Pleurotus ostreatus Can Significantly Improve the Nutritive Value of Lignocellulosic Crop Residues

Improvement in the nutritive value of corn stover after solid-state fermentation with Pleurotus ostreatus is reported. Two ruminally cannulated dairy cows were used in an in vitro study arranged in a 2 × 3 factorial design with four replicates using P. ostreatus-treated corn stover. The increase in crude protein (58.5%) and ash (25.8%) contents of the treated stover were significantly higher (p < 0.001) than the control. Results suggest a potential increase in in vitro microbial protein synthesis due to a consistent increase (p < 0.001) in microbial mass yield (106–681%), irrespective of the incubation time. The fiber components of the corn stover, except lignin, were significantly reduced (p < 0.05), and the non-fiber carbohydrates were increased by 118% in the treated samples. There was a significant (p < 0.001) increase in both in vitro dry matter disappearance (40.9–240%) and total VFA (5.85–11.2%). Treatment and time interaction was significant (p < 0.001) for propionate production (9.37–14.0%), indicating that the propionate rumen fermentation pathway was preferred. Acetate concentration was reduced (1.76–4.01%), which also resulted in a 7.09–11.42% decrease in the A:P ratio. Overall, results showed that P. ostreatus improved the nutritive value of corn stover by increasing its energetic values, crude protein, microbial mass, and total volatile fatty acid concentrations.