堆形艾美耳球虫早熟株选育及相关生物学特性研究

为了选育堆形艾美耳球虫（Eimeria acervulina）早熟株及观测其生物学特性，运用Jeffers创立的艾美耳属球虫早熟株选育方法，对实验室保存的堆形艾美耳球虫进行连续传代早熟选育，并对获得的早熟株与母株孢子化卵囊大小、繁殖能力、致病性以及免疫保护力等指标进行了测定，比较堆形艾美耳球虫早熟株与母株之间的基本生物学特性差异。经过18代早熟选育后，堆形艾美耳球虫的潜在期由母株的99h缩短至84h。与母株相比，早熟株的孢子化卵囊大小明显减小（P〈0．05），卵囊繁殖能力降低了17％～42%。致病性试验中，早熟株感染组的平均增重均高于母株，而病变记分相当。免疫保护试验中，早熟株与母株的免疫保护力相当，其卵囊抑制率略低于母株，差异不明显（P〉0．05）。结果表明，本研究成功选育出堆形艾关耳球虫早熟株，对母株攻击具有保护力，为鸡球虫疫苗的研制奠定了基础。

SELECTION AND CHARACTERISTICS OF A PRECOCIOUS LINE OF EIMERIA ACERVULINA

To find out the difference in biological characteristics between the precocious passage and parent strain of E. acervulina, 18 serial passages were performed through chickens using Jeffers＇ method. The differences between the parent strain and 18th passage were analyzed regarding sizes of sporulated oocysts, reproductive capacity, pathogenicity and immunogenicity. The preparent period of the precocious strain was shortened from 99 hours to 84 hours. The size of the sporulated oocysts of precocious strain was remarkably smaller than that of the parent strain （P〈0.05）, and reproductive potential was less than that of the parent strain. In the pathogenicity test, the average weight gains of 4 different doses of the precocious strain were much more than that of the parent strain, but the lesion scores remained similar. In the immunogenicity test, the immunoprotection of the precocious strain was similar to the parent strain and the oocysts inhibition rate was not significantly different although the strain was less than that of the parent strain. These results showed inhibition rate of the precocious that the precocious strain of E. acervulina possessed shorter preparent period, less pathogenicity and reduced reproductive capacity while it maintained good immunogenicity.