Evaluation of β-carotene assimilation in leopard geckos (Eublepharis macularius).

Although leopard geckos (Eublepharis macularius) are commonly kept under human care, their vitamin requirements are largely unknown. Many invertebrate preys display a low vitamin A concentration; thus, gut-loading insects with vitamin A or carotenoids is a common practice. The objective of this prospective experimental study was to investigate whether dietary supplementation with β-carotene, including prey gut-loading, leads to sufficient vitamin A hepatic storage and prevents epithelial squamous metaplasia development in leopard geckos. Ten clinically healthy female leopard geckos were randomly divided in two groups with various supplementations: a group receiving vitamin A supplementation and a group receiving β-carotene. Insects were gut-loaded continuously with a supplement containing vitamin A or β-carotene, depending on the group. Oral supplementation with cod liver oil or carrot juice was administered weekly to each lizard from "vitamin A group" and "carotenoid group" respectively. After 10 weeks of supplementation, surgical hepatic biopsies were obtained in three geckos of each group while the two remaining geckos were euthanized to undergo complete necropsy. Hepatic vitamin A concentration was determined for each lizard (n = 10) by ultra-performance liquid chromatography. Histopathology revealed hepatocellular vacuolization and vitellogenic follicles in five females. Epithelial squamous metaplasia was not observed in any of the geckos. Hepatic vitamin A concentration was significantly higher in the carotenoid-supplemented group than in the vitamin A-supplemented group (p = 0.03). Our results suggest that in leopard geckos, dietary supplementation with β-carotene allows sufficient vitamin A hepatic storage.