Effet chez le porcelet d'une exposition à un régime co-contaminé en ...

TRAVAIL EXPERIMENTALINTRODUCTIONMycotoxins are secondary metabolites of various fungi commonly found in feed and foodstuffs.Based on their known and suspected effects on human and animal health, aflatoxin, fumonisin,deoxynivalenol, ochratoxin A and zearalenone are recognized as the five most important agriculturalmycotoxins (Shephard, 2008). The toxic effects of Fusarium mycotoxins in animals include reducedgrowth, feed refusal, immunosupression, gastrointestinal lesions, and neurological and reproductivedisorders (Rocha et al., 2005).Recent surveys demonstrated regular occurrence of low levels of multiple mycotoxins in cereals(Roscoe et al., 2008; Tabuc et al., 2009; Scudamore and Patel, 2009). Also, mycotoxins may bepresent in grains in conjugated chemical forms that escape detection through conventional analyticalmethods (Zhou et al., 2007), resulting in an underestimation of the total amount of mycotoxins andfeed toxicity. Fusarium mycotoxins in combination can exert more pronounced effects in animalsthan individual mycotoxins (Smith et al., 1997; Grenier et al., 2011).The intestinal tract is the first barrier against ingested antigens, including mycotoxins andpathogenic bacteria. Following ingestion of mycotoxin-contaminated food, enterocytes may beexposed to high concentrations of toxins (Bouhet and Oswald, 2005). Studies focusing on theinfluence of food-derived antigens on intestinal morphology as an indicator of animal health arecommon; meanwhile, there are few publications on the effects of chronic exposure to a mycotoxinco-contaminated diet.Fumonisins (FB) are toxic and carcinogenic mycotoxins produced by Fusarium verticillioides, acommon contaminant of maize. Fumonisin B1 (FB1) causes porcine pulmonary edema and equineleukoencephalamalacia. An association between human esophageal cancer and FB1 exposure indeveloping countries has been reported (Zhang et al., 1997). Fumonisins are structurally related tosphingoid bases and cause inhibition of ceramide synthase, leading to accumulation of correspondingfree sphingoid bases, sphingoid base metabolites, and depletion of more complex sphingolipids(Wang et al., 1991). In vitro, FB1 induces apoptosis, necrosis, and inhibition of proliferation in pigrenal epithelial (LLC-PK1) cells and human colonic cells (HT29) (Gopee et al., 2003; Schmelz et al.,1998). FB1 can impair the intestinal absorption of nutrients. This can be explained by the villousfusion and atrophy observed in the intestines of pigs treated with 30 mg FB1/kg of feed and/or bysphingolipid disturbances (Taranu et al., 2005).Deoxynivalenol (DON) causes toxic and immunotoxic effects in a variety of cell systems andanimal species. DON is produced by F. graminearum and F. culmorum mainly in wheat, barley andmaize (Pestka and Smolinski, 2005). Swine is more sensitive to DON than other species, in part110