Isolation, propagation, identification and comparative pathogenicity of five Egyptian field strains of Eimeria tenella from broiler chickens in five different provinces in Egypt.

A battery trial was conducted to evaluate the comparative pathogenicity of five field strains of Eimeria tenella from Behera, Khafr El-Sheikh, Alexandria, Gharbia and Matrouh provinces in Egypt. Two-week-old broiler chickens were infected with 25×10(3) sporulated oocysts of each strain of E. tenella. The comparative pathogenicity of the strains was assessed by calculating body weight gain, feed conversion ratio, lesion scores, dropping nature scores, cecal scrapings, mortality percentage and oocysts count. Hematological parameters including hemoglobin (Hb) content, packed cell volume (PCV%) and total erythrocytic count, were also evaluated. There were different degrees of pathogenicity between the strains.