두 가지 수온에서 약욕 투여 후 뱀장어(Anguilla japonica)에서의 oxolinic acid 혈청 약동학

Abstract

This study investigated the pharmacokinetics of oxolinic acid (OA) in Japanese eel (Anguilla japon- ica) following bath treatment under varying water temperatures and concentrations to support rational antibiotic use and ensure food safety. Eels were exposed to OA at 10 mg/L and 20 mg/L for 12 h at two water temperatures (20℃ and 28℃). Serum OA concentrations were quantified via HPLC- MS/MS at time points ranging from 0.5 to 168 h post-treatment. Pharmacokinetic parameters including elimination half-life (T1/2), maximum serum concentration (Cmax), time to maximum serum concen- tration (Tmax), rea under the concentration-time curve (AUC0–168), and mean residence time (MRT0-168) were calculated using a non-compartmental model. The results demonstrated that OA was eliminated slowly in eels, with marked temperature-dependent differences. In particular, the elimination half-life decreased dramatically with increasing temperature from 231.71–352.20 h at 20℃ to 58.32–96.97 h at 28℃ representing up to a fourfold reduction. Although absorption was slower at higher temperatures (Tmax = 1.5 h at 28℃ vs. 0.5 h at 20℃), systemic exposure increased, as indicated by higher Cmax values (3.35–6.42 µg/mL at 28℃ vs. 2.26–4.69 µg/mL at 20℃). Based on the observed Cmax, the minimum inhibitory concentrations (MIC) required to achieve a Cmax/MIC ≥ 4 were estimated as 0.57-0.84 µg/mL for the 10 mg/L group and 1.17–1.61 µg/mL for the 20 mg/L group. These findings underscore the critical role of water temperature in shaping OA pharmacokinetics and provide valuable baseline data for establishing optimal dosing regimens and withdrawal periods in eel aquaculture.