毒害艾美耳球虫早熟株对鸡免疫效果的评价

The evaluation of immune effects of Eimeria necatrix precocious strain on chickens

【目的】探讨毒害艾美耳球虫(Eimeria necatrix)早熟株对鸡的免疫效果,为获得安全有效的鸡球虫疫苗株提供试验参考依据。【方法】取4日龄健康、体质量50~70 g鸡随机分为4组,分别为对照组、盐酸氨丙啉添加组、一免组和二免组,每组50只鸡地面饲养,试验期81 d。对照组、免疫组(免疫组包括一免组和二免组)鸡饲喂基础日粮,盐酸氨丙啉添加组鸡按照药物说明全程基础日粮加盐酸氨丙啉拌服。一免组鸡4日龄一免,剂量1 000个/只毒害艾美耳球虫早熟株孢子化卵囊;二免组鸡53日龄二免,剂量200个/只毒害艾美耳球虫早熟株孢子化卵囊。鸡25日龄、53日龄、74日龄时从地面饲养的各组随机抽取6只鸡移到笼上饲养,同时设置红对照组(鸡不免疫不喂药仅攻毒)。笼养鸡除对照组外,其他组鸡均攻毒,攻毒方法为逐只鸡经口接种毒害艾美耳球虫亲本株(10×10^(4)个孢子化卵囊/只)。肉眼观察鸡临床症状,测定鸡平均相对体增质量、小肠病变记分、小肠病变记分减少率、存活率、卵囊减少率与抗球虫指数等指标。【结果】免疫鸡攻毒后,临床观察对照组鸡精神状态良好,未出现任何异常症状;免疫组与红对照组相比精神状态良好、血便减少。不同日龄鸡(25日龄、53日龄和74日龄)攻毒后第7天,盐酸氨丙啉添加组和免疫组鸡相对体增质量均明显低于对照组但极显著高于红对照组且二免组高于一免组。免疫组鸡小肠平均病变记分均低于红对照组,小肠病变记分减少率高于红对照组,其中二免组不同日龄攻毒后鸡小肠平均病变记分均低于一免组,且74日龄鸡攻毒后小肠病变记分减少率最高。红对照组不同日龄鸡卵囊数极显著高于盐酸氨丙啉添加组和免疫组,其中免疫组53日龄鸡和74日龄鸡攻毒后卵囊数均显著高于盐酸氨丙啉添加组,卵囊减少率低于盐酸氨丙啉添加组,且二免组74日龄鸡攻毒后卵囊减少率高达90%。免疫组不同日龄鸡抗球虫指数极显著高于红对照组,二免组不同日龄鸡抗球虫指数均高于145且高于一免组,即二免组鸡抗球虫效果达到中效水平。【结论】毒害艾美耳球虫早熟株2次免疫对鸡具有良好的保护效果,且对鸡生长发育的影响较小。

【Objective】 The experiments was to investigate immune effects of Eimeria necatrix precocious strain on chickens, and to provide the experimental reference for obtaining safe and effective chicken coccidiosis vaccine strain. 【Methods】Healthy 4-day-old chickens with body weight of 50 to 70 g were randomly divided into 4 groups, namely the control group, aminoproline hydrochloride added group, first immunized group and second immunized group and raised on the ground with 50 chickens in each group. The experiment lasted for 81 days. Chickens in the control group and the immunized group(first immunized group and second immunized group) were fed with basal diet, and the chickens in the aminoproline hydrochloride added group were mixed with the basal diet plus aminoproline hydrochloride.Chickens were the first to be immunized at 4 days of age with a dose of 1000 sporidized oocysts per infected Eimeria necatrix precocious strain, and secondly at 53 days of age with a dose of 200 poridized oocysts. At 25 days of age, 53 days of age and 74 days of age, 6 chickens were randomly selected from each group raised on the ground and moved to the cage. Red control group was set up at the same time(chickens were not immune, not fed, only challenged). Except for the control group, chicks in other groups were challenged by oral inoculation with the parent strain of Eimeria necatrix(10×10^(4) sporulated oocysts/chick). The clinical symptoms of chicks were observed by naked eye, and the average relative body weight gain, small intestine lesion score, lesion score reduction rate, survival rate, oocyst reduction rate and coccidiosis resistance index were determined. 【Results】 After challenge, the chickens in the control group were in good mental state without any abnormal symptoms. Compared with the red control group, the mental state of the immunized group chickens was better and the blood stool decreased. On the 7 th day after challenge, the relative body weight gain of chickens in aminoproline hydrochloride supplemental group and immunized group was significantly lower than that in control group, but extremely significantly higher than that in red control group, and that in second immunized group was higher than that in first immunized group. The average lesion score of small intestine from chicks in the immunized group was lower than that in the red control group, and the lesion score reduction rate was higher than that in the red control group. The average lesion score of small intestine from chicks in the second immunized group after challenge was lower than that in the first immunized group at different ages, and the lesion score reduction rate of chickens small intestine at 74 days of age was the highest. Different day-old chickens oocyst number in the red control group was significantly higher than that in hydrochloric acid ammonia added group and immune group. The number of oocysts of chickens at 53 days of age and 74 days of age in immunization group was significantly higher than that in amproline hydrochloride group, and the reduction rate of oocysts was lower than that in amproline hydrochloride group, and the reduction rate of oocysts in chickens at 74 days of age in second immunization group was up to 90%. The coccidiosis resistance index of chickens at different ages in the immunized group was significantly higher than that in the red control group, and the coccidiosis resistance index of chickens at different ages in the second immunized group was higher than that in the first immunized group, which means the anti-coccidiosis effect of chickens at the second immunized group reached the intermediate level. 【Conclusion】 In conclusion, the secondary immunization of Eimeria necatrix precocious strain had good protective effect on chicks, and had little effect on the growth and development of chicks.