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ARS Home » Midwest Area » Bowling Green, Kentucky » Food Animal Environmental Systems Research » Research » Publications at this Location » Publication #424919
Research Project: Developing Agronomically and Environmentally Beneficial Management Practices to Increase the Sustainability and Safety of Animal Manure Utilization

Location: Food Animal Environmental Systems Research

Title: Effects of sound and air on antibiotic resistance genes during anaerobic digestion of poultry litter

Author
item Agga, Getahun
item Loughrin, John

Submitted to: Research Workers in Animal Diseases Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 11/13/2025
Publication Date: 1/13/2026
Citation: Agga, G.E., Loughrin, J.H. 2026. Effects of sound and air on antibiotic resistance genes during anaerobic digestion of poultry litter. Research Workers in Animal Diseases Conference Proceedings. [abstract] p. 330.

Interpretive Summary:

Technical Abstract: Removal of poultry litter (PL) from broiler farms is challenging and anaerobic digestion (AD) provides a great opportunity by converting waste into energy. Our team previously showed that microaeration and sound treatments of AD increase biogas production. Here, we investigated to see whether sound, micro-aeration, and their combination had any effects on the prevalence of antimicrobial resistance genes (ARG) during AD of PL. Four AD treatments with a control were maintained at ambient temperature. A total of 12 digestate samples collected at 6, 23, and 42 wk were shotgun sequenced using Illumina NovaSeq and DIAMOND sequence aligner. Negative binomial regression in STATA was used to analyze read count data aggregated at the treatment level. Overall, 3,190 gene accessions belonging to 337 unique genes conferring resistance mainly to antimicrobials (97%) were detected. Treatment did not significantly affect the mean number of ARG; although the total number of ARG decreased in the control, micro-aeration or sound treatment, or both, increased the number of ARG. Total ARG read counts increased on wk 23 in all treatments; averaged by treatment group, only sound-treated AD significantly (P = 0.035) reduced the mean total ARG abundance compared with the control AD, with no aeration effect. The number and abundance of ARG detected from the digestate and PL feed were lower than the AD samples. More than 80% of the resistome was composed of 4 antimicrobial classes: macrolides-lincosamides-streptogramins, tetracyclines, aminoglycosides, and glycopeptides. In conclusion, AD does not effectively remove ARG from animal manure, and aeration and sound did not improve its effect. The AD system may act as a hotspot for ARG, necessitating post-AD treatments such as composting.