Development of a highly sensitive monoclonal antibody-based indirect competitive enzyme-linked immunosorbent assay for the detection of avilamycin in feed.

An indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) was developed using a highly sensitive and specific monoclonal antibody against avilamycin. The immunising antigen synthesised through the carbonyldiimidazole (CDI) method was used to prepare antibodies. The established ic-ELISA, after optimisation of conditions, possessed a half maximum inhibitory concentration (IC) value of 7.44 ng mL-1 and the detection limit of 0.21 ng mL in the standard curve. The spiked experiments indicated that the limits of detection were 1.86 µg kg and 2.31 µg kg in swine feed and chicken feed, respectively. In addition, the average recoveries ranged from 74.7 to 105.4% with the coefficient of variation less than 11%. The good correlation (R = 0.9818) between the result of ic-ELISA and HPLC demonstrated the reliability of the developed ic-ELISA, which showed that the ic-ELISA developed here achieves the aim of strengthening the monitoring of avilamycin residues and the inspection of import and export related products.