Bacillus subtilis-based probiotic promotes bone growth by inhibition of inflammation in broilers subjected to cyclic heating episodes

Authors: YAN, F - Zhejiang Academy Of Agricultural Sciences; WANG, W - Purdue University; Cheng, Heng-Wei

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/20/2020
Publication Date: 10/30/2020
Citation: Yan, F.F., Wang, W.C., Cheng, H. 2020. Bacillus subtilis-based probiotic promotes bone growth by inhibition of inflammation in broilers subjected to cyclic heating episodes. Poultry Science. 99(11):5252-5260. https://doi.org/10.1016/j.psj.2020.08.051.
DOI: https://doi.org/10.1016/j.psj.2020.08.051

Interpretive Summary: Heat stress causes bone microarchitectural deterioration. The objective of this study was to investigate the effect of a Bacillus subtilis-based probiotic on bone health of broilers reared under high ambient temperatures. Day-old broiler chicks were randomly assigned to 2 dietary treatments: regular diet and the diet mixed with the probiotic. The results indicate that dietary supplementation of Bacillus subtilis-based probiotic increases bone growth in broilers under a cyclic heating episode via inhibition of bone resorption resulting from down-regulations of proinflammatory cytokines. The findings provide insights for poultry meat producers and scientists to develop novel management strategies for increasing skeletal health and welfare of broilers reared under hot weather conditions.

Technical Abstract: Heat stress as an environmental stressor causes abnormal bone remodeling and microarchitectural deterioration. The objective of this study was to investigate the effect of a Bacillus subtilis-based probiotic on bone health of broilers subjected to cycling high ambient temperatures. One hundred and twenty 1-day-old Ross 708 male broiler chicks were randomly assigned to 2 dietary treatments (n=12): regular diets and the diets mixed with 250 ppm probiotic consisting of 3 strains of Bacillus subtilis. The room temperature was increased from 28 to 32° C for 10 h (0700h to 1700h) daily from day 15 to day 44. At day 44, the blood, brain, and bone samples were collected. Compared to controls, probiotic supplementation increased bone mineral content, weight, size, weight to length index, and reduced robusticity index in the tibia and femur (P < 0.05) of broilers subjected to heat stress. Serum concentrations of c-terminal telopeptide of type I collagen (CTX) were reduced (P = 0.02) by the probiotic supplementation, while ionized calcium, phosphate, and osteocalcin were not affected (P > 0.05). In addition, tumor necrosis factor-a (TNF-a) in probiotic fed broilers was decreased (P = 0.003) without changes of plasma interleukin-6 (IL-6), IL-10, interferon-', and corticosterone concentrations (P > 0.05). There were no treatment effects on the concentrations of both peripheral and central serotonin and catecholamines (norepinephrine, epinephrine, and dopamine) as well as their metabolites (P>0 0.05) These results indicate that dietary supplementation of Bacillus subtilis-based probiotic increases bone growth in broilers under cyclic heating episodes via inhibition of bone resorption, resulting from down-regulations of the effects of TNF-a and CTX on bone resorption. Dietary probiotic supplementation may provide a novel management strategy for increasing skeletal health of broilers reared under hot weather conditions.