超高效液相色谱-串联质谱法检测饲料中4种硝基咪唑类药物

建立了同时检测饲料中洛硝哒唑、甲硝唑、二甲硝唑、替硝唑4种硝基咪唑类药物的超高效液相色谱-串联质谱法。样品经乙酸乙酯提取,Oasis MCX柱净化,以0.1%甲酸水-乙腈溶液为流动相梯度洗脱进行液相色谱-串联质谱检测。在10、50、100μg/kg的添加浓度下,饲料中各药物的回收率为70.3%～96.0%,相对标准偏差为4.2%～8.7%。检测限为3μg/kg,定量限为10μg/kg。     

超高效液相色谱-串联质谱法测定牛奶中三氯苯哒唑及其代谢物残留量的研究

建立了牛奶中三氯苯哒唑及其代谢物三氯苯唑酮残留量的超高效液相色谱-串联质谱（UPLC-MS/MS）测定方法。样品经乙酸乙酯提取后,正己烷除脂,经超高效液相色谱仪和C18色谱柱分离,以乙腈和5mmol/L乙酸铵溶液为流动相进行梯度洗脱。加热电喷雾负离子模式（HESI—）电离,选择反应监测模式（SRM）检测,外标法定量。结果表明：三氯苯哒唑和三氯苯哒唑酮标准溶液在5～500μg/L范围内呈现良好的线性关系,r2＞0.99,方法检测限为1μg/kg,定量限为2μg/kg。三氯苯哒唑和三氯苯唑酮在2～10μg/kg添加水平范围内的回收率为72.3%～110%,批内和批间变异系数均小于13.5%。该方法具有简便快捷、灵敏度高、准确度高等优点。     

HPLC-MS/MS法测定饲料中甲硝唑和二甲硝咪唑含量

建立了高效液相色谱-串联质谱法(HPLC-MS/MS)快速测定饲料中甲硝唑和二甲硝咪唑的含量。饲料样品用乙酸乙酯提取后,经PCX固相萃取柱净化处理,过0.22μm滤膜,以乙腈和含0.1%的甲酸水溶液为流动相,经Eclipse Plus C18色谱柱(3.0 mm×100 mm,1.8μm)分离,多级反应监测(MRM)正离子模式下扫描分析。结果表明,甲硝唑和二甲硝咪唑在0.2~50μg/L范围呈良好线性,线性相关系数均大于0.997,检出限均为0.2μg/kg,定量下限均为0.5μg/kg。样品在定量下限1倍、2倍、10倍3个加标水平下的平均回收率为95.3%~103.2%,相对标准偏差(RSD)为4.67%~8.46%。该方法灵敏、简便、准确,可用于饲料中甲硝唑和二甲硝咪唑的检测分析。     

液相色谱-串联质谱法测定血清和尿液中硝基咪唑类药物残留

为建立血清和尿液中甲硝唑、羟基甲硝唑、二甲硝咪唑和羟基二甲硝咪唑的高效液相色谱-串联质谱(HPLC-MS/MS)快速测定方法,样品用乙酸乙酯提取,经PCX固相萃取柱净化,Eclipse Plus C18色谱柱(3.0mm×100mm,1.8μm)分离,进行HPLC-MS/MS分析。结果表明,甲硝唑、羟基甲硝唑、二甲硝咪唑及羟基二甲硝咪唑在0.20μg/L~50μg/L范围呈良好线性,线性相关系数均大于0.995,检出限为0.20μg/L,定量下限为0.50μg/L。样品在定量下限1、2、10倍3个加标水平下的平均回收率为89.3%~108.2%,相对标准偏差(RSD)为2.63%~10.0%。该方法灵敏、简便、准确,可用于血清和尿液中硝基咪唑类药物的检测分析。     

牛奶中氯唑西林残留量的高效液相色谱法测定

为建立高效液相色谱法测定牛奶中氯唑西林残留的方法,牛奶样品用乙腈沉淀蛋白,三氯甲烷反萃取,有机相旋干用流动相溶解,正己烷除脂。0.02mol/L磷酸二氢钾溶液(pH 5.0)-乙腈(68∶32)比例为流动相,C18反相色谱柱分离,紫外检测。结果氯唑西林在15μg/kg～1 000μg/kg范围内呈现良好的线性关系,相关系数大于0.999 0;在15、30、60μg/kg三个添加水平,氯唑西林在牛奶中的平均回收率为70.25%～94.38%,批内变异系数小于8.34%,批间变异系数小于3.52%。方法检出限为5μg/kg,定量限为15μg/kg。表明该检测方法简单、灵敏、可靠,适用于牛奶中氯唑西林残留的分析检测。     

饲料中糖皮质激素类药物含量的UPLC-MS/MS检测方法的研究

试验建立了饲料中9种糖皮质激素类药物含量的UPLC-MS/MS检测方法。饲料中的糖皮质激素类药物经甲醇振荡提取,浓缩蒸干,溶解后用碳黑固相萃取柱串接氨基固相萃取柱净化后,液相色谱-串联质谱法测定,外标法定量。9种药物在2～100ng/ml浓度范围内呈线性相关,相关系数在0.997～0.9995,方法在饲料中最低检测限(LOD)为2μg/kg;定量限(LOQ)为5μg/kg。此方法在空白饲料中添加5～20ng/g浓度范围内,平均回收率在55.1%～88.2%,批内变异系数为3.3%～19.1%,批间变异系数为4.2%～13.5%。该方法具有较好的灵敏度、准确度和精密度,能完全满足饲料中此类药物含量的检测,可以作为此类药物的标准化检测方法。     

液相色谱-串联质谱测定饲料中7种硝基咪唑类药物

采用液相色谱-串联质谱法(LC-MS/MS)测定了饲料中甲硝唑(MNZ)、地美硝唑(DMZ)、洛硝唑(RNZ)、替硝唑(TNZ)、奥硝唑(ONZ)、异丙硝唑(IPZ)和塞克硝唑(SCZ)等7种硝基咪唑类药物。样品用乙酸乙酯提取,正己烷-磷酸溶液反萃取,MCX柱净化,以0.1%乙酸水溶液和乙腈作流动相进行梯度洗脱,电喷雾电离源正离子(ESI+)多反应监测(MRM)模式下检测。方法的检测限和定量限分别为0.03 mg/kg和0.1 mg/kg。添加浓度为0.1、1 mg/kg和10 mg/kg时的平均回收率为72.9%~98.8%,变异系数为4.9%~12.1%。     

牛奶中苯并咪唑类药物及其代谢物残留的UPLC-MS/MS检测方法研究

建立了牛奶中苯并咪唑类药物及代谢物残留的UPLC-MS/MS检测方法。牛奶样品在弱碱性条件下经乙腈沉淀蛋白后,用乙酸乙酯提取,再经正己烷脱脂,MCX固相萃取柱净化,采用UPLC-MS/MS多反应监测(MRM)模式检测,外标法定量。本方法对苯并咪唑类药物及代谢物的检测限均为5μg/g,定量限均为10μg/g,在10～200μg/L添加浓度范围内回收率为69.9%～113.1%之间,批内变异系数在1.36%～11.48%之间,批间变异系数在1.09%～9.87%之间。本方法分析速度快,灵敏度高,重现性好,各项技术指标均满足国内外相关法规要求,可用于牛奶中苯并咪唑类药物及代谢物残留的检测。     

猪肉中氟苯尼考残留量高效液相色谱-串联质谱检测方法的建立

本研究通过高效液相色谱-串联质谱法(High Performance Liquid Chromatography-Tandem Mass Spectrometry,HPLC-MS/MS)建立了猪肉中氟苯尼考残留物残留量的检测方法,检测限和定量限分别为5μg/kg和10μg/kg。在10μg/kg~4000μg/kg浓度范围内,空白猪肉样品的标准曲线线性关系良好,相关系数均在0.99以上。氟苯尼考和氟苯尼考胺的添加浓度在10μg/kg、500μg/kg和2000μg/kg时,回收率均大于85%,批间和批内变异系数均小于5%。该方法适用于猪可食性组织中氟苯尼考残留量的测定。     

鸡皮脂和肾脏中替米考星残留HPLC检测方法的建立

本试验旨在建立鸡皮脂和肾脏组织中替米考星残留量的HPLC测定方法。皮脂和肾脏组织中残留的替米考星用乙腈提取、MCX固相萃取柱净化,采用高效液相色谱-紫外检测法测定。皮脂组织和肾脏组织中替米考星检测限分别为20μg/kg和30μg/kg,定量限分别为35μg/kg和50μg/kg。空白皮脂组织添加替米考星在35～150μg/kg浓度水平,回收率在75%～98%之间,批内与批间变异系数均小于10%;空白肾脏组织添加替米考星在50～500μg/kg浓度水平,回收率在71%～97%之间,批内变异系数小于11%,批间变异系数小于10%。本试验建立的方法快速、准确、灵敏,适用于鸡皮脂和肾脏组织中替米考星残留量的检测。     

癸氧喹酯干混悬剂含量测定的改进

采用高效液相色谱法测定癸氧喹酯干混悬剂的含量,在2-250μg/mL范围内,峰面积的常用对数与进样量浓度的常用对数呈良好的线性关系,R^2=1(n=5),平均回收率为99.24%~99.51%,RSD在0.05%~0.28%。此方法分析时间短,样品前处理简便、定量结果准确,重现性好,结果满意,为其质量控制提供了依据。     

猪毛色遗传的研究进展

本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。     

商会自治的基石——商会自治规范研究

在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。     

Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF

Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo.     

中华人民共和国农业部公告 第267号

为贯彻落实《兽药生产质量管理规范》(简称《兽药GMP》),进一步推动兽药GMP实施进程,我部制定了《兽药生产质量管理规范检查验收办法》,现予公告。本公告自2003年6月1日起施行。附件:兽药生产质量管理规范检查验收办法二○○三年四月十日第一章 总则 第一条 为推动《兽药生产质量管理规范》(以下简称兽药GMP)的实施,规范兽药GMP检查验收工作,制定本办法。 第二条 农业部负责全国兽药GMP管理和检查验收工作;负责制修订兽药GMP检查验收管理规定;负责兽药GMP检查员队伍建设和监督管理工作,负责国际兽药贸易中GMP互认工作。 …     

鸡败血支原体垂直传播模式及其阻断方法

以国际标准强毒Ｒ株人工感染非免疫产蛋鸡,定时扑杀,分别从鼻窦、眶下孔、气管、肺、气囊、卵巢和输卵管分离ＭＧ,并收集感染鸡所产蛋分离ＭＧ。结果表明,人工感染４８小时后上、下呼吸道及肺已被全面感染,９６小时气囊已被感染,１２０小时输卵管已能分离到ＭＧ,卵巢始终分离不到ＭＧ。人工感染鸡自１４４小时便能在其所产蛋中分离出ＭＧ。药物治疗能在７２小时内消除感染,油乳剂苗则需２４天后逐渐降低蛋内ＭＧ分离率,药物卵内注射、种蛋药浴、高温处理均能杀死卵内ＭＧ,但以研制的种蛋浸泡剂药浴效果为最好。     

Mechanism of Action of Probiotic Function of Lactobacilli

乳酸杆菌作为益生菌广泛用于人和动物.本文综述了乳酸杆菌改善宿主健康的机制.乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道.文章重点讨论了乳酸杆菌表面成分(表面蛋白、脂磷壁酸和肽聚糖)与肠道受体(C型凝集素受体、Toll样受体和Nod样受体),阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制.     

Comparison of 2 methods of centesis of the bursa of the biceps brachii tendon of horses

REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air.