Michaels C J, Antwis R E, Preziosi R F
Faculty of Life Sciences, University of Manchester, Manchester, UK.
J Anim Physiol Anim Nutr (Berl). 2015 Apr;99(2):391-403. doi: 10.1111/jpn.12203. Epub 2014 May 9.
Many amphibian species are dependent on ex situ conservation interventions for their long-term persistence. However, projects have been jeopardised by husbandry issues involving poor calcium metabolism and nutritional metabolic bone disease (NMBD). Healthy calcium metabolism requires appropriate dietary calcium content and access to vitamin D3 . In many animals, vitamin D3 can be photobiosynthesised in skin exposed to UVB radiation, as well as extracted from the diet, but the extent of vitamin D3 photobiosynthesis in amphibians is poorly known. Additionally, prey insects for captive amphibians are deficient in calcium and calcium content must be artificially increased, but the effects of different levels of augmentation and their interaction with UVB exposure are also little understood. We fed captive fire-bellied toads (Bombina orientalis) with crickets augmented to contain 5% and 10% calcium and housed them with and without UVB exposure. Despite additional dietary vitamin D3 supplementation, we found that toads exposed to UVB radiation exhibited significantly higher serum vitamin D3 levels, indicating that this species may partly rely on photobiosynthesis sources of vitamin D3 . These data are the first to show a direct link between UVB exposure and serum vitamin D3 in an amphibian. We found significant positive effects of UVB exposure and 10% dietary calcium content on skeletal structure, as well as complex interactions between treatments. We also found UVB radiation exposure resulted in more rapid natural coloration acquisition. Together, this indicates that standard calcium plus vitamin D3 supplementation methods may not fully substitute for UVB exposure and for increased feeder insect calcium content. This may have implications for the success of ex situ amphibian conservation, as well as for the welfare of captive amphibians in general. Our data lend support for the provision of UVB radiation for captive, basking amphibians.
许多两栖动物物种的长期存续依赖于迁地保护措施。然而，一些项目因饲养问题而受到威胁，这些问题包括钙代谢不良和营养性代谢性骨病（NMBD）。健康的钙代谢需要适当的饮食钙含量以及获取维生素D3。在许多动物中，维生素D3可以在暴露于UVB辐射的皮肤中进行光生物合成，也可以从饮食中摄取，但两栖动物中维生素D3光生物合成的程度却鲜为人知。此外，圈养两栖动物的猎物昆虫钙含量不足，必须人工增加钙含量，但不同增加水平及其与UVB暴露相互作用的影响也知之甚少。我们用添加了5%和10%钙的蟋蟀喂养圈养的东方铃蟾，并将它们分别饲养在有UVB照射和无UVB照射的环境中。尽管在饮食中额外补充了维生素D3，但我们发现暴露于UVB辐射的蟾蜍血清维生素D3水平显著更高，这表明该物种可能部分依赖维生素D3的光生物合成来源。这些数据首次表明了两栖动物中UVB暴露与血清维生素D3之间的直接联系。我们发现UVB暴露和10%的饮食钙含量对骨骼结构有显著的积极影响，以及各处理之间存在复杂的相互作用。我们还发现UVB辐射暴露导致自然体色形成更快。总之，这表明标准的钙加维生素D3补充方法可能无法完全替代UVB暴露和增加饲料昆虫的钙含量。这可能对迁地两栖动物保护的成功以及一般圈养两栖动物的福利产生影响。我们的数据支持为圈养的、晒太阳的两栖动物提供UVB辐射。
