UVB and Amphibians... Theory and Musings

[Saedcantas]

We're on the cusp of a change.
It seems that at least here hobbyists have begun to open up to the idea that Amphibians could indeed utilise UVB and that they may infact benefit from exposure to it.
This is going to be a rambling exploration

First things first.
Amphibians like all vertebrates require Calcium in their bodies in sufficient amounts to be able to function optimally and thrive. Calcium is needed for not only bone density but also functions within the muscles, blood, nervous system, organs and exchanges on a cellular level.
Lack of Calcium is much more than just softer bones.
- The efficiency of nerves and the nervous system is compromised as the body tries to ration out the Calcium it does have (Hence twitching toes/legs or spasms).
- The ability for muscles to be controlled is damaged, (prolapses can be a direct result as the cloacal sphincter muscles cannot be maintained).
- Hormonal regulation and/or homeostasis may be impaired, the animal may lose it's ability to maintain it's bodily balance or fail to breed despite appearing in good health outwardly as a deficiency renders it infertile or unable to respond to breeding cues. If the animal is able to breed it's offspring may be damaged from conception as a result of health problems in the adult animals.
- Then the bones themselves, you'd be suprised to know how many fractures an otherwise normal looking and mobile amphibian can have. This may leave the animal in constant pain, or it may impair their ability to feed and breed in such a minor way that it is never questioned or suspected.


Often the major argument amongst hobbyists to evidence "Good health" is that animals have bred...
Unfortunately for many species of animals (and indeed plants) reproduction may often be the last ditch effort to ensure genes are passed on despite the health of the animal being dire and the living conditions almost unbearable.
If you could not get these animals to breed in captivity where competition is minimal, parasitism is reduced, predation is non-existant and food is abundant, THEN you'd really have something to worry about!
Breeding in captivity is not an indication of health nor 'happiness' in our animals. Sorry!


Amphibians, like all vertebrates, require Vitamin D3 in their bodies in order to utilise dietary Calcium, I won't go into the D3 pathway and specifically how it is used by the body to regulate calcium uptake, you can read about that here;
UV Lighting for Reptiles: Vitamin D synthesis in Ultraviolet Light

So, knowing this we are faced with two options which are the crux of this issue. Outlining them I hope to make it clear why UVB exposure is the safest, most logical and feasible option.


Dietary supplements.
Vitamin D3 can be absorbed by the body via the gut, however, this route of uptake is unregulated and allows for overdose and the resulting bodily imbalance.
The majority of amphibian keepers currently rely on multivitamin supplements to fulfill this role (although there are some who genuinely don't think it is needed for these animals!?!? and those who never use supplements).
Supplements come in little plastic pots that most people keep near their vivaria or in the cupboards below, people buy in bulk to save money so may have tubs stored at room temperature and above for 6-12 or more months... Vitamins are the entire purpose of our use of multivitamins instead of plain calcium (which as a pure mineral does not degrade or denature in a pot).
So then, we have a clear problem if we know that vitamins such as D3 are incredible fragile compounds, degraded or denatured by moisture, higher temperatures and exposure to atmospheric air. A tub of Nutrobal will be next to pointless after 6 months sat next to your viv and after 6 months worth of opening and closing, letting in moist atmospheric air...
So on one hand this method has the potential for overdose but also the potential to be completely pointless if the product is not stored and used appropriately, but, there is no way of the average hobbyist knowing when or how fast this occurs...


UVB exposure
The joy of opting for UVB exposure rather than plain supplements is that not only can you actually buy a meter to measure the exact level you are using and actively check for degradation of your chosen D3 provider, BUT this pathway is self limited within the skin of the animal!!!

Any Herptile in our care, amphibian or not, should be provided with a suitable environment in captivity this should include appropriate refugia - burrows/hiding spots, shade, foliage, caves, whatever. It should also include a full day/night cycle, the overall health of captive animals, their ability to breed and their hormonal balance is affected by their ability to experience Circadian Rhythms. (ALL animals whether nocturnal, diurnal or crepuscular). We should strive to provide a naturalistic light cycle including beneficial UVB (and UVA) exposure and we should design our vivaria to accomodate this.

Many reluctant keepers use the argument of;
"But they're nocturnal they would never be exposed to it!?!"
Go to the wild and see it for yourself These animals sleep in the relative open even if they are truly nocturnal, your average treefrog sleeps on leaves or treetrunks exposed directly or indirectly (via reflection) to UVB.

I can tell you that amphibians, like lizards for instance, can be more or less demanding in terms of UVB. Some species can be exposed to massive levels of UVB on a daily basis and still show room for improvement in their calcium levels (e.g: Canopy dwelling treefrog species), others can be exposed to short blasts of high UVB exposure once in a blue moon and have good calcium levels (e.g: Arid environment burrowing sps.)
There is clearly a difference in tolerance to UVB exposure (meaning their skin may have greater resistance) and actual physical levels needed (meaning they may require a much greater overall exposure than other species to achieve the same level of "health") between individual species.


Common sense must apply, vivariums may be constructed to provide naturalistic levels of exposure and cover as per the individual species.
There is no single answer and there never will be.

Just consider this, I have seen animals with no visible skeleton jumping around like there is no tomorrow and breeding. This does not mean that it is acceptable for these animals to subsist, to live under sub-lethal stresses and we will know about it eventually...
The amphibian hobby does not seem as negative towards WC animals as others, I can think of no species which has yet been bred consistently for a number of generations with no injection of WC genes at some point.
I can tell you that damage to offspring can be seen in the shorterm resulting directly from poorly kept adult stock, but no one is looking for it.

Poor success in metamorphs is blamed on bad water or bad luck.
1000 Amazonian milk frog eggs can be whittled down to 5 successful metamorphs a year later and people say "oh well that's why they lay so many"... No. They lay so many to get through metamorphosis AND have some survive predation. Juveniles are passed along so people don't get to see where they begin to fail to thrive, or breed.

Frogs that look perfectly healthy can be walking around with a shattered pelvis (I've seen it...) and amplexing females nightly as they are healthy breeding animals!

[Saedcantas]

Due to the fact my personal observations are made as part of current research, I can only offer them as opinion.

I cannot include a list of my references nor details of how we are quantifying the effects of UVB on amphibians.

I know for some people that will mean it is all just speculation and that's fine
I was asked to write this now, I had been waiting until such time as I could offer it with a link to a new publication to back it up, as I can't it's your choice as the reader, take it or leave it

Cheers
Lotte***

[Morgan Freeman]

Fantastic.

Sticky that badboy.

[ipreferaflan]

Well done.
I didn't know you could overdose your animals with calcium though!

[Saedcantas]

Originally Posted by ipreferaflan

Well done.
I didn't know you could overdose your animals with calcium though!

No, it said you can overdose on vitamin D3! Which in turn might result in an over-uptake of calcium.

Nowt's ever simple! lol

[ipreferaflan]

Originally Posted by Saedcantas

No, it said you can overdose on vitamin D3! Which in turn might result in an over-uptake of calcium.

Nowt's ever simple! lol

Oh bloomin' 'eck.

[Gaz_dbd]

great advice, in a way it goes against their 5 freedoms, the idea of natural behaviour, in nature they will come into contact with the sun, so why should we stop them in captivity?

[andaroo]

well now im worried, I have all my frogs under UV bulbs the two suppliments I use once a week are calcium+d3 and nutrobal (other week I use repton) so am i over doing the d3? I should probably just get a calcium only dust now right?

[Saedcantas]

We use Nutrobal on every feed here... For Dendrobatids that means daily.

It's another avenue that needs looking at to be honest, figuring out where the balance between supplements and UVB should lie.
The main problem is simply not knowing how much of the original contents of your pot of multivits remains in there and how fast it degrades.
To be honest my personal opinion on it, is that it probably degrades very fast and therefore the risk of overdose only lasts for a very short time with a brand new pot. That I have used it on every feed for many types of animal and never seen a single vitamin overdose (but I have seen animals that are still deficient) leads me to feel that the chances of this problem are very slim when the products are used normally.

[fatlad69]

Great advice, I look forward to reading the research when it is purchased. I have heard from a few PDF keepers that they give their frogs a blast of UV once a month, what are your views on this.