Acquired Immunity of Buquinolate-Medicated Chickens to Eimeria Tenella Infection

Abstract

INTRODUCTIONTHE most widely used program for coccidiosis control in replacement flocks reared under floor pen conditions depends on accidental exposure of chickens to infective oocysts while using a coccidiostat in the feed (Reid et al., 1968). Ideally, the coccidiostat of choice permits a low level of infection to proceed, thus allowing the host to gradually acquire protective immunity to the coccidial species present without losing weight or showing clinical signs of disease. Studies in this laboratory (unpublished) show that, in the case of Eimeria tenella, buquinolate is an ideal coccidiostat for use in cage layer replacement pullets. When chickens fed this coccidiostat are artifically infected with E. tenella they show no clinical signs of disease but still pass small numbers of oocysts (Brewer and Reid, 1967; Edgar and Flanagan, 1966). This observation suggests that the use of buquinolate does not interfere with the ability of the host to acquire…