Dynamics of the redox potential and rh of the rumen fluid of goats.
The redox potential (Eh) of the rumen fluid of goats varied from -145 to -190 mV and the corresponding rH values from 6.3 to 8.6. The redox potential values of the rumen fluid were influenced by changes in pH. The most oxidizing Eh values --and at the same time the lowest rH and pH values--were observed after a feeding ration containing readily available carbohydrates. No relationship was found between the fermentation rate and the redox potential. The association between the oxidation reduction state and the metabolic activity is best expressed by the rH values. In in vitro experiments, a higher pH or the addition of cysteine or sodium sulphide moved the redox potential of the rumen fluid towards more reducing values. A shift towards more oxidizing values occurred after acidification of the medium, or after the action of heavy metal ions or atmospheric O2. Various other compounds, including bubbling of the rumen fluid with hydrogen, had little or no effect. SH-groups probably play an important role in the formation of the negative redox potential in rumen fluid.
D000818:Animals; D006041:Goats; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D012417:Rumen / Q000378:metabolism*