Chemical composition and in vitro digestibility of rice straw treated with Pleurotus ostreatus, Pleurotus pulmonarius and Pleurotus tuber-regium

Abstract

The nutritive value of rice straw treated with three different edible mushrooms: Pleurotus ostreatus (POR), Pleurotus pulmonarius (PPR) and Pleurotus tuber-regium (PTR) were studied through analysis of their proximate composition, mineral composition, crude fibre fractions and in vitro digestibility. Results of the proximate analysis showed an increase in the crude protein from 4.69 % in control to 7.69 % for PTR. Fungal treatment decreased crude fibre from 32.89 % in control to 19.96 % in PTR. Treatment effect on cellulose, neutral detergent fibre, acid detergent fibre and acid detergent lignin was significant. The mineral contents (g.kg-1 DM) showed that PPR had the highest concentration of Ca (11.04) and Mg (5.00), and a significantly highest gas volume was obtained in PPR and the gas production rate constant (C) was not significant. The estimated metabolisable energy (ME) (MJ.kg-1 Dm), organic matter digestibility (OMD %) and short chain fatty acid (SCFA) (µm) ranged from 6.47 (control) to 7.54 (POR), 51.17 (control) to 57.02 (POR) and 0.657 (control) to 0.848 (POR). Treatment effect on the insoluble but degradable fraction (b) was significant ranging from 22 mL in control to 28.33 mL in PTR. It is therefore concluded from this study that treatment of rice straw with different edible mushrooms improved the potential feeding value of the resultant substrate. Therefore, the product of fungal treatment has a good potential as feed resources for ruminants.