Development of an ELISA for maduramicin and determination of the depletion kinetics of maduramicin residues in poultry.

Polyclonal antibodies against the coccidiostat maduramicin were produced by the immunization of rabbits with a conjugate between maduramicin and human serum albumin. The antibodies exhibited minimal cross-reactivity with structurally similar ionophoric coccidiostats (monensin, salinomycin, narasin and laslocid). An enzyme-linked immunosorbent assay (ELISA) was developed for maduramicin in poultry tissue using these antibodies. The ELISA had a limit of detection of approximately 0.02 ng/g in tissue (ng/ml in serum) and a limit of determination of 1.0 ng/g in tissue (ng/ml in serum). The half-life of maduramicin was measured in broiler chickens that had been treated with a therapeutic dose of maduramicin for 14 days. Following withdrawal of the medicated feed, the mean half-lives of maduramicin were 20, 39 and 13 h in liver, muscle and serum, respectively. At the recommended withdrawal period (5 days) the mean residual maduramicin concentration in liver was 1.6 ng/g, in muscle was 1.5 ng/g and in serum was 0.05 ng/ml.