抗球虫药在鸡胚球虫感染中活性峰期测定方法的研究

用鸡胚感染柔嫩艾美耳球虫子孢子作为抗球虫药活性峰期测定的模型。每一鸡胚在接种５０００个子孢子后，分别于感染的当天、第２天、第３天和第４天注入测试药物，以不同注药时间对鸡胚卵囊所产生的抑制率的差异，判定药物的活性峰期。结果表明，氯甲吡啶酚和丁氧喹啉的活性峰期是球虫生活史的第１天，卵囊抑制率分别为１００％和９８％；莫能菌素、盐霉素、球Ｒ和加福的作用峰期是第２天，卵囊抑制率均为１００％；氨丙啉的峰期是第３天，卵囊抑制率为１００％；尼卡巴嗪的峰期是第４天，卵囊抑制率为１００％；速丹则在球虫生活史的整个无性阶段均呈现活性作用。加福＋氨丙体＋乙氧乙胺苯甲酯、球Ｒ＋氨丙啉＋乙氧乙胺苯甲酯、加福＋速丹、加福＋尼卡巴嗪及加福＋乙氧乙胺苯甲酯等合剂亦在球虫生活史的整个无性阶段发挥高峰作用，其印囊的抑制率均为１００％；尼卡巴嗪＋氨丙啉合剂则在球虫生活史的第２～４天发挥最大作用，卵囊抑制率为１００％。作者认为，本方法具有操作简单，结果可信及成本低廉的特点，可作为抗球虫药的筛选方法。

STUDY ON DETERMINATION OF THE TIME OF PEAK ACTIVITY OF ANTICOCCIDIALS AGAINST E. TENELLA INFECTION IN CHICK EMBRYOS

Chick embryos inoculated with sporozoites of E. tenella. Were used as a model for testing the time of peak activity of anticoccidials. Each embryo inoculated with a dose 5000 pure sporozoites was injected with testing drugs on 1.2,3 and 4 days after sporozoite inoculation The varying oocyst inhibition rates of embryos brought abode by drugs that were giVen at various time were used as a criterion for determining the time of peak activity of anticoccidials.The results were as follow:As clopidol and buquinolate showed 100% add 98% of oocyst inhibition, respectively.the peak activity of them was found on day 1 in the life cycle of E.tenella.Monensin.salinomycin, anticoccidials R and maduramicin were also acted earlier in the life cycle and all achieved 100% of oocyst inhibition on day 2.The peak activity of amprolium,which produced a complete oocyst inhibition.appeared to be on day 3 of the life cycle.Nicarbazin had greatest activity on day 4 and gave 100% of oocyst inhibition. Halofuginone as well as combinations of maduramicin amprolium ethopabate.anticoccidials R amprolium ethopabate,maduramicin halofnginone, maduramicin nicarbazin and maduramicin ethopabate all exhibited 100% of oocyst inhibtion at the every stages of the life cycle. There was greatest efficacy which completely inhibited oocysts from day 2 to 4 in the life cycle for mixture of nicarbazi,amprolium and ethopabate.According to above mentioned experimental results,we believe that the use of chicken embryo infection with E. tenslla sporozoites for the determination of the time of peak activity of anticoccidials is a good method for screening an ticoccidial drugs.it offers some advantages,such as simplicity of operation,good accuracy and only small requirement of expenses.