Probiotic Prophylaxis for Enterococcus cecorum Prevalence in the Free Thoracic Vertebra of Broiler Chickens

Enterococcus cecorum has become a significant pathogen of broilers and broiler breeders worldwide, and there are few effective prevention, treatment, or control measures. Improved, preferably nonantibiotic tools are needed to control the disease. Two pen trials were conducted to assess the effectiveness of a day-of-age probiotic and a continuous direct fed microbial (DFM) in preventing colonization of the spleen and free thoracic vertebra after challenge with pathogenic E. cecorum in commercial broiler chickens. In Experiment 1, three treatment groups were administered either no treatment (challenge controls), a day-of-age probiotic gel plus DFM 1 continuously in the feed, or the probiotic plus DFM 2, and challenged orally on Day 0 with a known pathogenic strain of E. cecorum (SA3). Both treatments resulted in a significant decrease in prevalence of colonization of spleens and free thoracic vertebrae at Day 42 compared to the challenge controls, with no effects on performance parameters or total mortality. In Experiment 2, four treatment groups were administered either no treatment (challenge controls), the day-of-age probiotic gel alone, the probiotic gel plus DFM 1, or DFM 1 alone. At 42 days of age, both the probiotic alone and the probiotic plus DFM 1 resulted in a significant decrease in colonization of the free thoracic vertebrae compared to the challenge controls, with the DFM alone being statistically intermediate. There were no impacts on performance parameters, livability, or lameness compared to the challenge controls. These results suggest that the day-of-age probiotic and the DFM may be a useful tool in controlling enterococcal spondylitis, and further larger-scale trials are warranted to assess impacts on clinical signs and performance.