A study on residual elimination of florfenicol in different tissues of Xiushui yellow-feathered black-bone chickens

<bold>Objective</bold> This study aims to investigate the residue depletion patterns of florfenicol in different tissues of Xiushui yellow-feathered black-bone chickens and to determine the withdrawal time of florfenicol in these chickens.The findings will provide a scientific basis for establishing the withdrawal period of antimicrobial drugs in Xiushui yellow-feathered black-bone chickens，thereby ensuring the safety of Xiushui yellow-feathered black-bone chicken products. <bold>Method</bold> A total of forty-two healthy 160-day-old Xiushui yellow-feathered black-bone chickens were selected.They were administered florfenicol via drinking water at the recommended dosage of 1.5 g/L of 20% florfenicol powder for 5 consecutive days.Samples of muscle，liver，kidney，and skin fat were collected at 0.16，1，3，5，9，15，and 20 days after drug withdrawal.The residues of florfenicol and florfenicol amine in the samples were determined using liquid chromatography-tandem mass spectrometry（LC-MS/MS）.The withdrawal time for florfenicol in various tissues of Xiushui yellow-feathered black-bone chickens was calculated using withdrawal period software（WT 1.4）. <bold>Result</bold> The half-life and withdrawal time of florfenicol in Xiushui yellow-feathered black-bone chickens were longer than those in ordinary broiler chickens.The withdrawal times for florfenicol soluble powder in muscle，liver，kidney，and skin fat of Xiushui yellow-feathered black-bone chickens were 11.26 days，0 days，0 days，and 17.58 days，respectively. <bold>Conclusion</bold> To ensure the safety of Xiushui yellow-feathered black-bone chicken products and consumer health，it is recommended that the withdrawal times for florfenicol in Xiushui yellow-feathered black-bone chickens should be greater than 18 days.