Abstract
Experiments were conducted to determine the thiamine requirements of two coc-cidia, Eimeria tenella and Eimeria acervulina, in relation to the thiamine content of thediet and oocyst production. The results obtained are as follows: The minimum require-ments of thiamine for the growth of E. tenella and E. acervulina were 5.0 and 2.5 rug/kgin feed, respectively.On the other hand, the incorporation of triteated-thiamine into first schizonts wasobserved by electron microscope radioautography. The silver grains of H3-thiaminewere located over the nucleus, nucleolus, mitochondria, and endoplasmic reticulum ofthe first schizont.Moreover, amprolium and beclotiamine, when administered to chickens with feed, were shown to be coccidiostatic against coccidia of the alimentary tract without anyadverse effect upon the growth of chicks. Oxythiamine, however, did not reveal ananticoccidial action. The anticoccidial effects of beclotiamine and amprolium wereinfluenced by the variation of the dietary thiamine content.Therefore, the mode of action against coccidia of beclotiamine was conjectured tobe thiamine inhibition against the growth of coccidia.
