Factors Affecting Ketogenesis from Butyric Acid in the Ruminant

Abstract

Intraruminal infusion of butyrate at approximate rates of either 8 or 16 mmole/kg/24 hr to goats for 60 hr under varying degrees of fasting resulted in similar minor accumulations of blood ketone bodies. Under these conditions, no difference in the metabolism of butyrate was noted, whether it was administered as the free acid or at a pH of 6.5. Markedly increased ketone body accumulation resulted from increased rates of butyric acid infusion in goats with phlorizin-induced hypoglycemia. Intravenous glucose, intravenous propionate, or intraruminal propionate were equally effective in largely suppressing ketogenesis from butyric acid in the phlorizinized goat. The most marked ketogenesis from butyrate occurred when administered intraruminally to fasted goats in late pregnancy. Intraruminal propionic acid, when superimposed on the butyric acid infusion, essentially eliminated the ketone body accumulation in this condition. Elevated plasma nonesterifled fatty acids during fasting were lowered when marked ketone body accumulation occurred, even when no butyric acid was administered. The evidence for a feedback mechanism for control of ketogenesis is discussed. © 1966, American Dairy Science Association. All rights reserved.