Enhancing the nutritional value of canola meal through solid culture with Pleurotus ostreatus

Canola or rapeseed meal is a source of high-value protein, vitamins, and minerals. However, its feeding application for monogastric animals has been impeded due to the presence of antinutrients and undigestible fiber. Microbial bioconversion can be a viable method to degrade these components, increase the content of proteins and key amino acids, and improve the digestibility. In this study, edible Pleurotus ostreatus was inoculated on the canola meal for the fungal bioconversion. To assess the optimum fermentation conditions, critical feed parameters of the fermented samples were analyzed and compared to the non-fermented meal. The optimum growth conditions of P. ostreatus were at 65% moisture content and 8 days of fermentation. Illumination before spore germination and agitation during the cell cultivation could negatively affect the fungal protein production. With the bioconversion using P. ostreatus, the protein content of the fermented canola meal increased by 19.2%; meanwhile, the glucosinolates, sinapine, and phytate content of the meal decreased by 96.7%, 95.5%, and 55.0%, respectively. The total lipid content of the fermented samples decreased as this fungus is lipolytic rather than lipogenic. Furthermore, the applied treatment did not have any adverse effects on the in vitro digestibility of dry matter (DM) in the fermented meal. The obtained data demonstrate the feasibility of the P. ostreatus fermented canola meal to be applied as an economical, high-quality supplement in the monogastrics industry.