Measuring 25-Hydroxyvitamin D₃ Concentrations in Captive ​Northern Blue-Tongued Skinks (Tiliqua scincoides intermedia) Fed a Cat Diet

Presentation Type

Oral Presentation

Conference Date

Spring 4-17-2026

Abstract

Vitamin D is an essential hormone in vertebrates, and these animals can acquire vitamin D through their diet, ultraviolet B (UVB) radiation, or both. Determining the primary route of vitamin D acquisition is critical for appropriate reptile husbandry. This study evaluated vitamin D status in northern blue-tongued skinks (Tiliqua scincoides) fed a commercial wet cat food diet and subsequently assessed the effects of UVB exposure and withdrawal on plasma 25-hydroxyvitamin D₃ (25-OHD₃) concentrations. Initially, eleven yearling, captive-bred skinks raised exclusively on vitamin D supplemented wet cat food (573 IU/kg, as fed) without UVB exposure had low plasma 25-OHD₃ concentrations (17.1 ± 3.8 nmol/L; range: 9–22 nmol/L). These findings indicated that dietary vitamin D alone was insufficient, with values comparable to those of 25-OHD₃ in reptiles not exposed to UVB. In a subsequent experimental study, eleven adult skinks were exposed to either 12 or 2 hours of UVB daily for four weeks. Plasma 25-OHD₃ significantly increased post-UVB in both groups (p < 0.01), with the 12-hour group increasing from baseline concentrations of 18.5 [12.8-20.5] nmol/L to 820 [730-1251.3] nmol/L and the 2-hour group increasing from baseline concentrations of 22 [15.5-22] nmol/L to 635 [401-892.5] nmol/L. Following the discontinuation of UVB exposure, 25-OHD₃ gradually declined and was not significantly different from baseline concentrations at 7 and 4 months for the 12-hour and 2-hour groups, respectively. These findings strongly suggest that blue-tongued skinks rely on UVB exposure to increase their 25-OHD₃ concentrations.

Presenter

Ashleigh Godke

Faculty Mentor

Mark Mitchell

Award

1st Place, Oral Presentations - STEM Disciplines; 1st Place, LSU College of Agriculture

Academic Major

Animal Sciences

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