Converting beta carotene...

If the chameleons grew up in he wild and started producing their eggs before they were taken...and the eggs had retinol in them them either the chameleon ate something that already had preformed vitaminA in it or the chameleon can convert vitamin A from beta carotene from the stomach content in the insects since most insects have a limited amount of vitaminA in them according to studies...no???
 
If the chameleons grew up in he wild and started producing their eggs before they were taken...and the eggs had retinol in them them either the chameleon ate something that already had preformed vitaminA in it or the chameleon can convert vitamin A from beta carotene from the stomach content in the insects since most insects have a limited amount of vitaminA in them according to studies...no???
Yes, that would be the logical conclusion. And, of the two, the conversion of beta carotene (or other carotenoids) would be the answer that would make the most sense. Unfortunately, Dr. Ferguson and crew could not replicate those levels of retinol in the eggs laid by female panther in captivity that had been fed beta carotene. This is where the shade towards beta carotene comes from.
So we are left to debate options.
1) Chameleons use other carotenoids
2) Chameleons use a balance of carotenoids that was missed when beta carotene was given as an isolate
3) Chameleons are driven to eat vertebrates just before laying eggs (there are a number of issues with this one)
4) There was some aspect to the study that was off

Nothing here is clear, including the study. There are numerous examples of successful breeding programs that have gone on without supplementation of pre-formed vitamin A. Breeding was going on back when our supplements had beta carotene instead of vitamin A. But, on the other hand, the overall health of a clutch can measurably improve when retinol is given to gravid females that were having trouble before. There is no clear take away that gives us direction on preformed vitamin A at this time. So, this is quite the swamp.
 
@DeremensisBlue It is a swamp and I keep trying to figure it out...figure out what angle /information I'm missing.

I can tell you that I raised, bred, hatched, etc quite a few veiled chameleons and never used prEformed vitamin A for any of them. I never fed them or the insects any meat either. The only place any PrEformed vitamin A could have come from is the insects...but they were usually kept here and fed for a few days before the chameleons ate them so would there have been any meat products or vitamin A left in them by then? I thought my clutches were good (I always kept a few from each clutch to raise into adults.)....but maybe they could have been better with prEformed vitamin A. Who knows.

Is there an online copy of the study that Dr. Ferguson did?
I'd like to read how it was done.
 
So you got bill here posting, what else can any of us mortals offer lol, but common sense tells me they're eating things with preformed vitamin A, no?which is mostly in the liver of animals I believe... how many small lizards, rodents, birds, etc are around, guess it depends on the cham species too. Didn't I hear snails carry preformed vitamin A? Wonder how often they are eating snails/slugs if that is the case. Or how often are they eating insects that feed on carrion?
 
@DeremensisBlue ..I never thought about them eating vertebrates to have enough preformed A to put in the eggs. (It must include males eating those things )though too...no?)

@jamest0o0 ...you're talking about the wild ones eating lizards, birds, snails, etc? I suppose that could be tested easily enough in captivity. But then do young chameleons have enough from their eggs to be healthy until they are old enough to eat those things.
That makes me think a about stump tails and B Theili and smaller chams now too. I wonder if they could find small "meat" to eat.

Thanks to you both for giving me food for thought!
You might like this...
https://www.chameleonforums.com/threads/nutritional-value-of-insects-snails-and-more.171681/
 
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@DeremensisBlue ..I never thought about them eating vertebrates to have enough preformed A to put in the eggs. (It must include males eating those things )though too...no?)

@jamest0o0 ...you're talking about the wild ones eating lizards, birds, snails, etc? I suppose that could be tested easily enough in captivity. But then do young chameleons have enough from their eggs to be healthy until they are old enough to eat those things.
That makes me think a about stump tails and B Theili and smaller chams now too. I wonder if they could find small "meat" to eat.

Thanks to you both for giving me food for thought!
You might like this...
https://www.chameleonforums.com/threads/nutritional-value-of-insects-snails-and-more.171681/

The small animals/chams always had me wondering where their vit A came from too, being much small, I wonder if they're getting enough from what the gut contents of what they eat?
 
@DeremensisBlue It is a swamp and I keep trying to figure it out...figure out what angle /information I'm missing.

I can tell you that I raised, bred, hatched, etc quite a few veiled chameleons and never used prEformed vitamin A for any of them. I never fed them or the insects any meat either. The only place any PrEformed vitamin A could have come from is the insects...but they were usually kept here and fed for a few days before the chameleons ate them so would there have been any meat products or vitamin A left in them by then? I thought my clutches were good (I always kept a few from each clutch to raise into adults.)....but maybe they could have been better with prEformed vitamin A. Who knows.

Is there an online copy of the study that Dr. Ferguson did?
I'd like to read how it was done.
There are many breeding programs - including my own - that were successful without preformed vitamin A added so we cannot close the book on the subject with this one study.
The one study where they couldn't find the beta carotene conversion is

Carotenoids, Vitamin A, and Vitamin E Concentrations During Egg Development in Panther Chameleons (Furcifer pardalis)
Ellen S. Dierenfeld, Edward B. Norkus, Kathryn Carroll, and Gary W. Ferguson
published in Zoo Biology 21:295–303 (2002)

Ironically, that is where your original quotes come from! But they go on to be unable to show the beta carotene conversion happens. Because this leaves a huge hole in how this happens I'd love for someone to do the study again and maybe expand it to use other carotenoids.
So, yes, I think "swamp" is a great word for it...
 
The small animals/chams always had me wondering where their vit A came from too, being much small, I wonder if they're getting enough from what the gut contents of what they eat?
I thought I read that they only got enough from their mother for a few weeks...so they have to be getting it somehow from their diet if that's true.
 
I personally gut load my feeder with yolk.. I figure some insect in the wild must be gut loaded with preform vitamin A and not with fresh vegetables like we do in captivity.. hey must eat stuff like dead animals, dead eggs, and of course vegetable. Some bugs also got preformed Vit A. Its the case for the silkworm I think. Probably praying mantises also might contains some. They also probably eat small vertebra.
 
There are many breeding programs - including my own - that were successful without preformed vitamin A added so we cannot close the book on the subject with this one study.
The one study where they couldn't find the beta carotene conversion is

Carotenoids, Vitamin A, and Vitamin E Concentrations During Egg Development in Panther Chameleons (Furcifer pardalis)
Ellen S. Dierenfeld, Edward B. Norkus, Kathryn Carroll, and Gary W. Ferguson
published in Zoo Biology 21:295–303 (2002)

Ironically, that is where your original quotes come from! But they go on to be unable to show the beta carotene conversion happens. Because this leaves a huge hole in how this happens I'd love for someone to do the study again and maybe expand it to use other carotenoids.
So, yes, I think "swamp" is a great word for it...
I only ever used prEformed at the very beginning and stopped when one chameleon I took to the vets showed up with hypervitaminosos A...then I switched powders....and never looked back since I never had another show that result.

If it's the same site my original quote came from en I've already read it. I was hoping there was something I'd missed. :(

I'd love it if someone would pay attention to that too and do another study.
It's a definite swamp. Sigh.

(Wish someone would study Leptin in regards to veiled chameleon follicular stasis and dystopia too.)
 
Nutritional information on snails says they contain a small amount of vitamin A, It doesn't specify retinol but I assume it would be. In cooking they are not gut loaded but actually cleaned out before cooking so It wouldn't be beta carotene in the gastric contents.
 
I only ever used prEformed at the very beginning and stopped when one chameleon I took to the vets showed up with hypervitaminosos A...then I switched powders....and never looked back since I never had another show that result.

If it's the same site my original quote came from en I've already read it. I was hoping there was something I'd missed. :(

I'd love it if someone would pay attention to that too and do another study.
It's a definite swamp. Sigh.

(Wish someone would study Leptin in regards to veiled chameleon follicular stasis and dystopia too.)
rouget hypervitaminoses A only diagnosed post mortem? I should learn how they do this :)
 
I have to keep looking but it is only a trace amount and that it probably why it isn't listed on most nutritional data.
They contain 1% of the RDA for humans and 100 gm of snail contains 100 IU of vitamin A.
It's only a trace and not enough to explain the study results.
 
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