59
Holistic approach for the identification, risk assessment and mitigation of mycotoxins' impact in ruminant
The large number and structural diversity of mycotoxins has impeded rapid quantification owing to varying toxin extraction efficiencies and interferences from feed and food matrices. In turns, the lack of unbiased detection methods decreased the ability identifying the impact of multiple mycotoxin coming from various mold species that can contaminate feedstuffs pre-harvest or during storage phases, and produce mycotoxins. The complexity of ruminant feed formulations, makes those uncertainties even prone to greater variation and reliability issues due to matrix complexity and lack of validated rapid methods available. We have successfully tackled these challenges by fully validating the 37+™ method that evolved into a routine analytical tool. This novel method provides simultaneous and absolute quantification for more than 37 mycotoxins in feed in a cost-effective manner. Our method sets the basis for a novel approach using non-analogous mycotoxins to normalize classes of mycotoxins which have similar extractability and which experience similar matrix suppression/enhancement effect to the isotopologue during UPLC-MSMS analysis. Four isotopically labeled standards were used to normalize 10 groups of mycotoxins, making the method applicable any feed matrices or mixture.
Averaging 8 different mycotoxins per sample with a level of positive samples of 99.5% (n=6000), the data set generated was further interpreted and normalized according to known specie specific sensitivity. The latter was evaluated according to the principles of toxic equivalent factors used to perform dioxins risk assessment and adapted to mycotoxins. Specific threshold of risk related to animal performance impairment were determined, applied to dairy. The risk assessment calculates a risk equivalency quantity (REQ) expressed in ppb of AFB1-equivalent, which computes a multi-contamination complex situation pertaining to feedstuffs into one single value. Proportions of 28.2; 36.3 and 35.5% of samples were contaminated with level representing a high, moderate and low risk for dairy cows, respectively.
The use of REQ calculations enabled also to change the outcome of mitigation strategies. Evaluating the adsorption efficacy of yeast cell wall based product with extended carbohydrate network could now be performed by measuring REQ in (1) initial feedstuff and (2) post mycotoxins extraction and sequestering under digestive condition, and evaluating then a differential REQ. Data showed that in realistic contamination conditions involving 12 different mycotoxins as mixture, the adsorbent enabled to decrease the risk from 70.2% in ruminants. Continuous research is carried out to further refine the methods using in situ approaches for the monitoring of mycotoxin impact and remediation strategy.
Keywords: Mycotoxins, Detection, Risk Assessment, Mitigation