Kinetics of ethanol metabolism in sheep.

Kinetic aspects of ethanol metabolism were studied in sheep after intravenous or intraruminal infusion of ethanol. Vmax and Km in fed animals were respectively 295 +/- 10 mg.h-1.l-1 (l = litre of body water) and 32.1 +/- 2.4 mg.l-1. Elimination half-life was 1.47 +/- 0.26 h. The corresponding values in the fasted animal were not significantly different. During venous infusion an increase in plasma acetate, inversely correlated to plasma ethanol, was observed. No modification in glycemia occurred. Intraruminal infusion of ethanol increased the concentration of all SCFA in the rumen juice, the largest part of this modification being relative to acetate. Repetition of the infusion over a period of 11 consecutive days increased the number of SCFA in the rumen, indicating microflora adaptation to ethanol utilization. Taking into account the range of ethanol concentrations found in silage (10-50 g.kg-1 BW) we can consider that ethanol is readily metabolized simultaneously by the rumen microflora and the enzymatic system of the host. With a corresponding daily intake of ethanol (0.2-1 g.kg-1 BW) both systems are not saturated and plasma ethanol level always remains below 0.25 g.l-1.