oxalic acid

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Will
Posts: 5
Joined: 20 Dec 2017, 21:57

oxalic acid

Post by Will » 21 Dec 2017, 17:17

Hi All, This is my first post here, this is a friendly question. I'm looking for very specific information.

Does anyone have direct evidence that any 'stone' in any tortoises' urinary system was indeed a result of oxalate crystal accumulation or accretion?

By direct evidence I mean a mass spec or some some sort of actual analysis of the object, not just an assertion.

These folks have not found one in a tortoise. https://www.vetmed.umn.edu/centers-prog ... ith-center

Non analysed stones shown in radio graphs are not evidence. A vets anecdote is not evidence.

I really do seek to find at least one example. Just one would be great.

Will
Will, Live animal biologist
Kapidolo Farms on FB

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Nina
Posts: 810
Joined: 16 Mar 2017, 11:22

Re: oxalic acid

Post by Nina » 21 Dec 2017, 18:22

Hi Will, and welcome to the forum, and thanks for raising an nteresting question!

My understanding of oxalic acid is that it binds with calcium in the diet and prevents the tortoise from utilising that calcium, resulting in calcium deficiency (see our section on harmful properties, under 'Diet' on our website). I do not think that an excess of oxalic acid results in bladder or kidney stones.

From what I know, bladder or kidney stones are formed in several ways:
1. if there is an imbalance in the diet of too much protein or calcium, combined with dehydration then uric acid, which is naturally produced, can crystallise and form stones in the bladder.
2. If there is dehydration combined with too low a temperature, then the kidneys don't function well and they allow the uric acid to settle, solidify and become kidney stones.

So to get back to your original question, I think that the damage caused by oxalic acid results in a deficiency of calcium in the body, which of course directly affects the production of healthy bone and shell. I don't think it is a direct cause of stones (although it might be a contributing factor, but I have no evidence of that).

Nina


Will wrote:
> Hi All, This is my first post here, this is a friendly question. I'm
> looking for very specific information.
>
> Does anyone have direct evidence that any 'stone' in any tortoises' urinary
> system was indeed a result of oxalate crystal accumulation or accretion?
>
> By direct evidence I mean a mass spec or some some sort of actual analysis
> of the object, not just an assertion.
>
> These folks have not found one in a tortoise.
> https://www.vetmed.umn.edu/centers-prog ... ith-center
>
> Non analysed stones shown in radio graphs are not evidence. A vets
> anecdote is not evidence.
>
> I really do seek to find at least one example. Just one would be great.
>
> Will

Will
Posts: 5
Joined: 20 Dec 2017, 21:57

Re: oxalic acid

Post by Will » 21 Dec 2017, 20:29

Thanks for the reply.

I Vet near where I live spoke on this topic and somewhat suggested there is too much concern for oxalates in the diet, and went on for quite awhile about the concern, and the the corresponding lack of evidence to support the concern.

There is what could be thought of as a fate path for oxalates in the diet.

1) they are already bound to calcium in the plant source and pass through and are excreted with feces.
2) they bind with calcium somewhere while not still metabolized into the blood stream (free in the intestine and gut) so the bind and make unavailable co-digestion of calcium.
3) they get absorbed (enter the blood) and are utilized in some chemical pathways that occur in animals.
4) they get absorbed and are eliminated as excess to need for the animal (not doing anything productive or harmful)
5) They bind with other waste products in the kidneys or bladder. This last thing is not demonstrated anywhere in critical/peer reviewed literature as best as I can find.

Off the topic of the header, same Vet suggested that excess calcium would be very difficult to produce in a tortoise.

The Vet is Thomas Boyer, the founder of the Association of Reptile and Amphibian Veterinarians and the vet that teaches other vets about topics like this. It's my own deal to carry his lecture here. I don't think I have miss-quoted or taken any part out of context.

I no longer worry about the leaves of spinach in Spring Mix, nor the oxalate content of cactus pads.

You might have has sourced literature that indicated otherwise, seemed like a good question to ask.
Will, Live animal biologist
Kapidolo Farms on FB

MarcellusQ
Posts: 1
Joined: 15 Dec 2017, 10:52

Re: oxalic acid

Post by MarcellusQ » 23 Dec 2017, 18:15

Thanks for sharing those insights, Will. So what you're saying is we shouldn't worry about it all that much?

Will
Posts: 5
Joined: 20 Dec 2017, 21:57

Re: oxalic acid

Post by Will » 23 Dec 2017, 23:50

Some folks have gone a bit far with the concern. Underlying principle of variety can never be ignored. And some plants with this molecule in the grander variety is not a concern I have.

What I have found is people use the plant database here to sorta bully others about the stray spinach leaf in a spring mix, or the oxalates in opuntia (to stick with those two sources) to the point of souring interest in tortoises. I don't think that is okay.
Will, Live animal biologist
Kapidolo Farms on FB

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