Simultaneous measurements of the rates of production of acetic, propionic and butyric acids in the rumen of sheep on different diets and the correlation between production rates and concentrations of these acids in the rumen

Abstract

1. A technique using a constant infusion of [ U-¹⁴C]acetate, [U-¹⁴C]propionate and [2–3-T]– hutyrate has been developed to measure simultaneously the production rates of acetic, propionic and hutyric acids in the rumen of sheep. 2. Infusions of ¹⁴C-lahelled acids suggested that interconversions of acetic acid or hutyric acid with propionic acid and vice versa were small in extent, hut the conversion of acetic acid into butyric acid accounted for between 40 and 50% of the butyric acid produced. The conversion of hutyric acid into acetic acid accounted for 6–13% of the acetic acid produced in the rumen. 3. The production rates and the concentrations of individual acids in the rumen were simply related. 4. The difference between measured production rate and the rates of conversion of one acid into the other two acids for acctic, propionic and butyric acids, were 85–91%, 91–100% and 53–73% of the measured production rates respectively.