Effects on voluntary food intake of infusions of glucose and amino acids into the hepatic portal vein of chickens.

The hepatic portal veins of cockerels were catheterised to study the effects of 3-h infusions of nutrient solutions on voluntary food intake. An amino acid mixture, infused at rates up to 800 mg N/3 h, depressed intake of a standard diet in a significant linear manner (intakes with the highest dose and control: 1.6 g and 22.6 g/3 h respectively). Infusion of the highest dose into the jugular vein had a smaller and nonsignificant effect (17.2 and 25.3 g/3 h). The effects of combined infusion of amino acids and glucose into the portal vein on food intake were approximately additive.