猪组织和血浆中磺胺二甲嘧啶残留分布规律的数学模型分析

采用高效液相色谱法检测猪肌肉、肾脏、肝脏和血浆中的磺胺二甲嘧啶残留量,通过对饲料中磺胺二甲嘧啶添加量和组织、血浆中残留量回归关系不同数学模型的分析,确立残留分布的规律的最佳数学模型.饲料中SM2的添加量在100～300μg/g的范围内,饲料添加量与猪组织(肌肉、肾脏、肝脏)、血浆的残留数学模型分别为:y=0.241 6e0.006 1x;y=1.9691e0.002 5x;y=3.049 5e0.001 9x;y=4.386 2e0.003 7x.通过对猪活体血浆样品的检测,根据建立的最佳残留数学模型,可算出饲料中磺胺二甲嘧啶的添加量和肌肉、肾脏、肝脏中磺胺二甲嘧啶的残留量,实现活体的监测.     

猪组织和血浆中磺胺二甲嘧啶残留分布规律的数学模型分析

采用高效液相色谱法检测猪肌肉、肾脏、肝脏和血浆中的磺胺二甲嘧啶(Sulfamethazinum,SM2)残留量.通过对饲料中SM2添加量和组织、血浆中残留量回归关系不同数学模型的分析,确立残留分布规律的最佳数学模型.饲料中SM2的添加量在100～300μg/g的范围内,饲料添加量与猪组织(肌肉、肾脏、肝脏)、血浆中的残留数学模型分别为:y=0.241 6 e0.0061x,y=1.969 1 e0.0025x,y=3.049 5 e0.0019x,y=4.386 2 e0.0037x.通过对猪活体血浆样品的检测,根据建立的最佳残留数学模型,可算出饲料中SM2的添加量和肌肉、肾脏、肝脏中SM2的残留量,实现活体的监测.     

猪组织和血浆中金霉素残留分布规律的数学模型分析

试验采用高效液相色谱法检测猪组织(肌肉、肝脏、肾脏)和血浆中的金霉素残留量,通过对饲料中金霉素添加量和组织、血浆中金霉素残留量回归关系不同数学模型的分析,确立残留分布的规律最佳数学模型。饲料中金霉素的添加量在50～150μg/g的范围内饲料添加量与猪组织(肌肉、肾脏、肝脏)、血浆的残留数学模型分别为:y=0.5535e0.0072x;y=1.666e0.0116x;y=4.4048ln(x)-14.669;y=1.4527e0.0092x。     

猪组织中4种药物残留规律研究

试验采用高效液相色谱法检测猪组织(肌肉、肝和肾)中的金霉素、土霉素、磺胺二甲嘧啶和喹乙醇残留量,通过对饲料中4种药物添加量和组织中残留量的分析,研究其残留规律.结果表明,在药物的添加范围内,猪组织中磺胺二甲嘧啶的残留规律为肝＞肾＞肌肉;金霉素的残留规律为肾＞肝＞肌肉;土霉素的残留规律为肝＞肾＞肌肉;喹乙醇的残留规律为肝＞肾＞肌肉.     

恩诺沙星在猪组织中残留消除规律研究

在常规饲养条件下,对健康猪按2.5 mg/kg体重的剂量肌肉注射2.5%恩诺沙星注射液,每日2次,连续注射3 d.停药后第2、4、6、8、10、12、14天分别屠宰4头猪.分别采取每头猪的肌肉(注射部位)、脂肪(腹脂)、肝和肾脏等4种组织,用高效液相色谱法进行残留量测定.结果表明:残留在肌肉、脂肪组织中的药物消除较快,第8天总残留量(恩诺沙星 环丙沙星)已下降至检测限(20μg/kg)以下;肝和肾脏组织中的药物消除缓慢,第14天测得猪肾中药物总残留量为40μg/kg.     

盐酸土霉素可溶性粉在肉鸡组织中的残留消除研究

在常规养殖环境中,对不同日龄肉鸡分别给予250 mg/L和333 mg/L 50%盐酸土霉素可溶性粉,集中饮水给药,每日1次,连续5 d。停药后4 h,1 d,3 d,5 d,6 d,7 d,8 d,9 d,10 d宰杀肉鸡,采集可食性组织(肌肉、肝脏和鸡胗)样品,肌肉、肝脏和鸡胗组织中的残留量采用UPLC-MS/MS测定。结果表明:土霉素主要残留在肝脏组织中;肌肉、肝脏和鸡胗组织的消除速率相似;停药5 d后,两个剂量组的肌肉、肝脏中土霉素残留量均低于最高残留限量(MRL)。休药期计算软件WTl.4结果显示,上述两种方法给药后,建议休药期分别为7、8 d。     

土霉素在鸡蛋中的残留消除研究

研究临床使用常规剂量及养殖环节加大盐酸土霉素可溶性粉剂量后其在鸡蛋中的残留消除规律。对产蛋期蛋鸡分别给予500 mg/L和667 mg/L 50%盐酸土霉素可溶性粉,集中饮水给药,每日1次,连续5 d。分别采集停药后1～12 d的鸡蛋样品,采用UPLC-MS/MS测定鸡蛋中土霉素的残留量。按上述方法给药后,低、高剂量组分别在停药第1天和停药第2天达到土霉素残留量最高。低、高剂量组的最高残留量分别为142. 72、82. 84μg/kg,均低于国家规定的最高残留限量(200μg/kg),不会造成土霉素残留超标。本试验通过研究土霉素可溶性粉在鸡蛋中的残留情况,确定弃蛋期前后土霉素残留量,以期为蛋鸡产蛋期安全用药,保障食品安全提供科学依据。     

土霉素注射液在猪体内药代动力学比较

对长效土霉素注射液进行了猪体内药代动力学的比较研究。试验将三种产品（Ａ、Ｂ、Ｃ）分别一次肌肉注射猪３头,剂量２０ｍｇ／ｋｇ。结果表明,消除半衰期以产品Ｂ最长,血药峰浓度以产品Ｂ最高,达到峰浓度时间以产品Ａ最慢,药时曲线下面积以产品Ｂ最大,２４小时血药浓度以产品Ｂ最高,４８小时血药浓度以产品Ｃ最低。以血浆土霉素浓度０．５μｇ／ｍｌ为最小有效浓度,产品Ａ和Ｂ能够维持有效血药浓度２４小时,产品Ｃ仅能够维持有效血药浓度１２小时。     

Determination of trimethoprim and sulphadoxine residues in porcine tissues and plasma.

Healthy gilts and market-ready hogs were administered a single intramuscular (IM) injection of Borgal, a commercial formulation of trimethoprim-sulfadoxine (TMP-SDX), once or twice daily. The objectives were to determine if a newly-developed high-performance liquid chromatographic (HPLC) method would be suitable for measuring the residual concentrations of TMP in the plasma of these live animals, and to determine if the administration of this veterinary drug would leave measurable residues in their plasma and tissues at slaughter. Plasma and tissue concentrations of SDX and TMP from these animals were determined over a period of 14 d using thin-layer chromatography/densitometry (TLCD), and the newly-developed HPLC method, respectively. The lowest detectable limit (LDL) for SDX in plasma and tissue was 20 ppb by TLCD. The HPLC method had a LDL of 5 ppb for TMP in plasma and tissue. Both methods were then used to provide baseline data on the absorption and depletion of TMP and SDX from these healthy animals. It was observed that both TMP and SDX were readily absorbed into the blood and tissues, but TMP was eliminated much faster than SDX. No TMP residues were detected in the plasma of any of the gilts at and beyond 21 h after drug administration. Also, no TMP residues were detected in the plasma of any of the market-ready hogs 24 h after drug administration at either the label dose or twice the label dose. Sulfadoxine residues at concentrations above the maximum residue limit (MRL) of 100 ppb were, however, detected in the plasma, muscle, kidney, liver, and injection sites of hogs slaughtered 1 and 3 d after a single IM administration at the label dose. Although SDX residues were still detectable in the lungs, kidney, liver and plasma of some hogs 10 d after administration of the label dose and twice the label dose, these were below the MRL. Postmortem examination revealed necrosis and inflammation at the injection sites, but no visible deposits of the injected drug.     

Detection of melengestrol acetate residues in plasma and edible tissues of heifers

The aim of this study was to gain knowledge of residue formation after the use of melengestrol acetate (MGA) as a growth-promoting agent. Two Holstein-Friesian heifers each received a daily dose through the feed of 0, 0.5 mg (2 heifers with and without withdrawal each), 1.5 mg or 5.0 mg MGA for 8 weeks. MGA residues in plasma were screened by enzyme immuno-assay (EIA). Concentrations in kidney, liver, and muscle were quantified by liquid-chromatography-mass spectrometry (LC-MS), and in fat by gas chromatography-mass spectrometry (GC-MS). MGA levels in plasma were 40, 128, and 280 ng/L, respectively. Residues accumulated in muscle and kidney (5-fold), liver (20-to-40-fold), and fat (200-fold). After administration of 1.5 mg per day the mean MGA concentration in fat was 29 micrograms/kg and thus violated USA regulations which specify a limit of 25 ppb. Therefore the labelled use of MGA (0.5 mg per day) has to be officially controlled.     

Ceftiofur distribution in plasma and tissues following subcutaneously administration in ducks

A study was performed to determine the residues in blood and edible tissues of healthy ducks (25 days old, mean body weight 1.0+/-0.13 kg) after subcutaneous administration of ceftiofur sodium at a dose rate of 2 mg/kg body weight (Group I) and 4 mg/kg body weight (Group II). Blood, muscle, liver, kidney, and fat samples were collected from all of ducks on the 1st, 2nd, 3rd, 4th, and 5th day after treatment of drug, and ceftiofur was analyzed with a high-performance liquid chromatography (HPLC) assay with results reported as ceftiofur-free acid equivalent (CFAE). To study the spiked recovery, blank plasma and tissues were spiked with two different concentrations of ceftiofur sodium (0.1, 0.5 microg/g). Average recovery values for all samples ranged from 70.3 to 87.3%. In the group I, desfuroylceftiofur acetamide (DCA) was not detected in all of plasma, muscle, liver, and fat tissues on the 1st day after treatment. But, kidney samples on the 1st day were detected DCA (0.059+/-0.01 microg CFAE/g tissue). On the 2nd day of post-treatment, the concentrations of DCA in all tissues were lower than the detection limit, 0.05 microg CFAE /g tissue. In the group II on the 1st day after treatment, the concentration of DCA was 0.124+/-0.06 microg CFAE/g tissue, 0.103+/-0.03 microg CFAE/g tissue, and 0.071+/-0.010 microg CFAE/g tissue in plasma, kidney, and muscle samples, respectively. On the 2nd day after treatment of ceftiofur, the concentrations of DCA in all tissues were lower than 0.05 microg CFAE/g tissue. According to our results, the concentrations of DCA on the 1st day after treatment with 2 mg/kg body weight were below 0.05 microg CFAE/g tissue equivalent in all tissues except for kidney. On the 2nd day after administration at the dose of 4 mg/kg body weight, no DCA was also detected in all of the tissues although DCA was detected in all samples on the 1st day.     

规模化猪场不同通风模式下不同类型猪舍内空气细菌气溶胶分布规律的研究

为了研究自然通风模式下和湿帘-风机系统下妊娠舍和产仔舍空气细菌气溶胶的分布规律,筛选出更适合养猪生产的养殖模式,采用Andersen-6级撞击式空气微生物采样器对2种通风模式下的妊娠舍和产仔舍15个采样点细菌气溶胶的浓度和粒子分布规律进行了比较分析。结果显示:2种通风模式下产仔舍的细菌气溶胶浓度均显著低于妊娠舍(P0.05);相较于自然通风模式,湿帘-风机系统可以显著减少妊娠舍内细菌气溶胶的浓度(P0.05),但是对产仔舍影响不显著(P0.05);细菌气溶胶粒子均主要分布在7.0μm和2.1~3.3μm区间,通风模式和猪舍类型对细菌气溶胶粒子的分布无显著相关(P0.05)。研究表明,湿帘-风机系统可以显著降低妊娠舍细菌气溶胶的浓度。     

两种不同检测法对猪瘟抗体阴性猪筛检的比较

猪瘟抗体阴性猪是猪瘟活疫苗安检的重要实验动物,目前对于猪瘟抗体阴性猪筛选是采用兔体中和反应法,实验复杂,工作量大并且易受实验兔个体差异等因素影响。随着生物学及其技术的发展,ELISA被广泛用于生物制品的各个领域。本试验应用ELISA法和兔体中和反应法对猪瘟抗体阴性猪进行筛选,共检测160份血清,检测结果显示两种方法结果有很高的一致性,但ELISA法更为敏感,快捷,更适用于猪瘟抗体阴性猪的筛选。     

规模化猪场预防萎缩性鼻炎方法的比较试验

本试验对单独应用猪萎缩性鼻炎、多杀性巴氏杆菌二联苗和疫苗接种结合药物防制进行了效果比较。结果表明,7日龄首免1 mL/头,28日龄二免2 mL/头,可产生较强的免疫保护力。结合饲料中添加药物、哺乳仔猪药水滴鼻等药物防治措施,可使猪群的临床发病率由51.39％降至1.39％,生长肥育猪的综合性能指标得到较大改善。     

从江香猪和大白猪不同组织中GYS1、GYS2基因表达水平的研究

旨在研究糖原合成酶(GS)基因mRNA在从江香猪和大白猪表达情况,探究肌肉类型糖原合成酶(GYS1)和肝脏类型糖原合成酶(GYS2)基因表达规律。以大白猪和从江香猪为试验动物,分别提取心脏、肝脏、脾脏、肺脏、肾脏、胃、大肠、小肠、背最长肌、脂肪10个组织的总RNA,设计各自实时荧光定量引物,以猪GAPDH基因作为内参基因,应用实时定量PCR技术检测GYS1和GYS2基因不同组织中mRNA的相对表达量。结果发现:GYS1基因在大白猪和从江香猪所检测的组织中均有表达,在背最长肌中的表达量最高,且在大白猪背最长肌中表达量显著高于从江香猪(P0.05);GYS2基因在肝脏中表达量最高,其他组织中几乎不表达,具有肝脏组织特异性,且发现在从江香猪肝脏中表达量显著低于大白猪(P0.05)。本研究为GYS1和GYS2基因后续真核表达的研究提供了理论依据。