The role of glucose infusion on the metabolism of nitrogen in ruminants.
This work determined the time necessary to stabilize the decrease in urinary N excretion after initiating continuous i.v. glucose infusion and the quantity of glucose required to maximize N balance in growing wether lambs fed a high-protein diet (21.1% CP, DM basis). In the first experiment, six wethers (30 kg) were used in a 10-d crossover design comparing jugular infusion of glucose (600 kcal gross energy/d) plus saline with saline alone. The second infusion experiment was carried out with six wethers (31 kg) assigned to two 3 x 3 plus extra period latin squares, with glucose infusion rates of 0, 300 and 600, and 0, 450 and 900 kcal/d, respectively. Urinary N decreased (P less than .02) by d 2 of glucose infusion, remained stable to the end of the 10-d infusion period, and returned to the preinfusion level within 2 d after glucose infusion was discontinued. Urinary N decreased (P less than .01) and N balance increased (P less than .005) with an increasing level of glucose infusion through 600 kcal/d. Plasma glucose and insulin were elevated (P less than .05) only by infusion of 900 kcal/d of glucose. Glucose was present in the urine of wethers infused with 900 kcal/d of glucose. Glucose infusion had no effect on diet digestibility, hematocrit or plasma urea N. The level of glucose infused into growing wether lambs that maximized reduction of urinary N and was fully utilized for protein deposition without increasing plasma glucose and insulin was about 12 g.Wk-.75.d-1.
Matras
J
J
Texas Tech University, Lubbock 79409.
Preston
R L
RL
D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D004063:Digestion; D005947:Glucose / Q000008:administration & dosage* / Q000378:metabolism; D007262:Infusions, Intravenous / Q000662:veterinary; D007328:Insulin / Q000097:blood; D008297:Male; D009584:Nitrogen / Q000378:metabolism* / Q000652:urine; D012756:Sheep / Q000378:metabolism*; D012965:Sodium Chloride / Q000378:metabolism; D013997:Time Factors; D014508:Urea / Q000097:blood
D001786:Blood Glucose; D007328:Insulin; D012965:Sodium Chloride; D014508:Urea; D005947:Glucose; D009584:Nitrogen