Uvb and D3

[jasonm96]

I still provide low levels of d3 for all frogs receiving uvb just because it isn't the same as natural sunlight. It's an obvious one with dart frogs that they use uvb but when you look at species like horned frogs, african bull frogs, cane toads etc you probably do have to supplement moderate levels of d3 as they feed on vertebrates as well as inverts, so uvb itself might not be enough. There's always going to be a need for supplements as in captivity we rely mainly on crickets as a dietary source and other insects. Perhaps some do actually get all the d3 they need in their diet but smaller frogs like darts, mantellas, fire bellies, red eyed tree frogs for an example most likely use uv for their complete d3 needs.

[Diver]

Yep, I do too. Pretty much all of the multivitamin supplements around contain at least some D3 but I can't imagine the frogs getting enough to cause hypervitaminosis and the other vitamins are nice to have I definitely wouldn't rely on supplements to get adequate amounts of any vitamin let alone D3 though, much better to concentrate on a varied, well gut loaded diet and UVB and use supplements as a safety net. The problem in some circles is that a culture of feeding (usually one) easy to obtain feeder insect and throwing powder at it has developed. To me, that's a bit like giving a human a multivitamin pill and nothing but cheese sandwiches. You wouldn't die, but your health wouldn't exactly be optimum either.

[jasonm96]

Me neither but we're never really going to be able to provide the varied wild diet of some animals though and so the vitamins compensate for that. Think of horned frogs, a big part of their diet is other frogs (including their own)... To feed them other frogs in captivity isn't feasible considering frogs go for more or less a tenner each. People feed fish and pink mice to compensate for the calcium they'd get from this but pink mice are fatty and fish can be diseased.

[Herpvet]

Yep, I do too. Pretty much all of the multivitamin supplements around contain at least some D3 but I can't imagine the frogs getting enough to cause hypervitaminosis and the other vitamins are nice to have I definitely wouldn't rely on supplements to get adequate amounts of any vitamin let alone D3 though, much better to concentrate on a varied, well gut loaded diet and UVB and use supplements as a safety net. The problem in some circles is that a culture of feeding (usually one) easy to obtain feeder insect and throwing powder at it has developed. To me, that's a bit like giving a human a multivitamin pill and nothing but cheese sandwiches. You wouldn't die, but your health wouldn't exactly be optimum either.

Whilst I agree with much of what you say, I would take issue with your comment that "you can't imagine the frogs getting enough [vitamins] to cause hypervitaminosis". Again data is lacking in amphibians (one report is cited in Wright & Whitaker - but how many amphibs routinely undergo post-mortem exam?), but it is not uncommon to see older (usually male) reptiles with blood vessel calcification; hypervitaminosis D is a real possibility. And when you consider supplements are typically "1 pinch per kg of animal" or similar, the difference of a few particles to a dart frog, say, could be a huge overdose. Vitamin supplements are not risk-free by any means. I do use, and recommend, supplementation in many cases (and of course deficiency issues are FAR more common) but care is definitely needed.

Unfortunately as has been mentioned, ideally we need studies including serial radiographs/bone density assessments, and blood sampling if feasible, to evaluate our captive animals, and crucially compare them to wild specimens (the studies that have been done in herps tend to suggest that even our "clinically healthy" animals are often not comparable in bone density and/or blood vitamin D3 levels to wild animals). While certainly not decrying the efforts and skills of keepers who have reared many species/generations of apparently healthy animals, unless all animals are examined for evidence of pathology, particularly post-mortem, then there will always be doubt.

[Diver]

Whilst I agree with much of what you say, I would take issue with your comment that "you can't imagine the frogs getting enough [vitamins] to cause hypervitaminosis". Again data is lacking in amphibians (one report is cited in Wright & Whitaker - but how many amphibs routinely undergo post-mortem exam?), but it is not uncommon to see older (usually male) reptiles with blood vessel calcification; hypervitaminosis D is a real possibility. And when you consider supplements are typically "1 pinch per kg of animal" or similar, the difference of a few particles to a dart frog, say, could be a huge overdose. Vitamin supplements are not risk-free by any means. I do use, and recommend, supplementation in many cases (and of course deficiency issues are FAR more common) but care is definitely needed.

Unfortunately as has been mentioned, ideally we need studies including serial radiographs/bone density assessments, and blood sampling if feasible, to evaluate our captive animals, and crucially compare them to wild specimens (the studies that have been done in herps tend to suggest that even our "clinically healthy" animals are often not comparable in bone density and/or blood vitamin D3 levels to wild animals). While certainly not decrying the efforts and skills of keepers who have reared many species/generations of apparently healthy animals, unless all animals are examined for evidence of pathology, particularly post-mortem, then there will always be doubt.

Thanks! Good info and nice to have a contribution from a professional. I was working under the assumption that a multivitamin with low levels of D3 being given in the inefficient 'dusting' method would be tricky to overdose, but of course as it isn't metabolised as such would this be the reason that it would be possible? An accumulative effect? Would it therefore, in your opinion, be better practise to only use supplements not containg D3 when UVB is provided?

[Diver]

I haven't updated this thread for a while, but now UVB provision is accepted as a standard part of good husbandry, here's some solid scientific research to help people figure out exactly how to provide it correctly.

[jasonm96]

Thanks for sharing this is very helpful

but we should also remember not all amphibians are the same and their needs for UVB will differ. Large predatory frogs can get D3 from a diet that includes whole prey items like fish, mice, lizards or other frogs. There's just not enough evidence to support that all frogs need UVB, but they have been raised without for years and many have fared well. With such success, I highly doubt keepers or breeders will or should have to change their ways until more research on each species has been done. Most of the studies I have seen have been doing on small frogs that feed on insects (which naturally lack D3) or basking species.

Yes, some develop MBD and they might not have had UVB, but was this the cause or inadequate supplementation and gutloading of insects, lack of variety or wrong temperatures?

[Diver]

It is their differing needs that are addressed in the attached paper. I would think that on the contrary that there is little to no evidence to suggest that any frogs DON'T need UVB. D3 oral supplementation was invented when people realised that keeping animals indoors away from natural sunlight was causing them harm and figured out that it was the d3 that sunlight was formerly providing that was missing. Back then, the only remedy was to expose the animals to natural sunlight or administer a synthetic. We no longer need the synthetic (which is known to be a poor way to address the problem) as we now have freely available technology to replicate the missing sunlight.
It is not only frogs of course, we know that all animals with very few exceptions process sunlight to produce vitamin d3, and that includes humans. We get the majority of our d3 that way despite a hugely varied diet. As far as larger amphibians are concerned (you'll notice Bufo marinus on the list), while they may be able to meet a certain amount of their requirement IF they find prey that contains it, they wouldn't meet it all that way and almost certainly none at all as juveniles when their diet would be almost entirely insect in nature.