Co-fermentation with multiple-strains and cellulase enhances the nutritional quality of hot-pressed rapeseed meal by modifying its physicochemical properties

The thermal damage of proteins and the presence of anti-nutritional factors seriously affect the quality of hot-pressed rapeseed meal (RSM), thereby limiting its utilization in the feed and food industry. Previously, we developed a co-fermentation method with multi-strains and cellulase that can simultaneously degrade the protein and anti-nutrient components in hot-pressed RSM. This study aimed to evaluate the impact of fermentation on the physicochemical properties and nutritional value of hot-pressed RSM. After fermentation, the levels of neutral detergent fiber (NDF) and glucosinolate (GLS) in hot pressed RSM decreased by 41.47% and 77.30%, respectively, and the trichloroacetic acid-soluble protein (TASP) and lysine contents increased by 1007.62% and 65.25%, respectively. During the fermentation process, the extensive hydrolysis of rapeseed protein resulted in a 49.11% yield of peptides < 3K Da, and intensified the umami, saltiness, sweetness, and bitterness of fermented rapeseed meal (FRSM). Animal experiments demonstrated that co-fermentation effectively enhances the ileal digestibility of most amino acids in hot-pressed RSM, as well as the deposition of nitrogen and energy, thereby improving the growth of growing pigs. Overall, the co-fermentation with microbes and cellulase is an effective strategy for enhancing the quality of hot-pressed RSM. • Fermentation effectively degraded anti-nutritional factor in rapeseed meal (RSM). • The yield of peptides < 3 KDa in fermented RSM reached 49.11%. • Fermentation improved the digestibility of most amino acids of RSM. • Fermentation improved the nitrogen and energy utilization of RSM. • Fermented RSM improved the body weight gain and feed conversion rate of pigs.