PSXIII-20 Comparing the nutritive value of corn stover, corn silage and Pleurotus ostreatus spent mushroom substrate using rumen simulation technique (RUSITEC) as a ruminant feed.

Abstract This study compared the nutritive value of corn stover, corn silage and spent mushroom (Pleurotus ostreatus) substrate (SMS) in addition to corn silage and SMS mixture (1:1, w/w) using the rumen simulation technique (RUSITEC) system with sixteen fermentation vessels, four replicates per treatment in a completely randomized design. The experiment lasted for 9 d. Three rumen-cannulated Black Angus beef cows were used as the rumen inoculum donors. Corn silage had the highest nutrient quality, with significantly higher (P < 0.001) dry matter, organic matter, and crude protein than stover. Fiber fractions, including neutral detergent fiber (NDF), were highest in stover and reduced in silage and silage + SMS, with silage showing the greatest reductions. Corn silage exhibited the lowest (P < 0.001) fermentation pH, compared to stover, without significant effects on gas volume, fluid volume or ammonia-N. Moreover, no significant differences in methane, carbon dioxide, ammonia or hydrogen sulfide emissions were found between different substrates. Silage showed significantly higher DM digestibility (DMD) compared to stover, while SMS had the lowest DMD (P < 0.001). Corn silage showed a significant decrease (P < 0.001) in NDF and acid detergent fiber digestibility. Hemicellulose and cellulose digestibilities were highest in stover, with reductions in silage and SMS treatments (P < 0.001). Minimal changes were observed in total and individual volatile fatty acids. These findings suggest that corn silage, particularly when combined with SMS, enhances nutrient quality and fermentation efficiency, with potential benefits for livestock feeding strategies.