Protein fraction, mineral profile, and chemical compositions of various fiber-based substrates degraded by Pleurotus ostreatus

The objective of this study was to characterize the substrates after their degradation by P. ostreatus within 60 days of cultivation in four Mexican mushroom-producing companies, in order to use it as a complement feed for ruminants. The acid detergent fiber (ADF), neutral detergent fiber (NDF), protein fraction, and mineral profile were analyzed after degradation. Crude protein (CP) of companies 1 and 4 increased by 6.1% and 6.8%, respectively (p ≤ 0.05). Soluble nitrogen reached 60% relative to un-degraded substrate with 43.8%. Proteins A, B1, and B3 fractions increased compared to controls (p ≤ 0.05) at some companies. The B2 fraction was decreased in all the degraded substrates (p ≤ 0.05), but the C fraction at companies 1, 2, and 3 presented no significant differences with respect to their controls (p ≤ 0.05). Crude fiber (CF), ADF, NDF, and hemicellulose (HC) decreased while dry matter digestibility (DMD) increased to 55.5-58% on degrade substrates. The mineral composition increased disproportionately. The substrate degraded by P. ostreatus by improving its digestibility and soluble protein content may be a low-cost food supplement. However, due to its mineral imbalance, it is not recommended as the sole food source for ruminants.