Rat 90-day oral toxicity study of a novel coccidiostat - Ethanamizuril

In the current study, to support the safety assessment of ethanamizuril as a new potent anticoccidial agent of triazine compounds, a 90-day repeated-dose oral toxicity assay of ethanamizuril was investigated. Treatment related clinical signs of alopecia on back and neck have been observed in some male and female at the 65 and 130 mg/kg dose groups. The body weight and feed conversion efficacy of 65 and 130 mg/kg females and 65 mg/kg males were significantly increase than those of the control in treatment time, but noted decreased in the 130 mg/kg males. Dose related changes of hematologic and biochemical parameters such as MCV, MCH, TG, and the significant increased in the organ weight and the relative organ weight of the liver, kidney, heart, lung and spleen in both genders in the 65 and 130 mg/kg treated groups were observed. Furthermore, histopathological observations revealed that 65 and 130 mg/kg ethanamizuril induced pathological damage such as hepatocyte steatosis and focal necrosis, renal tubular atrophy, tubule protein casts. Fortunately, the observed toxicities were recoverable in convalescence. The results indicated that liver, kidneys and lung were the main target organs. The NOAEL of ethanamizuril for rats was estimated to be 20 mg/kg dietary dose level.