Influence of Escherichia coli endotoxemia on danofloxacin pharmacokinetics in broilers following single oral administration

As a fluoroquinolone antimicrobial agent, danofloxacin is mainly used to treat avian bacterial and mycoplasma infections. The pharmacokinetic characteristics of danofloxacin are usually explored in healthy animals, while those in endotoxemic broilers are still rare. This study aimed to investigate the pharmacokinetics of danofloxacin in endotoxemic broilers induced by Escherichia coli (E. coli) lipopolysaccharide (LPS) after single oral administration. Ten healthy 5-week-old Arbor Acres (AA) broilers with similar body weight (BW) were randomly and equally divided into LPS and control groups. The LPS group was intravenously injected with an LPS of E. coli O55: B5 at 2.5 mg/kg BW, and the control group was intravenously injected with the same volume of sterile saline. Danofloxacin was administered orally at a dose of 5 mg/kg BW immediately 1 h after the intravenous injection of LPS or sterile saline. Rectal temperature was measured at predetermined times points in all broilers, and plasma and serum samples were taken. The interleukin-6 (IL-6) levels in serum samples were detected by the enzyme-linked immunosorbent assay (ELISA) kits, and danofloxacin concentrations in plasma were detected through the high-performance liquid chromatography (HPLC) method and subjected to a compartmental analysis using Phoenix software. The LPS challenge led to biphasic adaptive changes in broiler body temperature and increased the levels of IL-6. Compared with the control group, LPS treatment significantly prolonged the time to the peak concentration (LPS: 8.75 +/- 3.88 h; Control: 3.20 +/- 2.20 h). However, there were no significant differences in the other pharmacokinetic parameters between both groups.