Effects of vitamin D3 supplementation and UVb exposure on the growth and plasma concentration of vitamin D3 metabolites in juvenile bearded dragons (Pogona vitticeps)

Comp Biochem Physiol B Biochem Mol Biol. 2010 Jun;156(2):122-8. doi: 10.1016/j.cbpb.2010.02.008. Epub 2010 Mar 4.


The effectiveness of dietary vitamin D3 and UVb exposure on plasma vitamin D metabolites in growing bearded dragons (Pogona vitticeps) was studied. A total of 84 (40 males and 44 females) newly hatched bearded dragons were allocated to six levels of oral vitamin D3 supplementation (0 to 400%) or six UVb exposure times (2 to 12 h). At 3 and 6 months of age, blood samples were obtained from each animal and analysed for 25(OH)D3 and 1,25(OH)2D3. At 3 months of age, plasma concentrations of 25(OH)D3 did not increase with increasing vitamin D3 supplementation unlike the 1,25(OH)2D3. At 6 months of age, plasma concentrations of both 25(OH)D(3) and 1,25(OH)2D3 increased with increasing vitamin D(3) supplementation. Plasma concentrations in UVb-exposed animals were 18 times higher for 25(OH)D3 (178.4+/-9.0 vs. 9.9+/-1.3 nmol/L) and 5.3 times higher for 1,25(OH)2D3 (1.205+/-0.100 vs. 0.229+/-0.025 nmol/L) than in vitamin D(3) supplemented animals at 6 months of age. This study shows that 2h of UVb exposure enables adequate physiological concentrations of plasma vitamin D metabolites to be maintained in growing bearded dragons. Oral supplementation of vitamin D(3) is ineffective in raising plasma concentrations of 25(OH)D3 and 1,25(OH)2D3 to concentrations observed in UVb-exposed animals.

MeSH terms

  • Animals
  • Calcifediol / blood*
  • Calcitriol / blood*
  • Cholecalciferol / administration & dosage
  • Cholecalciferol / pharmacology*
  • Dietary Supplements
  • Female
  • Lizards / blood*
  • Lizards / growth & development
  • Male
  • Ultraviolet Rays*
  • Vitamins / administration & dosage
  • Vitamins / pharmacology*


  • Vitamins
  • Cholecalciferol
  • Calcitriol
  • Calcifediol