Sara E. Childs-Sanford1, DVM, MS, DACZM; Rachel L. Hilliard2, BS; Andrew J. Makowski3; Joseph J. Wakshlag1, DVM, PhD, DACVN, DACVSMR
A herd of Asian elephants (Elephas maximus) maintained in a northern temperate climate was documented by the authors to have severely low total serum vitamin D levels over a period of 1 y. This is of concern, since vitamin D plays an essential role in normal calcium and phosphorus homeostasis and skeletal function. In addition, vitamin D also has been shown to have important functions in numerous other systems, including immune and reproductive systems.1,2 The goal of this study was to monitor the effectiveness of oral vitamin D3 supplementation for increasing serum 25(OH)D3 concentration in Asian elephants, and also to observe its effects on other parameters associated with calcium and vitamin D metabolism.
Six healthy adult Asian elephants were given 318 IU/kg of cholecalciferol orally once weekly for 16 weeks. Every 4 weeks during this period, serum was analyzed for 25(OH)D2/D3, 1,25(OH)2D2/D3, 24,25(OH)2D2/D3, parathyroid hormone, ionized calcium, and minerals (calcium, magnesium, phosphorus). Prior to the beginning of supplementation, the serum 25(OH)D3 level in all of the elephants was nondetectable. In all of the elephants, supplementation with cholecalciferol resulted in a steady rise in 25(OH)D3 during the treatment period to concentrations considered acceptable and safe. A positive correlation of 24,25(OH)2D3 with serum 25(OH)D3 concentration was observed. This study provides new and valuable information regarding the kinetics of vitamin D metabolism in the Asian elephant in response to cholecalciferol supplementation and provides a basis for further investigations exploring vitamin D metabolism and refining nutrient requirements in this species.
The authors would like to thank the staff of the Rosamond Gifford Zoo, including the elephant animal care team and Sue Faso, for assistance with sample collection and processing.
1. Holick MF, ed. Vitamin D: Physiology, Molecular Biology, and Clinical Applications. 2nd ed. New York, NY: Humana Press; 2010:3–33.
2. Norman AW. The history of the discovery of vitamin D and its daughter steroid hormone. Ann Nutr Metab. 2012;61:199–206.