MStudies have revealed that Se is incorporated into the P. ostreatus biomass, as this element was found to be associated with the membrane (44%) and cell wall (56%). Se incorporation into fungal proteins reveals a great potential to improve the nutritional value of the mushroom ( Munoz et al., 2006). In enriched mushrooms, the Se bioavailability was verified using in vivo methods. The higher levels of absorption of Se in rats fed with Se enriched mushrooms were verified by Silva et al. (2010), which compared these results with the ones achieved with rats with sodium selenate in their diets.