Age, not feed additives, affects antimicrobial resistance genes in chickens

What happened

For many years, antibiotics have been added to animal feed to help control harmful bacteria and improve growth. Researchers at Penn State have now found that feeding broiler chickens an antibiotic, a probiotic or essential oils did not significantly affect the overall diversity of antimicrobial resistance genes. Instead, the chickens' age had a much stronger effect on the resistome—the collection of antimicrobial resistance genes—as the birds grew.

Key facts

• Researchers at Penn State have now — found: that feeding broiler chickens an antibiotic, a probiotic or essential oils did not significantly affect the overall diversity of antimicrobial resistance genes