Action: Amphibians: Supplement diets with carotenoids (including for colouration)
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- One study in the USA found that adding carotenoids to fruit flies fed to frogs reduced the number of clutches, but increased the number of tadpoles and successful metamorphs.
In captivity, amphibian diets are often dramatically simplified, and prey species are often those that can be bred cheaply and efficiently in captivity. By providing amphibians with prey that have been in reared on a substrate dusted with carotenoids, which may not naturally be present in the prey, nutritional deficiencies could be avoided. Carotenoids are found in the yolk of eggs and are thought to provide a range of benefits, including improving neonate health.
Supporting evidence from individual studies
A replicated, before-and-after study in 2009-2012 in Louisiana, USA found that covering the rearing area (media) of prey fruit fly with carotenoid supplements increased the rate at which tadpoles successfully completed metamorphosis when fed to Strawberry poison frogs Oophaga pumilio compared to a diet of flies not supplemented with carotenoids. Pairs produced fewer clutches on the supplemented diet (average per pair: 8) compared to the unsupplemented diet (14), however, they produced more tadpoles (unsupplemented: 3; supplemented: 6) and more metamorphs (unsupplemented: 1; supplemented: 3). From August 2009 to January 2011 fruit flies were reared in conditions similar to commercially reared flies, from February 2011 to November 2012 the rearing media was augmented with carotenoid supplements Red phaffia yeast, powdered marine algae and Spirulina. The fruit flies were then fed to 50 male and 52 female poison frogs.