Effects of Short-Duration Artificial Ultraviolet B Exposure on 25-Hydroxyvitamin D(3) Concentrations in Domestic Rabbits (Oryctolagus cuniculus)

SIMPLE SUMMARY: Vitamin D is an important hormone that can be acquired through diet or exposure to ultraviolet B (UVB) radiation. Few studies have evaluated the effects of UVB radiation on vitamin D concentrations in the domestic rabbit (Oryctolagus cuniculus); however, initial findings have found they can increase their serum 25-hydroxyvitamin D(3) (25-OHD(3)) following 12 h of artificial UVB exposure. Current husbandry recommendations for rabbits do not include specific UVB lighting requirements. Rabbits are a common pet and research model and are frequently housed indoors without access to natural UVB lighting. Rabbits that are chronically vitamin D deficient may develop mineral deficiencies that can lead to poor calcification of the teeth and skull, predisposing these animals to dental abnormalities, bone infections, and other debilitating diseases. While initial results suggest artificial UVB is positive for rabbits, UVB can also be detrimental to the health of vertebrates. The aim of this study was to determine if shorter-duration UVB exposure could also increase 25-OHD(3) concentrations. Rabbits were provided 6 h of artificial UVB daily for 14 days, and there was a significant increase in 25-OHD(3) concentrations over time. These findings affirm that rabbits can use short-duration artificial UVB to increase 25-OHD(3) concentrations. ABSTRACT: Vitamin D is an important hormone that can be acquired through diet, exposure to ultraviolet B (UVB) radiation, or a combination of these methods. In domestic rabbits (Oryctolagus cuniculus), both methods appear viable, but there is limited research evaluating the effects of UVB on this species. Previous studies found that 12 h of artificial UVB radiation significantly increased 25-hydroxyvitamin D(3) (25-OHD(3)) concentrations over time. While these findings suggest UVB can be beneficial in rabbits, this form of radiation can also be detrimental to vertebrates. The purpose of this study was to determine if shorter-duration UVB could elicit a similar physiological response in rabbits while minimizing potential negative effects. Six rabbits were used for this pilot study. The baseline serum 25-OHD(3) was measured for each rabbit and following 14 days of 6 h/day exposure to artificial UVB, a second 25-OHD(3) sample was collected. There was a significant increase (p = 0.001) in serum 25-OHD(3) over time (Baseline: 27.7 ± 8.1 nmol/L; Day 14: 79.8 ± 9 nmol/L). This study affirmed that 6 h of UVB produced 25-OHD(3) concentrations similar to those found in rabbits exposed to 12 h of UVB. Future studies should continue to determine how the duration of UVB exposure affects 25-OHD(3) concentrations.