Development of Indirect Competitive Enzyme-Linked Immunosorbent Assay to Detect Fusarium verticillioides in Poultry Feed Samples

Abstract

Fumonisins are a group of toxic secondary metabolites that are produced by <i>Fusarium verticillioides</i> which are associated with poultry health hazard and great economic losses. The objective of the present study was to develop an immunological method to detect <i>F. verticillioides</i> in poultry feed samples. An indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) based on a polyclonal antibody against 67 kDa protein of the <i>F. verticillioides</i> 97K exoantigen was developed to detect this fungus. Antibody anti-67 kDa protein showed cross-reactivity against <i>F. graminearum</i> (2⁻7%) and <i>F. sporotrichioides</i> (10%), but no or low cross-reactivity against <i>Aspergillus</i> sp. and <i>Penicillium</i> sp. exoantigens. The detection limit for the 67 kDa protein of <i>F. verticillioides</i> was 29 ng/mL. Eighty-one poultry feed samples were analyzed for <i>Fusarium</i> sp. count, 67 kDa protein of <i>F. verticillioides</i> and fumonisin concentrations. Eighty of the 81 feed samples (98.6%) showed <i>Fusarium</i> sp. contamination (mean 6.2 x 10⁴ CFU/g). Mean 67 kDa protein and fumonisin concentration in the poultry feed samples was 21.0 µg/g and 1.02 µg/g, respectively. The concentration of 67 kDa protein, as determined by ic-ELISA correlated positively (p < 0.05) with fumonisin levels (r = 0.76). These results suggest that this ic-ELISA has potential to detect <i>F. verticillioides</i> and predict fumonisin contamination in poultry feed samples.