Biomonitoring of microcystin and aflatoxin co-occurrence in aquaculture using immunohistochemistry and genotoxicity assays

This work investigated the effects of co-occurring aflatoxin B sub(1) (AFB sub(1)) and microcystin (MC) in aquaculture, using immunohistochemistry and genotoxicity methods. Tilapia (Oreochromis niloticus) were exposed to AFB sub(1) by intraperitoneal and MC (cell extract of Microcystis aeruginosa) by intraperitoneal and immersion routes. The interaction of MC-AFB sub(1) was evaluated co-exposing the intraperitoneal doses. Blood samples were collected after 8, 24, and 48h to analyze the micronucleus frequency and comet score. The interaction of MC-AFB sub(1) showed a synergic mutagenic response by higher micronucleus frequency of co-exposed group. A slight genotoxic synergism was also observed in the comet score. Immunohistochemistry detected MC in all the fish liver tissues exposed to MC by intraperitoneal route, and only the immersed group with the highest dose of MC showed a positive response. Although MC was non-detectable in the edible muscle, the combination of immunohistochemistry with genotoxicity assay was an attractive biomonitoring tool in aquaculture, where the animals were frequently exposed to co-occurring synergic hazards.