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由于莱克多巴胺通过饲料饲喂动物会残留在动物的肌肉与内脏组织中．对饲料中莱克多巴胺进行监测也就显得尤为重要。本文以高效液相色谱一串联质谱法检测饲料中的莱克多巴胺．饲料样品中的莱克多巴胺经酸性三水合乙酸钠溶液提取．离心后经MCX固相萃取柱净化．最后用高效液相色谱一串联质谱仪检测器进行测定;同等条件下绘制工作曲线．莱克多巴胺含量与吸光度值在一定浓度范围内成正比,试样与工作曲线比较定量。经实验．应用高效液相色谱一串联质谱法检测饲料中莱克多巴胺．标准曲线r值≥0．99965;检测回收率均≥80％,批内RSD≤8％。批间RSD≤10％。 相似文献
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利用农业部第958号公告-4-2007及农业部第1031号公告-3-2008对莱克多巴胺阳性猪尿液进行检测,对比两种法中酸解及酶解方式对莱克多巴胺代谢物检测能力的差别,并初步分析了造成差别的原因。 相似文献
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莱克多巴胺属于β-兴奋剂。β-兴奋剂是营养重分配剂一种,是一类结构和功能类似肾上腺素和去甲肾上腺素的苯乙醇胺类衍生物,它可以加快畜禽生长速度,降低酮体脂肪含量,提高瘦肉率。随着我国对克伦特罗监管力度的加大,克伦特罗的使用逐渐减少,其它β-兴奋剂的使用逐渐增加。现有证据表明,莱克多巴胺作为"瘦肉精"替代品已在养猪生产中被使用。由于莱克多巴胺通过饲料对动物的饲喂会残留在动物的肌肉与内脏组织中,对饲料中莱克多巴胺进行监测也就显得尤为重要。试验以液相色谱-荧光法检测饲料中的莱克多巴胺,饲料样品中的莱克多巴胺经酸性甲醇溶液提取,离心后溶液碱化,经乙酸乙酯粹取和MCX固相萃取柱净化,最后用反相高效液相色谱仪-荧光检测器进行测定;荧光检测器激发波长226nm处,发射波长305nm处检测吸光度,同等条件下绘制工作曲线,莱克多巴胺含量与吸光度值在一定浓度范围内成正比,试样与工作曲线比较定量。经试验,应用HPLC法检测饲料中莱克多巴胺,标准曲线r值≥0.998732;变异系数(CV值)≤0.57%;检测回收率:82.8%～95.6%;回收率标准偏差≤1.0%。 相似文献
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魏静 《四川畜牧兽医学院学报》2009,(4):28-32
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。 相似文献
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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。 相似文献
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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。 相似文献
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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. 相似文献
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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. 相似文献