鸡群免疫失败原因分析

发展养鸡业最大的威胁是鸡病，特别是某些烈性传染病，如鸡瘟、鸡马立克氏病、鸡传染性法氏囊炎等，一旦发生常常对鸡群会造成毁灭性的危害，搞好疾病预防是发展养鸡业的重要保证，而免疫接种具有关键性的作用。在畜牧生产实践中，接种疫苗后未能获得满意的免疫效果则时有发生，原因是多方面的。笔者就其原因浅析如下，供同仁参考。1疫苗生产、运输或保有失误所致的疫苗质量不佳疫苗质量不合标准，如病毒含量不足、冻干不佳、密封不严、氢氧化铝性剂颗粒过粗等。疫苗在运输或保管过程中温度过高或过低，阳光直射，或超过有效保存期等因素所…     

浅析鸡群免疫失败的原因

鸡群免疫是预防鸡群发生传染病的生重要技术环节。但在实践中,由于种种原因,导致鸡群免疫失败,给养鸡业主造成很大的经济损失。主要原因有疫苗质量差、疫苗保存和运输不当、免疫程序不合理、鸡群健康状况差。现结合工作实践,对上述各方面逐一浅析,并提出相应对策。     

引起鸡群免疫失败的因素透析

疫苗的质量差疫苗不是正规生物制品厂生产，质量不合格或已过期失效。疫苗因运输、保存不当或疫苗取出后在免疫接种前受到日光的直接照射，或取出时间过长，或疫苗稀释后未在规定时间内用完，影响疫苗的效价甚至失效。     

鸡群免疫失败原因及防制对策

免疫接种是用人工的方法把有效的生物制剂(疫苗、菌苗、类毒素、高免血清等)引入动物体内,从而激发动物机体产生特异性抵抗力,使对某一病原微生物易感的动物转化成为对该病原微生物具有抵抗力,从而避免疫病的发生及流行。目前,疫苗的广泛应用已大大减少了养禽业的风险,但在     

鸡群免疫失败原因分析

在给鸡群实施主动免疫后又发生该种传染病时，我们称其为免疫失败。这种现象经常有一些饲养户反映，为什么会出现免疫失败呢，主要有如下几个原因。     

鸡群免疫失败的原因及对策

疫苗接种是预防传染病的有效方法之一,但是免疫接种能否获得成功,受许多因素的影响,接种过疫苗的鸡群不一定都能产生坚强的免疫力。近年来,一些免疫鸡群常常发生传染病,使养鸡生产者蒙受巨大的损失。笔者根据生产实践和调查分析,现就引起鸡群免疫失败的因素及防制对策综述如下: 1 造成免疫失败的因素 1．1 疫苗及稀释剂存在质量问题疫苗来源不正规,疫苗不是正规生物制品厂生产,质量不合格或已     

采取综合性措施预防免疫失败

要想避免鸡群免疫失败,就必须针对引起鸡群免疫失败的原因,考虑到每一个影响环节,做好每一个细节工作,才能真正保证鸡群免疫接种的效果,将免疫失败带来的经济损失降低到最低程度。     

鸡群免疫失败的原因及防治对策

<正> 近年来,一些鸡场虽然免疫了各种各样的疫苗,但还是不断的爆发传染病,给养鸡场造成很大的损失,究其原因,很多、很复杂,但主要有以下几方面的因素:1 环境方面的因素1.1 鸡群潜在感染免疫抑制性疾病与免疫包括马立克氏病、淋巴细胞白血病、鸡传染性贫血病、传染性法氏囊、腺病毒感染等。这些传染性病原体主要是侵袭、损害鸡的体液或细胞免疫中枢器官,使其淋巴细胞生成受到破坏、降低或不能产生免疫球蛋白,导致免疫机能障碍,使鸡群对疫苗接种的应答反应性降低,越是早期感染者应答反应越是明显,表现鸡群对多种其他疾病的易感性增强,出现免疫抑制现象。1.1.1 马立克氏病(MD)是由 B 型疱疹病毒引起的主要侵害鸡的一种肿瘤病,其特点是肿瘤细胞、多型细胞和淋巴细胞在神经干和内脏器官的浸润。马立克氏病毒具有干扰素原性和大的免疫抑制性,因此,马立克氏病常常伴有其他传染病的联合发生。MDV 感染的结果使法氏囊、胸腺和脾脏这些一级中枢免疫器官产生退行性变化,从而损伤了鸡体的免疫反应并导致免疫抑制。     

鸡群免疫失败原因浅析

近年来由于养鸡业集约化、规模化生产程度的提高，但防疫滞后，鸡群中新的疫病逐渐增多，严重影响养鸡业的发展和生产者的经济效益，因此鸡群免疫工作极为重要。鸡群免疫是指利用疫（菌）苗预防接种，让鸡体内产生对病原体的特异性抗体，提高鸡体抵抗力，保护鸡免受相对应的传染病危害。接种免疫是预防鸡传染病最重要的手段，但由于多种因素干扰，造成免疫应激、免疫力下降，甚至出现免疫失败，而使养鸡者蒙受极大的经济损失。几年来本人在鸡的免疫接种工作中对鸡群免疫失败原因进行了分析总结，现综述如下，供同行参考：１疫苗质量问题１．…     

如何促进生猪生产节本增效

如何从生产环节挖潜增效,降低成本,以较少的人力、物力,获得最佳的经济效益,是每个养猪人当前都在思考的问题。下面笔者从品种、饲料、环境、管理、防疫等五大技术环节探讨降低养殖成本应把握的关键技术措施。     

“六措施”提高动物防疫质量

随着动物防疫机制的健全,动物防疫率、免疫密度不断提高.在日常防疫工作中,也存在一些问题亟待解决.笔者就如何提高动物防疫质量,提出六点措施,供探讨.     

商用鸡免疫系统的评估

健康的鸡只在正常情况下会有良好的生产性能表现.但是,要养好健康的鸡群,则有赖于许多因素.这些因素包括管理、营养、免疫计划,而最重要的是有赖于免疫系统的健全发育.免疫系统的发育会受到数种病毒及非病毒因素的影响.在病毒方面,传染性法氏囊病病毒(IBDV)、马立克氏病病毒(MDV)、里奥病毒(REO)、鸡传染性贫血病病毒(CAV)、禽白血病病毒(ALV)等数种为引起免疫抑制的主要病毒.     

鸡群免疫失败原因浅析

１免疫程序不合理首免日龄过早易受雏禽高母源抗体水平的影响。养殖户一定要根据本地区疫病流行的情况、种鸡免疫情况和鸡体抗体水平等实际情况，制定切合实际的免疫程序，绝不能机械照搬他人的免疫程序，尤其是不能照搬外国的免疫程序，要获得合理正确的免疫程序，最好是请当地兽医技术部门确定。严格执行，并在生产实践中不断完善。２疫苗的质量问题免疫接种必须使用质量可靠的产品，但由于疫苗极易因运输、保存等不当而造成效价降低乃至失效，另外，疫苗毒力、免疫原性差以及生产工艺不合理等因素都可造成疫苗的质量不合格。因此应选择国…     

提高养鸡生产经济效益的技术措施

养鸡户缺乏科学的饲养管理技术，饲养工艺设计不合理，饲料营养浪费，重治不重防，滥用药物，导致治疗效果不佳，死淘率升高，甚至发生中毒等。已成为我国养鸡生产中较为普遍的问题，加上市场波动，直接影响养鸡业的经济效益。严重挫伤了养殖户的积极性。尤其是广大农村，水平低，投入高，效益差的“穷养鸡”方式一度存在。因此。科学的管理，最大限度降低养殖成本，是提高养鸡生产经济效益、确保养鸡业健康发展的重要举措。     

Cost-effectiveness of measures to prevent classical swine fever introduction into The Netherlands

Recent history has demonstrated that classical swine fever (CSF) epidemics can incur high economic losses, especially for exporting countries that have densely populated pig areas and apply a strategy of non-vaccination, such as The Netherlands. Introduction of CSF virus (CSFV) remains a continuing threat to the pig production sector in The Netherlands. Reducing the annual probability of CSFV introduction (P_CSFV) by preventive measures is therefore of utmost importance. The choice of preventive measures depends not only on the achieved reduction of the annual P_CSFV, but also on the expenditures required for implementing these measures. The objective of this study was to explore the cost-effectiveness of tactical measures aimed at the prevention of CSFV introduction into The Netherlands. For this purpose for each measure (i) model calculations were performed with a scenario tree model for CSFV introduction and (ii) its annual cost was estimated. The cost-effectiveness was then determined as the reduction of the annual P_CSFV achieved by each preventive measure (ΔP) divided by the annual cost of implementing that measure (ΔC). The measures analysed reduce the P_CSFV caused by import or export of pigs. Results showed that separation of national and international transport of pigs is the most cost-effective measure, especially when risk aversion is assumed. Although testing piglets and breeding pigs by a quick and reliable PCR also had a high cost-effectiveness ratio, this measure is not attractive due to the high cost per pig imported. Besides, implementing such a measure is not allowed under current EU law, as it is trade restrictive.     

雏鸡呼吸困难原因的探讨及控制对策

随着养鸡向集约化发展,饲养密度高、环境复杂,鸡群在育雏阶段极易感染传染病,尤其是呼吸道病。引起雏鸡发生呼吸道疾病的原因较为复杂,本文初步探讨了雏鸡发生呼吸道病的原因及防控对策,以提高雏鸡成活率和肉鸡生产成绩。     

Immune response to liposome-associated recombinant SEF21 following oral immunization in chickens

In order to generate Salmonella enterica serovar Enteritidis fimbriae antigens (rSEF21), the intact region encoding SEF21 was amplified from Salmonella Enteritidis by PCR and subcloned into a prokaryotic expression vector pET-28a(+) to yield pET-28a(+)-SEF21. The rSEF21 protein was highly expressed and purified by nickel affinity chromatography. Liposomeassociated rSEF21 was prepared for oral immunization to seek protective efficacy for intestinal infection with Salmonella Enteritidis. Evidence of IgA and IgG responses were found in the intestinal tracts and in the sera of a group of chickens immunized. Two weeks after the booster immunization, the chickens were challenged orally with 2 x 10(6) colony-forming units of live Salmonella Enteritidis, and fecal samples were examined for bacterial excretion from the intestinal tract. Significantly less fecal excretion of bacteria was observed in immunized chickens for 4 wk after challenge. The numbers of bacteria in the intestinal contents (cecum and rectum) were also significantly lower in immunized chickens than in unimmunized controls. Therefore, oral immunization with liposome-associated rSEF21 elicits both systemic and mucosal antibody responses, leading to a reduction in bacterial colonization in the intestinal tract and excretion of Salmonella Enteritidis in the feces.     

减缓肉鸡热应激的措施

我国大部分地区夏季炎热期达３个月之久,长江以南地区高温持续时间更长,严重影响肉鸡生产。现就热应激的减缓措施简介如下。１降低鸡舍小环境温度１．１在进风口处设置水帘使热空气经冷却后进入鸡舍,可在温度升高之前打开水帘,下午温度降低后关闭,这样可使舍内温度降低４℃～８℃。１．２三伏天喷雾采用高压低雾量旋转嘴喷雾器,向鸡舍顶部或鸡体直接喷凉水,每２～３ｈ一次,可降低舍温４℃～８℃。１．３鸡舍屋顶涂白可使舍温降低８℃～９℃,肉鸡成活率提高２３％。白色涂料的配方是石灰９．１ｋｇ。水９．１Ｌ、聚醋乙烯１Ｌ。１．…     

Passive immunization to reduce Campylobacter jejuni colonization and transmission in broiler chickens

Campylobacter jejuni is the most common cause of bacterium-mediated diarrheal disease in humans worldwide. Poultry products are considered the most important source of C. jejuni infections in humans but to date no effective strategy exists to eradicate this zoonotic pathogen from poultry production. Here, the potential use of passive immunization to reduce Campylobacter colonization in broiler chicks was examined. For this purpose, laying hens were immunized with either a whole-cell lysate or the hydrophobic protein fraction of C. jejuni and their eggs were collected. In vitro tests validated the induction of specific ImmunoglobulinY (IgY) against C. jejuni in the immunized hens’ egg yolks, in particular. In seeder experiments, preventive administration of hyperimmune egg yolk significantly (P < 0.01) reduced bacterial counts of seeder animals three days after oral inoculation with approximately 10⁴ cfu C. jejuni, compared with control birds. Moreover, transmission to non-seeder birds was dramatically reduced (hydrophobic protein fraction) or even completely prevented (whole-cell lysate). Purified IgY promoted bacterial binding to chicken intestinal mucus, suggesting enhanced mucosal clearance in vivo. Western blot analysis in combination with mass spectrometry after two-dimensional gel-electrophoresis revealed immunodominant antigens of C. jejuni that are involved in a variety of cell functions, including chemotaxis and adhesion. Some of these (AtpA, EF-Tu, GroEL and CtpA) are highly conserved proteins and could be promising targets for the development of subunit vaccines.