title: Effect of dietary energy intake on tubular reabsorption of urea in sheep.
abstract: The aim of the experiment was to determine the effect of dietary energy intake on renal urea excretion in sheep with different nitrogen intakes. The control sheep, with a high nitrogen and energy intake, were given a daily feed dose of 21.18 g N and 15.2 MJ digestible energy (DE). The two experimental groups, with an equal, low nitrogen intake, were given diets with a different energy content. The high energy diet contained 3.63 g N and 14.18 MJ DE, the low energy diet 3.4 g N and 6.44 MJ DE. After nine weeks' adaptation to the diets, renal functions were measured by a standard clearance technique. It was found that, under stable urine flow conditions, both groups given the low nitrogen diet had a significantly lower glomerular filtration rate, fractional urea excretion and total urea excretion. A reciprocal comparison of these two groups showed that fractional urea excretion by the sheep with a high energy intake was significantly lower than in the group with a low energy intake. There were no differences in the glomerular filtration rate. A raised dietary energy intake in the presence of a low nitrogen intake caused marked natriuresis and kaliuresis. The results indicate that a raised dietary energy intake can be a significant factor in potentiating the renal effect of urea retention in sheep with a low nitrogen intake.
authors.affiliation: Institute of Animal Physiology, Slovak Academy of Sciences, Kosice.
authors.forename: S
authors.initials: S
authors.lastname: Faix
authors.forename: L
authors.initials: L
authors.lastname: Leng
authors.forename: M
authors.initials: M
authors.lastname: Szanyiová
authors.forename: K
authors.initials: K
authors.lastname: Boda
mesh_terms: D000818:Animals; D004032:Diet; D002149:Energy Intake; D005919:Glomerular Filtration Rate; D007684:Kidney Tubules / Q000378:metabolism*; D009584:Nitrogen / Q000008:administration & dosage*; D012756:Sheep / Q000378:metabolism*; D014508:Urea / Q000097:blood / Q000378:metabolism*
chemical_list: D014508:Urea; D009584:Nitrogen