Visceral metabolism in sheep

The visceral system is represented by the portal system plus the liver. The portal system in turn is represented by the gastrointestinal tract (rumen reticulum omasum abomasum and intestines) pancreas spleen and mesenteric adipose tissue. The functions performed by this set of visceral organs have a significant and variable energy and protein cost either due to the proportions and types of substances that are metabolized by the tissues that compose them or due to the reactions involved. In fact the mass of the gastrointestinal tract corresponds to only 5 to 10% of total body mass and consumes approximately 20% of the oxygen used by the body. The liver on the other hand despite representing 1 to 3% of total body mass uses up to 40% of all oxygen consumed by the animal's body. The effect of food consumption levels as well as mesenteric infusion of ammonium bicarbonate alanine and arginine on metabolism and energy demand in the viscera drained by the portal vein and in the liver is presented in this work.