Carry-over of Fusarium toxins (deoxynivalenol and zearalenone) from naturally contaminated wheat to pigs

Abstract

The frequent contamination of grain with the Fusarium toxins, deoxynivalenol (DON) and zearalenone (ZON), is an important issue in animal and human nutrition. However, data on the exposure of humans to these toxins through consumption of animal tissues exposed to Fusarium toxins (carry-over) are fragmentary. Therefore, residues of DON, ZON and their metabolites were determined in tissues and body fluids of pigs (female and castrated male) from a fattening trial. Pigs were fed a control (n = 6, 0.24 mg DON and 0.009 mg ZON per kg diet as fed) or a Fusarium toxin-contaminated diet (n = 12, 6.68 mg DON and 0.056 mg ZON per kg diet as fed) either ad libitum or for restrictive consumption for 12 weeks. After slaughter (96.3 ± 11.6 kg live weight), the concentrations of DON and its metabolite, de-epoxy-DON, were measured in serum, bile, liver, kidney, musculus longissimus and back fat, while ZON and its metabolites, α- and β-zearalenol (α-/β-ZOL), were determined in serum, bile and liver. The mean carry-over factor of DON + de-epoxy-DON, defined as the concentration of both substances in the tissue/fluid divided by the DON concentration in the diet, for all pigs decreased from bile (0.1046 ± 0.0653) ≫ kidney (0.0151 ± 0.0070) > liver (0.0057 ± 0.0043) > serum (0.0023 ± 0.0018) > muscle (0.0016 ± 0.0016) ≫ back fat (0.0002 ± 0.0004). The time interval between the end of feeding and slaughter had no consistent effect on DON + de-epoxy-DON concentrations in the analysed specimen of Fusarium toxin-exposed pigs fed restrictively. No transfer of ZON and its metabolites could be observed into serum of pigs, while the mean carry-over factors of ZON + α-ZOL + β-ZOL were 0.0094 ± 0.0123 and 4.0 ± 2.2 for liver and bile, respectively. Therefore, it can be concluded that serum is a reliable indicator for DON exposure, but an inappropriate parameter to deduce ZON exposure, which is better represented by bile concentration of ZON + α-ZOL + β-ZOL. However, the exposure risk to humans by consumption of edible tissues of animals exposed to Fusarium toxins is negligible compared to the direct consumption of grain-based food.

Keywords:

• Carry over
• deoxynivalenol
• Fusarium
• pigs
• zearalenone

Acknowledgements

Financial support of the “Deutsche Forschungsgemeinschaft” (DFG-project DA 558/1-1) is gratefully acknowledged. The authors would like to thank co-workers of the Institute of Animal Nutrition of the German Federal Agricultural Research Centre in Braunschweig for performing the experiments and analyses. and Nicola Grove for excellent technical assistance.