Little is known about vitamin D and calcium metabolism in elephants, and reports of disease in resulting from imbalances in calcium homeostasis exist.1-3,5 This study monitored analytes associated with vitamin D and calcium status in a herd of healthy adult Asian elephants (Elephas maximus) maintained in Syracuse, NY for 1 yr and correlated that information with dietary vitamin D and calcium intake and ultraviolet light levels. It is hypothesized that seasonal differences in vitamin D status would be observed, regardless of diet, with maximum values during the summer and deficient values during the winter. Serum samples were analyzed monthly for 25(OH)D2/D3, 1,25(OH)2D2/D3, 24,25(OH)2D2/D3, parathyroid hormone, ionized calcium, and minerals (calcium, phosphorus, magnesium). Diet samples (hay and pelleted formula) were analyzed for vitamin D2 and D3, and minerals (calcium, phosphorus). Daily ultraviolet light levels were obtained from the Colorado State University’s UVB Monitoring and Research Program station in Geneva, NY (latitude: Geneva 42.868°N, Syracuse 43.048°N).
The major contribution to the total serum 25(OH)D was vitamin D2, indicating that forage and not cutaneous synthesis was the main source of vitamin D in this herd. Seasonal effects on vitamin D status were not observed in any of the elephants despite significant seasonal variations in ultraviolet irradiance. Total 25(OH)D levels in all elephants were markedly lower than those reported in other studies (mean 7.02±0.55 ng/ml).4-6 This study provides important new information regarding vitamin D metabolism in the Asian elephant, and will serve as a basis for future investigations to determine normal values, monitoring recommendations, and nutritional requirements.
The authors would like to thank the staff of the Rosamond Gifford Zoo, including Sue Faso and the elephant animal care team, for assistance with sample collection and processing.
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