Monoclonal Antibody-Based Immunoassay for the Detection of Maduramicin in Chicken Tissues

Comprehensive Screening of Salinomycin in Feed and Its Residues in Poultry Tissues Using Microbial Inhibition Tests Coupled to Enzyme-Linked Immunosorbent Assay (ELISA)

Salinomycin is a coccidiostat approved as a feed additive for the prevention of coccidiosis in poultry. Official control of its residues is set by the Commission Delegated Regulation (EU) 2022/1644. The aim of our study was to assess the suitability of three microbial inhibition tests (MITs), Premi®Test, Explorer 2.0, and the Screening Test for Antibiotic Residues (STAR) linked to the enzyme-linked immunosorbent assay (ELISA), for the screening of salinomycin residues in the tissues of broiler chickens (breast and thigh muscle, heart, liver, gizzard, kidneys, lungs, spleen, skin, and fat) fed commercially produced feed containing 70 mg.kg-1 of salinomycin in the complete feed. The first residue screening (Sampling A) was performed on the last day of administration of the salinomycin-medicated feed (day 30), and the second screening (Sampling B) was performed on the day of slaughter (day 37) after the expiry of the withdrawal period with the feeding of non-medicated feed. Based on the quantitative confirmation of salinomycin residues in the examined chicken tissues by the ELISA method (Sampling A from 0.025 to 0.241 mg.kg-1; Sampling B from 0.003 to 0.076 mg.kg-1), all the MITs with the preference of the bacterial strain Bacillus stearothermophilus var. calidolactis ATCC 10149 demonstrated the ability to detect the residues of salinomycin in the examined tissues of broiler chickens at the level of the maximum residue limits set from 0.015 to 0.150 mg.kg-1 by Commission Implementing Regulation (EU) 2017/1914 and confirmed the relevance of their sensitivity to the coccidiostat salinomycin.

One-Step Platform for Maduramicin and Salinomycin Detection Based on Bispecific Monoclonal Antibody and Interpretation of Molecular Recognition Mechanism

Maduramicin (MAD) and salinomycin (SAL) are the widely used poly(ether ionophore) antibiotics to control coccidiosis in animals. Due to their strong cytotoxicity, strict control over their dosage and residue in animal food is necessary. To improve the detection efficiency of the existing single-residue detection methods, a tetraploid tumor hybrid system was constructed using drug mutagenesis, and the bispecific monoclonal antibody (BsMAb) against MAD and SAL was obtained by hybridization-hybridoma technology. By optimizing the optimal working concentration of the tracer and antibody, a multiresidue fluorescence polarization immunoassay method based on BsMAb was successfully established. The whole detection process takes 10 min, and the LOD values of MAD and SAL were 4.71 and 3.49 ng·g-1, respectively. IC50 values were 6.45 and 6.24 ng·mL-1, respectively. There was no cross-reactivity with other polyether ionophore antibiotics. Finally, a breakthrough in detection was achieved: bispecific monoclonal antibody prepared by the hybridization-hybridoma technology was used to detect maduramicin and salinomycin.

Validated spectrophotometric determination of maduramicin ammonium using three charge transfer complexation reactions

Direct spectrophotometric determination of Maduramicin ammonium (MAD) represents an analytical challenge since it is a weak UV-absorbing and lacking a strong chromophore. This work represents the first spectrophotometric determination of MAD as no direct spectrophotometric or colorimetric determination methods for MAD are available in the literature. The present study illustrates the development of three simple, rapid and inexpensive colorimetric methods for the routine quality control analysis of MAD based on the formation of colored charge transfer complexes with three electron acceptors namely p-chloranilic acid (p-CA), 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and picric acid (PA). The color products of MAD with p-CA, DDQ and PA were measured at 519, 588 and 405nm respectively. The proposed methods were validated in terms of linearity, ranges, precision, accuracy, robustness and limits of detection and quantification. MAD was effectively determined over concentration ranges of 100-1000, 25-250 and 30-150μg/mL using p-CA, DDQ and PA, respectively with good linearity as shown by the values of correlation coefficients not less than 0.9991. The developed methods were successfully implemented in the assay of MAD powder pharmaceutical formulation for veterinary use.