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

Abstract

Extensive studies on in vitro rumen degradation of DM and fibrous components from 9 nutritively diffcrent substrates(CP 2.1 to 20.3%, NDF 50.3 to 77.7%) by Ruminococcus albus pure culture were discerned. The gases--generaled 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) whilte the corresponding values for NDF, ADF and cellulose varied tram 22.7,20.6 and 21.7% (sugarcane bagasse) to 29.2, 27.1 and 27.6% (wheat straw), respectively. Least (P<0.95) degradation of DM and cell wall components in sugarcane bagasse pinpointed its high cellulose crystallinity to impair rumihal cellulolysis. The DM degradation by Ruminococcus albus pure culture, which was correlated with hemicclfulose to cellulose ratio in feedstuffs, was not substantiated with rumen gas pool size. Of the fractionated ruminal gases, CO₂ (35.S ml) and CH₄ (28.1 ml/05g) 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 CO₂ and CH₄ production was in 60:40 ratio. D 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.