Dietary supplementation with Bacillus subtilis direct-fed microbials alters chicken intestinal metabolite levels

Authors: PARK, INKYUNG - US Department Of Agriculture (USDA); ZIMMERMAN, N - Arm & Hammer Animal And Food Production; SMITH, A - Arm & Hammer Animal And Food Production; REHBERGER, T - Arm & Hammer Animal And Food Production; LILLEHOJ, E - University Of Maryland; Lillehoj, Hyun

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/19/2020
Publication Date: 3/4/2020
Citation: Park, I., Zimmerman, N.P., Smith, A.H., Rehberger, T.G., Lillehoj, E.P., Lillehoj, H.S. 2020. Dietary supplementation with Bacillus subtilis direct-fed microbials alters chicken intestinal metabolite levels. Scientific Reports. https://doi.org/10.3389/fvets.2020.00123.
DOI: https://doi.org/10.3389/fvets.2020.00123

Interpretive Summary: Microbial resistance to antibiotics is a serious and growing public health problem worldwide. Dietary antibiotic growth promoters (AGPs) have been used in the food animal industry for more than 60 years to increase feed efficiency and improve growth performance but increasing scientific evidence suggests that probiotics such as Bacillus could be used in place of AGPs for sustainable animal production in the absence of antibiotics. In this report, ARS scientists collaborated with scientists at a private industry to show B. subtilis can promote growth, immunity, and overall gut health. To further investigate mechanisms of the health-promoting effects of probiotic Bacillus spp., genomics was used to characterize the metabolic alterations in the chicken gut following dietary supplementation with B. subtilis probiotics. Here, comprehensive analysis of metabolomics results identified many small molecular weight chemicals which are significantly altered with probiotic supplementation. For example, 83 metabolites were altered in the chickens gut given the B. subtilis 1781-supplemented diet, while 50 were altered (p < 0.05) (12 increased, 38 decreased) with the B. subtilis 747-supplemented diet. These results demonstrate importance of using probiotics to obtain beneficial effects on gut health. Identification of metabolites in the intestine will lead to further studies on their role in gut function that will enhance our understanding of how probiotics such as Bacillus works.

Technical Abstract: Direct-fed microbials (DFMs) are dietary supplements containing live microorganisms which confer a health benefit to the host, but the mechanisms are unclear. Here, a metabolomics approach was used to identify changes in intestinal metabolite levels in chickens fed an unsupplemented diet or a diet supplemented with B. subtilis strain 1781 or strain 747. Body weight gains of chickens fed the B. subtilis-supplemented diets were increased, compared with chickens fed the unsupplemented diet. Compared with unsupplemented controls, the levels of 83 metabolites were altered (25 increased, 58 decreased) in chickens given the B. subtilis 1781-supplemented diet, while 50 were altered (12 increased, 38 decreased) with the B. subtilis 747-supplemented diet. Twenty-two metabolites were altered (18 increased, 4 decreased) in the B. subtilis 1781 vs. B. subtilis 747 groups. Changes in the levels of these intestinal biochemicals provided a distinctive biochemical signature unique to each B. subtilis-supplemented group, and were characterized by alterations in the levels of dipeptides (alanylleucine, glutaminylleucine, phenylalanylalanine, valylglutamine), nucleosides (N1-methyladenosine, N6-methyladenosine, guanine, 2-deoxyguanosine), fatty acids (sebacate, valerylglycine, linoleoylcholine), and carbohydrates (fructose). These results provide the foundation for future studies to identify biochemicals that might be used to improve poultry growth performance in the absence of antibiotic growth promoters.