Preliminary observations on the relationship of calcium ingestion to vitamin D status in the green iguana (Iguana iguana)
Publication Type: |
Journal Article |
Year of Publication: |
1997 |
Authors: |
Olav T. Oftedal, Tai C. Chen, Jay Schulkin |
Publication/Journal: |
Zoo Biology |
Publisher: |
A Wiley Company, Inc., Wiley Subscription Services |
Keywords: |
food selection, minerals, reptiles, vitamin d deficiency |
ISBN: |
1098-2361 |
Abstract:
Abstract 10.1002/(SICI)1098-2361(1997)16:3<201::AID-ZOO1>3.3.CO;2-0 We hypothesized the vitamin D-deficient green iguanas with depleted calcium stores would seek to augment calcium intake by self-selection of a high calcium source. Eight green iguanas were offered free-choice ground oystershell in addition to their regular diet. Of these, two had not been exposed to ultraviolet (UV-B) radiation for > 5 years and were demonstrated to be vitamin D-deficient by low circulating levels of the principal vitamin D metabolite, calcidiol (25-hydroxy-cholecalciferol). The six others had been exposed to a UV-B emitting bulb for the previous 3 years and had high circulating calcidiol levels. Average daily food intake (expressed as dry matter per kg body mass) did not differ between the Low-D and High-D iguanas. The daily oystershell intake of the Low-D iguanas (0.02–0.03 g/kg) was lower than that of the High-D iguanas (0.06–0.70 g/kg), leading to a significant difference in calcium intake. The failure of iguanas to increase calcium intake in response to vitamin D-deficiency was puzzling and suggests that vitamin D, as a steroid hormone, may play some role in the expression of calcium appetite. Zoo Biol 16:201–207, 1997. © 1997 Wiley-Liss, Inc.