In vitro rumen fermentation characteristics of different cellulosic feeds by Ruminococcus albus pure culture

Intensive studies on in vitro rumen degradation of DM and fibrous components from 9 nutritively different substrates (CP 2.1 to 20.3%. NDF 50.3 to 77.7%) by Ruminococcus albus pure culture were discerned. The gases generated in the rumen by bacterial fermentation and mixed anaerobic fungi were also profiled. Highest (P<0.05) disappearances of DM (55.5%), NDF (40.1%), ADF (35.7%) and cellulose (36.5%) was from oat hay followed by sorghum stover (50.4, 37.3, 31.9 and 34.7%). Ruminal degradations, irrespective of test substrates concomitantly increased (P<0.05) with prolonging the incubation of feedstuffs, with bacterium from 12 to 96 hr. Highly lignified feedstuffs exhibited very low (P<0.05) disappearances of DM. which ranged from 34.0% (sugarcane bagasse) to 39.4% (wheat straw) while the corresponding values for NDF. ADF and cellulose varied from 22.7, 20.6 and 21.7% (sugarcane bagasse) to 29.2. 27.1 and 27.6% (wheat straw), respectively. Least (P<0.05) degradation of DM and cell wall components in sugarcane bagasse pinpointed its high cellulose crystallinity to impair ruminal cellulolysis. The DM degradation by Ruminococcus albus pure culture, which was correlated with hemicellulose to cellulose ratio in feedstuffs, was not substantiated with rumen gas pool size. Of the fractionated ruminal gases. CO 2 (35.5 ml) and CH 4 (28.1 ml/0.5g) were maximally produced by the fermentation of sorghum stover while the volume of such gases were least (14.1, 8.2 ml/0.5 g) due to paddy straw. Rumen CO 2 and CH 4 production was in 60:40 ratio. Dry matter degradations by Ruminococcus albus exceeded (P<0.05) than those due to anaerobic fungi either from cattle or buffalo. However, the profile on generated ruminal gases was better due to fungal than bacterial activity.