Effect of deoxynivalenol (DON) ingestion on expression of genes involved in intestinal integrity and immune response

Abstract Text: The effects of feeding DON contaminated grain to pigs are very diverse ranging from reduced growth performances to symptoms like immune suppression and diarrhea. Although the gastrointestinal tract represents the first barrier met by exogenous food/feed contaminants such as mycotoxins, little is known about the effect of DON on intestinal health. The purpose of this study was to evaluate the influence of DON ingestion on intestinal gene expression involved in the barrier and immune functions in growing pigs. Sixteen 4-week-old pigs were randomly allocated to two dietary treatments for 35 days: control diet (< 0.5 ppm) or diets contaminated with 3.5 ppm DON. Each group of pigs was housed in a different pen located in the same room. Feed and water were provided ad libitum. Growth performances were recorded weekly and at the end of the trial, all pigs were euthanized. Samples from mid-jejunum and ileum were collected for measurements of the expression of genes involved in epithelium integrity and barrier functions, inflammatory reaction and oxidative stress. Ingestion of 3.5 ppm DON diet reduced average daily gain of pigs compared to control diet (P < 0.05). In pigs fed 3.5 ppm DON diet, several genes involved in intestinal integrity and barrier function (claudins, occludins, BCL-2 and vimentin) in the ileum were down-regulated (P < 0.05) compared to pigs fed the control diet. Results also revealed that expression of two chemokines (IL-8, CXCL10), interferon-γ, and major antioxidant glutathione peroxidase 2 (GPX-2) were up-regulated (P < 0.05) whereas expression of other genes encoding enzymatic antioxidants such as GPX-3, GPX-4 and superoxide dismutase-3 (SOD-3) were down regulated in pigs fed DON-contaminated diet. In the jejunum, only the expression of CXCL10 and IL-4 genes was significantly up-regulated (P < 0.05) in pigs fed DON-contaminated diet. In conclusion, these results provide a strong evidence that ingestion of DON-contaminated feed significantly altered the expression of genes involved in intestinal barrier and immune functions which may predispose animals to infections by enteric pathogens.

Keywords: deoxynivalenol, immune response, intestine