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

INTRODUCTIONby a steeping period. Several studies reported a significant reduction in aflatoxins content (90-95%)in corn with this alkaline treatment. However, the apparent aflatoxin reduction in contaminatedmaize was not permanent, since it was reverted by an acidic treatment, which probably causedaflatoxin reformation by closing the open lactone ring (Mendez-Albores et al., 2004; Price andJorgensen, 1985). Acidification of the aflatoxin extracts, with a pH similar to the stomach as occursduring digestion, lead to a rebuilding of the aflatoxin molecule (see Table 7).Under alkaline conditions, fumonisins in contaminated corn are converted to the so-calledhydrolyzed fumonisins (HFB1). Dombrink-Kurtzman et al. (2000) showed that nixtamalizationreduced the FB1 concentration in tortillas by 81.5% and that the FB1 and HFB1 were mainly found inthe steeping and washing water. Cortez-Rocha et al. (2002) observed a 39% reduction of FB1concentration when raw corn was nixtamalized. Others found that the traditional nixtamalizationmethod used by the Mayan communities in Guatamala reduced total fumonisins (FB1 and HFB1) by50% and that the residual lime and washing water also contained 50% of the fumonisins initiallypresent in the corn (Palencia et al., 2003). However, when fed to rats, Voss et al. (1996) showed thatnixtamalized corn culture materials that contained HFB1, still induce toxicity (see Table 7). Thistoxicity was originally attributed to the hydrolyzed fumonisins, but the same author in 2009disclaimed the HFB1-induced toxicity, suggesting these effects were mediated by residual or“hidden” FB1 (matrix bound forms not detected by HPLC) remaining in the nixtamalizedpreparations, rather than HFB1.Park et al. (1995) observed that further decontamination and detoxification of FB1 contaminatedcorn was achieved by using a modified nixtamalization procedure. This procedure consisted in acombination of heat treatment with hydrogen peroxide/sodium bicarbonate with calcium hydroxideand gave up to 100% reduction of FB1 in contaminated maize (100 ppm). The best procedureinvolved treating corn with a combination of H 2 O 2 /NaHCO 3 alone for one hour. This is a simpletreatment that could be integrated into industrial processing procedures for corn. Furthermore,treatments of FB1-contaminated corn simulating modified nixtamalization have shown a reduction oftoxicity (see Table 7).Abbas et al. (1988) indicated that boiling deoxynivalenol-contaminated corn in lime-waterremoved 72-82% of DON and 100% of 15-acetyl-DON. In the same study, the authors observed areduction of 59-100% for zearalenone-contaminated corn. No data on the safety of treated feed,contaminated with either DON or ZEA, has been reported.64