影响琼脂扩散试验的因素

１ 琼脂凝胶的配制：先使琼脂或琼脂糖在ｐＨ７．２～７．４的磷酸缓冲液中融化后，再加入氯化钠；如果同时加琼脂（糖）和氯化钠，则会出现琼脂不透明，影响以后的结果观察。２ 缓冲液：ｐＨ７．２～７．６的磷酸缓冲液最适用。３ 琼脂浓度：浓度越低，扩散越快；浓度越高，扩散越慢。因此，以打孔后孔壁不塌的最低琼脂浓度为佳。质量较好的琼脂（如琼脂糖）可用０．８％～１．０％浓度，若气温较高时，可提高为１．２％～１．５％。４ 抗原抗体浓度：抗原抗体的浓度和量必须有适当的比例，比例合适则沉淀多而快；抗原过多或抗体过多，则沉…     

伊维菌素预混剂驱除野生动物体外寄生虫的试验观察

６ｇ／ｋｇ伊维菌素预混剂是伊维菌素的一种新制剂，对草食动物按０．２０ｍｇ／ｋｇ体重、肉食动物按０．２５ｍｇ／ｋｇ体重分别连续饲喂７ｄ和２ｄ。结果表明，伊维菌素预混剂对野生动物长角血蜱病、疥螨病、虱病的治愈率分别达到１００％、８７．５０％和８５．７１％，且安全、无任何毒副作用。     

饲料药物添加剂使用规范(续)

磷酸泰乐菌素、磺胺二甲嘧啶预混剂Ｔｙｌｏｓｉｎ　Ｐｈｏｓｐｈａｔｅ　ａｎｄ　Ｓｕｌｆａｍｅｔｈａｚｉｎｅ　Ｐｒｅｍｉｘ［有效成分］磷酸泰乐菌素和磺胺二甲嘧啶［含量规格］每１０００ ｇ中含泰乐菌素２２ ｇ和磺胺二甲嘧啶２２ｇ、泰乐菌素８８ ｇ和磺胺二甲嘧啶８８ ｇ或泰乐菌素１００ ｇ和磺胺二甲嘧啶１００ｇ。［适用动物］猪［作用与用途］用于预防猪痢疾，用于畜禽细菌及支原体感染。［用法与用量］混饲。每 １０００ ｋｇ饲料添加本品 ２００ ｇ（１００ ｇ泰乐菌素＋１００ｇ磺胺二甲嘧啶），连用５～７ｄ。［注意］体药…     

0.6%百虫杀预混剂对猪蛔虫病的治疗试验

０．６％百虫杀预混剂是伊维菌素的一种新制剂。在每吨饲料中添加３３３ｇ，连续饲喂７天，对猪蛔虫病的治愈率达１００％，且安全，无任何毒副作用，其效果与美国默沙东０．６％害获灭相同。     

阿维菌素预混剂对猪的应用效果

给公猪和母猪进行驱虫灭螨是猪场寄生虫病防治的重要措施，是净化环境、减少小猪寄生虫感染的重要环节。伊维菌素和阿维菌素注射液在公猪和母猪的应用，已收到良好的效果，但注射给药相当不方便，增加劳动力成本，并对猪有一定的刺激。国外已开发出伊维菌素猪用预混剂。为了验证国产阿维菌素预混剂在种公猪和妊娠母猪的应用效果，我们进行了本次试验。１材料与方法１．１试验药物供试药物为０．４％阿维菌素预混剂，中国农业大学新技术开发总公司出品。对照药物为０．６％伊维菌素预混剂，美国默沙东药厂出品。１．２试验动物与分组１．２．…     

0.6%伊维菌素预混剂驱除野生动物体外寄生虫的试验观察

０．６％伊维菌素预混剂是伊维菌素的一种新制剂。草食动物按０．２ｍｇ／ｋｇ体重、肉食动物０．２５ｍｇ／ｋｇ体重平均连续饲喂分别为７天和２天,对野生动物长角血蜱病、螨病、虱病的治愈率分别达１００％、８７．５０％、８５．７１％,且安全、无毒副作用,值得在野生动物上推广和应用。     

复方氨基比林注射液的双波长差示分光光度法测定

本文介绍了双波长差示分光光度法测定兽药复方氨基比林注射液中氨基比林和巴比妥的含量，稀释液为０．０１ｍｏｌ／Ｌ的盐酸和ｐＨ＝１０的氨－氯化氨缓冲液，测定波长为２３９ｎｍ，２６６ｎｍ，２７９ｎｍ。回收率氨基比林的ＲＳＤ为０．９４％，巴经妥的ＲＳＤ为０．７％。样品测定经ｔ值检验，Ｐ〉０．５无显著差异。     

0.6%百虫杀预混剂对仔猪疥螨病的治疗试验

０．６％百虫杀预混剂是伊维菌素的一种新制剂。在每吨饲料中添加３３３克,连续饲喂７天,对猪疥螨病的治愈率达１００％,且安全,无任何毒副作用,其效果与美国默沙东０．６％害获灭相同。     

高压液相色谱仪测定维生素B_(12)

维生素Ｂ１２是动物体内必不可少的一种维生素，由于Ｂ１２在酸碱环境中易失效，且易受盐酸硫胺素和抗坏血酸等的破坏，因此近几年市场上出现单纯的马。预混剂，一般多为０．０１％和０．００５％两种规格。由于０．０１％和０．００５％的Ｂ１２预混剂中Ｂ１２含量太低，用ＧＢ９８４１－８８测定其含量时因称样量过大（分别为２０９和４０ｇ），给操作带来了很多不便，且测定结果不准确。笔者经过反复试验，利用高压液相色谱仪较好地解决了０．０１％和０．００５％Ｂ１２预混剂的含量测定问题。１仪器和试剂高压液相色谱仪，带Ｃ１８柱；…     

不同包被液对ELISA检测五号病病毒抗体的比较试验

０．０５ＭｐＨ９．６碳酸盐缓冲液和０．０５ＭＰＨ１３ＮａＯＨ溶液作为包被液，分别用于间接ＥＬＩＳＡ检测乙型五号病病毒抗体。结果表明，用０．０５ＭＰＨ１３ＮａＯＨ溶泡包被可完全灭活五号病病毒抗原而用０．０５ＭＰＨ９．６碳酸盐缓冲液却有８７％的五号病病毒抗原未被杀灭；用于检测时，以０．０５ＭＰＨ１３ＮａＯＨ溶液为包被液在敏感性及检测结果的梯度方面都优于用０．０５ＭＰＨ９．６碳酸盐缓冲液。     

Comparative pharmacokinetics and bioavailability of tylosin tartrate and tylosin phosphate after a single oral and i.v. administration in chickens

The pharmacokinetics and oral bioavailability of tylosin tartrate and tylosin phosphate were carried out in broiler chickens according to a principle of single dose, random, parallel design. The two formulations of tylosin were given orally and intravenously at a dose level of 10 mg/kg b.w to chicken after an overnight fasting (n = 10 chickens/group). Serial blood samples were collected at different time points up to 24 h postdrug administration. A high performance liquid chromatography method was used for the determination of tylosin concentrations in chicken plasma. The tylosin plasma concentration's time plot of each chicken was analyzed by the 3P97 software. The pharmacokinetics of tylosin was best described by a one‐compartmental open model 1st absorption after oral administration. After intravenous administration the pharmacokinetics of tylosin was best described by a two‐compartmental open model, and there were no significant differences between tylosin tartrate and tylosin phosphate. After oral administration, there were significant differences in the C_max (0.18 ± 0.01, 0.44 ± 0.09) and AUC (0.82 ± 0.05, 1.57 ± 0.25)between tylosin phosphate and tylosin tartrate. The calculated oral bioavailability (F) of tylosin tartrate and tylosin phosphate were 25.78% and 13.73%, respectively. Above all, we can reasonably conclude that, the absorption of tylosin tartrate is better than tylosin phosphate after oral administration.     

双波长紫外分光光度法测定酒石酸泰乐菌素-盐酸多西环素可溶性粉的含量

建立了双波长紫外分光光度法同时测定酒石酸泰乐菌素-盐酸多西环素可溶性粉中酒石酸泰乐菌素和盐酸多西环素含量的检测方法。结果显示，吸收度与浓度呈良好线性关系。酒石酸泰乐菌素的平均回收率为99．90％，RSD为0．42％n=5）；盐酸多西环素的平均回收率为100．07％，RSD为0．74％（n=5）。     

表面等离子共振生物传感技术测定蜂蜜中残留的泰乐菌素

本文利用表面等离子共振生物传感器技术对蜂蜜样品中残留的泰乐菌素进行测定。蜂蜜样品通过缓冲溶液提取后在BIAcoreQ大分子互作仪上测定,并且与试剂盒方法进行对比。结果表明采用表面等离子共振生物传感器方法在0.5-10ng/g的线性范围内,检出限为0.5ng/g,平均回收率在90.3%-101.7%之间,日内变异系数和日间变异系数分别为2.1%-4.7%和3.9%-7.1%(n=6),准确度偏离均小于10%。     

磷酸泰乐菌素脂质体的制备及体外释放动力学研究

为延长磷酸泰乐菌素在体内的作用时间,通过比较采用硫酸铵梯度法制备其脂质体制剂。以包封率为指标,分别考察磷脂与胆固醇之比、药脂比、硫酸铵浓度、孵化温度和孵化时间对包封率的影响,并在此基础上进行正交试验筛选最优处方。同时,对所得脂质体的形态、粒径及分布、包封率及体外释放动力学进行研究。结果显示,正交试验优化得到的最佳处方工艺如下,磷脂与胆固醇质量比为4∶1,药脂比为1∶10,硫酸铵浓度为300 mmol/L,体系pH值为7.0,孵化温度为50℃,孵化时间为20 m in。电镜下观察脂质体呈球形或类球形,分布均匀,平均粒径为6.526μm,且大部分在1μm~12μm之间,包封率为58.32%,体外释药符合W eibull方程(r=0.976 4)。研究证实硫酸铵梯度法制备磷酸泰乐菌素脂质体方法可行,包封率高,稳定性好,体外释药具有一定的缓释效应。     

Growth performance of pigs fed diets with and without tylosin phosphate supplementation and reared in a biosecure all-in all-out housing system

Three hundred and eighty-four pigs, mean initial live weight of 20.8 kg, were assigned randomly to groups of 24 (12 females, 12 castrated males). Each group was randomly assigned to 1 of 2 dietary treatments consisting of the same commercial barley-based diet, with or without the addition of tylosin phosphate. The barn where the animals were housed operates as an all-in all-out facility, and all pigs arrived on the same day as part of a group of 960 pigs. No new pigs were introduced into the facility during the period of this trial and pigs were sent to market over a 4-week period upon achieving a live weight of 110 kg. The pigs were weighed at the beginning of the trial and when they left the facility for slaughter. Feed consumption and incidence of disease, mortality, or both were recorded daily. At slaughter, carcass backfat depth over the last rib, 6.5 cm ventral to the dorsal midline (P-2 site); loin depth; carcass weight; predicted lean yield; and grade index were recorded. The sow herd supplying pigs to the unit was known to be free of the major swine diseases such as swine influenza, mycoplasma pneumonia, porcine reproductive and respiratory syndrome (PRRS), necroproliferative enteritis, and ascarids. A strict biosecurity protocol was employed to minimize the risk of introducing disease organisms into the unit. Prior to this study, no subtherapeutic antibiotics had been used in this facility. Tylosin phosphate supplementation had no significant effect on final weight, days on test, total gain, and daily gain. In both treatments, the pigs reached a mean market weight of 110.2 kg within 94.1 days, resulting in daily gains of the order of 950 grams per day. Due to the design of the trial, it was difficult to measure significant feed consumption effects. Feed consumption and conversion appeared to be similar for pigs in both treatment groups. At slaughter, tylosin phosphate supplementation appeared to significantly increase lean muscle content of the carcass as measured by loin muscle depth (P = 0.04). Mortality rates and the number of underweight pigs sent to market were low for this trial. Mortality was similar for both treatments; however, more of the control pigs than of the tylosin phosphate fed pigs were underweight when sent to market. From the results of this study, it appears that pigs of fast growing genotypes fed adequate diets and housed in a biosecure environment do not require dietary tylosin phosphate supplementation in order to maximize growth. There is some indication that tylosin phosphate supplementation may improve lean content of the carcass in pigs housed in such an environment.     

泰乐菌素检测方法研究进展

本文主要综述了近年来微生物法、酶联免疫法、紫外分光光度法、生物传感器法、高效液相色谱法、高效液相一质谱联用法等泰乐菌素的检测分析的方法及进展。     

微生物浊度法测定3种兽用抗生素效价的研究

分别以金黄色葡萄球菌和大肠杆菌为试验菌,抗生素检定培养基Ⅲ号为试验用培养基,制成菌悬液。将硫酸安普霉素、泰乐菌素、硫酸黏菌素稀释成不同的浓度加入菌悬液中,37℃培养3～4h,确立浓度的对数值与相对应的吸光度呈直线相关的线性范围,并对所建立的浊度法进行准确度、精密度、浊度法与管碟法比较及专属性等验证。结果表明硫酸安普霉素、泰乐菌素、硫酸黏菌素的线性浓度范围分别为2．9—7．2、0．6～2．0、44．9～93．2u／mL,相关系数r分别为0．9974、0．9984、0。9978。硫酸安普霉素、泰乐菌素、硫酸黏菌素所建立的浊度法平均回收率及平均可信限率分别为99．82％,2．48％、99．66％,2．80％、99．61％,7．62％。管碟法与浊度法所测结果无显著差异。硫酸安普霉素和泰乐菌素浊度法具有可信限率低、灵敏度高、精密度高、快速等优点;硫酸黏菌素建立的浊度法可信限率与管碟法接近。     

液相色谱串联质谱法测定鸡蛋、牛奶和羊奶中泰乐菌素A残留的研究

建立了鸡蛋、牛奶和羊奶中泰乐菌素A残留的液相色谱-串联质谱法.样品经乙腈提取后,Prime HLB固相萃取柱净化,以0.1％甲酸水和乙腈为流动相,液相色谱-串联质谱法测定,内标法定量.试验结果表明:泰乐菌素A在1～100 ng/mL浓度范围内线性关系良好,相关系数r大于0.99;在鸡蛋、牛奶和羊奶中的检测限为2 ng/...     

Increased bioavailability of tylosin phosphate as in-feed medication formulated for long-action pellets in broiler chickens

Circadian variation of serum concentrations of tylosin in broiler chickens after in-feed medication prompted a comparison study of the serum profiles of this drug after in-feed medication with standard tylosin phosphate (Tprf reference formulation group), and after in-feed medication with a sustained-release pellet formulation (Tpsr group), based on Patent No.MX/a/2012/013222 and PCT/MX2013/000137, in broiler chickens. Six hundred 4-week-old Ross broiler chickens were in-feed medicated with tylosin phosphate at an approximate dose of 25.2 mg/kg/d, based on daily feed consumption values and a final concentration of tylosin in feed of 200 mg/kg of feed. Approximately 2 to 3 mL of blood were obtained per 5 chickens every 2 h, avoiding the sampling of a bird more than once and during 72 h after making medicated feed available for the first time. Serum concentrations of tylosin were determined by HPLC. Gaussian multi-peak regressions were then fitted to serum concentration vs. time profiles. Day by d areas under the serum concentration vs. time profiles (AUC_0–24), as well as overall AUC_0–72, were statistically higher for the Tpsr group (P < 0.001). Also, maximum serum concentrations obtained and relative bioavailability for the Tpsr formulation were statistically higher (382.8%) as compared to the Tprf group (P < 0.01). Considering the referred improved values of AUC observed in the Tpsr formulation, as well as the fact that tylosin is a time-dependent antibacterial drug, better clinical responses are postulated with this pharmaceutical preparation intended for chickens. Tissue deposition studies for this new formulation of tylosin are required.     

Bacterial flora of liver abscesses in feedlot cattle fed tylosin or no tylosin.

Bacterial flora of liver abscesses from cattle fed tylosin or no tylosin and susceptibilities of the predominant bacterial isolates to tylosin and other antimicrobial compounds were determined. Abscessed livers were collected at slaughter from cattle originating from feedlots that had fed tylosin (n = 36) or no tylosin (n = 41) for at least 2 yr, and segments of livers with one or two intact abscesses were transported to the laboratory. Abscesses were cultured for anaerobic and facultative bacteria. Fusobacterium necrophorum, either as single culture or mixed with other bacteria, was isolated from all abscesses. The incidence of subsp. necrophorum, as part of the mixed infection, was lower (P < .05) in the tylosin group than in the no-tylosin group (33 vs 61%). However, the incidence of Actinomyces pyogenes was higher (P < .01) in the tylosin group than in the no-tylosin group (53 vs 10%). Totals of 119 F. necrophorum and 21 A. pyogenes isolates were used for determinations of susceptibilities to bacitracin, oxytetracycline, chlortetracycline, lasalocid, monensin, tylosin, tilmicosin, and virginiamycin. The minimum inhibitory concentrations (MIC) of antibiotics were determined with a broth microdilution method. The mean MIC of tylosin for F. necrophorum and A. pyogenes were not different between isolates from tylosin and no-tylosin groups. We concluded that continuous feeding of tylosin did not induce resistance in F. necrophorum or A. pyogenes. Also, the higher incidence of mixed infection of F. necrophorum and A. pyogenes in liver abscesses of tylosin-fed cattle suggests a potential synergistic interaction between the two organisms in causing liver abscesses.