Editor: Jim Prosser
Quantitative analysis of cellulose degradation and growth of cellulolytic bacteria in the rumen
Article first published online: 19 DEC 2008
Journal compilation © 2008 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. No claim to original US government works
FEMS Microbiology Ecology
Volume 67, Issue 2, pages 183–197, February 2009
How to Cite
Russell, J. B., Muck, R. E. and Weimer, P. J. (2009), Quantitative analysis of cellulose degradation and growth of cellulolytic bacteria in the rumen. FEMS Microbiology Ecology, 67: 183–197. doi: 10.1111/j.1574-6941.2008.00633.x
- Issue published online: 22 DEC 2008
- Article first published online: 19 DEC 2008
- Received 5 August 2008; revised 26 September 2008; accepted 28 September 2008.First published online December 2008.
- cellulose digestion;
- bacterial growth;
Ruminant animals digest cellulose via a symbiotic relationship with ruminal microorganisms. Because feedstuffs only remain in the rumen for a short time, the rate of cellulose digestion must be very rapid. This speed is facilitated by rumination, a process that returns food to the mouth to be rechewed. By decreasing particle size, the cellulose surface area can be increased by up to 106-fold. The amount of cellulose digested is then a function of two competing rates, namely the digestion rate (Kd) and the rate of passage of solids from the rumen (Kp). Estimation of bacterial growth on cellulose is complicated by several factors: (1) energy must be expended for maintenance and growth of the cells, (2) only adherent cells are capable of degrading cellulose and (3) adherent cells can provide nonadherent cells with cellodextrins. Additionally, when ruminants are fed large amounts of cereal grain along with fiber, ruminal pH can decrease to a point where cellulolytic bacteria no longer grow. A dynamic model based on stella® software is presented. This model evaluates all of the major aspects of ruminal cellulose degradation: (1) ingestion, digestion and passage of feed particles, (2) maintenance and growth of cellulolytic bacteria and (3) pH effects.