Bacillus subtilis PS-216 Spores Supplemented in Broiler Chicken Drinking Water Reduce Campylobacter jejuni Colonization and Increases Weight Gain

Abstract

<i>Campylobacter jejuni</i> is the leading cause of bacterial gastroenteritis, or campylobacteriosis, in humans worldwide, and poultry serves as a major source of infection. To reduce the risk associated with <i>C. jejuni</i> transmission via poultry meat, effective interventions during poultry production are needed, and the use of probiotics is a promising approach. In this study, 15 <i>Bacillus subtilis</i> strains were initially screened for their anti-<i>Campylobacter</i> activities. <i>B. subtilis</i> PS-216 strain demonstrated the best anti-<i>Campylobacter</i> activity against 15 <i>C. jejuni</i> isolates when examined using <i>in vitro</i> co-cultures. To evaluate the suitability of <i>B. subtilis</i> PS-216 for probiotic use, its susceptibility to eight clinically important antimicrobials and simulated gastric conditions was investigated. <i>B. subtilis</i> PS-216 was sensitive to all of the tested antibiotics. Although vegetative cells were sensitive to gastric conditions, <i>B. subtilis</i> PS-216 spores were highly resistant. We further evaluated the use of a <i>B. subtilis</i> PS-216 spore preparation (2.5 × 10⁶ CFU/mL water) to prevent and/or reduce <i>C. jejuni</i> colonization in broiler chickens <i>in vivo</i>. Compared to the untreated group, significantly lower <i>Campylobacter</i> counts were detected in caeca of broilers continuously treated with <i>B. subtilis</i> PS-216 spores in their drinking water. Furthermore, broilers continuously treated with <i>B. subtilis</i> PS-216 spores showed improved weight gain, compared to the control group. Together, these results demonstrate the potential of <i>B. subtilis</i> PS-216 for use in poultry to reduce <i>C. jejuni</i> colonization and improve weight gain.