Influence of Fibrolytic Enzymes on the in vitro Hydrolysis and Fermentation of Different Types of Roughages Treatment

The effects of pre-treating different types of roughages with alkali on the efficacy of exogenous fibrolytic enzymes for improving their digestibility were studied in vitro in factorial arrangement 4 × 3 × 5 (enzyme, treatment and roughage types). Two fibrolytic feed enzymes novozyme (N) and celloclast (C) their combi-nation (N+C) were evaluated for their potential to improve in vitro degradation of different roughages in-cluding two straws (wheat straw: WS; barley straw: BS), grass hay (GH), corn stover (CS) and corn cobs (CC) as untreated or alkaline treated (NaOH or urea). The enzyme products were in liquid form and applied at a rate of 1 mg enzyme protein/g DM substrate. Anaerobic buffer medium and strained ruminal fluid were added to the in vitro incubations. Degradabilities of dry matter (DM), neutral detergent fibre (NDF), cellu-lose, soluble protein and reducing sugar profiles were determined at the end of the 24 h incubation. Overall NDF degradability of roughages were slightly increased by alkaline treatment (P < 0.05) but, the addition of fibrolytic enzymes directly to the ruminal fluid at the application rates could not increase significantly DM or cellulose degradation (P > 0.05). Use of fibrolytic enzymes released higher amounts of reducing sugars and lower soluble protein compared to control (P < 0.05). Alkali treatment increased (P < 0.05) the degrad-ability of DM and fiber degradability. It was higher in NaOH treated forage compared to urea treated for-ages (P < 0.05).