The effects of preformed vitamin A and provitamin A carotenoid supplementation on tadpoles of the poison frog Phyllobates vittatus

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Roberto Marquez, Rachel Arkin


Understanding the nutritional requirements of captive animals is necessary for proper animal husbandry, however, the specific dietary requirements for many amphibian species commonly kept in captivity are unknown. Like most vertebrates, frogs cannot synthesize carotenoids or vitamin A, and must therefore obtain these essential nutrients through diet. It is unclear if amphibians can cleave provitamin A carotenoids to form vitamin A metabolically within the body, so common practice is to supplement their captive diets with both preformed vitamin A and provitamin A carotenoids. We carried out a feeding experiment in tadpoles of Phyllobates vittatus, a commonly kept poison frog species, to test the effects of supplementing a fish flake diet with a provitamin A carotenoid (2.5mg/g β-carotene) and vitamin A (0.5 mg/g retinyl acetate), both individually and in combination. Contrary to our expectations, supplementation had either no effect or adverse effects on tadpole growth and survivorship. Tadpoles reared under supplemented diets showed higher mortality rates, coupled with symptoms of hypervitaminosis A. Survivors had a smaller body size and mass at metamorphosis. The vitamin A and β-carotene levels in our supplemented diet have been shown to benefit tadpoles of other species, yet our results indicate that adding these amounts to what is found in a generalist fish flake mix (5.466 μg/g and 1.88 μg/g, respectively) beyond can have detrimental effects on P. vittatus tadpoles. More broadly, this study highlights the importance of creating husbandry guidelines based on the specific physiological needs of the species (or species groups) being kept in captivity, rather than general ones for all amphibians, as is often done.



Biology, Life Sciences, Veterinary Medicine, Zoology



Published: 2023-02-27 09:26

Last Updated: 2023-03-02 00:39

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CC-By Attribution-NonCommercial-NoDerivatives 4.0 International

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Conflict of interest statement:
The Authors declare no conflict of interest.

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