LAUSR

The objective of this experiment was to investigate the effects of dietary supplementation of Bacillus amyloquefaciens on diarrhea and growth performance of weaned pigs experimentally infected with a pathogenic E. coli. A total of 50 weaned pigs (7.41 ± 1.35 kg) were individually housed in disease containment rooms and randomly assigned to one of the 5 treatments: sham control (CON-), sham B. amyloquefaciens (BAM-), challenged control (CON+), challenged B. amyloquefaciens (BAM+) and challenged carbadox (CAR+). The experiment lasted 28 days with 7 days’ adaptation and 21 days after the first E. coli inoculation. The doses of F18 E. coli inoculum were 1010 CFU/3 mL oral dose daily for 3 consecutive days. Pigs were weighed on d -7, and d 0, 7, 14, and 21 PI and feed intake was recorded weekly to calculate growth performance. Diarrhea score was recorded twice daily ranging score from 1 (normal feces) to 5 (watery diarrhea). Fecal swabs were performed on each pig on d 2, 7, 14, and 21 PI to test the percentage of β-hemolytic coliforms in total coliforms. All data were analyzed with PROC MIXED of SAS. E. coli challenge reduced (P < 0.05) growth rate through the entire experiment. However, supplementation of CAR enhanced (P < 0.05) growth performance, while inclusion of BAM tended (P < 0.10) to increase growth performance of weaned pigs. No differences were observed in growth performance of pigs between BAM+ and CAR+ throughout the experiment. E. coli challenge did not change the percentage of β-hemolytic coliforms but increased (P < 0.05) frequency of diarrhea. However, no difference was observed in diarrhea among 3 dietary treatments. In conclusion, supplementing B. amyloquefaciens tended to enhance growth performance but had limited effects on diarrhea of weaned pigs challenged with E. coli.