Lactic acid bacteria silage treatment to reduce antibiotic-resistance genes and viral spread in livestock feed

Overview

This research investigates how different silage additives influence the content of viruses and antibiotic-resistance (ARO) genes in fermented animal feed. Findings indicate that lactic acid bacteria additives, particularly heterofermentative Lactobacillus brevis (LB), significantly reduce antibiotic-resistance gene abundance compared to chemical additives such as vanillin. The work has important implications for livestock producers, feed manufacturers, and the agricultural industry by offering a biological approach to lowering antimicrobial resistance risks in animal production systems and surrounding farm environments.

The research hypothesis proposes that lactic acid bacteria-treated silages can reduce the recombination and horizontal transfer of antibiotic-resistance genes in animal guts, thereby lessening the potential for these genes to become environmental contaminants around farms. This addresses a growing global concern about antimicrobial resistance spreading through agricultural practices.

Technical specifications

The research employs a controlled between-subjects experimental design comparing four silage treatments on high-moisture corn kernels:

• Control (CK): distilled water at 1% g/g fresh kernels
• Lactobacillus brevis (LB): heterofermentative lactic acid bacteria at 1×10⁶ cfu/g fresh kernels
• Lactobacillus plantarum (LP): homofermentative lactic acid bacteria at 1×10⁶ cfu/g fresh kernels
• Vanillin (V): chemical additive at 1% g/g fresh kernels

Key findings from initial validation:

• A total of 135 antibiotic-resistance genes were detected across all treatments
• LB-treated silage contained 116 ARO genes, the fewest among all treatments
• V-treated silage contained 129 ARO genes, the highest among treatments
• Relative abundance of ARO genes was highest in vanillin-treated silage

The methodology involves metagenomic sequencing to analyze microbial communities, metabolome profiles, viral distributions, and antibiotic-resistance gene content in silage samples.

Technology readiness level

The technology is currently at an advanced research stage with completed initial validation on sweet corn kernel silage. The research team has demonstrated that Lactobacillus brevis treatment consistently produces the lowest antibiotic-resistance gene content among tested additives. Future validation will extend the work to full corn silage applications and animal feeding trials over a one-year period, collecting and sequencing gut microbiota and animal excrement samples to assess horizontal gene transfer and environmental contamination potential.

The research team is actively seeking partnerships to support animal feed provision, sample collections, metagenome sequencing, and funding for key personnel to advance this work toward practical agricultural application.