Effects of feeding maize or lucerne on blood metabolites, plasma insulin, and pancreatic insulin concentrations in lambs

Abstract

Pancreatic insulin concentrations are influenced by the composition of the diet but the mechanism responsible for the change is not always clear. Possible mechanisms were investigated in this work by feeding maize or lucerne pellets to lambs and examining the effect on blood metabolites, glucose tolerance, and pancreatic insulin concentrations. Feeding maize pellets significantly increased blood glucose (54.1 v. 46.9 mg01o), plasma insulin (27.3 v. 16.3 flU/ml), pancreatic insulin (435 v. 235 IU/lOO g pancreas), and glucose clearance (T~= 20.5 v. 25.3 min) compared to lucerne pellets. There were no significant differences in the molar percentages of blood propionate or concentrations of blood urea. It is concluded that starch escaping rumen fermentation in lambs fed maize increases blood glucose concentrations which stimulates the pancreatic secretion of insulin; the latter is responsible for the elevation in plasma and pancreatic insulin concentrations.