ORIGINAL ARTICLE Influence of deoxynivalenol on the D-glucose transport across the isolated epithelium of different intestinal segments of laying hens W. A. Awad, E. Razzazi-Fazeli, J. Bo ¨ hm and J. Zentek Department of Veterinary Public Health and Food Science, Institute of Animal Nutrition, University of Veterinary Medicine, Vienna, Austria Keywords laying hen, deoxynivalenol, Ussing chamber, electrophysiological parameter, intestinal transport, D-glucose Correspondence Wageha Awad, Department of Veterinary Public Health and Food Science, Institute of Animal Nutrition, University of Veterinary Medicine, Veterina ¨ rplatz 1, A-1210 Vienna, Austria. Tel.: +43 1 25077 3214; Fax: +43 1 25077 3290; E-mail: wageha.awad@ vu-wien.ac.at Presented at the 9th International Congress of the European Society of Vet. Comparat. Nutri- tion. In Grugliasco (Turin), Italy, 22–24 September 2005, Page 3. Summary Deoxynivalenol (DON) decreases glucose absorption in the proximal jejunum of laying hens in vitro and this effect is apparently mediated by the inhibition of the sodium d-glucose co-transporter. DON could modu- late the sugar transport of other intestinal regions of chickens. For this purpose, we have measured the effects of DON on the Na + d-glucose co-transporter, by addition of DON after and before a glucose addition in the isolated epithelium from chicken duodenum, jejunum, ileum, caecum and colon by using the Ussing chamber technique in the voltage clamp technique. The data showed in all segments of the gut that the addition of d-glucose on the mucosal side produced an increase in the current (Isc) compared with the basal values, the Isc after glucose addi- tion to the small intestine was greater than the Isc of the large intestine compared with the basal values, specially of the jejunum (p < 0.002), indicating that the jejunum is the segment that is the best prepared for Na + -d-glucose co-transport. Further addition of 10 lg DON/ml to the mucosal solution decreased the Isc in all segments and the Isc returned to the basal value, especially in the duodenum and mid jejunum (p < 0.05). In contrast, the addition of 5 mmol d-glucose/l on the mucosal side after incubation of the tissues with DON in all segments had no effect on the Isc (p > 0.05), suggesting that DON previously inhibited the Na + d-glucose co-transport. The blocking effects of DON in duodenum and jejunum were greater than the other regions of the gut. It can be concluded that the small intestine of laying hens has the most relevant role in the carrier mediated glucose transport and the large intestine, having non-significant capacity to transport sugars, appears to offer a minor contribution to glucose transport because the surface area is small. The effect of d-glucose on the Isc was reversed by DON in all segments, especially in the duodenum and jejunum, suggesting that DON entirely inhibited Na + -d-glucose co-transport. This finding indicates that the inhibition of Na + co-transport system in all segments could be an important mode of action for DON toxicity of hens. Zusammenfassung Deoxynivalenol (DON) erniedrigt in vitro die Glukoseabsorption im proximalen Jejunum von Legehennen. Dieser Effekt ist vermutlich durch eine Hemmung des Natrium-d-Glukose-Cotransportsystems bedingt. Journal of Animal Physiology and Animal Nutrition 91 (2007) 175–180 ª 2007 The Authors. Journal compilation ª 2007 Blackwell Publishing Ltd 175