Effect of food intake level on arterial glycaemia, portal glucose appearance and intestinal oxygen consumption in the pig

摘要

In this study the glycaemic and insulinic responses to a mixed meal of graded size, have been investigated in a pig model in relation to portal glucose appearance. Additionally, nutrients potentially contributing to intestinal energy demand during absorption were identified. Nutrient (glucose, glutamine, and glutamate) and oxygen balances across the small intestine were thus measured over 3 h in conscious 50-60 kg Large White pigs receiving graded levels of a casein-starch based diet (200, 400 or 800 g). Arterial blood glucose response was similar, irrespective of the food intake level, remaining high 3 h after the meal, whereas the pattern of net glucose appearance in the portal vein clearly differed between the 200 g and 800 g feeding level. Intestinal oxygen uptake was highly correlated with nutrient (glucose) absorption, both being maximum within 2 h after the meal. This was accompanied by a high glutamine and glutamate consumption by the intestine, which could account for the additional oxygen consumption during nutrient absorption. In conclusion, changes in blood glucose concentration in the peripheral blood do not adequately reflect glucose absorption. The latter is accompanied by an increase of oxygen consumption in the intestine, supported by glutamine and glutamate (rather than glucose) metabolism.