摘要
鸡艾美耳球虫病由隶属顶复门7种艾美耳球虫（E.tenella、E.necatrix、E.acervulina、E.maxima、E.brunetti、E.praecox、E.mitis）引起,常混合感染,有很高的发病率和死亡率,轻者则影响鸡的增重和饲料转化率。微线是顶器的结构之一,位于子孢子和裂殖子前端,EtMIC-2是其50 kDa左右的酸性蛋白,在虫体入侵时表达,该蛋白可能在虫体入侵时起重要作用。用Pet载体经原核表达该蛋白,7、14日龄经口服、肌注不同剂量工程活菌和菌体裂解蛋白二次免疫鸡,免疫后1周用3种艾美耳球虫（E.tenella、E.acervulina、E.maxima）攻虫,发现相对增重率随菌体蛋白含量增加呈现增强趋势,E.tenella攻虫表现最有效的是口服PBS200μg活菌组为96％,E.ac-ervulina、E.maxima分别为96％、87％。从攻虫后7～14 d卵囊排出曲线看,每天排卵囊数和相对卵囊产量均低于红对照;相对卵囊产量,E.tenella攻虫后,口服PBS 200μg活菌组最低,为17％,E.acervulina、E.maxima攻虫后,口服PBS 200μg裂解菌组最高,分别为90％、93％。从增重与卵囊产量来看,EtMIC-2对E.tenella、E.ac-ervulina和E.maxima这3种球虫有一定的免疫保护作用,尤其口服200μgPBS活菌时,对E.tenella保护作用最明显。说明来源于E.tenella子孢子的Etmic-2基因的表达产物对E.tenella、E.
Chicken coccidiosis is caused by one or seven species of Eimeria (Apicomplexa ). The incidence is high and clinical disease causese high mortality; the subclinical disease hinders weight gain and feed conversion. Mi-croneme,a common structure of Apicomplexa , is located in the anterior part of sporozoites and merozoites. EtMIC-2 is a 50 kDa acidic protein of microneme,expressed during parasite invasion,and possibly plays a role in invading host. Chickens were vaccinated per os or via intramuscular injection with living recombined bacteria,lysis recombined bacteria and pure protein at 7、14 days old,then challenged with sporulated oocysts of E. tenella、E. acervulina、E. maxima individually. The result indicated that the weight gain of vaccinated chickens increased along with the content of expressed protein compared with the unvaccinated chickens, weight gain of chickens o-rally given PBS 200 μg living recombined bacteria challenged with E. tenella was 96 % and E. maxima with 87% .At 7-14 days post challenge, oocyst production of E. tenella in vaccinated chickens orally given PBS 200 μg living recombined bacteria decreased 17% ,93% and 82% respectively in chickens challenged with E. maxima and E. acervulina orally given PBS 200 μg living recombined bacteria. In view of weight gain and oocyst production,EtMIC-2 could induce partial protection against challenge with three species of Eimeria ,especially in the chickens challenged with E. tenella and orally given PBS 200 μg living recombined bacteria.
出处
《畜牧兽医学报》
CAS
CSCD
北大核心
2002年第2期205-208,共4页
ACTA VETERINARIA ET ZOOTECHNICA SINICA
基金
国家自然科学基金项目(30170695)
