Effects of Crude Fibrolytic Enzymes from Pleurotus ostreatus Spent Mushroom Substrate on the In vitro Digestibility and Nutrient Utilization of Broiler Diet

Abstract

Pleurotus ostreatus (oyster mushroom) can grow on agricultural waste with their ability to produce the fibrolytic enzymes including cellulase, hemicellulase, and lignin-degrading enzymes. The objective of this project was to evaluate the effect of spent mushroom substrates (SMS) supplementation on the in vitro digestibility and nutrients utilization of broiler diet. The experimental diets were divided to 5 groups including basal diet (CON), basal diet supplemented with commercial fibrolytic enzymes 1 and 2 with endo-glucanase activity at 500 U per kg diet (CFE1 and CFE2) and basal diet supplemented with Pleurotus ostreatus spent mushroom substrate with endo-glucanase activity at 250, 500 and 1,000 U per kg diet (SMS 0.5×, SMS 1×, and SMS 2×, respectively). SMS contained various fibrolytic activities including cellulose (549.6 and 615.94 U/g for pH 3.0 and 6.8), xylanase (90.75 and 101.71 U/g for pH 3.0 and 6.8), and endo-glucanase (496.42 and 486.14 U/g for pH 3.0 and 6.8). Besides SMS also showed the laccase and protease activities higher than both commercial fibrolytic enzymes (P < 0.05). Fibrolytic enzymes supplementation improved in vitro digestibility and nutrients utilization compared with basal diet (P < 0.05). SMS 1× and SMS 2× showed higher in vitro digestibility and nutrients utilization compared with CFE1 and CFE2 (P < 0.05). It can be summarized that SMS of P. ostreatus have the potential for a source of enzyme supplement in animal feed.