Upcycling Canola Meal as Compared to Soybean Meal by Fungal Bioconversion for Potential Monogastric Animal Nutrition

Abstract

Canola meal (CM) produced after oil extraction has potential to be used as a nutrient-rich feeding ingredient for monogastric animals if its fiber and anti-nutritional factors can be reduced while essential amino acids (AA) are increased. Fungal bioconversion provides a way of improving feeding value in CM for monogastric animals. This study explored the effects of three fungal strains namely, Rhizopus oryzae (R. oryzae), Mucor indicus (M. indicus), and Trichoderma reesei (T. reesei), via solid state fermentation, on profiles of AA, structure carbohydrates (SC), sinapic acid, and in vitro dry matter digestibility (IVDMD) of CM with and without supplement of urea as a nitrogen source. Soybean meal (SM) was investigated at the same condition as CM for comparison. Flask trials using each substrate with 70% moisture content (MC) were conducted for 192 h at 28 °C. T. reesei was determined as the most effective fungal strain due to its higher improvement of total AA by 10.7%, and threonine (Thr), methionine (Met), and lysine (Lys) by 19.2%, 20.4%, and 14.4%, respectively, when 1% N urea was supplied. T. reesei also degraded more SC (up to 26.6%) and produced more digestible sugars, compared to other strains. In addition, T. reesei treated SM and CM showed higher IVDMD than non-treated compared with other fungi. This study demonstrated the feasibility of fungal strain in improving feeding value of CM and SM for better monogastric animal diet.Graphical Abstract