Mitigating Tetracycline antibiotic contamination in chicken manure using ex situ fermentation system

Area of Science:

• Environmental Science
• Microbiology
• Agricultural Science

Background:

• Poultry farming's excessive tetracycline use leads to antibiotic residues and resistance genes in chicken manure.
• These contaminants pose risks to environmental and human health.

Purpose of the Study:

• Investigate chlortetracycline (CTC) and tetracycline resistance genes (TRGs) removal in an ex situ fermentation system (EFS).
• Identify key bacteria and environmental factors influencing TRG dynamics.
• Determine optimal conditions for contaminant removal in chicken waste treatment.

Main Methods:

• Analysis of CTC and TRG concentrations across different EFS layers.
• Microbial community profiling using network analysis.
• Correlation of physical and chemical conditions with TRG removal efficiency.

Main Results:

• CTC degradation half-lives ranged from 3.3-5.8 days.
• TRG removal efficiency reached 86.82%–99.52%.
• The middle EFS layer demonstrated superior removal of CTC and key TRGs (tetW, tetG, tetX, intI2).
• Proteobacteria and Actinobacteria were crucial for TRG elimination.

Conclusions:

• EFS is effective for removing CTC and TRGs from chicken manure.
• Microbial communities and environmental conditions significantly impact contaminant removal.
• The middle EFS layer is the most effective for treating chicken waste and mitigating antibiotic resistance spread.