三株柔嫩艾美球虫野外分离株的致病性分析

用每鸡4×104和8×104个孢子化卵囊的剂量感染黄羽肉雏,以临床症状、肉眼病变、平均增重、病变记分和死亡率为判定指标,对柔嫩艾美球虫EtCZ-1、EtCZ-2、EtCZ-3株的致病性进行了比较分析。结果显示:各虫株引起的临床症状和肠道肉眼病变基本相似,致病性随着感染剂量的增加而增强。各感染组的增重与对照组相比均有显著差异(P<0.50),相对增重率分别下降了74.4%～83.2%、68.7%～72.2%和70.6%～74.4%;感染后鸡出现血便的时间较一致,即第108小时开始排血便,在120h～144h达高峰;病变值和卵囊值均随着感染剂量的增加而增大;除EtCZ-1株高剂量组的存活率是90%以外,其余各组均为100%。显示3株球虫的致病性相似。

Pathogenicity of three field strains of Eimeria tenella

The pathogenicity of three field strains of Eimeria tenella,EtCZ-1,EtCZ-2 and EtCZ-3 was compared according to clinical symptom,gross pathology,weight gain,lesion score and mortality after the chickens were infected with the dose of 4×104 and 8×104 sporulated oocysts per chicken,respectively.The results were that the clinical symptoms and the gross intestinal pathology were similar in all infected chickens.The weight gains of infected groups were significantly different from those of the control groups(P<0.50).The rates of relative gains were reduced to 74.4%~83.2%,68.7%~72.2% and 70.6%~74.4%,respectively.The bloody stools were discharged from infected chickens at 108 h post-inoculation(PI),and reached the peak from 120 h to 144 h PI.The lesion scores and occysts production became larger with the increase of dose.The survival rates were 100% except the group with 8×104 of EtCZ-1 sporulated oocysts(90%).It suggested that three strains of E.tenella were similar to each other in their pathogenicity.