Production and Absorption of Organic Acids by the Perfused Goat Rumen. ∗

Abstract

Summary

1) Any inferences drawn from data of perfusion experiments must obviously be tempered by artificial conditions under which the tissue is operating. While recognizing that there are limitations it seems that a picture of the overall metabolism of the rumen may be formulated. 2) Large quantities of organic acids are normally produced in the rumen. On a diet of hay and grain relative rates of production of the VFA are in the order acetate > propionate > butyrate > valerate. Lactate may also be produced. Calculations based on data from perfusion experiments indicates that the organic acids are capable of providing up to 53% of the estimated net energy requirements of the animal. 3) Inter-conversion of organic acids may occur in the rumen. Butyrate in the rumen was converted to appreciable amounts of acetate and propionate and to lesser amounts of valerate and lactate. The interconversion of propionate in the rumen was negligible. 4) Acids produced in the rumen are absorbed as such into the blood of the animal, and relative quantities of these acids absorbed are, in general, a reflection of their production in the rumen. Rumen acids do not serve as the immediate precursors of blood acetone bodies. However, these acids apparently can contribute in part to the metabolism of the ruminal tissue.