氧氟沙星在肉鸡体内残留的研究

建立了氧氟沙星在肉鸡组织内残留的高效液相色谱分析法。采用荧光检测器，激发波长278nm，发射波长445nm。色谱柱为Hypersil BDS—C18，柱温40℃；以磷酸（三乙胺调pH至2．5）-乙腈（86：14）为流动相，流速1．0mL／min；进样量为20μL。氧氟沙星在肌肉、肝脏和肾脏中的平均回收率分别为96．3％、87．5％和76．4％，检测限为10ng／g，在10～1000ng／mL浓度范围内，氧氟沙星的峰面积与其浓度呈良好的线性相关，达到了氧氟沙星残留分析的要求。利用建立的方法对氧氟沙星在肉鸡体内的残留消除规律进行了研究，以1L水添加500mg的剂量，对120只肉鸡连续给药5d，对不同停药时间所取肌肉、肝脏和肾脏样品中的药物残留进行分析。结果表明，氧氟沙星在肉仔鸡组织中的残留消除速度较为缓慢，至休药23d时，仍可在肝脏和肾脏分别检出39和35μg/kg的氧氟沙星残留。在本实验的条件下，建议氧氟沙星临床休药期以25d为宜。     

液相色谱-串联质谱法研究地克珠利在家兔组织中残留及消除规律

[目的]建立一种检测家兔组织中地克珠利含量的液相色谱-串联质谱法（LC—MS／MS）,研究地克珠利在家兔组织中的残留及消除规律。[方法]选择48只家兔（雌雄各半）,在饲料中加入10g／1000kg地克珠利混饲,连续饲喂30d。分别于休药后的第0、1、2、3、4、5、6天,每个时间点随机处死6只家兔（雌雄各半）,取肌肉、肝脏、肾脏组织,DMF,乙腈沉淀法提取并用LC—MS,MS法检测地克珠利残留量。[结果]地克珠利在肾脏中的残留量最高（休药0d为912．6μg／kg）,肝脏次之（休药0d为156．μg／kg）,肌肉最低（休药0d为43．1μg／kg）,在肾脏中的消除速度最快。[结论]该方法适于检测家免组织中的地克珠利含量。休药0d即可满足欧盟要求     

恩诺沙星混悬液的研制及其在鸡组织中的残留研究

以恩诺沙星为主药,采用正交试验筛选配方,研制恩诺沙星混悬液,并对该制剂的药剂学特征及其在鸡组织中的残留进行研究。药剂学研究表明,混悬液的性状、pH及药物含量均符合混悬剂质量要求,且稳定性良好、易于再分散。健康鸡在饮水中添加75 mg/L(以恩诺沙星计)混悬液,自由饮水,连续用药5 d后休药;休药第5天,肌肉、肝脏及"皮肤+脂肪"组织中药物总残留量(恩诺沙星+环丙沙星)分别为11.12±10.53、79.29±28.86、50.08μg/kg±22.09μg/kg,而肾脏组织未检出;休药第8天,肌肉、肾脏、肝脏组织中均未检出恩诺沙星及环丙沙星,"皮肤+脂肪"的总残留量为13.84μg/kg±10.82μg/kg。采用WT1.4软件处理数据,计算出该混悬液在鸡体内的休药期为6 d。     

恩诺沙星固体分散剂在肉鸡组织中残留的研究

为了研究恩诺沙星固体分散剂在肉鸡组织中的残留情况,试验选择150只1日龄AA肉鸡,试验组喂养至35日龄在饮水中添加75 mg/L恩诺沙星固体分散剂,自由饮水,连续用5 d后休药,采集不同时间的样本用高效液相色谱法(HPLC)进行检测。结果表明:休药第5天,肝脏、胸肌及脂肪组织中药物总残留量(恩诺沙星+环丙沙星)分别为(77.07±15.21),(12.56±9.65),(26.36±11.72)μg/kg,而肾脏组织中未检出;休药第7天,肝脏、肾脏、胸肌及脂肪组织中均未检出恩诺沙星及环丙沙星。采用WT 1.4软件处理试验数据,肝脏、肾脏、胸肌和脂肪的休药期(WDT)分别为5.92,4.36,5.21,5.63 d。说明肉鸡按照推荐剂量饮水给药,建议休药期至少为6 d。     

HPLC法检测环丙沙星在肉鸡组织中残留的研究

本文建立了检测环丙沙星在肉鸡组织中残留的高效液相色谱分析法。并利用建立的方法对环丙沙星在肉鸡体内的残留和消除规律进行了研究。每1L水中添加200mg环丙沙星，对120只肉鸡连续给药5d，使用高效液相色谱法对肌肉、肝脏和肾脏进行药物残留分析。残留结果研究表明，至体药13d时，在肝脏和肾脏中仍可检出0．015mg／kg和0．008mg／kg环丙沙星。在本试验条件下，建议环丙沙星，临床体药期为15d左右。     

地美硝唑在鸽组织中的残留分布及代谢规律研究

为了探索亲鸽哺育乳鸽期间使用地美硝唑后亲鸽和乳鸽体内地美硝唑(DMZ)残留分布及代谢规律，制定适合肉鸽生产的休药期规范。本试验于亲鸽开始哺乳第1天以拌料和灌胃2种方式投喂DMZ,停药后不同时间采集亲鸽、乳鸽组织和鸽乳，采用液相色谱串联质谱法测定DMZ及其代谢物残留量。结果显示，亲鸽采用饲喂和灌胃2种方式投喂DMZ后第1天亲鸽肌肉、肝脏、肾脏和皮脂中DMZ及其代谢物残留量均达到峰值，灌胃方式给药后第1天皮脂中DMZ及其代谢物含量高达6 591.7μg/kg,随后各组织残留量逐渐下降；饲喂方式给药后亲鸽肌肉、肝脏、肾脏和皮脂中药物消除时间分别为16 d、19 d、19 d和19 d,灌胃方式下分别为22 d、22 d、19 d和19 d;乳鸽各组织中药物残留代谢规律与亲鸽基本类似，最高残留量是灌胃后乳鸽皮脂组织，为500.7μg/kg;饲喂方式给药后乳鸽肌肉、肝脏、肾脏和皮脂中药物消除时间分别为16 d、16 d、16 d和13 d,灌胃方式下分别为13 d、19 d、16 d和13 d; 2种给药方式下第10天鸽乳中均无药物检出。结果表明，亲鸽使用DMZ,饲喂方式给药建议亲鸽休药时间为1...     

恩诺沙星可溶性粉在白羽乌骨鸡组织中残留消除规律研究

为研究恩诺沙星可溶性粉在乌骨鸡体内的残留消除规律。50只11日龄健康白羽乌骨鸡,随机分为2组,给药组40只,对照组10只,给药组混饮恩诺沙星水溶液,浓度为75 mg/L,2次/d,连续用药5 d,对照组不给任何抗菌药物,与给药组同环境饲养。在最后一次给药后9、20、40、70、106 d采集肌肉、肝脏、肾脏、皮脂等样本,经LC-MS/MS法测定组织中的恩诺沙星及环丙沙星残留量,并利用WT1.4软件计算休药期。恩诺沙星可溶性粉在乌骨鸡肌肉、肝脏、肾脏及皮脂中的休药期分别是102.48、0、41.93、116.38 d。为保证消费者健康和食品安全,推荐恩诺沙星可溶性粉在乌骨鸡体内的休药期应大于117 d。     

阿莫西林在鸡组织中的残留消除规律

本试验旨在研究阿莫西林在鸡组织中残留消除规律。鸡组织样品经磷酸二氢钠溶液提取,乙腈去蛋白,正己烷去脂肪,饱和二氯甲烷萃取,上清液经水杨醛在酸性条件下沸水浴衍生化后,在激发波长358nm、发射波长440nm处用高效液相色谱荧光检测器检测。该方法测定鸡组织中阿莫西林的检测限为5μg/kg、定量限为13μg/kg。阿莫西林在鸡组织样品中平均回收率为73.64%~88.82%,相对标准差为6.21%~9.63%。各试验组京海黄鸡分别按体质量以30、60mg/kg剂量内服阿莫西林,每天1次,连续给药7d,休药4h后(零休药期)各组织中阿莫西林残留量最高,休药第3天各组织中阿莫西林残留量均迅速降低;休药后第5天阿莫西林残留量低于最高残留限量(50μg/kg);休药第9天所有组织中阿莫西林残留量均低于检测限;休药后相同时间点鸡肌肉中药物残留量最低,肝脏中的药物残留量最高;阿莫西林在鸡肾脏中残留比鸡肌肉、肝脏消除缓慢且消除时间长;阿莫西林在鸡组织中的残留量与给药剂量呈正相关。根据WT1.4软件计算所得,建议黄羽肉鸡按体质量以30、60mg/kg剂量给药,每天1次,连续7d后,其休药期(WT)分别为3、4d。     

恩诺沙星在肉鸡组织中残留消除规律研究

选择250只1日龄"AA"肉鸡,喂养至35日龄开始在饮水中添加75 mg/L恩诺沙星,自由饮水,连续用药5日后休药.休药0时,肉鸡胸肌、肝脏、脂肪和肾脏中恩诺沙星含量分别为1 381.62、2 247.20、219.45、1 616.81μg/kg.休药48 h后,肉鸡组织中未检出恩诺沙星.结果表明农业部规定恩诺沙星在肉鸡中的休药期为8日是科学合理的.     

替米考星预混剂在猪组织中残留消除规律的研究

为了研究替米考星预混剂在猪体内残留消除规律,试验采用400 mg/kg替米考星预混剂饲喂猪,饲喂过程中及饲喂后不同时间取猪肌肉、肝脏和肾脏,用高效液相色谱法检测替米考星浓度。结果表明:饲喂期间,猪肌肉、肝脏、肾脏中替米考星含量在0.1~1.5μg/g之间,停药14天猪肌肉、肝脏和肾脏中替米考星含量已经降到最高残留限量以下。     

灰黄霉素在家兔组织中的分布及残留消除规律研究

研究灰黄霉素在家兔组织中的分布及消除规律,为灰黄霉素用于治疗家兔真菌病的安全性评价提供依据。选择42只新西兰白兔,于饲料中添加灰黄霉素（800g／1000kg）混饲,连续饲喂14d,分别于停药后1、3、5、7、9、14、21d,各处死6只,取其肝、肾、肌肉、皮肤及脑组织。以盐酸普萘洛尔为内标,二氯甲烷提取后用高效液相色谱-串联质谱仪（HPLC—MS／MS）进行各种组织中灰黄霉素浓度分析。结果显示,连续用药14d后,灰黄霉素在家兔组织中的分布情况为：肝组织浓度最高（134．61μg／kg）,肾组织次之（54．09μg／kg）,脑组织浓度最低（未检出）;停药后,随着时间的延长,灰黄霉素在肌肉、肝、肾和皮肤组织中的浓度逐渐下降,且在肝脏中的消除速度最快,停药21d后,灰黄霉素在肾组织中浓度为3．39μg／kg,在肝组织中浓度为12．36μg／kg,其他组织低于定量限或未检出。建议家兔生产中慎用灰黄霉素。     

三种喹诺酮类药物在鸡蛋中残留消除规律的研究

建立了一种检测三种喹诺酮类药物在鸡蛋中残留的高效液相色谱-荧光检测法。利用建立的方法对三种喹诺酮类药物在产蛋期蛋鸡用药后鸡蛋中的浓度进行了测定,并根据测定值研究了鸡蛋中药物的残留消除规律。400kg水中分别添加不同含量的诺氟沙星、氧氟沙星、恩诺沙星．连续给药3d,使用高效液相色谱法对鸡蛋中三种喹诺酮类药物残留进行分析。结果表明,停药8d时,鸡蛋中检出的诺氟沙星和氧氟沙星的浓度均低于10μg/kg;停药12d时,鸡蛋中检出的恩诺沙星的浓度低于10μg／蚝。建议诺氟沙星和氧氟沙星在临床上蛋鸡产蛋前10d左右停用,恩诺沙星在临床上蛋鸡产蛋前14d左右停用。     

磺胺二甲嘧啶在黑鲪体内的药物代谢动力学和残留消除研究

在(14±1)℃水温条件下,对黑鲪单次口灌100 mg/kg体重的磺胺二甲嘧啶,进行药物代谢动力学研究。在(20±2)℃水温条件下,按照《中华人民共和国水产行业标准磺胺类药物水产养殖使用规范》推荐剂量对黑鮶连续5天口灌给予磺胺二甲嘧啶,研究其在黑鮶体内的残留消除规律。血浆、肌肉和肝脏样品采用高效液相色谱检测,DAS2.0药物代谢动力学软件对数据进行处理分析。结果表明磺胺二甲嘧啶在黑鲪血浆、肌肉和肝脏中均符合一室模型,肝脏、血液和肌肉中药物达峰时间分别为6 h,8 h和10 h;峰值浓度分别为26.45μg/g、25.57μg/g和31.15μg/g;连续多次给药后,黑鮶血液、肌肉、肝脏中药物浓度分别在给药后12d、14d、15d后小于最大残留限量要求(0.1mg/kg)。     

Dietary exposure assessment of cyadox based on tissue depletion of cyadox and its major metabolites in pigs,chickens, and carp

The tissue kinetics of cyadox, an antibacterial agent used in food animals, and its major metabolites in pigs, chickens, and carp were investigated followed by a complete dietary exposure assessment to evaluate the food safety of cyadox. Cyadox and its major metabolites, bisdeoxycyadox (Cy1), 4‐desoxycyadox (Cy2), N ‐(quinoxaline‐2‐methyl)‐cyanide acetyl hydrazine (Cy4), quinoxaline‐2‐carboxylic acid (Cy6), and 2‐hydromethyl‐3‐hydroxy‐quinoxaline (Cy12), were simultaneously quantitated with a high‐performance liquid chromatography?ultraviolet (HPLC ‐UV ) method. Pigs, chickens, and carp were fed with 150 mg/kg cyadox in feed for consecutive 60, 40, and 30 days, respectively. The residue amount of cyadox and its major metabolites in liver, kidney, muscle, and fat (skin) tissues was determined. Cy2 was below the limit of quantitation even at the withdrawal time of 6 hr, cyadox, Cy4, Cy6, and Cy12 could be detected at 6–24 hr with low level less than 50 μg/kg. By contrast, Cy1 persisted for 3 days in the kidney of pigs and chickens, and in the liver of carp. Based on these residue depletion data and previous toxicology results, the global estimated chronic dietary exposure assessment of cyadox for general population was conducted, indicating a zero withdrawal time (WDT ) may be appropriate for cyadox in food animals when used in feed for prolonged administration. These results provide analytical techniques and safety standards suitable for residue monitoring of cyadox in food animals.     

Disposition kinetics of doxycycline in chickens naturally infected with Mycoplasma gallisepticum

1. The pharmacokinetic properties of doxycycline were determined in healthy chickens and chickens naturally infected with Mycoplasma gallisepticum after a single intravenous (i.v.) and oral administration of the drug at 20 mg/kg body weight. Tissue residues of the tested drug after an oral dose of 20 mg/kg given twice daily for 5 consecutive days were also estimated in diseased chickens. 2. The plasma concentrations of doxycycline following single i.v. and oral administration were higher in healthy chickens than in diseased ones. Following i.v. injection, the elimination half-life (t1/2beta), distribution half-life and mean residence time (MRT) were longer in healthy chickens than in diseased birds. The values of total body clearance (ClB) and volume of distribution (Vdss) were larger in healthy chickens than in diseased birds. 3. After single oral administration, the absorption half-life (tl/2ab) and the elimination half-life were longer in normal birds than in diseased ones. The maximum plasma concentration of the drug was higher in normal chickens than in diseased ones. 4. Following repeated oral administration, the concentration of doxycycline in all tissues except muscle was higher than the corresponding concentrations in plasma. Concentrations of doxycycline in different tissues were in the following order: kidney > liver > lung > muscle. The drug was detected in liver and kidney in substantial concentrations on d 5 post administration of the last dose whereas, on d 7, its concentration in all tissues was below the lower limit of the sensitivity of the assay method used. Because of the low sensitivity of the microbiological assay method used in this study, a safe withdrawal time for doxycycline in diseased birds could not be estimated for the meanwhile.     

Determination of sulphachloropyrazine-diaveridine residues by high performance liquid chromatography in broiler edible tissues

Diaveridine (DVD) is used in combination with sulphachloropyrazine (SPZ) as an effective antibacterial agent and antiprotozoal agent, respectively, in humans and animals. To gain a better understanding of the metabolism of SPZ and DVD in the food-producing animals, a high performance liquid chromatography (HPLC) method to determine and quantify sulphachloropyrazine (SPZ) and diaveridine (DVD) suspension residues from broilers is reported. Thirty healthy chickens were orally administered with sulphachloropyrazine-diaveridine (SPZ-DVD) suspension in water of 300 mg/l (SPZ) per day for seven successive days. Six chickens per day were slaughtered at 0, 1, 3, 5 and 7 days after the last administration. This procedure permitted SPZ and DVD to be separated from muscle tissue, liver, kidneys and skin with fat after extraction with acetonitrile and acetone under slightly acidic conditions. From the detected residuals in different tissues, we found that SPZ was quickly eliminated in liver and muscle, and slowly eliminated in kidney and skin with fat. DVD was quickly eliminated in liver and slowly eliminated in kidney. The withdrawal period of SPZ was 3.26, 3.72, 4.39 and 5.43 days in muscle, liver, kidney and skin with fat, respectively. The withdrawal period of DVD was 4.77, 4.94, 6.74 and 4.58 days in muscle, liver, kidney and skin with fat, respectively. Therefore, the suggested withdrawal period for SPZ-DVD suspension should be 7 days after dosing for seven successive days.     

Plasma and tissue pharmacokinetics of marbofloxacin in experimentally infected chickens with Mycoplasma gallisepticum and Escherichia coli

The plasma and tissue pharmacokinetics of marbofloxacin in chickens experimentally infected with Mycoplasma gallisepticum and Escherichia coli were studied. Marbofloxacin was given to 66 infected chickens by oral administration at a dosage of 5 mg/kg b.w., once a day for three days. Plasma, brain, kidney, liver, lung, muscle and trachea were collected and marbofloxacin concentrations were analyzed by a high performance liquid chromatography method. In the infected chickens, maximal marbofloxacin concentrations in plasma, brain, kidney, liver, lung, muscle and trachea were 1.84, 1.33, 7.35, 5.61, 3.12, 2.98, and 4.51 g/mL (g); the elimination half‐lives of marbofloxacin were 6.8, 2.74, 9.31, 8.45, 9.55, 11.53 and 5.46 h for plasma, brain, kidney, liver, lung, muscle and trachea, respectively. AUC were calculated to be 9.68, 8.04, 45.1, 27.03, 20.56, 19.47, and 32.68 μg/mL (g) ·h for plasma, brain, kidney, liver, lung, muscle and trachea, respectively. Marbofloxacin concentration in tissues except for brain exceeded marbofloxacin concentration in plasma, with AUC_tissue/AUC_plasma ranging from 2.01 to 4.66 and Peak_tissue/Peak_plasma ranging from 1.62 to 3.99. The results showed that a marbofloxacin dosage of 5 mg/kg administered orally at 24 h intervals may provide successful treatment of chicken with MG and E. coli infection.     

超高效液相色谱-串联质谱法研究克伦特罗在绒山羊体内消除规律

建立了超高效液相色谱-串联质谱法并对克伦特罗（Clenbuterol）在绒山羊体内残留消除规律进行了研究。选取60只健康绒山羊（30±4．8）kg,平均分成2组,分别在饲料中添加150μg／kgb．w．（A组）和300μg／kgb．w．（B组）克伦特罗,连续饲喂25d后停药。建立UPLC—MS／MS检测方法监测喂药期尿液、休药期尿液和组织中克伦特罗含量。克伦特罗在饲喂期间,A组尿液中平均含量为289～5313μg／L,B组尿液中平均含量为1323～11378μg／L。停药后尿液中克伦特罗含量迅速下降,停药40d后,A、B两组均下降至10μg／L以下;停药后,取绒山羊肝脏、肾脏、肺脏、肌肉测定其残留量。A、B两组停药后组织中克伦特罗含量持续下降,停药40d后,肝脏含量33μg／kg,肾脏约5μg／kg,其余组织均未检出。     

Depletion study and withdrawal period calculation of florfenicol in the crucian carp (Carassius auratus) following multiple intramuscular injections

The previously adopted marker residue for florfenicol (FF) in China was only florfenicol amine (FFA); however, the marker residue has been changed to FF plus FFA since the end of 2017. The previous official withdrawal period determined based on the only concentration of FFA may no longer be suitable. Therefore, the present study aimed to determine the depletion profiles of FF and FFA and further calculate the withdrawal period in the crucian carp (Carassius auratus) based on the new marker residues. Florfenicol was intramuscularly administered at 10 mg/kg bodyweight daily for five consecutive days to crucian carps reared in freshwater at 10°C. After the last dose, plasma and tissue samples were randomly collected from 10 fish at different time points. The FF and FFA concentrations were simultaneously determined by high-performance liquid chromatography (HPLC) with a fluorescence detector and further subjected to noncompartmental analysis. The elimination half-life (h) of FF in different tissues decreased as follows: liver (39.1) > kidney (36.3) > skin plus muscle (34.6) > plasma (31.7), whereas that of FFA decreased as follows: kidney (41.4) > skin plus muscle (39.4) > liver (39.3) > plasma (35.7). Considering a maximum residue limit of 1 μg/g for the total concentration of FF and FFA in the skin plus muscle, a withdrawal period of 6 days was calculated based on the upper limit of the one-sided 95% confidence interval.     

鸡组织中对羟基肉桂酸残留的UPLC检测方法研究

建立了鸡组织(肌肉、肝脏、肾脏)中对羟基肉桂酸(PCA)超高效液相色谱检测方法。组织样品用无水乙醚提取,提取液50℃氮气吹干,20%的甲醇溶液复溶,用0.22μm滤膜过滤。以C18为色谱柱,甲醇-1%乙酸溶液(20/80,v/v)为流动相,检测波长310 nm,流速0.3 mL/min,用超高效液相色谱检测。对羟基肉桂酸标准品工作液在5～400 ng/mL浓度范围内线性关系良好(r=0.9996);组织中药物添加浓度分别为20、50、100μg/kg时,其样品中药物平均回收率分别98.46%～103.66%、85.09%～107.15%和80.27%～97.63%;日内、日间变异系数均≤10%。在该检测条件下,PCA在鸡肌肉、肝脏、肾脏中检测限分别为1μg/kg、2μg/kg和1μg/kg。定量限分别为2μg/kg、4μg/kg和2μg/kg。该方法样品处理简单,且准确度和精密度均符合残留检测方法要求,可以作为对羟基肉桂酸在鸡组织内的残留检测方法。