堆型艾美耳球虫早熟减毒株的选育

Selection of Precocious and Attenuated Strains of Eimeria ac- ervulina

用早熟选育方法对堆型艾美耳球虫保定株进行了12代早熟选育,获得了潜隐期为74h的P_9株和62h的P_(12)株两个早熟株.两个早熟株不经选择传递2代,仍保持了早熟的特性.早熟株较其亲代株繁殖能力下降,致病力降低,但仍然保持了良好的免疫原性.早熟选育改变了虫体的内生性发育过程,引起了潜隐期的缩短.P_9株的裂体生殖为3代,P_(12)株的裂体生殖为2代.

By 12 generations of serial selection for precociousness, P9 and P12 strains of E. acervulina having their respective prepatent times of 74 and 62 hours were obtained. These two strains retained their precociousness following 2 passages without selection pressure. The reproductive potences lowered and the pathogencities reduced, but the immunogencities were retained. Selection for precocious development wes accompanied by the alternation of the endogenous development of the parasite and thus results in the reduction of the prepatent time. The endogenous development of P9 strain was 3 instead of 4 generations of schizonts and that of P12 strain was 2 instead of 4 generations of schizonts.