Excretion pattern of enrofloxacin after oral treatment of chicken broilers.

The metabolism and excretion of enrofloxacin were studied when applied as oral solution to chicken broilers for five consecutive days. Sixty 9-day-old broilers were isolated within an intensively rearing poultry farm during enrofloxacin therapy (15.5 mg/kg per day). The excreta of the isolated broilers were collected daily, 9 days after therapy termination, for 13 consecutive days, and analyzed for the presence of enrofloxacin and its metabolites [ciprofloxacin, desethylene-enrofloxacin (DES-EF) and desethylene-ciprofloxacin (DES-CF)]. Enrofloxacin was excreted predominantly in the form of the parent compound between days 1 and 13. Ciprofloxacin was detected in the excreta between days 1 and 6, whereas minor amounts of DES-EF and DES-CF were excreted only between days 1-7 and 1-6, respectively. In conclusion, the analysis of the excreta showed that approximately 74% of orally applied enrofloxacin was excreted as the parent compound, approximately 25% as the main metabolite ciprofloxacin, and approximately 1% as the minor metabolites desethylene-enrofloxacin and desethylene-ciprofloxacin.