The Assessment of Withdrawal Interval for Enrofloxacin in Yellow Catfish (Pelteobagrus fulvidraco) after Multiple Oral Administrations at Disparate Temperatures

Simple Summary: Enrofloxacin (EF) is an important antibiotic in global aquaculture. Due to the abuse and the emergence of drug resistance, the excess use of EF has occurred in recent years to result in residue exceeding in the edible tissues of aquatic animals. Withdrawal time (WT) is a red line to ensure food safety for humans. However, there is no related report of WT for EF in yellow catfish (Pelteobagrus fulvidraco). In addition to yellow catfish being sensitive to temperature, it can alter the disposition and elimination of EF and its main metabolite in fish bodies, ciprofloxacin (CF), thereby changing the WT in tissues. Therefore, we will conduct a WT estimation of EF in yellow catfish at different temperatures to establish related regulations to help residue surveillance in fish products. The objective of the present study was to investigate the residue depletion of EF and CF in yellow catfish to estimate its WTs in plasma and tissues after multiple oral doses for 3 days at 20 mg/kg at 15, 20, and 25 degrees C. Samples were collected at pre-designed time points after oral doses. A validated method was performed to quantify EF and CF in plasma and tissues by high-performance liquid chromatography. Statistical differences were conducted using one-way ANOVA analysis. According to the maximum residue limit of China and Europe considering 95% percentile with 95% confidence, the WTs were estimated to be 44, 72, 66, 99, and 95 days at 15 degrees C; 32, 66, 65, 86, and 73 days at 20 degrees C; and 32, 61, 64, 55, and 59 days at 25 degrees C in the plasma, muscle and skin, gill, liver, and kidney, respectively. We found that increased temperature shortened the WTs in plasma and tissues. Therefore, this study can help the risk assessment of EF in aquatic products for human health at different temperatures to avoid residue violation.