| Popis: |
This study was completed to investigate whether a fibrolytic enzyme preparation with xylanase and cellulase activities (Fibrozyme™, Alltech Inc., Nicholasville, KY, USA), could stimulate in vitro rumen fermentation of alfalfa hay, grass hay and barley straw, and their isolated cell walls as neutral detergent fibre (NDF). Samples (500 mg) of each substrate were incubated in 120 ml bottles with 50 ml of buffered rumen fluid from sheep at 39 °C. The enzyme preparation was added directly to the bottles at the beginning of the incubation at levels of: 0 (control; CON), 50 mg/g substrate DM (LOWFIB) and 100 mg/g substrate DM (HIGHFIB). Effects on volatile fatty acid (VFA) production depended on substrate and incubation time. After incubation for 5 h, enzyme addition increased (P versus CON for both alfalfa hay and its isolated cell wall, and decreased (P versus LOWFIB in all variables. Both doses of enzyme addition reduced (P versus CON, with some dose effects on both substrates. Enzyme supplementation also increased (P versus CON in barley straw and its isolated cell wall at 5 and 10 h of incubation, with dose dependent effects after incubation for 5 h with higher (P versus LOWFIB in both substrates. Both enzyme doses also reduced (P in vitro fermentation of substrates at short (5 and 10 h), but not at long (24 h) incubation times, and that effects depended on both the dose used and the presence of neutral detergent soluble components in the substrate. |
Full Text from ScienceDirect