Polluting macrophytes Colombian lake Fúquene used as substrate by edible fungus Pleurotus ostreatus

Invasive aquatic plants from Lake Fúquene (Cundinamarca, Colombia), water hyacinth (Eichhornia crassipes C. Mart.) and Brazilian elodea (Egeria densa Planch.) have been removed mechanically from the lake and can be used for edible mushrooms production. The growth of the oyster mushroom (Pleurotus ostreatus) on these aquatic macrophytes was investigated in order to evaluate the possible use of fruiting bodies and spent biomass in food production for human and animal nutrition, respectively. Treatments included: water hyacinth, Brazilian elodea, sawdust, rice hulls and their combinations, inoculated with P. ostreatus at 3 %. Water hyacinth mixed with sawdust stimulated significantly fruiting bodies production (P = 3.3 × 10^-7) with 71 % biological efficacy, followed by water hyacinth with rice husk (55 %) and elodea with rice husk (48 %), all of these have protein contents between 26 and 47 %. Loss of lignin (0.9-21.6 %), cellulose (3.7-58.3 %) and hemicellulose (1.9-53.8 %) and increment in vitro digestibility (16.7-139.3 %) and reducing sugars (73.4-838.4 %) were observed in most treatments. Treatments spent biomass presented Relative Forage Values (RFV) from 46.1 to 232.4 %. The results demonstrated the fungus degrading ability and its potential use in aquatic macrophytes conversion biomass into digestible ruminant feed as added value to the fruiting bodies production for human nutrition.