Figure 5. Gross Energy content (MJ/kg DM) of substrate after 18 weeks of solid-state fermentation using G. lucidum , P .ostreatus and Ganoderma #1 compared to an undigested control.

Quantifying solid-state fermentation

Analysis of variance (ANOVA) indicated time of experimental sampling as the only main effect resulting in significant differences (p < 0.05) for the mean ADF (Table 3) and mean NDF (Table 4). However, mushroom species and time of experimental sampling contributed to significant differences in the mean ADL (Table 5). Means separation indicated all time 0 samples held the highest concentration for all measured degradation parameters, ADF, NDF and ADL. After 18 weeks of solid-state fermentation, all concentrations had collectively reduced by 11.66, 14.84 and 4.76 % (equating to g per 100 g dry matter; DM) for mean ADF, NDF and ADL, respectively (Table 6). The mushroom species which had supreme ability to degrade ADL was Ganoderma # 1, where the lowest mean ADL (16.47 g per 100 g DM) was recorded. Consequently,Pleurotus ostreatus and Ganoderma lucidum had reduced abilities to degrade ADL compared to that of Ganoderma#1, although all mushroom species held the ability to significantly degrade ADL through SSF collectively (Table 6). When viewed individually (Table 7), as indicated by means separation,Ganoderma #1 showed increased degradation of all measured parameters, with the exception of ADF. Additionally, Ganoderma#1 performed significantly greater in degradation capacity when compared to benchmark strains G. lucidum and P. ostreatus(p < 0.05) which did not degrade parameters significantly when compared between each other, although did degrade parameters significantly more than the control (p < 0.05).
Table 3. Analysis of variance for mean acid detergent fibre (ADF) across three mushroom species (Ganoderma lucidum, Ganoderma#1 and Pleurotus ostreatus ), with three substrate grind consistency G2, where samples were taken from experiment initiation (week 0) to competition (week 18).