Enrofloxacin pharmacokinetics in yellow catfish (Pelteobagrus fulvidraco): A comparative analysis of oral, intramuscular, and bath administration

Enrofloxacin (ENR) residues in yellow catfish (Pelteobagrus fulvidraco) often exceed the standard due to excessive use. This study explored the pharmacokinetics of ENR and its metabolite ciprofloxacin (CIP) in yellow catfish following a single dose of 10 mg/kg body weight via intramuscular injection (IM), oral gavage (PO), or a 5-h drug bath at 10 mg/L and 25°C. High-performance liquid chromatography-mass spectrometry was used to determine the ENR and CIP concentrations in various tissues. The highest ENR concentration occurred with IM administration, peaking at 4.124 mg/L in the plasma, 8.359 mg/kg in the kidney, 6.272 mg/kg in the liver, and 5.192 mg/kg in the muscle. However, PO administration resulted in the longest metabolic time, with elimination half-lives of 56.47 h in plasma, 86.43 h in the kidney, 76.25 h in the liver, and 64.75 h in muscle. Additionally, the area under the concentration-time curve values for IM, PO, and bath administration in yellow catfish plasma were 108.36, 88.96, and 22.08 mg·h/L, respectively. These results indicate the effectiveness of all three administration methods in treating bacterial diseases in yellow catfish. The selection of an appropriate administration method depends on the minimal inhibitory concentration of ENR against pathogenic bacteria. Yellow catfish subjected to PO and IM administration require longer resting periods before they can be marketed than those receiving drug bath administration.