title: Dietary nitrogen and calcium modulate bone metabolism in young goats.
abstract: Ruminants, possessing the rumino-hepatic circulation, are thought to cope easily with reduced dietary nitrogen (N) supply which is of economic and environmental interest to diminish N output. Nevertheless, feeding an N reduced diet to young goats resulted in a decrease in calcitriol and calcium (Ca) plasma concentrations. Although a dietary Ca reduction alone stimulated calcitriol synthesis and plasma Ca concentrations were restored, in combination with a reduced N supply this stimulating effect was abolished. Based on the important role bone tissue plays in maintaining Ca homeostasis, aim of the present study was to determine effects of an N reduced diet with or without a concomitant Ca reduction on bone metabolism in young goats. A dietary N reduction alone resulted in a significant rise in plasma concentrations of bone resorption marker C-terminal telopeptide of type I collagen (CTX) and bone formation marker osteocalcin (OC), while reduced intake of Ca as well as the combination of both dietary interventions increased bone markers only slightly. Bone mineral content and bone mineral density of metatarsi were decreased by reduced N intake, while Ca and phosphorus (P) content of dried bones remained unaffected. In contrast, a dietary Ca reduction alone led to decreased Ca and P content of dried bones. From these data it can be concluded that a dietary N reduction alone or in combination with a reduced dietary Ca supply modulated bone metabolism in young goats.
authors.affiliation: Department of Physiology, University of Veterinary Medicine Hannover, Bischofsholer Damm 15/102, 30173 Hannover, Germany.
authors.forename: Kristin
authors.initials: K
authors.lastname: Elfers
authors.affiliation: Institute of Animal Nutrition, Vetsuisse Faculty Zurich, University of Zurich, 8057 Zurich, Switzerland; Center for Applied Biotechnology and Molecular Medicine (CABMM), Zurich, Switzerland.
authors.forename: Annette
authors.initials: A
authors.lastname: Liesegang
authors.affiliation: Department of Physiology, University of Veterinary Medicine Hannover, Bischofsholer Damm 15/102, 30173 Hannover, Germany.
authors.forename: Mirja R
authors.initials: MR
authors.lastname: Wilkens
authors.affiliation: Department of Physiology, University of Veterinary Medicine Hannover, Bischofsholer Damm 15/102, 30173 Hannover, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Breves
authors.affiliation: Department of Physiology, University of Veterinary Medicine Hannover, Bischofsholer Damm 15/102, 30173 Hannover, Germany. Electronic address: alexandra.muscher@tiho-hannover.de.
authors.forename: Alexandra S
authors.initials: AS
authors.lastname: Muscher-Banse
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000818:Animals; D015519:Bone Density; D001842:Bone and Bones / Q000378:metabolism; D002136:Calcium, Dietary / Q000378:metabolism*; D006041:Goats / Q000097:blood / Q000254:growth & development* / Q000378:metabolism; D008297:Male; D009584:Nitrogen / Q000378:metabolism*; D015430:Weight Gain
chemical_list: D002136:Calcium, Dietary; D009584:Nitrogen
keywords: Bone metabolism; Calcium; Goat; Nitrogen