The withdrawal time of enrofloxacin, sulfachloropyrazine sodium, and doxycycline as well as the in vitro binding interaction with melanin in black-feathered silky fowl

The problem of veterinary drug residues in black-feathered silky fowl (BFS) has garnered significant attention. This study investigated the residue elimination patterns and causes of enrofloxacin (ENR), sulfachloropyrazine sodium (SPZ), and doxycycline (DOX) in BFS using ultra-high performance liquid chromatography mass spectrometry (UPLC-MS), along with the drug adsorption and melanin binding tests. The findings indicated that ENR and SPZ were metabolized slowly, DOX was metabolized faster in BFS, with optimum withdrawal time was 87.8, 37.26, and 24.7 days, respectively. The adsorption capacity of skin + fat to drugs and the binding capacity of melanin to the three drugs in BFS were in the order of ENR > SPZ > DOX, confirming that melanin's binding ability influences the drug residues in BFS. This study is highly significant for addressing the issue of veterinary drug residues in BFS.