抗球虫药对鸡球虫免疫影响的探讨

INFLUENCE OF ANTICOCCIDIAL DRUGS UPON DEVELOPMENT OF IMMUNITY TO EIMERIA TENELLA INFECTION IN CHICKENS

17组15日龄来航鸡,连续20天递增经口免疫接种一定量的卵囊,并同时饲喂有两种不同浓度的抗球虫药的饲料,49日龄时用大剂量卵囊(10万/羽)攻击。根据每克粪便卵囊数(O.P.G.)、盲肠病变评分和增重等指标,评定8种抗球虫药对鸡球虫免疫的影响。由两次结果可知:严重抑制免疫的有氯甲吡啶酚(250ppm)、丁氧喹啉(175ppm)、莫能菌素(150ppm)和盐霉素(120ppm)。轻度抑制免疫的有氨丙啉(250ppm)和尼卡巴嗪(250ppm)。各低剂量药物均对免疫无影响。

17 groups of 15-day-old chickens of White leghorn were inoculated orally with a suspension of sporulated oocysts of E. teneila for the challenge immunity at progressively increasing daily doses beginning from 20 infective oocysts then with 10 oocysts increase day by day for 20 consecutive days, while 16 medicated-feed groups were treated with eight anticoccidials,each for two groups,one group at higher dose the other at lower dose. By 49 days each bird was challenged with a larger dose of oocysts (100,000) for tolerance toward infection. Lesion scores, weight gains and ooeysts per gram of feces (O. P. G.) were used as the criteria for measuring immunity on 8 days following challenge of infective oocysts. In two tests, the influence of each drug treatment on the immunity development of birds could be ranked as follows: Strongly sup- pressive for clopidol (250 ppm), Monensin (150 ppm), Salinomycin (120ppm), and Buqinolate (175ppm); Weakly suppressive for Amprolium (250ppm), and Nicarbazin (250ppm): Non suppressive for all lower-dosage of former drugs and higher-dosage of SM_2 and tetracycline.