和缓艾美耳球虫早熟系选育及其生物学特性研究

Eimeria mitis : Selection and Characteristics of a Precocious Line

按照Jeffers建立的艾美耳属球虫早熟系选育方法,对和缓艾美耳球虫涿州株(Eimeria mitis Zhuozhoustrain, EmiZ)进行了早熟选育。经石歧杂肉仔鸡15次传代之后,EmiZ潜在期由96 h缩短至77 h, 缩短了19 h。选育出的和缓艾美耳球虫涿州株早熟系(Eimeria mitis Zhuozhou strain precocious line, EmiZP)在致病性与繁殖力上均较母株弱,但保留了母株的免疫原性。经EmiZP免疫的石歧杂肉仔鸡,可抵抗母株EmiZ的攻虫。对选育的早熟系EmiZP进行放松选择传代10代,其潜在期、排卵囊高峰、卵囊产量和致病性均保持了早熟系的特征,说明所选育的EmiZP已在遗传上保持了稳定。

A line of Eimeria mitis with an abbreviated life cycle (i.e. a “precocious ” line) was derived from the Zhuozhou strain by repeated passage of the oocysts which were the first to be recovered from infections in chickens. The prepatent period was reduced by 19 hours. The precocious parasite is less pathogenic than the parent strain, has a reduced reproductive potential, and remains much of the immunogenicity of the parent strain. Shiqiza chicks inoculated with the parasites of the precocious line were well protected against challenge with the Zhuozhou strain. Through a relaxed selection of 10 passages, it was showed that the precocious line is genetically stable in its prepatent time, reproduction peak and potential, and pathogenicity.