Skip to main content Accessibility help

Effects of inoculum source, pH, redox potential and headspace di-hydrogen on rumen in vitro fermentation yields

  • L. P. Broudiscou (a1), A. Offner (a1) and D. Sauvant (a2)


This in vitro study aimed at understanding how abiotic, that is chemical and electrochemical potentials, and biotic factors combine to impact the outputs of rumen volatile fatty acid (VFA). Using a 48-run design optimized by means of an exchange algorithm, the curvilinear effects of pH, Eh and partial pressure of dihydrogen (H2) on fermentation yields were investigated in 6-h batch cultures of mixed rumen microbes, fed on glucose so as to bypass the enzymatic hydrolysis and conversion steps preceding the glycolytic pathway. The role played by rumen microbiota in the expression of these effects was explored by testing three inocula grown on feeds supplying a microflora adapted to fibre, slowly degradable or readily degradable starch as the dominant dietary polysaccharide. Data were fitted to 2nd-order polynomial models. In fibre-adapted cultures, the yields of major VFA were mainly influenced by pH and H2 partial pressure, in opposite ways. In wheat grain-adapted cultures, the VFA yields underwent the opposite influences of pH, in a curvilinear way for propionate, and Eh since acetate production yield was not significantly modified by any factor. In maize grain-adapted cultures, acetate production yield was not modified by any factor but H2 in a quadratic way when the production yields of higher VFA underwent opposite influences of pH and Eh. In conclusion, the effects of environmental factors were dependent on the nature of the inoculum, a major source of variation, and more particularly on its adaptation to high- or low-fibre diets. These effects were loosely interrelated, the pH being the most active factor before the Eh and H2 partial pressure.


Corresponding author


Hide All
Abbe, K, Takahashi, S and Yamada, T 1982. Involvement of oxygen-sensitive pyruvate formate-lyase in mixed-acid fermentation by streptococcus-mutans under strictly anaerobic conditions. Journal of Bacteriology 152, 175182.
Alemu, AW, Dijkstra, J, Bannink, A, France, J and Kebreab, E 2011. Rumen stoichiometric models and their contribution and challenges in predicting enteric methane production. Animal Feed Science and Technology 166–167, 761778.
Barry, TN, Thompson, A and Armstrong, DG 1977. Rumen fermentation studies on 2 contrasting diets. 1. Some characteristics of invivo fermentation, with special reference to composition of gas-phase, oxidation-reduction state and volatile fatty-acid proportions. Journal of Agricultural Science 89, 183195.
Bergman, EN 1990. Energy contributions of volatile fatty-acids from the gastrointestinal-tract in various species. Physiological Reviews 70, 567590.
Broudiscou, LP, Papon, Y and Broudiscou, AF 1999. Optimal mineral composition of artificial saliva for fermentation and methanogenesis in continuous culture of rumen microorganisms. Animal Feed Science and Technology 79, 4355.
Demeyer, DI and Van Nevel, CJ 1975. Methanogenesis, an integrated part of carbohydrate fermentation and its control. In Digestion and metabolism in the ruminant (ed. IW McDonald and ACI Warner), pp. 366382. University of New England Publishing Unit, Armidale.
Grant, RJ and Weidner, SJ 1992. Digestion kinetics of fiber – influence of in vitro buffer ph varied within observed physiological range. Journal of Dairy Science 75, 10601068.
Hoover, WH 1986. Chemical factors involved in ruminal fiber digestion. Journal of Dairy Science 69, 27552766.
Hungate, RE 1966. The rumen and its microbes. Academic Press, New York, USA.
Kristensen, NB 2000. Quantification of whole blood short-chain fatty acids by gas chromatographic determination of plasma 2-chloroethyl derivatives and correction for dilution space in erythrocytes. Acta Agriculturae Scandinavica Section A Animal Science 50, 231236.
Leedle, JA, Barsuhn, K and Hespell, RB 1986. Postprandial trends in estimated ruminal digesta polysaccharides and their relation to changes in bacterial groups and ruminal fluid characteristics. Journal of Animal Science 62, 789803.
McAllister, TA and Newbold, CJ 2008. Redirecting rumen fermentation to reduce methanogenesis. Australian Journal of Experimental Agriculture 48, 713.
Miller, TL and Wolin, MJ 1995. Bioconversion of cellulose to acetate with pure cultures of ruminococcus albus and a hydrogen-using acetogen. Applied and Environmental Microbiology 61, 38323835.
Mitchell, TJ and Bayne, CK 1978. D-optimal fractions of three-level factorial designs. Technometrics 20, 369383.
Offner, A and Sauvant, D 2006. Thermodynamic modeling of ruminal fermentations. Animal Research 55, 343365.
Richter, M, Krizova, L and Trinacty, J 2010. The effect of individuality of animal on diurnal pattern of ph and redox potential in the rumen of dry cows. Czech Journal of Animal Science 55, 401407.
Russell, JB 1992. Glucose toxicity and inability of bacteroides ruminicola to regulate glucose transport and utilization. Applied and Environmental Microbiology 58, 20402045.
Russell, JB and Hino, T 1985. Regulation of lactate production in streptococcus-bovis – a spiraling effect that contributes to rumen acidosis. Journal of Dairy Science 68, 17121721.
Shriver, BJ, Hoover, WH, Sargent, JP, Crawford, RJ and Thayne, WV 1986. Fermentation of high concentrate diet as affected by ruminal ph and digesta flow. Journal of Dairy Science 69, 413419.
Sweeney, RA and Rexroad, PR 1987. Comparison of LECO FP-228 ‘nitrogen determinator’ with AOAC copper catalyst kjeldahl method for crude protein. Journal of AOAC International 70, 10281030.
Thauer, RK, Jungermann, K and Decker, K 1977. Energy-conservation in chemotrophic anaerobic bacteria. Bacteriological Reviews 41, 100180.
Van Soest, PJ, Robertson, JB and Lewis, BA 1991. Methods for dietary fiber, neutral detergent fiber, and nonstarch polysaccharides in relation to animal nutrition. Journal of Dairy Science 74, 35833597.
Weatherburn, MW 1967. Phenol-hypochlorite reaction for determination of ammonia. Analytical Chemistry 39, 971.


Type Description Title
Supplementary materials

Broudiscou supplementary material
Broudiscou supplementary material

 Word (61 KB)
61 KB

Effects of inoculum source, pH, redox potential and headspace di-hydrogen on rumen in vitro fermentation yields

  • L. P. Broudiscou (a1), A. Offner (a1) and D. Sauvant (a2)


Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed