engleski

Levamisole residues in eggs following oral administration to laying hans

Levamisol is a broad spectrum synthetic antihelmintic used in the treatment of gastrointestinal nematodes and lungworms in domestic ruminants, pigs and poultry. In present study, levamisole residues were determined in eggs following oral administration to hens with a single dose of 50 mg kg-1 body weight, i.e. a dose twice times the prescribed therapeutic dose. Sampling of eggs was conducted for 37 days following the end of treatment. Levamisole concentrations were measured by liquid chromatography–tandem mass spectrometry (LC–MS/MS) by positive electrospray ionisation. Method was validated according to the Commission Decision 2002/657/EC. The limit of detection (LOD) was 0.04 µg kg-1, limit of quantification (LOQ) 0.15 µg kg-1 and recovery 92.9%. The maximal concentrations of 556.2 and 166.5 ug kg-1 were measured in egg yolk and white on second day after the treatment. Gradual elimination of levamisole occurred and on seventh day after the cessation of treatment levamisole levels in yolk and white dropped to 14.1 and 2.68 ug kg-1. In yolk and white levamisole residues were above the LOQ values up to 19 and 10 days after the end of the treatment. Residues were still detectable for up to 34 and 22 days after the cessation of administration.

levamisole ; egg ; laying hans ; LC-MS/MS

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