Buquinolate and Immunization to Eimeria Acervulina

Abstract

The immune state of buquinolate-medicated chickens infected with Eimeria acervulina was examined subsequent to drug withdrawal. Chickens fed a ration containing buquinolate1 0.011% together with chickens fed an unmedicated ration were immunized by oral inoculations of 5,000, 50,000, 100,000, and 2,000,000 E. acervulina oocysts, given when the birds were 2, 3, 4, and 6 weeks of age, respectively. Three weeks after the last immunizing dose, when the birds were 9 weeks of age, each immunized bird was challenged with 10,000,000 oocysts administered per os. At that time previously uninfected chickens, from the same hatch as the immunized birds, were given an initial inoculation of the same magnitude. The degree of immunity obtained by immunized birds was measured by comparing differences in weight gain, fecal scores, and oocyst production with that of the nonimmunized control birds during a 7-day period (days 4–10) following challenge inoculation (initial inoculation for controls) Results show that when buquinolate medicated chickens are immunized by multiple doses of E. acervulina oocysts, the drug does not interfere with the hosts’ development of acquired immunity to that coccidial species.