鸡球虫苗(LCV-2号)安全性和免疫效果研究

在实验条件下,研究了鸡球虫苗LCV-2号对笼养鸡的安全性和免疫保护效果。试验设空白对照组、攻虫对照组、免疫1组(1个免疫剂量)、免疫2组(2个免疫剂量)和免疫3组(0.5个免疫剂量),共5个试验组,每组10只鸡。试验结果表明:①空白对照组、攻虫对照组和三个免疫组的相对增重率依次为100%、84.0%、96.9%、91.0%和91.0%;②攻虫后第8 d,每组剖检2只鸡,肠道病变记分5个组依次为0、4、1、3和4分。③免疫期间,免疫1、2和3组的每克粪便卵囊数(OPG)平均值依次为4.2×10~3个、9.2×10~3个和5.4×10~3个;攻虫期间,攻虫对照组5.117×10~5个、免疫1、2和3组依次为0.797×10~5个、0.522×10~5个和1.171×10~5个。④攻虫后各组死亡率依次为0、75%、25%、25%和50%。⑤抗球虫指数(ACI),5个组依次为200.0、88.0、166.9、148.5和120.0。总的来看,免疫鸡群对大剂量卵囊攻击有较强的抵抗力,其中免疫1组结果良好,免疫2组和3组结果尚不理想,因此,LCV-2免疫1组的剂量(1头份卵囊/只)为优选剂量。     

强效艾美耳牌鸡球虫苗的免疫效果

在实验条件下,研究了强效艾美耳牌鸡球虫苗对平养鸡群的免疫效果。实验１比较了免疫鸡群和对照鸡群在接种后１、２、３、４、５、６周的肠道病变分,结果表明免疫鸡群较自然感染建立免疫的对照鸡群的免疫整齐度高,判断依据是免疫后２周盲肠细小、内容物亦少的眼观指标。实验２比较了免疫鸡群、不免疫不用药鸡群、不免疫用药鸡群在攻虫后的三处肠道病变,结果表明免疫鸡群对大剂量卵囊攻击有很强的抵抗力。实验３比较了免疫鸡群、不     

鸡球虫致弱虫苗的免疫效果及其使用方法

随着我研究所对鸡球虫致弱虫苗的研究成功及推广,养鸡生产单位使用球虫苗后,降低了生产成本,节省了球虫病预防用药费用。鸡球虫虫苗从1988年7月至1990年6月先后在上海、江苏、浙江、安徽、河北、广州、新疆、武汉等15个省市部分鸡场应用,免疫鸡数达678万余羽,保护率高达98％以上,取得了很好的经济效益。     

四价鸡球虫苗的免疫效果研究

在实验条件下观察自主研制的四价鸡球虫苗(LCV)对平养鸡的安全性和免疫保护效果.试验设空白对照组(NC)、攻虫对ECX(PC)和免疫组(VC)3个试验组,每组30只鸡.试验结果:空白对照组、攻虫对照组和免疫组的相对增重率依次为100%、84.77%和94.97%;免疫后(免疫后攻虫前)排卵囊高峰期间(免疫后5 d～10 d),免疫组平均OPG(即每克粪便申的卵囊数)为2.70 X 104,攻虫后排卵囊高峰期间(攻虫后6 d～13 d)攻虫对照组组平均OPG为2.32 X 106,高于免疫组(2.69 X 103)(P<0.01);攻虫后各组死亡率依次为0、10%和o;3个组的ACI(抗球虫指数)分别为200,0、154.77和184.97,免疫组试验效果最佳.结果表明,LCV安全性高、免疫保护效果理想.接种该疫苗后的鸡对较大剂量攻虫具有较强的抵抗力.     

鸡球虫苗的研究进展

由于抗药性和研制新药成本增加，周期延长，药物使用中存在的一些问题，促进了免疫学防治的发展，利用鸡球虫苗来控制鸡球虫病成为一种有效途径，通过对鸡球虫苗的种类，作用特点，研究概况等方面的论述，进一步提出该虫苗的应用前景及展望，为更好地防治鸡球虫提供科学依据。     

强效艾美尔康牌鸡球虫苗鸡体免疫毒力及安全范围的测定

本试验进行鸡体强效艾美尔球虫苗生物免疫毒力、安全范围的测定。试验分两个阶段,共１００ 只鸡。第一阶段对３ 日龄雏鸡分组免疫,隔离饲养。１,２,３,４,５,６ 个组分别予以标准剂量,５,１０,２０,３０、４０ 倍剂量免疫,第７ 组为空白对照组,６ ｄ 后剖杀部分鸡只,观察到１ 倍、５ 倍剂量组没有病变或病变很轻微,１０ 倍、２０ 倍病变很轻,３０ 倍、４０ 倍剂量组发现轻度病变,但病变程度不可忽视;空白组和标准剂量组及 ５倍剂量组鸡只在增重上无显著差异。第二 阶段是首免后第１６ ｄ,将首免１ 倍剂量剩余鸡只又分为７ 组,分别予以标准剂量,５,１０、２０,３０,４０ 倍剂量免疫,第７ 组为免疫空白对照组,首免空白组剩余鸡只为第８组,做空白组,６ ｄ 剖杀,发现标准剂量组基本上无病变,５、１０ 倍组病变很轻微,２０、３０、４０ 倍组病变也很轻,且病变程度不一,基本上对鸡体没什么影响;８ 组鸡只在增重上无显著差异。     

鸡球虫微囊型疫苗的研制及免疫效果

研制了微囊型鸡球虫疫苗并对其免疫效果进行探讨。结果表明,强毒微囊组获得的饲养效果最好,其相对增重率和相对饲料转换率分别为104.8%和100%;弱毒水剂组为74.1%和136%,而弱毒微囊组为49.4%和188%。强毒微囊组对球虫病的控制效果也明显好于其他组,其发病率、病变记分、血便记分分别为20%,6分和3分,而弱毒水剂组和弱毒微囊组分别为40%、10分、7分和50%、18分、8分。所研制的这种新型微囊球虫疫苗,具有使用方便,节省人力物力;疫苗大小适中,流动性好容易与小鸡饲料混合均匀等优点。由于微囊型球虫疫苗投服方便,因此能适合各种规模的鸡场使用,也适合鸡场进行多次或长期免疫使用。这种微囊剂型球虫疫苗的进一步完善和推广应用,可为我国鸡球虫病的免疫预防提供新的剂型。     

强效艾美耳鸡球虫苗使用效果观察

多年来,鸡球虫病一直是困饶我市养鸡业发展的一大难题,是影响鸡存活率和生产水平的主要疾病之一。许多养鸡场和养鸡专业户试图用高效药物和环境卫生控制彻底消除鸡体内和养鸡场地中的球虫卵囊而达到控制球虫病的目的,非但效果不理想,而且往往造成球虫病暴发。作者也曾试图通过控制环境中卵囊含量,利用少量的自然界野毒卵囊实现机体的自身免疫,但效果也不满意,因为感染量、用药量以及时间很难掌握。目前我市大部分养鸡场、户还是依赖药物防制球虫病,但因耐药性问题的严重,常常出现药物控制下仍有球虫病暴发的事件。因此鸡球虫苗的研…     

鸡混合联苗免疫效果的研究

鸡混合联苗免疫效果的研究康吉克孜钟旗玛依拉蔡宏（新疆畜牧科学院兽医研究所，乌鲁木齐８３００００）林承业赵雪梅李在兰（新疆华新牧工商公司）由于禽传染病种类的增加，用于免疫接种的疫苗种类也日益增多，而且有的疫苗还要做多次免疫，这必然增加免疫环节，给免疫接...     

鸡球虫病早熟弱毒苗实验室应用研究

鸡球虫病是一种全球性的原虫病 ,它是集约化养鸡业最为多发、严重和防治困难的疾病之一 ,其发病率高达 5 0 %～ 70 % ,死亡率为 2 0 %～ 30 % ,严重者可达 80 %。我国是养鸡大国 ,占世界总养鸡量的 1 /1 0 ,每年因鸡球虫病造成的直接和间接经济损失难以估量。迄今为止 ,鸡球虫病的防治主要依赖药物预防 ,但目前药物防治球虫病遇到了两大问题的困扰 ,首先是球虫极易产生抗药性 ,其次是药物残留 ,一些国家对禽肉、蛋制品中球虫药含量有着严格的限制 ,我国已加入 WTO,解决禽蛋制品的药物残留问题已成当务之急。因此利用免疫预防来代替药物防…     

鸡球虫病四价活疫苗对毒害艾美耳球虫和柔嫩艾美耳球虫的免疫效果观察

为评价一种商品化鸡球虫病四价活疫苗[柔嫩艾美耳球虫(E.tenella)、毒害艾美耳球虫(E.necatrix)、巨型艾美耳球虫和堆型艾美耳球虫]对E.necatrix和E.tenella的免疫保护效果,本研究基于试验鸡血便记分、存活率、相对增重率、病变值、卵囊值及抗球虫指数(ACI)等指标对其免疫效果进行检测.结果表明,免疫攻虫组抗E.necatrix和E.tenella的ACI分别为157.3和135.6,均低于160,表明该球虫疫苗抗两种球虫的效果均为低效.然而,免疫攻虫组鸡血便数量、血便记分、增重、卵囊产量和病变记分等指标均优于阳性对照组.综合指标显示,该疫苗对E.necatrix和E.tenella具有一定的免疫保护力,但单纯采用疫苗并不能够达到防控鸡球虫病的目的.     

Efficacy of a novel in ovo-attenuated live vaccine and recombinant vaccine against a very virulent infectious bursal disease virus in chickens

Infectious bursal disease (IBD) causes severe economic damage to the poultry industry worldwide. To prevent IBD virus (IBDV) infection, live virus vaccines have been widely used in chickens having wide-ranging levels of maternally derived antibodies. But, the risks of infection with other pathogens because of lesions related to atrophy of the bursa of Fabricius in vaccinated chickens are a concern. To resolve the problems, a recombinant turkey herpesvirus (HVT) vaccine expressing IBDV-VP2 protein (rHVT-IBD) has been developed. However, the induction of neutralizing antibodies by rHVT-IBD against a virulent IBDV might be delayed compared with that by the live IBD vaccine, leading to the high risks of IBDV infection for young chickens. To find the best selection of IBDV vaccine for the onset of immunity, we examine the protective efficacy of a novel in ovo-attenuated live IBDV (IBD-CA) vaccine and the rHVT-IBD vaccine in young chickens challenged with a very virulent IBDV (vvIBDV) strain. We show that the protective efficacy of IBD-CA vaccine was higher than that of the rHVT-IBD vaccine in 14-day-old chickens challenged with the vvIBDV strain, leading to the risk of IBDV infection for young chickens when vaccinated with rHVT-IBD. Our results suggest that farmers should select the best vaccines to maximize vaccine efficacy in consideration of the vaccine characteristics, prevalence levels of IBDV in the areas, and initial MDA levels of the chickens since the attenuated live and recombinant vaccines play a role in the different vaccine efficacies.     

Efficacy of an oral live vaccine for veterinary use against pseudotuberculosis

Pseudotuberculosis, an infection caused by the ubiquitous enteropathogenic bacterium Yersinia pseudotuberculosis, is a recurrent veterinary problem in livestock and zoo animals. The only vaccine currently available in zoos is Pseudovac (a mixture of killed strains of various serotypes), but its efficacy is not well established. We show here that Pseudovac does not protect guinea pigs against a severe Y. pseudotuberculosis infection. We thus evaluated the possibility of using a live attenuated Y. pseudotuberculosis strain (IP32680) as an oral vaccine against animal pseudotuberculosis. We report that IP32680 is avirulent for guinea pigs and induces a strong IgG response against various serotypes of Y. pseudotuberculosis. One and two oral inoculations of IP32680 provided 50% and 83% protection, respectively against a severe infection with a highly pathogenic strain. The avirulent Y. pseudotuberculosis IP32680 is therefore much more protective than Pseudovac and may represent a valuable oral vaccine against pseudotuberculosis in zoo animals.     

Co-expression of EtMic2 protein and chicken interleukin-18 for DNA vaccine against chicken coccidiosis

In the present study, a naked EtMIC2 DNA vaccine, a ChIL-18 expression vector and a EtMIC2 and ChIL-18 co-expression DNA vaccine were constructed and their protective efficacies against homologous challenge were compared and evaluated by examining the body weight gain, oocyst shedding, cecal lesion, ACI as well as specific anti-EtMic2 antibody level, the proliferation ability and percentages of CD4+ and CD8+ of splenocytes. The results showed the naked EtMIC2 DNA vaccine could increase the weight gain and decrease the oocyst shedding, but could not alleviate the cecal lesion of immunized chickens compared to unimmunized chickens. Chickens immunized with the co-expression vector pVAX1-MIC2-IL-18 exhibited much improved immune protection against challenge compared to chickens immunized with naked EtMIC2 DNA vaccine, or with naked EtMIC2 DNA vaccine and ChIL-18 expression vector applied separately. These results suggest that the co-expression of ChIL-18 with EtMic2 together could significantly improve the immune protection of the EtMic2 protein.