Bacillus subtilis (DSM17299) significantly reduces Salmonella in broilers.

Salmonella continues to be a major public health burden worldwide. Poultry are known to be one of the main reservoirs for this zoonotic pathogen. It has previously been shown that a single dose of Bacillus subtilis reduces fecal shedding of Salmonella enterica serovar Enteritidis, whereas no effect on long-term colonization of the cecum has been observed. Here we report experiments that were undertaken to test the efficacy of a conventional diet supplemented with a probiotic (B. subtilis DSM17299) on 1) Salmonella colonization in the intestinal tract of broiler chickens, and 2) fecal shedding of Salmonella under production-like conditions. The trial birds fed the B. subtilis diet showed a significant 58% reduction in Salmonella-positive drag swabs compared with control birds, which had 100% presence of Salmonella. Feeding B. subtilis significantly reduced the average Salmonella load of cecum samples of the chickens, by 3 log units. This reduction in Salmonella colonization might not only positively affect broilers on the live production side by reducing the risk of infection between birds, but could also aid on the processing side by decreasing the amount of Salmonella entering the facility and improving food safety. Furthermore, numerical, but not statistically significant, improvements in feed conversion rate and BW gain at d 42 were observed in the B. subtilis-treated group compared with control birds.

Bacillus licheniformis prevents necrotic enteritis in broiler chickens.

Three studies were conducted using Clostridium perfringens as an intestinal challenge to produce necrotic enteritis (NE). The studies consisted of two battery screening studies and one production study in floor pens, which were used to test the effect of the addition of Bacillus licheniformis (DSM 17236) spores at different doses and feeding periods in comparison to birds fed diets with subtherapeutic levels of virginiamycin (15 g/ton feed). In all three studies the use of B. licheniformis (1.6 x 10(6) - 8 x 10(7) CFUs/g) or virginiamycin (15 g/ton feed) showed no difference in effect with regard to feed conversion ratio, weight gain, NE lesion score, and NE mortality. In the two battery studies, both treatments showed a significantly decreased feed conversion ratio, increased weight gain, reduced NE lesion score, and NE-reduced mortality compared to the nonmedicated C. perfringens-challenged group. In general, none of the treatments performed as well as the no-challenge group. The present data indicate that the use of B. licheniformis spores as a probiotic or direct-fed microbial could be an alternative to adding medication to the feed to overcome NE under commercial-like conditions and could therefore be of direct use in preventing antibiotic-resistant pathogens in chickens.