Elimination of oxolinic acid in eggs after oral treatment of laying hens

Abstract

1. Oxolinic acid is often used in poultry as a therapeutic agent. The aim of this study was to determine both its elimination into eggs, following oral dosing through the drinking water (12 mg/kg/d) or diet (13 mg/kg/d) for 5 d and its plasma concentrations. 2. Samples (albumen, yolk, plasma) were analysed by high performance liquid chromatography (HPLC) with fluorimetric detection. The limits of quantification were 10 ng/g in plasma and 5 ng/g in albumen and yolk. Residues were much higher in albumen than in plasma, whereas they were lower in yolk. 3. 95% of the overall oxolinic acid detected in eggs was concentrated in the albumen. 4. Detectable residues persisted for 9 d and 7 d, respectively, in albumen and yolk after the treatment was discontinued.