Efficacy of a Novel, Native Microbial Feed Supplement on the Mitigation of Necrotic Enteritis in Cobb 500 Broiler Chickens

Background and Objectives: Necrotic enteritis, a potentially fatal intestinal disease, has been a recurring issue in the poultry industry. This problem has been exacerbated due to the phasing out of widespread prophylactic antibiotic usage. This study assessed the efficacy of a microbial feed supplement (MFS) (Native Microbials, San Diego, CA)comprised of bacteria native to the chicken gastrointestinal tractas an antibiotic alternative that prevents both clinical and subclinical necrotic enteritis. This MFS is composed of two chicken gastrointestinal microbiome members, Hungatella xylanolytica ASCUSBR21 and Clostridium beijerinckii ASCUSBR67. Materials and Methods: The effect of this MFS was tested in two trials by challenging broiler chickens with direct administration of Clostridium perfringens, the causative agent of necrotic enteritis. Methods were similar between Trial 1 and Trial 2, with the main variance being the number of birds used (Trial 1, n = 540; Trial 2, n = 936). Production and mortality data were collected over the entire study period (42-days). Results: Trial 1 revealed no statistically significant effects on production metrics (bird gain, feed intake, feed conversion ratio) but there was a positive improvement in feed conversion ratio in the group receiving the MFS (FCR: 1.61±0.01; p>0.05). Additionally, in Trial 1 there was a significant reduction in mortality from necrotic enteritis in the treated groups (2.89±2.68%; p = 0.05) and reduced severity of intestinal lesions (0.73±0.25; p<0.01). Trial 2 showed a 4-point improvement in feed conversion ratio compared to the positive control (FCR: 1.64±0.02; p < 0.05). Conclusion: The diet supplemented with MFS reduced mortality attributable to necrotic enteritis and improved feed conversion ratio. Further testing is needed to better understand the response and variability of these factors as they relate to the MFS.