New development in Aflatoxin research: from aquafeed to marine cells

Available data on the real impact of aflatoxins on farm aquatic species are very limited. Since long time, aflatoxin B1 (AFB) has been considered the most potent food-born hepatotoxicant, frequently found in animal feedstuff. At present, it has been reported as responsible agent in unforeseen outbreaks of fish mortality due to acute or chronic aflatoxicosis, mainly well documented in freshwater species. The lack of information on the incidence of aflatoxicosis in marine reared teleosts may be partially due to the difficulty in accurately diagnosing the disease in fish, as well as to the lack of specie-specific in vitro models for toxicity studies. In this work: 1) we have verified that pelletted fish feed might be considered as sources of AFB1 contamination in aquaculture due to the isolation and identification of blue eye fungi (Aspergillus spp., Penicillium spp.) in feed samples, as well as other several genera (Fusarium, Cladosporium, Alternaria, Geotrichum, Mucor, Rizophus, Acremonium); 2) we have performed an in vitro evaluation of AFB potential cytotoxic on Sparus aurata hepatocyte primary cultures (SaHePs), using a multiple endpoint screening. Our results demonstrate that seabream hepatocytes are highly sensitive to AFB1 exposure and especially indicate three distinct pathways of cytotoxic response: necrotic cell death, apoptotic cell death and uncontrolled cell proliferation; 3) we have compared the dose response curves obtained by measuring the bioluminescence of Vibrio fischeri upon AFB exposure to those obtained from in vitro cell culture system. Results show equivalent and overlapping toxic responses with those from seabream hepatocytes.