140 Effects of Bacillus subtilis probiotics on growth performance, diarrhea, and fecal β-hemolytic coliforms of weaned pigs experimentally infected with an enterotoxigenic Escherichia coli

Abstract

Abstract The objective of this experiment was to investigate the effects of Bacillus subtilis on growth performance, diarrhea and fecal β-hemolytic coliforms of weaned pigs experimentally infected with a strain of E. coli (F18, express genes of LT, STb, and SLT 2 toxins). Weaned pigs (n = 48, 6.17 ± 0.36 kg BW) were individually housed in disease containment rooms and randomly allotted to one of four dietary treatments: negative control (NC, control diet without E. coli challenge), positive control (PC, control diet with E. coli challenge), and supplementation of 50 mg/kg of carbadox or 500 mg/kg of Bacillus subtilis probiotics. The experiment lasted 28 d with 7 d before and 21 d after the first E. coli inoculation. The F18 E. coli were given to pigs at 1010 CFU/3 mL dose for three consecutive d. Diarrhea score was daily recorded for each pig to calculate frequency of diarrhea. Fecal samples were collected on d 0, 3, 7, 14, and 21 PI to analyze β-hemolytic coliforms. Data were analyzed using the Mixed Procedure of SAS. Pigs supplemented with carbadox had greater (P < 0.05) body weight on d 7, 14, and 21 PI than pigs in the PC and probiotics group. Supplementation of probiotics enhanced pig body weight on d 21 PI, compared with the PC. E. coli challenge reduced (P < 0.05) ADG and feed efficiency from d 0 to 21 PI, while supplementation of antibiotics or probiotics enhanced ADG and feed efficiency from d 0 to 21 PI. Pigs in carbadox and probiotics groups had reduced (P < 0.05) frequency of diarrhea throughout the experiment and fecal β-hemolytic coliforms on d 7 PI than pigs in the PC. In conclusion, supplementation of Bacillus subtilis could enhance disease resistance and promote growth performance of weaned pigs under disease challenge condition.