Prolonged persistence of chloramphenicol residues in chicken feathers: implications for retrospective exposure detection

Abstract

Chloramphenicol (CAP) is a prohibited antimicrobial and its detection is important for residue monitoring programmes. This study compared CAP depletion in different types of chicken feathers, plasma, liver and muscle following experimental exposure (approximately 18–25 mg kg⁻¹ body weight day⁻¹ for 7 days). A QuEChERS-based LC–MS/MS method was developed and validated for CAP determination in feathers, plasma, liver and muscle. Apparent recoveries ranged from 90.3% to 97.2%, within-laboratory reproducibility ranged from 6.3% to 9.4%, and the decision limit (CCα) was 0.10 μg kg⁻¹ for all matrices. The highest CAP concentrations one day after treatment withdrawal were observed in plasma (2493 μg kg−1) and tail feathers (2460 μg kg−1). CAP concentrations in plasma, liver and muscle remained above CCα through day 14 after treatment withdrawal but were below CCα from day 21 onward, whereas concentrations in all four analysed feather types (wings, tail, neck and legs) remained above CCα throughout the 28-day observation period. At the final sampling point (49 days of age), the highest CAP concentration was observed in wing feathers (84 μg kg−1). Depletion analysis indicated prolonged persistence of CAP in feathers, particularly in wing and neck feathers. These results support the potential use of feathers as a matrix for retrospective assessment of CAP exposure in poultry.