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为探明鸭坦布苏病毒对产蛋鸡的致病性和不同感染途径对其产蛋性能的影响,分别选用罗曼蛋鸡、海兰蛋鸡和淮南麻黄鸡3个品种进行人工接种病毒试验。结果表明,3个品种产蛋鸡接种病毒后均出现产蛋下降,产蛋率最高下降80%以上,除产蛋和早期采食量下降及后期严重脱羽外,感染鸡无其他临床症状,产蛋恢复的速度和程度不同品种间存在一定差异,感染后无鸡只死亡;滴鼻组和同居组鸡群产蛋下降和恢复的程度低于肌肉注射组,重复感染组未发生明显产蛋下降;剖检病变可见一致的卵巢组织出血、变性、坏死和萎缩,其他器官无肉眼可见病变;从感染鸡卵巢组织中可检测到鸭坦布苏病毒核酸。综上所述,鸭坦布苏病毒对不同品种产蛋鸡均具有致病性,主要引发产蛋下降,病毒在鸡群中的传播可能不仅限于吸血昆虫,空气传播感染也是其重要的传播途径;感染康复鸡只对再次感染具有一定的抵抗力。研究结果为产蛋鸡不明原因产蛋下降提供了新的诊断方向,为坦布苏病毒病的有效防控发出了预警信号。 相似文献
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《云南畜牧兽医》2020,(1)
宜良县某鸭场产蛋期樱桃谷母鸭群出现产蛋异常,对发病鸭群进行了病理剖检以及细菌分离培养、主要疫病血清学抗体的检测和病原核酸的RT-PCR检测与分析。结果显示所检样品无大肠杆菌、沙门氏菌等细菌感染;ND、H5、H7、H9抗体水平没有异常变化,A型流感病毒、新城疫病毒RT-PCR检测结果均呈阴性;鸭坦布苏病毒RT-PCR检测结果阳性,样品PCR产物测序分析显示该核酸序列来源于DTMUV基因组,表明该样品感染了坦布苏病毒。结合临床症状、剖检变化、实验室检测结果以及针对感染鸭坦布苏病毒的防治措施与效果观察,诊断该鸭场产蛋下降的异常情况是由鸭坦布苏病毒感染所引起的。 相似文献
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《中国兽医学报》2017,(12)
为了明确持续低产蛋率开产蛋鸭群的主要病毒病感染情况,应用已建立的间接ELISA方法和血凝抑制试验对2013年1月至2015年10月采自福建、广东、广西、江西、浙江、江苏和安徽等7省(区)免疫过H5亚型和H9亚型禽流感灭活疫苗但未免疫禽1型副黏病毒病疫苗和禽坦布苏病毒病疫苗,表现为持续低产蛋率的29个开产蛋鸭群的4 737份血清样品进行抗体检测,同时采集蛋鸭卵巢组织进行RT-PCR检测。结果显示,29个开产蛋鸭群中,H5亚型禽流感、H9亚型禽流感、禽1型副黏病毒病和禽坦布苏病毒病抗体的群阳性率分别为100.0%,100.0%,10.3%和100.0%,群内阳性率分别为79.4%~100.0%,82.5%~100.0%,0.0%~13.1%和33.7%~100.0%;蛋鸭卵巢组织中H5亚型禽流感病毒、H9亚型禽流感病毒、禽1型副黏病毒和禽坦布苏病毒的阳性率依次为13.8%(4/29),0.0%(0/0),3.5%(1/29)和86.2%(25/29)。上述结果表明,我国以上7省(区)表现持续低产蛋率的开产蛋鸭群存在禽坦布苏病毒的严重感染,应引起养鸭生产者的高度重视。 相似文献
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《养殖与饲料.饲料世界》2021,(9)
本研究采集疑似感染鸭坦布苏病毒的蛋鸭卵巢病变组织,经RT-PCR鉴定其结果为鸭坦布苏病毒阳性。将组织处理液接种到SPF鸡胚并盲传3代后成功分离到1株鸭坦布苏病毒,连续传代10代后,病毒含量达到10~(5.0)ELD_(50)/m L。为建立鸭坦布苏病毒病的发病模型,将分离到的鸭坦布苏病毒腿部肌肉接种蛋鸭,每日对鸭只采血并对分离的血清进行病毒分离,摸索鸭坦布苏病毒病的病毒血症规律;另外每日随机挑选10只感染鸭进行剖杀,观察卵泡病变情况,摸索卵泡病变规律。结果显示,感染鸭只第1~3日血清中病毒分离率均为100%,第4日病毒血症阳性率开始下降,第6日病毒血症消失;感染鸭只卵泡第3日开始出现变形、破裂或出血等病理变化,第8~10日病变率达到100%。本研究建立了一种鸭坦布苏病毒感染产蛋鸭的发病模型并确定了发病评判标准,为鸭坦布苏疫苗的免疫效果评价提供了基础。 相似文献
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为了检测鸭群中鸭坦布苏病毒的血清学流行情况,本研究在前期成功表达鸭坦布苏病毒NS1蛋白的基础上,建立了检测鸭血清中鸭坦布苏病毒抗体的间接ELISA方法。棋盘法确定了当纯化的NS1蛋白包被量为0.188μg/孔,待检血清1:200稀释,HRP标记的兔抗鸭二抗1:16000倍稀释时反应条件最佳。在最佳反应条件下,阴阳性临界值判定标准为0.467。用建立的间接ELISA方法对番鸭细小病毒、鹅细小病毒、鸭肝炎病毒、鸭疫里默氏杆菌阳性血清进行了检测,均无交叉反应,表明该方法具有良好的特异性。批内和批间重复试验的最大变异系数分别为6%和10%,显示该方法具有很好的稳定性。用建立的ELISA方法检测临床鸭坦布苏病毒感染鸭及攻毒蛋鸭的55份临床血清样品,测得52份为阳性,阳性率为94.5%,对36份阴性鸭群血清样品进行检测,36份为阴性,阴性率为100%。该方法为鸭坦布苏病毒的诊断和流行病学监测奠定了基础。 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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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
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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. 相似文献