Dual real-time fluorescent and colorimetric LAMP assay for rapid and on-site identification of sturgeon (Acipenser and Huso).

Abstract

Fraudulent substitution of sturgeon caviar with lower-value roe or non-sturgeon eggs poses risks to consumer protection and sturgeon conservation. In this study, a dual-mode loop-mediated isothermal amplification (LAMP) assay was developed for rapid and on-site authentication of sturgeon (Acipenseridae)-derived components in caviar. This assay integrates SYTO-9 real-time fluorescence and hydroxynaphthol blue colorimetry within a closed-tube system. Primers targeting a conserved region of the Acipenser and Huso cytochrome b gene generated a 190-bp amplicon, enabling detection of sturgeon genomic DNA down to 0.1 pg at 64 °C within 10 min, accompanied by a visible sky-blue color change and fluorescence signal. High analytical specificity was demonstrated with no amplification observed from 14 non-Acipenseridae fish samples. Validation using 17 commercial caviar products showed complete agreement with sequencing-based species identification. The simplicity, speed, and closed-tube format of this assay reduce equipment needs and contamination risks, supporting its suitability for regulatory, commercial, and conservation applications.