Nuevas metodologías para el análisis de microcistinas en peces. Estudio de Astraloheros Facetus expuestos in vitro.

The high incidence of cyanobacterial blooms producing microcystins in Uruguay and its region, represent a very high risk for humans and animals. To study the impact and the presence of microcystins (MCs) in animals, it is important to use simple, low-cost methods. As a first approach to these objectives in fish, a sub-chronic bioassay (18 days) was performed with Astraloheros facetus (Castanetas) exposed to a Microcystis spp, bloom containing MCs (60 and 600 µg MCs/L). Even though there was no mortality, the histopathology showed fatty infiltration of the liver, which was more relevant in fish exposed to the highest concentration. To analyze MCs in tissues, two sensitive immunochemical methods based on a highly specific recombinant llama antibody (nanobody) were optimized: ELISA and quantitative MALDI-TOF, using functionalized magnetic particles. The methods were recently developed locally. The excellent correlation ELISA/MALDI-TOF (r Spearman = 0.988, p <10-7), highlights the potential of this ELISA as a simple and cost-effective tool to minimize the samples to be analyzed by reference methods. The concentrations of MCs in tissue of Astraloheros facetus were relevant, consistent with bioassays in other species and fish from nature. This highlights the importance of analyzing MCs in fish for consumption.