Determining the amount of chitin and degradation of dry matter and cell wall in treated rapeseed straw by white rot fungus Trametes versicolor

In this study, the effect of white rot fungus Trametes versicolor on chemical composition and rumen degradability of rapeseed (Brassica napus) straw was investigated. Rapeseed straw was inoculated with fungus mycelium and kept in plastic bags for 21 and 40 days. Then straw was dried and milled. Chemical compositions of treated and untreated samples were measured by standard methods and their rumen degradability was estimated using the nylon bag technique by 3 rams. The results showed that the loss of organic matter (OM) only in treated rapeseed straw for 40 days was significant, compared with control (P<0.05). Crude protein (CP) content in treated rapeseed straw for 21 days was significantly higher than control and was not significant with increasing days of fermentation to 40. After treatment with fungus for 40 days, the amount of neutral detergent fiber (NDF), hemicellulose and lignin (ADL) reduced (P<0.05). Total phenolic compounds and tannins in treated straw for 21 days decreased and thereafter at day 40^th was not changed (P<0.05). Amount of chitin/dry matter in treated rapeseed straw for 40 days increased, compared with day 21^th (P<0.05). According to degradability parameters of dry matter, total degradability (a+b) of rapeseed straw showed a significant increase after 40 days treatment (P<0.05). As well as rumen degradability of cell wall constituents in treated rapeseed straw for 40 days was enhanced considerably. The findings showed that treated rapeseed straw by Trametes versicolor has the potential to be a valuable feed source for ruminants.