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Vitamin D status in growing dairy goats and sheep: influence of UVB radiation on bone metabolism and calcium homeostasis


Nemeth, Malin Veronique. Vitamin D status in growing dairy goats and sheep: influence of UVB radiation on bone metabolism and calcium homeostasis. 2017, University of Zurich, Vetsuisse Faculty.

Abstract

The aim of this study was to investigate how UVB irradiation in combination with reduced nutritional vitamin D supply affects the vitD status and Ca metabolism of growing goats and sheep. Sixteen lambs and fourteen goat kids aged 14 weeks were housed in an UVB free environment and fed with hay and vitD free concentrate for 13 weeks. One group of each species was daily exposed to UVB lamps, the other served as controls. Serum, urine and faeces samples were taken in monthly intervals. Serum was analyzed for vitD metabolites, bone markers, GH, IGF- I, Ca and P. Apparent digestibility and urinary excretion of Ca and P were determined. Bone mineral density of the metatarsus was analyzed before starting and at the end of the trial. In the 13th week, all animals were slaughtered and samples of skin, rumen, duodenum, kidney and bone were collected for further analyses (sterols of vitD in the skin, Ca flux rates in rumen and duodenum, VDR expression in duodenum and VDR, Calb-D28k, 1α- OHase and 24-OHase in kidney). UVB exposure lead to lower 7-DHC content in skin and higher serum 25-OH-D. However the dropped vitD status in the control groups did not affect the Ca homeostasis and no signs of vitD deficiency were detected. Differences between the two species were seen in bone metabolism and sterol contents in the skin. The results indicated that growing lambs and goat kids are able to fully compensate a vitD reduced diet by cutaneous vitD synthesis when exposed to UVB irradiation.

Abstract

The aim of this study was to investigate how UVB irradiation in combination with reduced nutritional vitamin D supply affects the vitD status and Ca metabolism of growing goats and sheep. Sixteen lambs and fourteen goat kids aged 14 weeks were housed in an UVB free environment and fed with hay and vitD free concentrate for 13 weeks. One group of each species was daily exposed to UVB lamps, the other served as controls. Serum, urine and faeces samples were taken in monthly intervals. Serum was analyzed for vitD metabolites, bone markers, GH, IGF- I, Ca and P. Apparent digestibility and urinary excretion of Ca and P were determined. Bone mineral density of the metatarsus was analyzed before starting and at the end of the trial. In the 13th week, all animals were slaughtered and samples of skin, rumen, duodenum, kidney and bone were collected for further analyses (sterols of vitD in the skin, Ca flux rates in rumen and duodenum, VDR expression in duodenum and VDR, Calb-D28k, 1α- OHase and 24-OHase in kidney). UVB exposure lead to lower 7-DHC content in skin and higher serum 25-OH-D. However the dropped vitD status in the control groups did not affect the Ca homeostasis and no signs of vitD deficiency were detected. Differences between the two species were seen in bone metabolism and sterol contents in the skin. The results indicated that growing lambs and goat kids are able to fully compensate a vitD reduced diet by cutaneous vitD synthesis when exposed to UVB irradiation.

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Additional indexing

Item Type:Dissertation (monographical)
Referees:Liesegang Annette
Communities & Collections:05 Vetsuisse Faculty > Institute of Animal Nutrition
UZH Dissertations
Dewey Decimal Classification:630 Agriculture
Uncontrolled Keywords:Bone And Bones, Metabolism, Calcium, Skin
Language:English
Place of Publication:Zürich
Date:2017
Deposited On:27 Oct 2017 11:18
Last Modified:28 Feb 2020 16:32
Number of Pages:33
Additional Information:Publiziert in: J Dairy Sci. 2017 Oct;100(10):8072-8086. doi: 10.3168/jds.2017-13061
OA Status:Green
Related URLs:https://www.recherche-portal.ch/primo-explore/fulldisplay?docid=ebi01_prod011056647&context=L&vid=ZAD&search_scope=default_scope&tab=default_tab&lang=de_DE (Library Catalogue)

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