Methane production and substrate degradation by rumen microbial communities containing single protozoal species in vitro
Article first published online: 17 OCT 2007
Letters in Applied Microbiology
Volume 45, Issue 6, pages 675–680, December 2007
How to Cite
Ranilla, M.J., Jouany, J.-P. and Morgavi, D.P. (2007), Methane production and substrate degradation by rumen microbial communities containing single protozoal species in vitro. Letters in Applied Microbiology, 45: 675–680. doi: 10.1111/j.1472-765X.2007.02251.x
- Issue published online: 17 OCT 2007
- Article first published online: 17 OCT 2007
- 2007/0049: received 12 January 2007, revised 10 August 2007 and accepted 20 August 2007
- Entodinium caudatum;
- Eudiplodinium maggii;
- Isotricha intestinalis;
- Metadinium medium;
Aims: To assess the effect of protozoal species on rumen fermentation characteristics in vitro.
Methods and Results: Entodinium caudatum, Isotricha intestinalis, Metadinium medium, and Eudiplodinium maggii from monofaunated wethers and mixed protozoa from conventional wethers were obtained by centrifugation, re-suspended at their normal densities in rumen fluid supernatants from defaunated or conventional wethers and incubated in vitro. The presence of protozoa increased the concentration of ammonia and altered the volatile fatty acids balance with more acetate and butyrate produced at the expense of propionate. Differences among species were observed, notably in the production of methane, which increased with E. caudatum as compared to other ciliates and to defaunated and mixed protozoa treatments (P < 0·05). The increased methanogenesis was not correlated to protozoal biomass indicating that the metabolism of this protozoan and/or its influence on the microbial ecosystem was responsible for this effect.
Conclusions: Entodinium caudatum stimulated the production of methane, a negative effect that was reinforced by a concomitant increase in protein degradation.
Significance and Impact of the Study: Comparison of individual species of protozoa highlighted the particular influence of E. caudatum on rumen fermentation. Its elimination (targeted defaunation) from the rumen could reduce methane production without affecting feed degradation.