Vitamin D Status in Wild Toque Macaques (Macaca sinica) in Sri Lanka


Power M, Dittus W. 2017. Vitamin D Status in Wild Toque Macaques (Macaca sinica) in Sri Lanka. In Ward A, Coslik A, Brooks M Eds. Proceedings of the Twelfth Conference on Zoo and Wildlife Nutrition, Zoo and Wildlife Nutrition Foundation and AZA Nutrition Advisory Group, Frisco, TX.


The vitamin D receptor is found on most cells, including active immune cells, implying that vitamin D has important biological functions beyond calcium metabolism and bone health. Although captive primates should be given a dietary source of vitamin D, under free-living conditions vitamin D is not a required nutrient, but rather is produced in skin when exposed to UV-B light. The circulating level of 25 hydroxyvitamin D (25-OH-D) considered adequate for human health is a topic of controversy. Levels of circulating 25-OH-D sufficient for good health for macaques and other Old World anthropoids are assumed to be the same as human values, but data from free-living animals are scant. This study reports values for 25-OH-D and the active vitamin D metabolite, 1,25-dihydroxyvitamin D (1,25[OH]2 D) for wild, forest-ranging toque macaques (Macaca sinica) in Sri Lanka.  Plasma samples were obtained from 8 adult males, 7 juvenile males, 6 young nulliparous females, 9 adult females not pregnant or lactating, and 11 lactating adult females. Mean values for the complete sample were 61.3±4.0 ng/ml for 25-OH-D and 155.6±8.7 pg/ml for 1,25[OH]2 D. There were no significant differences for either metabolite among age and sex classes. Values from the literature for circulating 25-OH-D in captive macaques are three times higher than those found in this wild population, however, 1,25[OH]2 D values in captive animals were similar to the wild values. The data from this study indicate that anthropoid primates exposed to extensive sunlight will have circulating values of 25-OH-D generally above 30 ng/ml, providing some support for the Endocrine Society recommendations for humans. Current dietary vitamin D supplementation of captive macaques likely exceeds requirement. This may affect metabolism and immune function, with possible consequences for macaque health and biomedical research results.

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