替米考星肠溶颗粒在猪体内的残留消除试验

Study on Residue Depletion of Enteric-coated Tilmicosin Pellets in Swine

为了解替米考星肠溶颗粒混饲给药在猪体内的残留消除和组织分布,为制定休药期提供依据,本试验用高效液相色谱(HPLC)对猪可食性组织中替米考星残留进行测定。结果显示,HPLC在猪的脂肪、肌肉、肝脏和肾脏中对替米考星的检测限(LOD)和定量限(LOQ)均分别为0.025μg/g和0.050μg/g。当空白肌肉和脂肪组织中替米考星添加浓度为0.05、0.1μg/g和1μg/g,肝脏和肾脏组织中替米考星添加浓度为0.05、0.5μg/g和5μg/g时,平均回收率均达到80%以上,批间和批内变异系数均小于5%。替米考星在肾和肝脏中的残留较高,而在肌肉和脂肪组织中较低。将停药后各实测残留数据采用WT1.4计算软件拟合计算休药期,在猪肝脏的休药期为6.17 d、肾脏为4.96 d、脂肪和肌肉均为3 d。因此,按推荐给药方案在猪中使用替米考星肠溶颗粒的休药期应为7 d。

In order to to understand the residue depletion and tissue distribution of tilmicosin(which is added into the feed in the form of enteric-coated tilmicosin pellets)in swine and provide the basis for determining the withdrawal time,this study utilized high-performance liquid chromatography(HPLC)to assess the residual quantity of tilmicosin in swine edible tissues.The results showed that HPLC had the limits of detection and quantitation at 0.025μg/g(LOD)and 0.050μg/g(LOQ),respectively,in swine fat,muscle,liver and kidney;that the average recovery of tilmicosin was more than 80% and the inter and intra assay coefficients of variation were less than 5%,when the added concentrations of tilmicosin in blank muscle and adipose tissue were 0.05,0.1μg/g and 1μg/g,and those in blank liver and kidney tissue were 0.05,0.5μg/g and 5μg/g;and that the residue levels were higher in kidney and liver,and lower in muscle and fat as found by residue elimination test.The withdrawal time was calculated at 6.17d in liver,4.96d in kidney,3d in muscle and fat with software WT1.4 according to the measured datas of tilmicosin residues in swine tissues at different time points after drug withdrawa.Thus,the withdrawal time of enteric-coated tilmicosin pellets used under the recommended dosage scheme for swine should be 7 days.