The effect of the host's age on the pathology of Eimeria stiedai infection in rabbits.

The pathology of experimental Eimeria stiedai infection in 2- and 4-month-old rabbits raised coccidia-free was studied. Over 50 days of infection, the serum activities of aspartate (AST) and alanine (ALT) aminotransferases, alkaline phosphatase (AP) and gamma-glutamyltranspeptidase (GGTP) were analyzed as indicators of hepatic lesions and total serum globulins with respect to the immune response of the host; parasite development was followed by oocyst output; weight gain, food intake and relative liver weight were analyzed to control the performance of infected animals. The age of the host strongly affected parasite development and consequently the biochemical and zootechnical parameters differed more markedly in the younger animals; however, the enzyme ALT showed an increase independent of parasite development, and infection did not affect GGTP activity. The increase in age was responsible for resistance of rabbits to hepatic coccidiosis and older animals were less affected than young ones.