title: Development of a five-plex flow cytometric immunoassay for the simultaneous detection of six coccidiostats in feed and eggs.
abstract: Coccidiostats are the only veterinary drugs still permitted to be used as feed additives to treat poultry for coccidiosis. To protect consumers, maximum levels for their presence in food and feed have been set by the European Union (EU). To monitor these coccidiostats, a rapid and inexpensive screening method would be a useful tool. The development of such a screening method, using a flow cytometry-based immunoassay, is described. The assay uses five sets of colour-coded paramagnetic microspheres for the detection of six selected priority coccidiostats. Different coccidiostats, with and without carrier proteins, were covalently coupled onto different bead sets and tested in combination with polyclonal antisera and with a fluorescent-labelled secondary antibody. The five optimal combinations were selected for this multiplex and a simple-to-use sample extraction method was applied for screening blank and spiked eggs and feed samples. A very good correlation (r ranging from 0.995 to 0.999) was obtained with the responses obtained in two different flow cytometers (Luminex 100 and FLEXMAP 3D). The sensitivities obtained were in accordance with the levels set by the EU as the measured limits of detection for narasin/salinomycin, lasalocid, diclazuril, nicarbazin (4,4'-dinitrocarbanilide) and monensin in eggs were 0.01, 0.1, 0.5, 53 and 0.1 μg/kg and in feed 0.1, 0.2, 0.3, 9 and 1.5 μg/kg, respectively.
authors.affiliation: RIKILT-Institute of Food Safety, Wageningen UR, Wageningen, The Netherlands. monique.bienenmann@wur.nl
authors.forename: Monique E
authors.initials: ME
authors.lastname: Bienenmann-Ploum
authors.forename: Anne-Catherine
authors.initials: AC
authors.lastname: Huet
authors.forename: Katrina
authors.initials: K
authors.lastname: Campbell
authors.forename: Terence L
authors.initials: TL
authors.lastname: Fodey
authors.forename: Ursula
authors.initials: U
authors.lastname: Vincent
authors.forename: Willem
authors.initials: W
authors.lastname: Haasnoot
authors.forename: Philippe
authors.initials: P
authors.lastname: Delahaut
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Elliott
authors.forename: Michel W F
authors.initials: MW
authors.lastname: Nielen
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D000906:Antibodies / Q000032:analysis / Q000276:immunology; D003049:Coccidiostats / Q000032:analysis* / Q000276:immunology; D004531:Eggs / Q000032:analysis*; D005434:Flow Cytometry / Q000191:economics / Q000379:methods*; D007118:Immunoassay / Q000191:economics / Q000379:methods; D011200:Poultry; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D000906:Antibodies; D003049:Coccidiostats