In vitro removal of deoxynivalenol by a mixture of organic and inorganic adsorbents

The objective of this study was to evaluate the efficacy of a mixture of inorganic (activated carbon) and organic (yeast cell wall) adsorbents on in vitro removal of deoxynivalenol (DON). The study was carried out using a 24 incomplete factorial design with three replications at the central point, totalling 11 experiments. The independent variables were pH (3.0, 5.0 and 7.0), adsorbent concentration (0.2, 1.1 and 2.0%), DON concentration (2,500, 5,000 and 7,500 ng/ml) and ratio of activated carbon and yeast cell wall (0:100, 15:85 and 30:70), evaluated at 30, 60 and 90 min incubation periods. The highest percentage of adsorption occurred with 2.0% activated carbon and yeast cell wall at 30:70 ratio (>95.6%) for 30, 60 and 90 min. The lowest adsorption was detected using 0.2% of activated carbon and yeast cell wall at 0:100 ratio (from 14.4 to 77.3%). The pH values (3.0, 5.0 and 7.0) showed no influence on the adsorption of DON in vitro only at 2.0% inclusion level. The predictive model of integrated optimisation of the independent variables of in vitro DON adsorption describes that the maximum adsorption (100%) occurs when the variables pH and adsorbent concentration are set at +1 coded level (pH 7.0 and 2.0%, respectively) and the toxin concentration and the ratio of activated carbon and yeast cell wall at -1 coded level (2,500 ng/ml and 30:70, respectively) for 30, 60 and 90 min. Statistical analysis showed that the equation model obtained can be applied to predict the adsorption percentage of DON in vitro and that the mixture of activated carbon and yeast cell wall at a 2.0% concentration was effective from pH 3.0 to 7.0, which is the range found in the gastrointestinal tract of monogastric animals, thus indicating its potential to minimise the contamination risk by DON. Nevertheless, in vivo efficacy of activated carbon and yeast cell wall at 30:70 ratio should be confirmed with animal experiments.