|PARK, INKYUNG - US Department Of Agriculture (USDA)|
|LEE, YOUNGSUB - US Department Of Agriculture (USDA)|
|ZIMMERMAN, N.P - Arm & Hammer Animal And Food Production|
|SMITH, A.H - Arm & Hammer Animal And Food Production|
|REHBERGER, T - Arm & Hammer Animal And Food Production|
Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/26/2019
Publication Date: 2/1/2020
Citation: Park, I., Lee, Y., Zimmerman, N., Smith, A., Rehberger, T., Lillehoj, H.S. 2020. The effects of dietary Bacillus subtilis supplementation, as an alternative to antibiotics, on growth performance, intestinal immunity, and epithelial barrier integrity in broiler chickens infected with Eimeria maxima. Poultry Science. https://doi.org/10.1016/j.psj.2019.12.002.
Technical Abstract: The objective of this study was to investigate the effect of dietary Bacillus subtilis supplementation on growth performance, jejunal lesion score, oocyst shedding, cytokine expression, and tight junction protein expression of broiler chickens infected with E. maxima. Fourteen-day-old broiler chickens (n = 196) were randomly assigned to one of seven dietary treatments: two basal diets (CON and NC); CON + virginiamycin (AB1); CON + Bacitracin methylene disalicylate (BMD; AB2); CON + B. subtilis 1781 (PB1); CON + B. subtilis 747 (PB2); CON + B. subtilis 1781 + 747 (PB3). At day 21, all chickens except CON were orally inoculated with E. maxima oocysts. Body weight gains of chickens fed PB2 and PB3 were increased (P = 0.032) as much as AB2. At day 28, body weight gain and feed efficiency of chickens fed PB2 were significantly increased (P < 0.001) and showed (P = 0.005) the lowest lesion score following E. maxima infection. Infection with E. maxima increased cytokine mRNA expression (IL-1ß, IL-2, IL-6, and INF-') in jejunal tissue whereas chickens fed PB2 showed lower mRNA expression of IL-1ß in infected chicken. Chickens fed diet with all supplements (AB1, AB2, PB1, PB2, and PB3) showed a greater mRNA expression of JAM2 in jejunal tissue whereas occludin expression was increased in jejunal tissue of chickens fed AB2 or PB2. Chickens who were treated with dietary supplementation of B. subtilis 1781 and 747 during the early growth period showed significantly improved growth performance which was comparable to those that were given antibiotics under normal growth conditions without E. maxima infection. Following infection with E. maxima, dietary virginiamycin and BMD supplementation significantly enhanced the epithelial barrier integrity while B. subtilis 747 group showed significantly enhanced growth performance, intestinal immunity and epithelial barrier integrity of chickens. Taken together, dietary B. subtilis supplementation has a potential to replace antibiotics fed to broiler chickens.