Improvement of in situ ruminal cellulose and hemicellulose degradation of corn stover with 2-methylbutyrate supplementation
was attributed to increased microbial enzyme activities of CMCase, xylanase and -glucosidase, while reduction
in CP degradability of concentrate and in methane production was attributed to the decrease in microbial enzyme activities
of protease and in population of total methanogens or protozoa. Changes in the microbial enzyme activities were due to the
altered microbial population profiles in the rumen. Increasing 2-methylbutyrate supplementation linearly increased population
of predominant cellulolytic bacteria (R. albus, R. flavefaciens, B. fibrisolvens and F. succinogenes). The results suggested that
2-methylbutyrate modulated the ruminal microbial population or microbial enzyme activities in a dose-dependent manner
with the optimum daily dose of 16.8 g per steer being suggested because the further increase in the dose of 2-methylbutyrate
had limited beneficial effect under the present feeding condition.