Detection of Tetracycline and Colistin Residue in Broiler Meat of Siddharthanagar Municipality, Rupandehi, Nepal

The widespread and unregulated use of antibiotics in poultry production has led to growing concerns over the presence of antibiotic residues in meat, contributing to the global crisis of antimicrobial resistance (AMR). In Nepal, some studies have shown that up to 62% of broiler meat samples in major cities contain antibiotic residues. However, data from international border districts such as Rupandehi remain scarce despite their high poultry trade volume and potential for informal antibiotic usage. A descriptive cross-sectional study was conducted from August to November 2023 to detect antibiotic residues in broiler meat sold in Siddharthanagar Municipality, Rupandehi District, Nepal. A total of 82 samples (54 breast muscle and 28 liver samples) were randomly collected from retail meat shops. Each sample was tested for tetracycline and colistin sulfate residues using ELISA kits, resulting in 164 individual tests. The results revealed that the mean residue level of tetracycline was 2.86 μg/kg, while that of colistin sulfate was 20.65 μg/kg. Residue levels exceeded the mean in 28.05% of samples for tetracycline and 29.26% for colistin sulfate. Residue levels were significantly higher in liver samples compared to breast muscle (p < 0.05). Overall, out of 164 tests conducted, 97 tests (59.15%) were positive for antibiotic residue, while 67 tests (40.85%) were negative. This study revealed that both groups of antibiotics were within the national maximum residue limit (MRL). However, the high levels of colistin sulfate residues suggest ongoing illegal use, despite its ban in Nepal since 2019. This highlights the urgent need for a stronger regulatory framework to ensure the enforcement of existing bans on last-resort antibiotics. Sustainable alternatives-such as probiotics, vaccines, and other nonantibiotic interventions-should be promoted to reduce antibiotic usage in poultry production.