Effects of Incubation Temperature and Period on the Digestibility of Spent Corncob Meal Substrate after Cultivation of Pleurotus eryngii

Abstract

To improve the digestibility of spent corncob meal substrate after cultivation of Pleurotus eryngii at a shorter incubation period, we examined the effects of incubation temperature and period on the chemical composition and digestibility of the spent substrate. In Experiment 1, samples of the spent substrate, after cultivating P. eryngii on the substrate consisting of corncob meal and rice bran, were incubated at 17, 20 and 24.DEG.C., each for 20, 40, 60 and 80 days. In Experiment 2, samples of the spent substrate, after cultivating P. eryngii on a substrate containing corncob meal, collected from a mushroom growing company, were incubated at 17, 20 and 24.DEG.C., each for 30 and 60 days. In both experiments, the change of chemical composition in the spent substrate incubated at 24.DEG.C. was greater in the shorter incubation period compared to the other temperatures. In Experiment 1, the in vitro organic matter digestibility (IVOMD) in the spent substrate before incubating was 65.3%, and was elevated to 80.0% by incubating at 24.DEG.C. for 40 days. However, there was no significant difference in IVOMD between 40 and 80 days. In Experiment 2, the IVOMD was elevated from 53.3% to 73.0% through incubating at 24.DEG.C. for 60 days. The IVOMD of the spent substrate used in both experiments was higher than that of rice straw used as control. Since the results of in vitro gas production also showed that digestibility in spent substrate was most improved by incubating at 24.DEG.C., it is concluded that the digestibility of spent substrate is improved by a shorter incubation period at higher temperature. (author abst.)