Glucose in Ruminants: a Review

Abstract

The role of glucose as an essential nutrient has been evaluated in various ways. Assays with in vitro systems, usually carried out near optimal conditions, provide information about which organ or tissue is capable of metabolizing glucose under normal condition, and the adaptive effect on enzyme activities caused by diet, hormones, or specific metabolites. In the intact animal, metabolism is regulated by homeostatic mechanisms inckding nervous and hormonal control. Furthermore, there are functional relationships between different organs and tissues in the body which are lacking in in vitm systems. Information on glucose metabolism in the intact animal has depended on changes in blood glucose concentration as an index of e.g. the glucogenic behaviour of precursors, although this type of information is ambiguous since blood concentration of metabolites or substrates at any time is the net result of the compound's release and utilization. Special attention will be given to data on transfer quotient (TQ) from precursor into product (glucose) which demonstrate the high glucogenic capacity of our indigenous lactating and latepregnant ruminants.