不同抗生素参与下呋喃唑酮代谢物 在鲫鱼体内的残留消除规律

本文研究了土霉素、恩诺沙星、磺胺间甲氧嘧啶分别与呋喃唑酮联合药浴给药后,呋喃唑酮代谢物3-氨基-2-恶唑烷酮(AOZ)在鲫鱼体内的残留消除规律。结果表明,呋喃唑酮在进入鲫鱼体内后迅速代谢成AOZ,停药0 h,呋喃唑酮对照组中鲫鱼肾脏、肝脏、肌肉中AOZ残留量便达到最高,分别为88.87、59.20、14.91μg/kg,平均消除速率为0.86、0.52、0.14μg/(kg·h);与对照组相比,土霉素-呋喃唑酮组鲫鱼肾脏、肝脏、肌肉中AOZ最大残留浓度明显增加,分别为165.40、125.29、28.69μg/kg,平均消除速率为1.71、1.17、0.31μg/(kg·h);而恩诺沙星-呋喃唑酮组鲫鱼肾脏、肝脏、肌肉中AOZ最大残留浓度与对照组相比显著减少,仅为46.70、41.64、9.69μg/kg,平均消除速率为0.36、0.31、0.03μg/(kg·h);磺胺间甲氧嘧啶-呋喃唑酮组中鲫鱼体内AOZ最大残留量及平均消除速率与对照组相比也有差异但变化不大。消除96 h后,各实验组鲫鱼体内仍有大量AOZ残留。本实验初步表明AOZ在鲫鱼体内难消除,且土霉素、恩诺沙星、磺胺间甲氧嘧啶能够不同程度的影响AOZ在鲫鱼体内的残留与消除,这为水产品质量安全监管和渔药残留研究提供了理论基础。     

三聚氰胺在凡纳滨对虾中的残留消除规律研究

在室温(23~29℃)条件下,凡纳滨对虾用普通饲料驯化7d后再用含有不同剂量的三聚氰胺的饲料连续投喂25d,研究三聚氰胺在凡纳滨对虾血液、肌肉和肝胰腺组织中的残留消除规律。结果表明:凡纳滨对虾投喂含有三聚氰胺的饲料后,三聚氰胺在对虾血液、肌肉和肝胰腺组织中均有残留,当饲料三聚氰胺含量为800mg/kg时,对虾中三聚氰胺残留量最高部位是肝胰腺,其残留量达到6.10mg/kg;停喂含有三聚氰胺的饲料后,三聚氰胺在对虾血液、肌肉和肝胰腺组织中消除时间分别为1、4、6d;三聚氰胺在凡纳滨对虾体内可代谢为三聚氰酸,当饲料中三聚氰胺含量为200~800mg/kg时,三聚氰酸只在肝胰腺组织中检出,在血液和肌肉中均未检出,在肝胰腺组织中消除时间为3d。因此,肝胰腺可作为凡纳滨对虾体内三聚氰胺残留监控的靶器官。     

水产品及其苗种中硝基呋喃代谢物的高效液相色谱- 串联质谱法测定

对115 个水产品及鱼苗样品进行呋喃妥因(AHD)、呋喃它酮(AMOZ)、呋喃唑酮(AOZ)和呋喃西林(SEM)4 种硝基呋喃代谢物残留量分析。样品水解、衍生和净化后,采用液相色谱- 电喷雾三重四级杆串联质谱仪检测,多反应监测扫描模式和同位素内标法定量。各类硝基呋喃代谢物线性范围为0.5～20ng/mL、检出限0.25μg/kg,在0.25～5μg/kg 范围内样品添加回收率为89.0%～117.2%,相对标准偏差小于10%。结果表明,水产鱼苗中的硝基呋喃代谢物残留量远远高于成鱼,其中大黄鱼苗中AOZ 的检出率为62%,最大残留量3890μg/kg,而大黄鱼成鱼AOZ 的检出率17%,最大残留量2.81μg/kg,同时淡水鱼的硝基呋喃类药物残留小于海产鱼。     

三聚氰胺在罗非鱼体内的残留和消除规律研究

以罗非鱼(Tilapia)为研究对象,通过在罗非鱼饲料中添加不同剂量三聚氰胺进行罗非鱼摄食生长试验,研究三聚氰胺在罗非鱼肝脏和肌肉中的残留和消除规律。实验结果表明:(1)罗非鱼连续饲喂含三聚氰胺的饲料50d,添加不同剂量的三聚氰胺对各组罗非鱼的平均体重增长无显著影响(P>0.05);(2)肝脏和肌肉中三聚氰胺的残留量随着各实验组饲料中添加量的增加呈显著递增趋势(P<0.05),低剂量组(1000、5000mg/kg)的肝脏和肌肉中的残留量在2～20mg/kg间,高剂量组(10000、50000mg/kg)的残留量均超过40mg/kg,各组中肝脏的残留量均显著高于肌肉(P<0.05)。停药5d后,罗非鱼的肝脏和肌肉中三聚氰胺的残留量均内显著下降,各实验组的三聚氰胺残留量均降至2.0mg/kg以下,此后则缓慢下降。各实验组中,肌肉的消除时间比肝脏的消除时间长。     

酶联免疫法检测水产品中呋喃唑酮代谢物AOZ的残留

用酶联免疫试剂盒(灵敏度为0.125 μg/kg)检测威海出口水产品中3氨基-2-恶唑烷酮(AOZ)的残留,测定试剂盒的加样回收率.结果表明除个别产品不符合规定外,绝大部分水产品符合规定,试剂盒在添加量为0.45、0.90、1.80 μg/kg 时,回收率分别为94.37%、98.78%、97.90%.酶联免疫法适合时水产品中AOZ的残留做快速检测.     

液相色谱-串联质谱法测定大菱鲆鱼粉中呋喃唑酮代谢物残留

目的 建立一种大菱鲆鱼粉中呋喃唑酮代谢物3-氨基-2-噁唑烷基酮（3-amino-2-oxazolidinone, AOZ）残留的液相色谱-串联质谱（liquid chromatography-tandem mass spectrometry, LC-MS/MS）高准确度定值方法。方法 大菱鲆冻干鱼粉样品复水后,经盐酸水解,2-硝基苯甲醛衍生化,乙酸乙酯提取,高速离心净化,采用2 mmol/L乙酸铵（A）和甲醇（B）作为流动相进行梯度洗脱,质谱（electron spray ionization, ESI+）选择反应监测模式对AOZ进行定性和定量测定。结果 本方法在1.0~40 μg/L范围内线性关系良好,相关系数大于0.999。AOZ在2.00、5.00、10.0和20.0 μg/kg添加水平的回收率在94.2%~100%之间,批内和批间相对标准偏差均<10%。本方法冻干鱼粉中AOZ的定量限为2.00 μg/kg。结论 该方法灵敏、准确,操作简便,适用于大菱鲆鱼粉中AOZ残留基体标准物质的定值测定。     

酶联免疫和气质联用检测动物不同组织中残留甲羟孕酮

本文应用酶联免疫分析(ELISA)测定了MPA在动物源可食性组织中的残留量,并采用气相色谱-质谱联用(GC-MS)方法加以确证。以0.8mg/kg剂量连续喂服5d,停药7d后,白兔的腿肌肉、肝脏和肾脏中中MPA残留量分别为白兔腿肌肉残留量为7、6、23μg/kg水平。分析GC-MS确证方法与ELISA方法所得结果,两者检测结果相关性良好。     

池塘养殖模式下氟苯尼考及其代谢产物在斑点叉尾鮰体内的药代动力学

目的在实际大池塘养殖模式下,研究氟苯尼考(florfenicol,FF)及其代谢产物在斑点叉尾鮰(Letaurus以下简称鮰)体内药代动力学。方法选择4口标准化池塘(2300 m~2/口),养殖密度按每666.67 m~2投放鱼苗1000尾投放,设3个实验组和1个对照组。实验组分别以1.25、2.50、5.00 g/kg 3个剂量水平在鮰饲料中添加FF,每天投喂饲料4 kg(一次投入),对照组投喂不含FF的等量饲料。连续投喂5 d后,分别于首次投药后的第1、2、3、4、5、6、7、8、11、14、30、60、90和170 d采集鮰肌肉、肝脏及血液,采用高效液相色谱-串联质谱法(high performance liquid chromatography-tandem mass spectrometry,HPLC-MS/MS)检测FF及氟苯尼考胺(florfenicol amine,FFA)含量,采用PKSolver药动学药效学数据处理软件V2.0的药动学房室模型拟合方法分析药时数据。结果 FF在鮰血液中的药代动力学特征符合一级吸收一室模型,而在肝脏及肌肉中均符合一级吸收二室模型,FFA在不同组织中均符合一级吸收二室模型。结论 FF在鮰体内主要以原型的方式代谢消除,分布广泛且FF消除速率远高于FFA,肝脏可作为残留分析的靶组织。     

重金属Cd与Cu在克氏原螯虾体内富集与释放规律

研究克氏原螯虾分别在Cd2+质量浓度为0、0.05、0.10 mg/L和Cu2+质量浓度为0、0.5、1.0 mg/L的单一水环境中暴露时,肝胰腺、鳃和肌肉对Cd和Cu的生物富集和释放特性。通过非线性拟合得到克氏原螯虾对Cd和Cu的生物富集动力学参数：富集速率常数k1、排出速率常数k2、生物富集系数（bioconcentration factors,BCF）和生物半衰期（T1/2）,并得出理论富集平衡状态时生物体内Cd和Cu富集量（ρAmax）。结果表明：克氏原螯虾的肝胰腺和鳃对水体中Cd2+和Cu2+都有很强的富集特性,且富集量与富集时间、水体中Cd2+和Cu2+的质量浓度成正相关;肌肉组织中富集规律则不明显。同种重金属在不同组织中的富集量不同,即重金属富集具有组织选择性：在分别含Cd2+和Cu2+的水体中暴露实验9 d后,3 种组织对Cd的富集量顺序为鳃＞肝胰腺＞肌肉;对Cu的富集量顺序为肝胰腺＞鳃＞肌肉。克氏原螯虾对Cu和Cd的富集代谢都较缓慢,暴露9 d仍未达到稳定。克氏原螯虾体内Cd和Cu的BCF范围分别约为2～207、3～226;T1/2分别约为3～29、7～36 d;在理论平衡状态下,鳃、肝胰腺和肌肉中Cu和Cd的ρAmax随着环境中Cu2+和Cd2+质量浓度的增大而增大,且呈正相关。     

MS-222对大菱鲆麻醉效果及富集消除规律研究

目的 确立大菱鲆的有效麻醉浓度,研究MS-222在大菱鲆体内的生物富集和消除规律。方法 考察大菱鲆在不同MS-222浓度下麻醉、苏醒过程中的行为变化以及呼吸频率的变化,采用液相色谱-串联质谱法测定大菱鲆组织中的药物水平。结果 MS-222麻醉大菱鲆的有效浓度为60 mg/L,在此浓度下,鱼体能够在5 min之内达到第IV期麻醉状态,5 min之内苏醒恢复。大菱鲆肝脏中MS-222的富集浓度高于肌肉,经48 h消除实验后肌肉和肝脏中的MS-222均低于1 μg/kg,其消除半衰期分别为13.14 h（肌肉）和14.15 h（肝脏）。结论 在水温不低于（12±0.3）℃条件下,建议将MS-222的休药期定为3天。     

Furazolidone residues in pigs: criteria to distinguish between treatment and contamination

The use of furazolidone in food-producing animals has been banned in the EU. The ban can most effectively be enforced by monitoring for bound residues containing the 3-amino-2-oxazolidinone (AOZ) moiety. Unlike the parent drug, AOZ residues are stable and can be detected for prolonged periods after cessation of treatment. However, AOZ can be passed from pig-to-pig following brief exposure of unmedicated animals to housing that previously contained medicated pigs. We describe criteria by which a distinction may be drawn between pigs treated illegally with the drug and pigs that contain detectable AOZ residues as a result of exposure to contaminated housing. These criteria are that illegally treated pigs will have a concentration ratio of AOZ in bile: kidney of less than 0.3; while unmedicated pigs will have a concentration ratio of AOZ in bile: kidney of greater than 3.0. Using this criteria, 12 pigs, either treated with the drug or exposed to contaminated housing were analysed in a blind study. The pigs were classified as 'Treated' or 'Contaminated' on the basis of the criteria described above. All 12 pigs were assigned to the correct group. This shows that it is possible to differentiate between furazolidone abuse and contamination.     

Depletion of protein-bound furazolidone metabolites containing the 3-amino-2-oxazolidinone side-chain from liver, kidney and muscle tissues from pigs.

Ten 3-month-old pigs were treated with feed containing 300 mg furazolidone per kg for a period of 7 days, followed by withdrawal periods of 0, 1, 2, 3 or 4 weeks (two per group). The treatment resulted in the formation of protein-bound metabolites containing an intact 3-amino-2-oxazolidinone (AOZ) side-chain that could be chemically released and then detected in liver, kidney and rump muscle tissues even 4 weeks after dosing. In tissues from animals killed at the end of the medication period, 993, 600 and 124 ng of AOZ were released from 1 g of liver, kidney and muscle respectively. In the tissues of the animals killed after a further 4 weeks the corresponding levels were 41, 7 and 10 ng/g respectively. It may be concluded that long withdrawal periods prior to slaughter for human consumption are required for pigs treated with furazolidone, because of the long residence time of protein-bound AOZ and the possibility that it might be released from its protein-bound form in the stomach and subsequently be transformed into a hydrazine.     

Evaluation of the residues of furazolidone and its metabolite, 3-amino-2-oxazolidinone (AOZ), in eggs

The use of furazolidone in food-producing animals is banned within the EU. Detection of the protein-bound side-chain metabolite, 3-amino-2-oxazolidinone (AOZ), in animal tissues is the most effective method of enforcing the ban. The study was undertaken to find out if the same applies to eggs. The concentrations of furazolidone and AOZ in eggs reached a plateau of ~360-380 μgkg -1 by the fourth day of treating birds with 400mgkg -1 furazolidone. After a 4-day withdrawal from treatment, intact furazolidone could not be detected. AOZ residues could still be detected up to 21 days following withdrawal from treatment. During treatment, most intact furazolidone residues occur in the albumen. For AOZ, there is a more even distribution of residues between albumen and the yolk. The concentration of furazolidone in egg homogenates stored at -20°C decreases by 44% after 55 days. AOZ residues are stable during this period. From these results, it is clear that AOZ is a more suitable marker residue than the parent compound for monitoring concentrations of the drug in eggs.     

Residues of nitrofuran antibiotic parent compounds and metabolites in eyes of broiler chickens.

Nitrofuran antibiotic residues in food continue to be of international concern. The finding of sources of semicarbazide (SEM), other than through the misuse of nitrofurazone, present a challenge to the use of SEM as a definitive marker residue for this drug. Detection of intact (parent) nitrofurazone would avoid confusion over the source of SEM residues. Broiler chickens were fed sub-therapeutic nitrofuran-containing diets and their tissues were analysed for parent compounds and metabolites by liquid chromatography coupled with tandem mass spectrometry detection (LC-MS/MS). Depletion half-lives in muscle were longer for tissue-bound metabolite residues, 3.4 days --3-amino-2-oxazolidinone (AOZ), 3-amino-5-morpholinomethyl-2-oxazolidone (AMOZ) -- to 4.5 days (SEM), than total metabolite residues, 2.0 days (AOZ) to 3.2 days (SEM). Metabolite concentrations were higher in eyes than in muscle. Metabolite half-lives in eyes ranged from 8.5 days (1-aminohydantoin (AHD)) to 20.3 days (SEM). Nitrofuran parent compounds were also detected in eyes. Furaltadone was detected in single eyes after 21 days' withdrawal of a 6 mg kg(-1) furaltadone diet. When 50 eyes from broilers containing metabolites in muscle close to the 1 microg kg(-1) minimum required performance level (MRPL) were pooled into single samples, 1.2 ng of furazolidone and 31.1 ng of furaltadone were detected, but nitrofurazone was not detected due to the long depletion half-life of SEM in muscle. Further studies are required to improve LC-MS/MS nitrofurazone sensitivity and refine the sample size necessary to use nitrofurazone detection in pooled eyes as a complement to SEM detection in muscle.     

Residues of nitrofuran antibiotic parent compounds and metabolites in eyes of broiler chickens

Nitrofuran antibiotic residues in food continue to be of international concern. The finding of sources of semicarbazide (SEM), other than through the misuse of nitrofurazone, present a challenge to the use of SEM as a definitive marker residue for this drug. Detection of intact (parent) nitrofurazone would avoid confusion over the source of SEM residues. Broiler chickens were fed sub-therapeutic nitrofuran-containing diets and their tissues were analysed for parent compounds and metabolites by liquid chromatography coupled with tandem mass spectrometry detection (LC-MS/MS). Depletion half-lives in muscle were longer for tissue-bound metabolite residues, 3.4 days --3-amino-2-oxazolidinone (AOZ), 3-amino-5-morpholinomethyl-2-oxazolidone (AMOZ) -- to 4.5 days (SEM), than total metabolite residues, 2.0 days (AOZ) to 3.2 days (SEM). Metabolite concentrations were higher in eyes than in muscle. Metabolite half-lives in eyes ranged from 8.5 days (1-aminohydantoin (AHD)) to 20.3 days (SEM). Nitrofuran parent compounds were also detected in eyes. Furaltadone was detected in single eyes after 21 days' withdrawal of a 6 mg kg(-1) furaltadone diet. When 50 eyes from broilers containing metabolites in muscle close to the 1 microg kg(-1) minimum required performance level (MRPL) were pooled into single samples, 1.2 ng of furazolidone and 31.1 ng of furaltadone were detected, but nitrofurazone was not detected due to the long depletion half-life of SEM in muscle. Further studies are required to improve LC-MS/MS nitrofurazone sensitivity and refine the sample size necessary to use nitrofurazone detection in pooled eyes as a complement to SEM detection in muscle.     

基于不同半抗原的呋喃唑酮代谢物免疫检测方法的建立与比较

为实现呋喃唑酮代谢物3-氨基-2-恶唑烷酮（3-amino-2-oxazolidinone,AOZ）的快速定量检测,制备AOZ- 牛血清蛋白单克隆抗体,建立2 种分别基于抗3-（4-羧基苯亚甲基）-氨基-2-恶唑烷酮（CPAOZ）、抗AOZ的单克 隆抗体酶联免疫检测试剂盒。CPAOZ检测试剂盒在1.0～100.0 ng/mL范围具有较好的线性,IC50值为14.6 ng/mL, 检测限为6.56 ng/mL,回收率为97.6%～101.3%;AOZ检测试剂盒在0.5～12.5 ng/mL范围具有良好线性,IC50值为 3.9 ng/mL,检测限为0.45 ng/mL,回收率为94.1%～97.4%。这2 种检测试剂盒对于其他硝基呋喃类抗生素及其代谢 物均不存在交叉反应。从经济、方便、快速、灵敏等因素来考虑,后者更具有发展前景。     

酶联免疫法检测猪肉中呋喃唑酮代谢物残留

通过检测猪肉中呋喃唑酮代谢物的残留以评价试剂盒的性能,采用酶联免疫法对猪肉中的呋喃唑酮代谢物残留量进行测定。结果表明:该方法的线性检测范围为0.025～2.025μg/L,最低检测限为0.1μg/kg,样本添加回收率为78.2%～100.3%,变异系数为4.7%～10.3%,与呋喃唑酮的交叉反应率为16.3%,与其他药物的交叉反应率均小于1%,且对实际样本的检测结果与液相色谱-串联质谱法基本一致。该法灵敏准确、重复性好、特异性高,适用于猪肉中呋喃唑酮代谢物残留的检测。     

酶联技术在水产品中呋喃唑酮代谢物AOZ的检测中的应用

用酶联免疫检验技术（ELISA）检测呋喃唑酮（Furazolidone）代谢物AOZ。AOZ经过16h的衍生后和酶联结合物对微孔中的抗体进行竞争反应，利用抗原与抗体的特异性免疫化学反应的基本原理，在酶标仪上450nm处测定吸光强度。进行定性定量分析。     

Ivermectin residues in the edible tissues of swine and cattle: effect of cooking and toxicological evaluation

Young male pigs (25-40 kg bw) were treated experimentally with a single 0.4 mg/kg bw, s.c. dose of ivermectin (Ivomec vet. inj., MSD). The disappearance of the drug from the edible tissues 7-21 days after treatment was studied using a sensitive high-performance liquid chromatographic method. The highest residue levels were found at the injection site (up to 59 and 2.6 mg/kg 7 and 14 days post-injection, respectively). Among the other tissues studied, the residue levels 7 days post-injection showed the following order: liver (less than or equal to 50 micrograms/kg) greater than kidney (less than or equal to 25 micrograms/kg) greater than muscle (less than or equal to 20 micrograms/kg). After 21 days only traces of ivermectin (less than or equal to 2 micrograms/kg) could be detected in the muscle and other edible tissues, including the injection site. Similar residue concentrations were found in slaughterhouse material from sows therapeutically treated with ivermectin for parasite infestation. An ordinary culinary preparation of the minced beef muscle from a bull treated with ivermectin resulted in a 45% (boiling) or 50% (frying) decrease in the drug residue. Based on the known toxic effects of the drug and the results of the present and other residue studies, the suggested withdrawal time for Ivomec in edible tissues of swine and cattle is 21 and 28 days, respectively.     

Determination of lasalocid residues in the tissues of broiler chickens by liquid chromatography-tandem mass spectrometry

Lasalocid is a polyether ionophoric coccidiostat used for the prevention of coccidiosis in poultry at a prescribed concentration and during a certain time interval. Due to a public health concern about the presence of coccidiostat residues in poultry, the aim of the present study was to determine the levels of lasalocid residues in the edible tissues of broiler chickens (breast muscle, thigh muscle, heart, liver, gizzard, kidneys and skin/fat) fed commercially produced feed containing 100?mg?kg?1) of lasalocid in complete feed throughout the 5-day withdrawal period (WP). The residues were investigated by liquid chromatography coupled with electrospray ionisation (ESI) tandem mass spectrometry (MS/MS) with triple quadrupole. The limit of detection (LOD) and the limit of quantification (LOQ) of the method were 0.47 and 1.44?μg?kg?1, respectively. The average recovery based on the matrix-fortified calibrations for chicken tissues ranged between 79% and 98%. Lasalocid was found to accumulate in the liver, followed by the heart, skin/fat, kidneys, thigh muscle and gizzard. The lowest concentrations of lasalocid residues were found in the breast muscle. On day 5 of the WP, residue concentrations of lasalocid did not decline below the LOQ of the method, but were far below the maximum residue level (MRL) established for lasalocid in poultry from 20 to 100?μg kg?1 by European Commission Regulation (EU) No. 37/2010. The results confirmed that the WP established for lasalocid is sufficient to ensure the decline of its residues in the tissues of broiler chickens to the safe residue level.