Sequential use of coccidiostats: effect on development by Eimeria tenella of resistance to amprolium, nicarbazin, Unistat, and zoalene.

D K McLoughlin, M B Chute

Index: Avian Dis. 19(3) , 424-8, (1975)

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Abstract

A strain of the cecal coccidian of chickens, Eimeria tenella, was propagated serially in chickens fed mash containing amprolium, nicarbazin, Unistat, or zoalene. Each group of chickens received a different coccidiostat on a rotating basis. The strain was propagated through 40 groups of chickens; thus, the strain was intermittently exposed 10 times to each coccidiostat. The end product of this simulated shuttle program of prophylactic anticoccidial medication was a strain resistant to three of the four coccidiostats involved. Resistance to nicarbazin was not evident.