The Use of Intestinal D-Xylose Absorption and Other Parameters to Determine the Pathogenicity of and Immunity to Eimeria acervulina

The degree of pathogenicity of Eimeria acervulina infection in broiler chickens was evaluated by body weight gain, feed conversion ratio, oocyst production, gross morphologic lesion score, and intestinal D-xylose absorption. The least pathogenic effects, after challenge, occurred in birds immunized with 5 X 10(4) oocysts and challenged on Day 14 with 3 X 10(6) oocysts. Intestinal D-xylose absorption was found to be a sensitive method for evaluating the effects of coccidial infection and correlated well with body weight gain and feed conversion ratio. Oocyst production and morphologic lesion scoring were less sensitive techniques than D-xylose absorption, weight gain, and feed conversion for determination of pathogenic effects between the groups of birds tested.