Abstract：
Enrofloxacin (EF) is a broad-spectrum and highly efficient antibiotic commonly used for treating diseases in aquatic animals. However, its abuse in aquaculture applications often leads to excess residue in tissues of grass carp (Ctenopharyngodon idella). Hence, this study aimed to estimate the withdrawal time (WT) of EF and its metabolite of ciprofloxacin (CF) administered medicated feed in natural culture environments and conduct a risk assessment. Plasma and tissue samples were gathered at appropriate time points and detected by high-performance liquid chromatography. The data homogeneity was evaluated by Bartlett\'s test and Cochran\'s test. The linearity of the regressed line was evaluated by visual inspection and F test. Outliers were estimated on a normal probability scale by plotting the standardized residual versus their cumulative frequency distribution. Finally, the WT was calculated to be 51 days in muscle + skin based on the maximum residue limit of 100 µg/kg. After 51 days, the concentration of EF and CF fell below 10 µg/kg. The estimated daily intake was calculated to be 0.009 µg/kg/d. Hazard quotient was computed to be 0.002, which was far below one. These results suggested that calculated WT of EF could ensure the safety of products from grass carp for humans.
摘要：
恩诺沙星（EF）是一种广谱高效的抗生素，通常用于治疗水生动物的疾病。然而,在水产养殖应用中的滥用通常会导致草鱼（Ctenopharyngodonidella）组织中残留过多。因此，本研究旨在评估EF及其代谢产物环丙沙星(CF)含药饲料在自然培养环境中的停药时间(WT),并进行风险评估.在适当的时间点收集血浆和组织样品，并通过高效液相色谱法检测。通过Bartlett检验和Cochran检验评估数据的同质性。通过目视检查和F测试评价回归线的线性。通过绘制标准化残差与其累积频率分布的关系，在正态概率量表上估计异常值。最后,根据100µg/kg的最大残留限值，WT在肌肉+皮肤中计算为51天。51天后,EF和CF的浓度降至10µg/kg以下。估计的每日摄入量为0.009µg/kg/d。危险商数计算为0.002，远低于1。这些结果表明，计算的EFWT可以确保草鱼产品对人类的安全性。
