Influence of treating some low-quality forages with exogenous fibrolytic enzymes on ruminal fermentation [electronic resource].

Includes references.

A study was undertaken to assess appropriate fibrolytic enzymes inclusion effects of three fibrolytic enzymes treatments on the In vitro ruminal fermentation of five low-quality forages (three cereal straws (barley, wheat and rice), com stover and Rhodes grass hay) were investigated using batch cultures of mixed ruminal microorganisms. Four different treatments were investigated: no additive (control; CON), cellulase from Aspergillus niger (CEL; Flub Chemie GmbH), xylanase from ruminal microorganisms (XYL; Megazyme International Ireland Ltd), and a 1: 1 mixture cellulase:xylanase (MIX). Enzymes (20 IU/g forage dry matter (DM)) were applied directly into the forages 24 h before incubation with buffered ruminal fluid at 39C for 24 h. The treatment with CEL increased (P<0.05) gas production after 24 h of incubation for wheat straw, barley straw and grass hay. Meanwhile, the treatment with MIX and XYL did not affect (P>0.05) gas production for all forage. For all forages, there was no change (p>0.05) in NH3-N concentration with added enzymes, indicating no differences in protein degradability and/or ammonia-N incorporation by ruminal microorganisms. Also, Natural detergent fiber degradability (NDFD) concentration were not affected (P>0.05) by the addition of enzymes. The treatment of low-quality forages with CEL increased the production of propionate for Rhodes grass hay, com stover and barley straw, and increased (P<0.05) total VFA production for wheat straw and com stover. No effects (p>0.05) of MIX and XYL treatments on VFA production were observed for any substrate. Under the conditions of the present experiment, the pre-treatment of low-quality forages with cellulase and xylanase enzymes produced subtle effects on In vitro ruminal fermentation, suggesting that the used enzymes contributed little, if any, to ruminal fibrolytic activity.

Summary in Arabic.

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