The objective of this trial was to evaluate the effect of fibrolytic enzymes (cellulase and xylanase) on particle passage rate, dilution rate and ruminal parameters (pH and ammonia N) in animals fed diets containing corn silage or Tifton 85 hay (Cynodon spp.). Eight bovines fitted with ruminal and duodenal cannulas were randomly assigned to two 4 x 4 Latin squares in a 2 x 2 factorial arrangement of treatments (two forage sources supplemented or not with fibrolytic enzymes). A commercial enzymatic complex containing enzymes extracted from Aspergillus niger and Trichoderma longibrachiatum fungi was mixed in the ration and fed (12 g) daily to each animal. Chromium-mordant and Co-EDTA were used as solid and liquid phase markers, respectively, to estimate passage rates. There was no effect of enzymatic supplementation on ruminal pH and ammonia N averaging 6.5 and 22.10 mg/100 mL, respectively, across diets. Similarly, ruminal particle passage rate was not affected by the enzymatic supplementation with mean values of 3.4 and 3.0%/h for animals fed corn silage and Tifton hay, respectively. However, ruminal dilution rate increased from 10.07 to11.84%/h with enzymatic supplementation. Feeding fibrolytic enzymes to bovines had little effect on the measured variables.
cellulase; corn silage; ruminants; tifton hay
