Spent Wheat Straw Compost of Agaricus bisporus Mushroom as Ruminant Feed

Spent compost wheat straw is an available by-product from edible mushroom production, which constitutes a potential pollutant and is cost effective for disposal. This study was conducted to determine the nutritive value as ruminant feed of spent wheat straw compost from Agaricus bisporus mushroom production. The compost was provided from a mushroom farm, the casing soil was removed from the whole compost, and then it was sun dried and sampled for chemical analysis. An experiment was conducted, in which four wheat straw-based diets comprising control (I), 10% spent straw (II), 20% spent straw (III) and 30% spent straw (IV) were tested in a cross-over design using 8 sheep. Dry matter intake (DMI) was 74.0, 73.8, 70.2 and 57.1 and organic matter intake (OMI) was 62.7, 63.4, 58.0 and 44.4 g per kg $BW^{0.75}$ for diets I, II, III and IV, respectively, which, were significantly (p<0.05) lower for diet IV. Digestible OMI was respectively 33.1, 32.6, 30.6 and, 20.2 g per kg $BW^{0.75}$ on the four diets which were significantly (p<0.05) different between the treatments. Inclusion of spent compost straw up to 20% of the diet did not affect the digestibility of DM, OM, CF, ADF and NDF, but the diet containing 30% compost straw had statistically (p<0.05) lower digestibilities. Nitrogen balance was also significantly (p<0.05) different between the treatments.