Feeding value improvement of corn-ethanol co-product and soybean hull by fungal fermentation: Fiber degradation and digestibility improvement

Abstract

Fungal pre-treatment and fermentation could improve nutritional value of wet corn distillers’ grains and solubles (WDGS), soybean hull (SH), and their blend in swine and poultry diets, which can potentially increase revenues for corn-ethanol and soybean processing industries while reducing feed cost in swine and poultry production systems. This study evaluated the effectiveness of pre-treatment of SH, WDGS, and their mixture by Trichoderma reesei and fermentation by Aspergillus oryzae to improve the nutritional profile and digestibility of these ingredients. T. reesei produced cellulase and xylanase, resulting in structural carbohydrates reduction by 69.2% while concentrating amino acids from 6.8% to 11% in SH. Fermentation with A. oryzae degraded phytate by over 50% and improved in vitro digestibility of amino acids in WDGS and its mixture with SH. Fermenting T. reesei pre-treated SH by A. oryzae showed higher in vitro dry matter digestibility than non-fermented substrate. Moreover, the proportion of key amino acids (arginine, threonine, methionine, and lysine) in both T. reesei and A. oryzae fermented substrates were significantly improved. The results demonstrated the feasibility of combining T. reesei and A. oryzae in improving feeding value of WDGS and SH for potential use as feed ingredients for monogastric animals.