A Relationship Between Coccidiosis and Dietary Vitamin A Levels in Chickens

Broiler-cross male chickens, reared for two weeks on vitamin A-free diet, were administered vitamin A at 165, 495, 1,485, 4,455 and 13,365 U.S.P. units per kg. of feed. Seven days later the chickens on each dietary vitamin A level were administered inoculum of coccidial suspensions. All chickens were maintained in wire floor batteries during the experimental period. The calculated vitamin A requirement for optimum growth for coccidiosis-infected chickens were higher than non-infected chickens. The coccidiosis-infected chickens had lower blood plasma and liver levels of vitamin A than non-infected chickens at the end of the first week post-infection. The severity of coccidiosis was greater in chickens receiving low vitamin A levels than chickens receiving higher levels of vitamin A. There was an inverse linear relationship between dietary vitamin A level and fecal sporulated oocyst count.