Fumonisina B1 em alimentos para eqüinos: interações em sistemas de digestão in vitro com Saccharomyces cerevisiae

Abstract

This study aimed to evaluate the in vitro adsorption of fumonisin B1 (FB1) through the use of different strains and concentrations of Saccharomyces cerevisiae in conditions simulating the digestive tract of horses. The experimental design was completely randomized in a factorial 4x5 with four yeast strains (1, 2, 3 and 4) and five concentrations for each strain of 1x107, 5x107, 1x108, 5x108 and 1x109 CFU.mL-1 at pH 2 and 6.8 with three replicates per treatment. In vitro adsorption experiments were carried out in microcentrifuge tubes containing buffered solution mycotoxin and yeast at 39 ° C. The concentration of FB1 was 5 μg.mL-1. The supernatant of samples containing fumonisin not adsorbed were analyzed and quantified by CLAE. The results of the in vitro adsorption were subjected to a regression analysis based on the S. cerevisiae concentration and yeast strains. It was observed at pH 2 and 6.8 a significant interaction between S. cerevisiae concentration and yeast strain (P <0.001). At pH 2, the the amount of FB1 adsorbed by different yeast strains did not differ with 1x107, 5x107, 1x108 CFU.mL-1, only showed effects for the highest concentrations of 5x108 and 1x109 CFU.mL-1 (P<0.001). At pH 6.8, the differences occurred to concentration of 1x108, 5x108 and 1x109 CFU.mL-1 (P<0.001), but had no effect on lower concentrations (5x107 and 1x107 celulas.mL-1). At the highest concentration of 1x109 CFU.mL-1, strain 4 (SC-47) demonstrated a greater capacity to adsorb FB1, 39.4% and 37.5% at pH 2.0 and 6.8, respectively. In addition, linear responses were observed in the adsorption capacity in all strains evaluated under conditions of acidic and neutral pH. The results demonstrate that the ability of S. cerevisiae to adsorb FB1 is strain-dependent and the pH value may influence the amount of FB1 removed from the solution according to the strain used