氯霉素在罗非鱼体内的代谢和消除规律

水产养殖动物口服氯霉素后可能在可食组织中造成残留,本文通过以50mg/kg鱼体重的氯霉素(CAP)的剂量对尼罗罗非鱼单次口灌给药,采用HPLC和GC-ECD分析方法研究了CAP在罗非鱼体内的代谢和消除规律。给药0.5h后,CAP在血浆和肝脏中的浓度均迅速上升,分别为4288.01±1285.53ng/mL和5214.18±1105.62ng/g,2h达到峰值22246.42±355.84ng/mL和25717.47±1740.66ng/g;而肌肉中CAP却上升较慢,2h仅为7744.08±2118.74ng/g,8h才达到峰值13232.89±1612.74ng/g,峰值仅约为血浆和肝脏的1/2。CAP在罗非鱼肌肉和肝脏中的消除速度均较慢,但肌肉比肝脏稍快,肌肉中第96d CAP降至为0.07±0.01ng/g,而肝脏中第120d尚在0.1ng/g以上,为0.25±0.06ng/g。肌肉和肝脏浓度常用对数-时间消除曲线方程分别为y=-0.0966x+5.4292;y=-0.053x+4.7258,二者的T1/2β为7.14d和13.08d。若要使CAP在罗非鱼肌肉和肝脏中的浓度降至0.1ng/g以下,则休药期分别需80.47d和132.61d。试验表明CAP在罗非鱼组织中消除缓慢,尤其在肝脏中,因此肝脏可以作为CAP残留监测的首选组织。  

METABOLISM AND ELIMINATION OF CHLORAMPHENICOL IN TISSUES OF NILE TILAPIA ( OREOCHROMIS NILOTICUS , GIFT)

Chloramphenicol(CAP) administered orally has the potential to cause to antibiotic residue in the edible part of aquatic animals.Thus, in this study, metabolism and elimination of CAP following oral treatment at dose of 50mg/kg body weight were studied in Nile tilapia, Oreochomis niloticus, Gift, under 26 ℃, CAP analysis was analyzed byHPLC and GC \ ECD. After 0.5h of administration,CAP in plasma and increased rapidly up to 4288.01 ±1285.53ng/mL and 5214.18 ± 1105.62ng/g, and the peak CAP concentrations in plasma(Cmax22246.42 ± 355.84ng/mL) and liver (Cmax25717.47 ± 1740.66ng/g) achieved after 2h,which were higher than that in muscle.The concentration of CAP in muscle increased slowly up to 7744.08 ± 2118.74ng/g after 2h.The peak CAP concentrations in muscle(Cmax13232.89 ± 1612.74ng/g), was about half of those in plasma or liver, which achieved after 8h. Elimination was slow both in muscle and in liver.After 96 days 0.07 ± 0.01ng CAP/g was detected in muscle and 0.25 0.06ng CAP/g was still determined in the liver. CAP concentration more than in liver was still higher than 0.1ng/g after 120 days.Therefore, the speed of elimination in liver was slower than that in muscle. A linear models was used to describe CAP elimination kinetics in tissues, y=-0.0966x+ 5.4292(in muscle) and y=-0.053x+ 4.7258(in liver) .The cap half lives of elimination phase in muscle and liver were 71.4 and 13.08 days, respectively. Predicted withdrawal times of muscle and liverwere 80.47 and 132.61 days (based on 0.1L ug kg-1). In conclusion, the tissue residue evaluation showed that, CAP can achieved high concentration in tested tissues of Nile tilapia and was slowly eliminated, especially in ilver.