Evaluation of Microbially Ensiled Spent Mushroom (Pleurotus osteratus) Substrates (Bed-Type Cultivation) as a Roughage for Ruminants

An in situ ruminal disappearance trial and an in vivo sheep metabolism trial were conducted to evaluate the nutritional value of spent mushroom substrate (SMS, originated from Pleurotus osteratus bed-type cultivation). The raw SMS was ensiled (ESMS) for 30 days with 5% (w/w, DM basis) molasses, 0.5% (v/w) yeast (Saccharomyces cerevisiae) and 0.5% (v/w) lactic acid bacteria (Lactobacillus plantarum). Two ruminally cannulated Holsteins (average BW 620 kg) were used to evaluate in situ disappearance. Six sheeps (average BW 48 kg) were fed, in 3 × 3 Latin square design, rice straw alone (Control), 25% (ESMS-25) and 50% (ESMS-50) of rice straw were replaced with ensiled SMS. For an in situ trial, ruminal DM and neutral detergent fiber (NDF) disappearance of SMS were increased after ensiling (P 0.05) as rice straw was replaced with ensiled SMS. Ruminating time was decreased by an average of 28% by feeding ensiled SMS (P<0.05). Ensiled SMS (Bed-type cultivation) had 76% of energy value of rice straw. Consequently, ensiled SMS (Bed-type cultivation, 100% cotton waste) could be used as a roughage source appropriate for maintenance type rations for ruminants. (Key words : Spent mushroom substrate, Spent mushroom compost, By-products, Ensiling, Roughage, Ruminant)