From Molecular Recognition to On-Site Detection: A Highly Selective Strategy for Monitoring Gizzerosine in Feed by...

Gizzerosine, a toxic biogenic amine from overheated fish meal, induces gizzard erosion and black vomit in poultry with 1000-fold higher toxicity than its precursor histamine, thus requiring specific on-site detection. Immunoassay development for gizzerosine is hindered by histamine cross-reactivity. Molecular recognition analysis of the anti-gizzerosine monoclonal antibody (anti-GZ mAb, IC₅₀ = 3.88 ng/mL) revealed that cross-reactivity originates from the shared imidazole ring, while exclusive hydrogen bonding to the terminal carboxyl group confers 139-fold selectivity. Guided by this mechanism, a mixed-mode anion-exchange (MAX) column exploiting both the amphoteric property and high polarity of gizzerosine removes >95% histamine with quantitative recovery. Using this pretreatment, a gold immunochromatographic assay (GICA) achieved an IC₅₀ of 32.63 ng/mL, a visual cutoff of 128 ng/mL, and negligible cross-reactivity. Recoveries from spiked feeds (90.0-109.1%) correlated well with UHPLC-MS/MS. This instrument-free, visualreadout platform constitutes the first gizzerosine-specific GICA enabled by mechanism-based pretreatment, offering a robust field screening tool.