa-associated microbiota.