levels of 3.4 ± 0.7 and 4.5 ± 0.5 log CFU/mL, respectively (Fig. 2). B. pullicaecorum that had been subjected to pH 4 or pH 6 during gastric incubation were unaffected during small intestine incubation, displaying levels of 7.1 ± 0.5 and 8.1 ± 0.4 log CFU/mL, respectively after 6 h.