Combined toxicity of prevalent mycotoxins studied in fish cell line and zebrafish larvae revealed that type of interactions is dose-dependent

While, Aflatoxin B-1 (AFB(1)), deoxynivalenol (DON) and zearalenone (ZEN) are the most prevalent mycotoxins coexisting in grain products and animal feeds, little is known about their combinatorial toxicities on aquatic life forms. We studied the individual and combined effects of these mycotoxins in a fish cell line (BF-2) and zebrafish larvae (wild-type and transgenic). The types of interactions in mycotoxins combinations on cell viability were determined by using Chou-Talalay model. Induction of oxidative stress pathway in mycotoxins-exposed BF-2 cells was assessed using high content screening (HCS). Mycotoxin-exposed wild-type zebrafish larvae were examined for mortality and morphological abnormalities and transgenic zebrafish larvae (expressing DsRed in the liver) were imaged using HCS and examined for liver abnormalities. Results showed that the cytotoxicity of mycotoxins in a decreasing order was AFB(1) > DON > ZEN, however, the highest mortality rate and liver damage in zebrafish were observed for AFB(1) followed by ZEN. AFB(1) + DON and AFB(1) + ZEN synergistically enhanced the toxic effects on BF-2 cells and zebrafish while DON + ZEN showed antagonism. Interestingly, in the tertiary combination, the synergism seen at lower individual concentrations of mycotoxins progressively turned to an overall antagonism at higher doses. The results provide a scientific basis for the necessity to consider co-exposure when formulating risk-management strategies.