Overview
Research conducted at Penn State investigated factors influencing the diversity of antimicrobial resistance genes (resistome) in broiler chickens. The study specifically examined the comparative effects of chicken age and various feed additives, including antibiotics, probiotics, and essential oils.
Research Context
Antibiotics have historically been incorporated into animal feed to manage harmful bacteria and promote growth in livestock. However, rising concerns regarding antibiotic resistance—where bacteria develop mechanisms to withstand treatments that would typically eradicate them—have prompted poultry producers to explore alternative strategies. These alternatives include probiotics, which introduce beneficial bacteria, and essential oils, derived from plants and potentially possessing antimicrobial properties.
Approach
Researchers at Penn State conducted a study involving broiler chickens. The experimental design included feeding regimens that incorporated either an antibiotic, a probiotic, or essential oils. The primary outcome measured was the overall diversity of antimicrobial resistance genes within the chickens.
Findings
The study observed that feeding broiler chickens an antibiotic, a probiotic, or essential oils did not produce a significant effect on the overall diversity of antimicrobial resistance genes. In contrast, the age of the chickens demonstrated a substantially stronger impact on the resistome. As the birds matured, their resistome—the collective set of antimicrobial resistance genes—was more strongly affected by their developmental stage than by the specific feed additives administered.
Why This Matters
The findings suggest that the developmental stage of broiler chickens, specifically their age, is a more influential determinant of antimicrobial resistance gene diversity than the use of certain feed additives. This insight contributes to the understanding of factors shaping the resistome in poultry.