Efficacy of Ipronidazole in Feed and Water Against Histomoniasis in Turkeys 4 to 10 Weeks of Age

Abstract

Three experiments were conducted with Large White turkeys four to 10 weeks of age. Antihistomonal activity of different levels of ipronidazole (1-methyl-2-isopropyl-5-nitroimidazole) in feed and water plus the recommended levels of five other drugs in feed were studied. Poults were exposed with approximately 100 embryonated Heterakis gallinae ova (containing Histomonas meleagridis) administered orally. Histomoniasis mortality was recorded during post-exposure periods of 27–35 days. Dead birds and those surviving (including controls) the post-exposure periods were examined for hepatic and cecal lesions typical for the disease.The 0.00625 percent level of ipronidazole in feed was highly effective in preventing histomoniasis mortality. Dimetridazole and ronidazole fed at recommended levels showed the same prophylactic efficacy in one experiment. Carbarsone, nitarsone and 2-acetylamino-5-nitrothiazole, when fed at manufacturer’s recommended levels, were significantly (P < 0.05) less effective than ipronidazole (0.00625%) in preventing mortality and morbidity in the same experiment. However, 21.4 percent of the surviving birds fed 0.00625 percent of ipronidazole did show hepatic and cecal lesions in one experiment. Ipronidazole was highly effective therapeutically against advanced infections. However, drug level, route and timing of therapy were extremely important. Levels of 0.025 and 0.0125 percent of ipronidazole in feed and water, respectively, when administered 10–17 days post-exposure, completely prevented mortality and morbidity from histomoniasis.