Abstract
This work assesses the cell-mediated immune reaction IL-6, TNF-α, and IFN-γ of experimentally challenged broiler chicken with Eimeria tenella (E. tenella). Therefore, ninety, 2-weeks-old healthy broiler chicks were allocated as eighty chicks infected orally with 2.5 × 10(4 )E. tenella sporulated oocysts, and the other ten birds were kept as control negative birds. Post-challenge, mortality rate, symptoms, oocysts shedding, and lesion score were evaluated. Tissue samples (cecum and spleen) were collected at 0, 4, 8, and 12 days post-infection (dpi). Ten chickens were ethically slaughtered at 0, 4, 8, and 12 days post-infection, as well as two birds from the negative control group; parts from cecal and spleen samples were kept in cryopreservation containers, and other parts were preserved in formaline 10% for further investigation. The evaluated genes (IL-6, TNF-α, and IFN-γ) were normal at 0 days and upregulated at 4 and 8 days, which reached maximum upregulation at eight dpi. The histopathological examination of the ceca and spleen were evaluated before and after challenge. It could be concluded that E. tenella revealed direct severe macroscopic and microscopic changes in cecal tissues and indirectly induced alteration in splenic tissues, resulting in upregulation of different cell mediated immune response in cecum and spleen in relation to the experimental period.