A comparison of UV b compact lamps in enabling cutaneous vitamin D synthesis in growing bearded dragons

Summary The effect of exposure to different UV b compact lamps on the vitamin D status of growing bearded dragons (Pogona vitticeps) was studied. Forty‐two newly hatched bearded dragons (<24 h old) were allocated to six treatment groups ( n  = 7 per group). Five groups were exposed to different UV b compact lamps for two hours per day, with a control group not exposed to UV b radiation. At 120 days of age, blood samples were obtained and concentrations of 25( OH )D 3 , Ca, P and uric acid were determined. In addition, plasma 25( OH )D 3 concentration was determined in free‐living adult bearded dragons to provide a reference level. Only one treatment resulted in elevated levels of 25( OH )D 3 compared to the control group (41.0 ± 12.85 vs. 2.0 ± 0.0 nmol/L). All UV b‐exposed groups had low 25( OH )D 3 plasma levels compared to earlier studies on captive bearded dragons as well as in comparison with the free‐living adult bearded dragons (409 ± 56 nmol/L). Spectral analysis indicated that all treatment lamps emitted UV b wavelengths effective for some cutaneous vitamin D synthesis. None of these lamps, under this regime, appeared to have provided a sufficient UV b dose to enable synthesis of plasma 25( OH )D 3 levels similar to those of free‐living bearded dragons in their native habitat.