Variation in susceptibility of inbred lines of chickens to seven species ofEimeria

Abstract

The pattern of oocyst production of 8 inbred lines of chickens was compared for each of the 7 species ofEimeriawhich infect this host. Both the overall numbers and the pattern of oocyst production differed in the inbred lines, but there was no evidence of prolonged cycling of schizogenic developmental stages. Comparison of the numbers of oocysts produced by the different lines indicates that there may be common genetic factors affecting susceptibility to 6 of the 7 species. Surprisingly there appears to be an inverse relationship between susceptibility toE. tenellaand susceptibility to the other species: lines which produced most oocysts ofE. tenellaproduced least oocysts of the other species andvice-versa.