Fine structural changes in Eimeria tenella, from infections in chick embryos and chickens, after exposure to the anticoccidial drug robenidene

Abstract

The structure of the various stages of Eimeria tenella grown in the chorioallantoic membranes of the chick embryo has been shown to be similar to the stages in the caecum of the bird. The effects of the anticoccidial drug, Robenidine, on the fine structure of the various stages of E. tenella, grown in the chick embryo and in the caecum of the bird, have been described. The first noticeable change occurs in the endoplasmic reticulum, including the nuclear envelope, and in the Golgi complexes of all stages. The nucleus itself, and the mitochondria, do not appear to be affected by the drug until much later, and this effect is probably due to the degeneration of the cell. It is suggested that the drug may have a direct effect upon protein metabolism of the parasite, resulting in swelling of the granular endoplasmic reticulum and Golgi complexes, or that it may have a primary effect upon some other organelle or metabolic process, and that the swelling of the endoplasmic reticulum and Golgi complexes is a secondary or tertiary phenomenon.