Formulation of silages from spent mushroom substrates of Pleurotus ostreatus and Lentinula edodes: Organoleptic properties, phenolic content, in vitro digestibility, gas production and ruminal kinetics

To fulfill the global demand for sustainable livestock production and the implementation of circular economy models, the search for alternative feed sources to lower production cost has increased significantly. The use of agro-industrial waste has proven to be a low-cost strategy for animal feed. The present study evaluates the use of spent mushroom substrate (SMS) from Pleurotus ostreatus (strain Po-IAP) and Lentinula edodes (strain L5) as an ingredient for silage. A total of eight micro-silages were formulated using SMS and ground yellow corn in the following proportions (%SMS: % corn): 100:0, 90:10, 80:20 and 70:30. Differences in the nutritional composition, secondary metabolite content, in vitro digestibility (IVDMD), and fermentation parameters were evaluated. Organoleptic analysis showed that silages with 70% SMS had better color and odor profile compared with silages with 80, 90 and 100% SMS. Lentinula edodes silages had the highest content of phenolic compounds (8.2-9.0 mg GAE/g DM) compared with Pleurotus ostreatus (strain Po-IAP) silages. Silages with 70% SMS inclusion had higher IVDMD. Silages with 70% Lentinula edodes (strain L5) SMS had the highest gas production and Silages with 70% Pleurotus ostreatus (strain Po-IAP) SMS showed a shorter lag phase. Overall, the results obtained in the present study indicate that the formulation of silages with 70% of SMS had good organoleptic characteristics and nutritional qualities that improves IVDMD, and fermentative parameters and they therefore could be used as animal feed. Further, in vivo studies are recommended to fully evaluate the possible health effects of these silages on animal health and to evaluate its impact on production cost.