associated protozoa (PAP). The biomass was relatively stable throughout a day, but the highest mass was recorded at 2h after feeding. Both the total and specific activities of CMCase and xylanase from the strained solid, LP, and SP decreased until 6h (P<0.05), and then recovered to the level at 0h. SP tended to have a higher specific activity of CMCase than LP with significance (P<0.05) at 2h. No significant difference was observed in total activities of CMCase and xylanase between LP and SP,

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... cept a higher total activity of xylanase at 0h in LP (P<0.05). More PAB was separable at 0h from strained solid and LP than other sampling times. The PAP mass was higher in LP than in SP at 2h and 6h after feeding (P<0.05). Neutral detergent fiber disappearance of feed particles collected from the rumen at various time points was determined by in situ incubation for 120h and showed that LP taken at any time points is more digestible than SP, though the difference tended to decline at late stage after feeding. From these results, it is suggested that rumen microbes, in particular bacteria, play a main role in plant fiber degradation via attachment and enzyme production, which extents vary with fiber size and age in the rumen.