The effect of intragastric infusion of glucose, lipids or acetate on fasting nitrogen excretion and blood metabolites in sheep.

Two experiments are reported in which the effect of the intragastric infusion of non-protein energy on fasting nitrogen losses was studied. Expt 1 was a preliminary trial with two 35 kg lambs given 0, 144, 288 or 432 kJ/kg live weight (W)0.75 per d as lipid or glucose infused into the abomasum for periods of 3 d. Expt 2 was of a 4 X 4 Latin square design with four sheep of about 30 kg live weight. The four treatments were control (fasted with water infusion), or the infusion of 144 kJ/kg W0.75 per d as glucose or lipid into the abomasum or as acetic acid into the reticulo-rumen. Compared with the fasted control, glucose infusion reduced (P less than 0.05) N excretion to about 0.6 of that of the control, increased (P less than 0.05) plasma glucose, decreased (P less than 0.05) plasma urea and beta-hydroxybutyrate, and was without effect on plasma amino-N or creatinine excretion. Lipid and acetate infusions were without statistically significant effect on N or creatinine excretion or any of the blood indices measured, with the exception of plasma glucose which was reduced (P less than 0.05) with acetate infusion.