Drug Resistance in Eimeria tenella. V. The Experimental Development of a Nicarbazin-Resistant Strain

Abstract

A strain of E. tenella that heretofore had never been exposed to drugs was serially propagated in groups of chickens that were initially fed suboptimal levels of nicarbazin. Differences in the response of experimental and control organisms to the recommended level of 0.0125% nicarbazin were detectable after the experimental strain was passed 11 times. After 40 passages in the presence of nicarbazin, the experimental strain had no detectable cross-resistance to amprolium, aresenosobenzene, glycarbylamide, nitrofurazone, Trithiadol, Unistat, or Zoalene.