Remediation of deoxynivalenol (DON) : developing an in vitro model to screen potential detoxifying agents on DON degradation and detoxification in a simulated gastro-intestinal tract of a pig

Deoxynivalenol (DON) is a trichothecene mycotoxin produced by Fusarium species and is occurring worldwide with high incidence in feed. Strategies are needed to eliminate its health risk for livestock and to minimize its economic impact on production. In order to assess the efficacy of potential physical, chemical and biological DON detoxifying agents, a good in vitro model is necessary to perform a fast screening of numerous new compounds before in vivo trials are set up. In this project, two in vitro screening models were developed to screen compounds for DON degradation and detoxification, acting as potential feed additives defined as ‘substances for reduction of the contamination of feed by DON’ by the European Food Safety Authority (EFSA). The first screening model was performed in a buffer environment (single concentration, isotherm experiment), whereas the second in vitro screening model employed a feed matrix in a simulated gastro-intestinal tract (GIT) of a pig, as both matrix and incubation parameters can affect the binding, removal or degradation of DON by the compounds. For each in vitro model, residual DON concentration was analyzed with ELISA and the residual toxicity with a bioassay using the aquatic water plant Lemna minor L. Twelve compounds with different modes of action were tested in the in vitro buffer model of which three were tested in the in vitro feed model. One product seemed very promising in both in vitro models and could reduce DON for almost 100% in feed after 6h. Further in vitro experiments have been performed to characterize the most effective use of this additive. Finally, DON metabolites were found with LC-MS/MS at 2h, 4h and 6h. This in vitro model seems a promising tool to use as a fast screening method to screen and differentiate compounds detoxifying DON