title: Body fat deposition does not originate from carbohydrates in milk-fed calves.
abstract: Milk-fed heavy calves utilize dietary protein with a low efficiency and often develop hyperglycemia and insulin resistance. Distributing the daily nutrient intake over an increasing number of meals increases protein deposition and improves glucose homeostasis. Therefore, we examined effects of feeding frequency (FF) and feeding level (FL) on the diurnal pattern of substrate oxidation and on the fate of dietary carbohydrates in milk-fed heavy calves. Eighteen milk-fed calves weighing 136 +/- 3 kg were assigned to FF (1, 2, or 4 meals daily) at each of 2 FL (1.5 or 2.5 times maintenance), except for calves at FF1 (only at a low FL). Urea, leucine, and glucose kinetics were assessed for each treatment by use of [(13)C]urea, [1-(13)C]leucine, [U-(13)C], and [2-(13)C]glucose, respectively. FF altered the diurnal pattern, but not the total, of urea production production. Although urea production correlated well with nitrogen retention, oxidation of oral l-[1-(13)C]leucine did not. Dietary glucose was almost completely oxidized (80% based on [(13)C]glucose and 94% from indirect calorimetry measurements) regardless of FL. Fatty acid synthesis from glucose appeared to be negligible based on similar recoveries of (13)CO(2) from orally supplied [U-(13)C]glucose and [2-(13)C]glucose. The increased fat deposition at the higher FL originated almost exclusively from greater transfer of fatty acids to body lipid stores. These findings contrast with both glucose and lipid metabolism in growing pigs and indicate that alternative adaptive mechanisms operate in heavy milk-fed calves.
authors: Animal Nutrition Group, Department of Animal Sciences, Wageningen University, 6700 AH Wageningen, The Netherlands. joost.vandenborne@wur.nl
authors: Joost J G C
authors: JJ
authors: van den Borne
authors: Gerald E
authors: GE
authors: Lobley
authors: Martin W A
authors: MW
authors: Verstegen
authors: Jane-Martine
authors: JM
authors: Muijlaert
authors: Sven J J
authors: SJ
authors: Alferink
authors: Walter J J
authors: WJ
authors: Gerrits
mesh_terms: D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D050218:Body Fat Distribution / Q000662:veterinary*; D050260:Carbohydrate Metabolism / Q000187:drug effects; D002417:Cattle / Q000378:metabolism*; D004032:Diet; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000378:metabolism* / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism; D007930:Leucine / Q000378:metabolism; D008892:Milk / Q000737:chemistry / Q000378:metabolism*; D013997:Time Factors; D014508:Urea / Q000378:metabolism
chemical_list: D004040:Dietary Carbohydrates; D014508:Urea; D007930:Leucine; D005947:Glucose