Comparison of chemical composition and rumen degradability among four types of straws treated by Trametes versicolor fungus

In this study, the effect of white rot fungus Trametes versicolor on chemical composition and rumen degradability of cumin, wheat, barley and rapeseed straws were investigated and compared. Straws were inoculated with fungus mycelium and were kept in plastic bags at 25-30 °C and 70-80% relative humidity for 21 days. Then straws were dried, milled and their chemical compositions were measured. Rumen degradability was estimated using the nylon bag technique by 3 rams. The results showed that the loss of organic matter only in treated cumin straw was significant (P<0.05). Crude protein content in treated wheat, barley and rapeseed straw was increased whereas in treated cumin straw was significantly lower than control (P<0.05). After treatment with fungus, NDF in cumin straw increased while in the other treatments reduced. The amount of lignin (ADL) in treated wheat straw was lower than control (P<0.05). Among the treated straws, the cumin straw was contained the highest amount of fungal biomass (chitin)/dry matter (P<0.05). Degradability parameters of dry matter among varieties of straw were different and the highest values were observed in treated wheat and barley straw. Degradability of treated cumin straw decreased with increasing incubation time, compared with control (P<0.05). As well as degradability of dry matter at the treated rapeseed straw, showed a significant increase only at 0 and 6 hours (P<0.05). According to findings, it was concluded that effects of growth Trametes versicolor on chemical composition, cell wall components and rumen degradability among varieties of straw was different and in cumin straw, was not effective.