|KENNEY, SOPHIA - Pennsylvania State University|
|ERB, LOGAN - Kalmbach Feeds|
|BONEY, JOHN - Pennsylvania State University|
|GANDA, ERIKA - Pennsylvania State University|
Submitted to: American Society for Microbiology
Publication Type: Abstract Only
Publication Acceptance Date: 2/24/2022
Publication Date: 6/9/2022
Citation: Kenney, S., Miles, A.M., Erb, L., Boney, J., Ganda, E. 2022. Effects of direct-fed microbial inclusion on turkey intestinal resistome [abstract]. American Society for Microbiology. June 9-13, Washington, D.C., United States.
Technical Abstract: Antimicrobial resistance (AMR) is a globally recognized threat to animal and human health. While microorganisms harbor a level of natural resistance, the selective pressure of antibiotic misuse has accelerated it requiring the implementation of biosurveillance strategies to identify types and abundance of antimicrobial resistance genes (ARGs) across reservoirs. These ARG profiles, or resistomes, can be leveraged to monitor the evolution of AMR potential of specific pathogens and their dissemination between reservoirs. Given the historical role of antibiotic growth promoters in agriculture and the departure from their use, probiotics have been explored for their potential as performance enhancing feed additives. While the effects of probiotics on the resistome of human patients has been studied, little is known about their influence on the of resistome livestock, specifically turkeys. To examine the effects of probiotic feed additives on the resistome of turkeys, turkeys were reared on a conventional diet or a diet supplemented with Bacillus subtilis C-3102 over a 19 week period. Samples were collected using cloacal swabs on the last day of study as well as from the pens in which the birds were housed using boot sock covers. The DNA extracted from these samples was then sequenced using shotgun metagenomics on the NovaSeq platform. Sequence alignment was performed using NCBI’s nucleotide BLAST against the MEGARes 2.0 database. Following decontamination according to negative controls and normalization, the relative abundance of each identified gene was determined and compared between treatment groups and sample collection sites. Across all samples, 533 ARGs were identified. Between treatment groups, there were no significant differences in relative abundance of these genes nor in the per sample average gene count, indicating the probiotic did not significantly alter the resistome of the turkeys in this study relative to their conventionally fed counterparts. Between cloacal swab and boot sock sampling methods, there were statistically significant differences in the relative abundance of 151 genes, with the boot sock being more sensitive. Of these, 105 were associated with drug resistance, 28 to metal resistance, 2 to biocides, and 16 to multi-compound resistance. Furthermore, there were no significant differences in the average per sample gene count. While Bacillus subtilis C-3102 does not significantly alter the bacterial resistome of turkeys, site collection influences the relative abundance of ARGs detected.