Observations on serum 25-hydroxyvitamin D and calcium concentrations from wild-caught and captive neotropical bats,...

Most bats of the suborder Microchiroptera are nocturnal, actively avoid sunlight, and eat mineral-poor diets. In those bats previously studied with respect to mineral metabolism, extensive bone remodeling occurs, and it has been suggested that calcium has been an important constraint on reproduction. There have been no previous studies of vitamin D or its metabolites in microchiropteran bats with respect to calcium metabolism. Reported is the utilization of current advances for the determination of serum levels of the vitamin D metabolite 25-hyroxyvitamin D (25-OH-D) in a neotropical bat, Artibeus jamaicensis. Serum from wild-caught animals contained low levels of 25-OH-D (5.6 +/- 3.0 ng/ml, n = 8). Bats maintained on a vitamin-D-supplemented diet had higher serum 25-OH-D levels and when the diet containing vitamin D was discontinued, mean serum 25-OH-D levels declined significantly after 6 months. Serum calcium concentrations in wild-caught bats (8.5 +/- 0.4 mg%) showed very little variation and were not significantly different in any of the vitamin-D-supplemented animals. A pairwise correlation analysis between 25-OH-D and serum calcium levels revealed no linear correlation. The results indicate either that 25-OH-D does not appear to play a key role or that low levels of 25-OH-D may be adequate in regulating serum calcium levels in this bat.