Accumulation and Clearance of Orally Administered Erythromycin in Adult Nile Tilapia (Oreochromis niloticus) and Giant Freshwater Prawn (Macrobrachium rosenbergii)

Abstract

Nile tilapia (Oreochromis niloticus) and giant freshwater prawns (Macrobrachium rosenbergii) were medicated with erythromycin base via a medicated ration at 50 mg and 100 mg erythromycin·kg−1 fish body weight−1·d−1 for seven days. Erythromycin residues in muscle were determined by LC-MS/MS. After 23 days, erythromycin A residues in the 50 mg treatment were 34.7 ± 9.6 μg/kg in tilapia and 2.8 ± 0.8 μg/kg, and in the 100 mg treatment were 42.9 ± 17.4 μg/kg in tilapia and 31.4 ± 7.5 μg/kg in prawn. Interpolation following European Agency for the Evaluation of Medicinal Products guidelines predicted withdrawal time in tilapia was 33 days (908°C/day) at 50 mg or 42 days (1,150°C/day) at 100 mg under our experimental conditions. After 23 days of withdrawal, erythromycin A residues in prawn tissue were within acceptable limits at a dose of 50 mg, while treatment with 100 mg of erythromycin required a withdrawal time of 35 days (976°C-days), estimated through interpolation. Erythromycin derivatives appeared in the post-dosing stage, but were all depleted to a safe level within the normal withdrawal period.