A diet naturally contaminated with the Fusarium mycotoxin deoxynivalenol (DON) downregulates gene expression of glucose transporters in the intestine of broiler chickens

Abstract

This study was conducted to determine whether a diet with moderate contamination of Fusarium mycotoxin deoxynivalenol (DON) alters the glucose absorption and whether this might be linked to altered SGLT-1 and GLUT-2 mRNA expression in the small intestine of chickens. Forty-five 1-d-old broiler chickens were randomly assigned into three groups (15 per group, 2–3 birds per pen). The birds in treated groups were fed a diet naturally contaminated with DON (1 and 5mg/kg). After 5weeks, one bird per pen from 6 pens was randomly selected from each group to assess glucose transport in small intestinal tissues (Ussing chamber). The mRNA expression of the Na+-dependent glucose transporter SGLT-1 and the facilitative GLUT-2 were assayed by real-time PCR to clarify genomic regulation of glucose transport by DON. The morphology of the jejunal mucosa was also investigated in order to assess non-specific effects of DON. The results showed that DON significantly inhibited glucose-induced currents in jejunal tissues and decreased the expression of SGLT-1 and GLUT-2 mRNA for both DON-supplemented groups (P<0.01). The mRNA of SGLT-1 was down-regulated in duodenal and jejunal tissues of both DON-supplemented groups (P<0.01). GLUT-2 mRNA was down-regulated only in duodenal tissues for both DON-supplemented groups. Additionally, DON at both concentrations altered the small intestinal morphology by decreasing villi length and the absorptive surface area (P<0.01). We conclude that DON contaminated diet suppresses the mRNA abundance and activity of intestinal glucose transporters in chicken intestine under practically relevant feeding conditions. This further suggests that DON has indeed a specific inhibitory effect on glucose transport in addition to a concurrent decrease of intestinal surface area even at low to moderate dietary concentrations.