Probiotic supplementation protects weaned pigs against enterotoxigenic Escherichia coli K88 challenge and improves performance similar to antibiotics

These studies evaluated the effects of probiotics (PB) as a potential substitute for antibiotics (AB) on diarrhea in relation to immune responses and intestinal health in weaned pigs challenged with enterotoxigenic Escherichia coli (ETEC) K88 (Exp. 1) and the effects of PB on performance and nutrient digestibility in weaned pigs (Exp. 2). In Exp. 1, 24 weaned barrows (4.9 +/- 0.4 kg initial BW) were randomly assigned to 1 of 4 treatments. The treatments consisted of pigs fed an unsupplemented corn-soybean meal basal diet and not challenged (NON-C) or challenged with ETEC K88 (CHA-C) on d 9 and pigs fed the same basal diet supplemented with AB (100 mg/kg zinc bacitracin, 50 mg/kg colistin sulfate, and 100 mg/ kg olaquindox; CHA-AB) or 500 mg/kg PB (Bacillus licheniformis and Saccharomyces cerevisiae; CHAPB) and challenged with ETEC K88 on d 9. In Exp. 2, 108 weaned pigs (7.5 +/- 0.9 kg initial BW) not challenged with ETEC K88 were randomly assigned to 1 of 3 treatments, including an AB-free basal diet (CON) and the basal diet with AB (ABD) or 500 mg/ kg PB supplementation (PBD). In Exp. 1, after challenge, CHA-C decreased (P < 0.05) ADG and ADFI, whereas CHA-AB and CHA-PB revealed no significant change compared with NON-C. Compared with CHA-C, CHA-AB and CHA-PB improved (P < 0.05) ADG and ADFI and decreased (P < 0.05) the diarrhea incidence in pigs. Mucosal secretory Ig A contents in the jejunum and ileum were greater in CHA-C than in NON-C (P < 0.05) and lower than in CHA-PB (P < 0.05). The diet containing PB alleviated the increase in the endotoxin and diamine oxidase concentration and cecal E. coli count (P < 0.05) and the decrease in intestinal villus height, cecal Lactobacillus count, and jejunal mucosal occludin protein abundance (P < 0.05). In Exp. 2, dietary supplementation with AB and PB had positive effects on ADG and feed efficiency (P < 0.05). Compared with CON, apparent digestibility of nutrients in PBD was improved (P < 0.05). Collectively, PB supplementation protected the pigs against ETEC K88 infection by enhancing immune responses and attenuating intestinal damage and improved the performance and nutrient digestibility of weaned pigs. Therefore, PB could be a potential effective alternative to AB for ameliorating diarrhea and improving performance in weaned pigs.