Effect of level of nutrition on splanchnic blood flow and oxygen consumption in sheep

Abstract

The objective of the present study was to measure changes in splanchnic blood flow and oxygen consumption in sheep fed on a high-concentrate diet ad lib. (ADLIB) or an amount sufficient to maintain body-weight (MAINT) for 21 d. Eleven ram lambs were surgically implanted with chronic indwelling catheters in the portal, hepatic and mesenteric veins and mesenteric artery to measure blood flow and net O 2 flux through the liver and portal-drained viscera (PDV). During the 21 d period, PDV ( P < 0.05) and liver ( P < 0.01) blood flow increased in ADLIB and decreased in MAINT lambs (treatment x day, linear). After 21 d, O 2 consumptions in PDV and liver of MAINT lambs were 37 and 63% lower than in ADLIB lambs. In the control period, total splanchnic tissues represented an average of 52% of whole body O 2 consumption. After 21 d, the relative contributions of PDV and liver to whole-body O 2 consumption were 28 and 41% in ADLIB and 19 and 22% in MAINT lambs respectively. Allometric regression variables indicate that liver O 2 consumption responds more rapidly to changes in metabolizable energy intake than portal O 2 consumption. These results indicate that blood flow and O 2 consumption in both PDV and liver are related to level of nutrition. Furthermore, splanchnic tissues represent a significant component of whole-body O 2 consumption that is subject to manipulation by level of nutrition.