Variation in Serum 25-Hydroxyvitamin D in Free-Ranging New-World Tropical Bats

Vitamin D (represented by D2 or D3) is considered essential for normal calcium homeostasis. It is either synthesized in the skin following ultraviolet-B irradiation of provitamin D3 (7-dehydrocholesterol), or ingested in the diet as vitamin D2 or vitamin D3. Most neotropical bats are nocturnal, roost in dark places, and consume diets that lack vitamin D and thus have no other known source of this important nutrient. A few species, namely fish-eating (piscivores) and blood-eating (sanguivores), however, have the potential to ingest large quantities of dietary vitamin D. In this study, blood serum collected from five nocturnal, neotropical bats (including three plant-visiting species, one fish-eating species and one blood-eating species), was analyzed using a competitive protein binding assay (CPBA) to determine concentrations of 25-hydroxyvitamin D [25(OH)D], the major circulating vitamin D metabolite. Caveroosting (absence of sunlight), plant-visiting species (Artibeus jamaicensis, Brachyphylla cavernarum...