鸡胚接种柔嫩艾美耳球虫和堆形艾美耳球虫活卵囊的免疫保护试验

给18日龄鸡胚接种一定剂量的柔嫩艾美耳球虫(Eim eria tenella)和/或堆形艾美耳球虫(E.acervulina)孢子化卵囊,出雏后在无球虫环境中笼养,1~10日龄每天收集各组粪便样本,计数克粪便卵囊数(OPG),并于14日龄时以大剂量同源孢子化卵囊攻虫,以相对增重率(RWG)、饲料转化率(FCR)、相对卵囊产量(ROP)评价免疫保护效果。结果显示,以E.tenella或E.acervulina卵囊免疫18日龄鸡胚,其卵囊排出的潜隐期及达到峰值的时间与1日龄雏鸡接种组相一致,有相似的排卵囊曲线,提示其诱导免疫的建立是在出雏后开始建立的。攻虫后各免疫组的RWG由攻虫对照组的31.9%~51.7%提高到了76.5%~83.6%,RCR由攻虫对照组的4.11~4.89改善为2.72~2.96,ROP降至4.7%~23.5%。结果表明以一定剂量E.tenella和E.acervulina卵囊单独或混合经羊膜腔免疫18日龄鸡胚都可以建立起针对出雏后14日龄同源攻虫的良好免疫保护力。比较混合免疫E.tenella和E.acervulina卵囊组与单一接种E.tenella或E.acervulina卵囊组的免疫效果发现,混合免疫组的各项指标均稍优于后者。     

Vaccination of chickens with DNA vaccine expressing Eimeria tenella MZ5-7 against coccidiosis

A chimeric DNA vaccine co-expressing Eimeria tenella MZ5-7 and chicken IL-17 gene was constructed and its efficacy against E. tenella challenge was evaluated. The ORF of MZ5-7 from E. tenella's second generation merozoite and the mature interleukin 17 gene of chicken were cloned into the expression vector of pcDNA4.0 to construct DNA vaccine pcDNA4.0-MZ and pcDNA4.0-MZ-IL17. The expression of aim gene products in vivo was detected by western blotting. The expression of IL-2 and IFN-γ in chicken splenocytes was detected by RT-PCR 7 days post-immunization. The expression levels of the two cytokines in the pcDNA4.0-MZ-IL17 DNA vaccine immunized group were significantly higher than that in the pcDNA4.0-MZ immunized group (p<0.05). Either pcDNA4.0-MZ or pcDNA4.0-MZ-IL17 DNA vaccine could obviously alleviate cecal lesions, body weight loss and increase oocyst decrease ratio. The ACI of pcDNA4.0-MZ-IL17 group was 190, which is higher than that of pcDNA4.0-MZ group and all the three control groups. In short, MZ5-7 was an effective candidate antigen for vaccine and co-expression of cytokine with antigen was an alternative method to enhance the immunity DNA vaccine.     

Immunization with Eimeria ninakohlyakimovae-live attenuated oocysts protect goat kids from clinical coccidiosis

Caprine coccidiosis, affecting mainly young goat kids around the weaning period, is worldwide the most important disease in the goat industry. Control of caprine coccidiosis is increasingly hampered by resistances developed against coccidiostatic drugs leading to an enhanced need for anticoccidial vaccines. In the current study we conducted an oral immunization trial with live attenuated sporulated Eimeria ninakohlyakimovae oocysts. Sporulated E. ninakohlyakimovae oocysts were attenuated by X-irradiation technique. The experimental design included a total of 18 goat kids divided into the following groups: (i) animals immunized with attenuated E. ninakohlyakimovae oocysts at 5 weeks of age and challenged 3 weeks later with non-irradiated homologous oocysts (group 1); (ii) animals infected with non-attenuated E. ninakohlyakimovae oocysts at 5 weeks of age and challenged 3 weeks later with non-attenuated homologous oocysts (group 2); (iii) animals primary-infected with untreated E. ninakohlyakimovae oocysts at 8 weeks of age (control of the challenge infection, group 3); (iv) non-infected control animals (group 4). Goat kids immunized with live attenuated E. ninakohlyakimovae oocysts (group 1) excreted significantly less oocysts in the faeces (95.3% reduction) than kids infected with non-attenuated ones (group 2). Furthermore, immunization with live but attenuated oocysts resulted in ameliorated clinical coccidiosis compared to goat kids infected with untreated oocysts (group 2) and resulted in equally reduced signs of coccidiosis after challenge infection compared to acquired immunity driven by non-attenuated oocysts. Overall, the present study demonstrates for the first time that live attenuated E. ninakohlyakimovae oocysts orally administered showed almost no pathogenicity but enough immunogenicity in terms of immunoprotection. Importantly, vaccinated animals still shed low amounts of oocysts, guaranteeing environmental contamination and consecutive booster infections to sustain ongoing immunity.     

Column chromatographic characterization of cytoplasmic proteins in Eimeria maxima oocysts from chickens

Cytoplasmic proteins from unsporulated and sporulated Eimeria maxima oocysts were analyzed by gel-filtration column chromatography. Unsporulated oocysts were characterized as having 3 major cytoplasmic proteins and sporulated oocysts as having 5 major cytoplasmic proteins. Molecular weights ranged from 5 x 10(3) to 1.4 x 10(6). Larger molecular weight proteins were detected in sporulated and unsporulated oocysts, but were associated more with sporocysts of sporulated oocysts.     

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.     

Acquisition of immunity to Eimeria maxima in newly hatched chickens given 100 oocysts

The acquisition of immunity to Eimeria maxima by chicks infected 18 hr after hatch with a single dose of 100 oocysts was investigated. In the first experiment, birds were moved each day to clean cages in order to prevent the possibility of secondary infection resulting from ingestion of oocysts passed in their feces. Immunity was measured at 4 wk of age by calculation of oocyst production following challenge with 500 oocysts or weight gain following challenge with 100,000 oocysts. Large numbers of oocysts were produced by infected birds following challenge, although numbers were significantly less than those from birds that had been reared in the absence of infection (susceptible controls). The weight gain of infected birds following challenge was significantly greater than that of susceptible controls but less than that of unchallenged controls. Thus, only partial protection had been acquired, whether parasite replication or body weight gain was used to assess the extent of immunity development. In a second experiment, acquisition of immunity at 4 wk by chicks infected 18 hr after hatch with 100 oocysts of E. maxima and reared in floor pens in contact with their droppings was investigated. Infected birds produced no oocysts following challenge, and weight gains were not significantly different from the unchallenged controls, which indicates that full immunity had developed by 4 wk. It is concluded that if oocysts of Eimeria species are used to vaccinate day-old chicks, reinfection by oocysts present in the litter is necessary for the establishment of protective immunity.     

海南霉素对鸡球虫病的预防和治疗效果评价

为评价海南霉素对鸡球虫病的防治效果 ,作者用海南霉素和马杜拉霉素分别进行了抗鸡球虫病的预防和治疗试验。二个试验各设 7个组 ,每组 12羽 17日龄 AA肉鸡 ;在 18日龄 ,除不感染组外 ,每羽鸡接种柔嫩艾美耳球虫孢子化卵囊 6万 ;药物组分别在感染前 1天和感染后第 4天 ,开始投服含药饲料 ;感染后第 8天结束试验 ,以抗球虫指数、病变记分、卵囊数、粪便记分等作为试验指标。结果在预防试验中 ,海南霉素的平均抗球虫指数为 182 ,病变记分减少 96 % ,粪便和盲肠卵囊数减少 98% ,粪便记分为 0 ;在治疗试验中 ,海南霉素的平均抗球虫指数为 14 6 ,病变记分减少 33% ,粪便和盲肠卵囊数减少 5 3%。海南霉素是一种高效抗鸡球虫病药物 ,其预防效果明显优于治疗效果     

Vaccination of rabbits against coccidiosis using precocious lines of Eimeria magna and Eimeria media in Benin

Three groups of twelve 35-day-old rabbits were used for the experiment. Two groups were vaccinated with a mixture of precocious lines of Eimeria magna and Eimeria media originating from corresponding wild strains isolated in Benin. One group benefited of a booster whereas the second one was kept without booster. A third non-vaccinated group was used as control. All groups were challenged per os with an equal mixture of the wild strains of E. magna and E. media at a dose of 104 oocysts per animal. Three weeks after the challenge inoculation, no case of diarrhoea was recorded in the two groups of vaccinated rabbits, as compared to the non-vaccinated rabbits that developed diarrhoea. No mortality was recorded in the three groups. During the patent period, oocyst output of vaccinated rabbits was significantly lower than that of control animals (P < 0.01), confirming a good immunogenic characteristic of the precocious lines. No booster effect was noticed for the boost vaccinated group. The daily weigh gain of the two groups of vaccinated rabbits was significantly higher than that of the non-vaccinated rabbits (P < 0.05). Consequently the precocious lines of Benin origin turned out to be immunogenic and therefore constitute good potential candidates for vaccine production for this country.     

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…     

Vaccination of chickens with a chimeric DNA vaccine encoding Eimeria tenella TA4 and chicken IL-2 induces protective immunity against coccidiosis

A fusion DNA vaccine co-expressed Eimeria tenella TA4 and chicken IL-2 (chIL-2) was constructed and its efficacy against E. tenella challenge was observed. TA4 gene of E. tenella and chIL-2 gene were cloned into expression vector pcDNA3.1 and pcDNA4.0c in different forms, producing vaccines pcDNA3.1-TA4-IL-2, pcDNA3.1-TA4 and pcDNA4.0c-IL-2. The expression of aim genes in vivo was detected by RT-PCR and western blot. Animal experiment was carried out to evaluate the immune efficacy of the vaccines. Results indicated these DNA vaccines were successfully constructed and the antigen genes could be expressed effectively in vivo. The animal experimental results showed that DNA vaccines could obviously alleviate cecal lesions, body weight loss and increase oocyst decrease ratio. The ACI of pcDNA3.0-TA4-IL-2 group was 192, higher than that of pcDNA3.1-TA4 group. The results suggested that TA4 was an effective candidate antigen for vaccine and co-expression of cytokine with antigen was an alternative method to enhance DNA vaccine immunity.     

柔嫩艾美耳球虫卵囊免疫后鸡盲肠扁桃体IL-2基因表达的动态变化

为检测和评价鸡白细胞介素2(ChIL-2)在抗球虫免疫过程中的作用,以RT-PCR技术从鸡盲肠扁桃体中克隆获得了长度为391 bp的ChIL-2.将实验鸡随机分为对照组和试验组,试验组于12日龄和22日龄时用E.tenella孢子化卵囊进行免疫,分别于设定时间每组取5只鸡的盲肠扁桃体,以鸡β-Actin为参照建立半定量RT-PCR方法检测ChIL-2的表达动态变化.结果表明,试验组在第一次免疫后的第几天和第二次免疫后的第七天ChIL-2的表达量明显升高,提示ChIL-2参与了鸡体的抗球虫感染过程,为进一步探讨ChIL-2的生物学活性及作为鸡球虫病基因工程疫苗佐剂的研究奠定基础.     

鸡球虫病的致病因素

鸡球虫病是由艾美耳属的9种球虫寄生于鸡的肠道而引起的高度传染性的疾病,以15~40日龄最易感染且患病严重死亡率极高,危害较明显的有6种,下面结合实际谈一谈鸡球虫病的致病因素。     

抗鸡球虫病的新型三嗪类化合物AC-2的疗效试验

自20世纪80年代初盐霉素(Salinomycin)的问市到80年代末地克珠利(Diclazuril)的推出，期间，世界上一些大制药公司还相继开发了那拉霉素(Narasin)、马杜拉霉素(Marduramicin)等多个新型抗球虫药。进入20世纪90年代后，由于研究开发成本的不断提高，新型抗球虫药的研究处于相对停滞     

中药防治人工感染鸡柔嫩艾美尔球虫病药效试验

鸡球虫病是对养鸡业危害最大的疾病之一。暴发球虫病的雏鸡群病死率过40%-80%，甚至更高。目前鸡球虫病仍以药物防治为主，但药物防治鸡球虫病的高昂费用、球虫对抗球虫药的抗药性、对食品安全的空前关注而日益凸显的药物残留等问题，严重制约着养鸡业发展。中草药作为天然药物，在抗鸡球虫病方面有其独特的优点，为了探讨中药不同组方对人工感染鸡球虫病的防治效果，我们进行了本试验。     

Immunization of chukar partridges against coccidia (Eimeria kofoidi and Eimeria legionensis) with low doses of live oocysts

Experiments were conducted to determine whether chukar partridge (Alectoris chukar) chicks would develop protective immunity after inoculation with coccidia. Young chukar chicks in battery cages inoculated with 100 or more oocysts of Eimeria kofoidi or Eimeria legionensis had significant protection at challenge 4 wk later, as measured by greatly reduced oocyst shedding and improved weight gain as compared with unvaccinated, challenged controls. However, when birds were housed in litter pens and vaccinated by various regimens (including two species of chukar coccidia at 100/dose), coccidiosis rapidly spread through all treatments and caused significant mortality. Vaccination with Coccivac-T or with 100 oocysts of Eimeria dispersa did not prevent mortality resulting from accidental contamination, and feed treatment with a Lactobacillus competitive-exclusion product had no benefit. Most if not all of the mortality was from E. kofoidi. This study illustrated the natural fecundity of chukar coccidia in a floor-pen environment where multiplication rate and reinfection combine to produce clinical disease from a small original exposure. Further, these results cast doubt on the potential use of low doses of live oocysts as a vaccine in the chukar partridge.