Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1976066 | Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology | 2010 | 7 Pages |
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)D3 and 1,25(OH)2D3 increased with increasing vitamin D3 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 D3 supplemented animals at 6 months of age. This study shows that 2 h of UVb exposure enables adequate physiological concentrations of plasma vitamin D metabolites to be maintained in growing bearded dragons. Oral supplementation of vitamin D3 is ineffective in raising plasma concentrations of 25(OH)D3 and 1,25(OH)2D3 to concentrations observed in UVb-exposed animals.