In-feed bacitracin methylene disalicylate modulates the turkey microbiota and metabolome in a dose-dependent manner

Authors: JOHNSON, TIMOTHY - Orise Fellow; Sylte, Matthew; Looft, Torey

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/10/2019
Publication Date: 6/3/2019
Citation: Johnson, T., Sylte, M.J., Looft, T.P. 2019. In-feed bacitracin methylene disalicylate modulates the turkey microbiota and metabolome in a dose-dependent manner. Scientific Reports. 9:8212. https://doi.org/10.1038/s41598-019-44338-5.
DOI: https://doi.org/10.1038/s41598-019-44338-5

Interpretive Summary: Beginning in 2017, several antibiotics used in animal production to improve feed efficiency were restricted in an attempt to slow the development of antibiotic resistant bacteria. To minimize the disruption of these restrictions on animal agriculture, there is a need to identify how growth promoting antibiotics promote production efficiencies for development of new methods. Growth promoting antibiotic(s) may improve animal production by enhancing the beneficial functions of the bacteria living in the animal’s digestive tract. In this study, we described the effects of feeding different concentrations of an antibiotic commonly used in poultry production, to commercial turkeys for 14 weeks. Data were compared to identify beneficial bacteria and functions within the gut of the medicated birds. The antibiotic had an immediate and lasting change by eliminating many members of the bacterial communities, and reducing the overall diversity of bacteria in the gut. Chemicals that the bacterial community made also shifted, with most chemicals that were detected, changing in concentration after antibiotic treatment. Some of the chemicals that changed the turkey intestine after antibiotic administration are known to be important for animal health. Beneficial traits of bacteria that can be targeted without antibiotics may improve animal health and production and reduce our usage of antibiotics.

Technical Abstract: Beginning in 2017, the subtherapeutic use of most antibiotic compounds for growth promotion in food producing animals in the US was prohibited, highlighting the need discover alternative growth promotants. Identifying the mechanism of action of growth promoting antibiotics may aid in the discovery of antibiotic alternatives. We describe the effects of feeding a subtherapeutic (50g/ton of feed) and therapeutic (200g/ton) concentration of bacitracin methylene disalicylate (BMD) to commercial turkeys for 14 weeks, and its effect on turkey microbial communities and cecal metabolomes. Both BMD concentrations had an immediate and lasting impact on the microbiota structure, and reduced bacterial richness through the end of the study (12 weeks). Metabolomic analysis identified 712 biochemicals, and 69 percent of metabolites were differentially present in BMD treated turkeys for at least one time point (q less than 0.1). Amino acids, carbohydrates, nucleotides, peptides, and lipids were decreased in the turkey cecum early after BMD administration. Long-term metabolome alterations continued even after withdrawal of BMD. The microbial composition, determined by 16S rRNA gene sequencing, was predictive of the metabolome, indicating a connection between the microbiome and metabolome. In-feed BMD may cause bacterial metabolic shifts, leading to beneficial traits that can be targeted to improve animal health and production.