Chalk sacs, vitamins A and D, and calcium in Phelsuma

[BryanF]

Hi everyone -

I'm hoping to get some clarification on the relationship between calcium and vitamins A and D, and chalk sacs in Phelsuma.

My understanding is that these sacs store calcium, and that vitamin D allows absorption of this calcium, and that too much vitamin A can prevent absorption of calcium (and by absorption I mean making it physiologically useful). Is this right?

If yes, then my primary question is: what can we infer about appropriate supplementation of vitamin D and chalk sac size, if anything? I'm thinking that if a gecko has well-formed chalk sacs, we can know that it is getting enough dietary calcium, but the absorption of that calcium - as regulated by vitamins A and D - is unknown from sac size alone.

I've been using UVB lighting and I'm always paranoid that it's just placebo lighting and not providing UVB. I'm getting rid of the lights and switching over to dietary vitamin D, but it'd be nice to be able to assess if an animal is absorbing enough calcium before it gets sick.

Thanks!

 

[colinmelsom]

I am unsure about the relationship of vitamin A to the others but have a couple of observations.Its a complex area becuse vitamin A is needded for other functions.

Firstly if you are worried about U.V.B. why not buy a U.V.B. meter? These are very useful if you are running lots of tubes ,they let you know when output falls.In the long run they pay fror themselves.

I have never seen a female in my collection that has got calcium sacs but has got metabolic bone disease so I have deduced that if they have calcium sacs they have enough calcium.These sacs are usually depleted when the females lays eggs.I have noticed that if females are getting low on calcium and possibly at the start of m.b.d. they get a small dip at the base of the spine where the body joins the tail.

 

[BryanF]

Cool - thanks.

I also thought about the meter, but after reading this (great) thread and re-reading Day Geckos in Captivity, I decided to see what happens when I get rid of the UV lights.

I saw you posted in that thread, and that you've had success using UV lighting. I only have a couple cages with Phelsuma though, so in terms of cost and the quality of lights available for smaller setups, maybe dietary D3 will be better. That's why my original question - this is an experiment, and it'd be nice if there was a way (e.g., chalk sac size) to evaluate which is better for my geckos.