Accumulation and elimination of four nitrofuran metabolites in muscle of grouper (Epinephelus awoara)

To investigate the accumulation and elimination of four nitrofuran metabolites in muscle of grouper, we fed the groupers with 100 mg·kg^–1 of nitrofurantoin, furazolidone, furaltadone and nitrofurazone for seven days. The concentrations of semicarbazide (SEM), 3-amino-2-oxazolidone (AOZ), 5-morpholinomethyl-3-amino-2-oxazolidone (AMOZ) and 1-aminohydantoin (AHD) in muscle were determined by UPLC-MS/MS and quantified by internal standard method. The maximum concentrations of nitrofuran metabolites in grouper muscle are as follows: SEM: 1 104.10 μg·kg^–1, AOZ: 781.09 μg·kg^–1, AMOZ: 679.75 μg·kg^–1 and AHD: 437.18 μg·kg^–1. The rules of elimination for the four nitrofuran metabolites in grouper muscle are similar. The half-life time of nitrofuran metabolites in grouper muscle is as follows: SEM: 23.90 d, AHD: 23.10 d, AOZ: 22.35 d and AMOZ: 21.00 d. The eliminating rate of SEM is the lowest. By 163^rd day of elimination, the concentrations of SEM, AOZ, AMOZ and AHD in grouper muscle had still been over 0.5 μg·kg^–1. It is suggested that nitrofurans should be banned in the prevention or treatment of grouper disease.