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Discussion Starter · #1 ·
As I was reading the ingredients on my calcium supplement I realized that they are all based on calcium carbonate, an alkaline buffer. This got me thinking about safety and disruption of the acid-base balance system in dart frogs. Chronic calcium carbonate intake in people can cause milk alkali syndrome and kidney stones. Have these problems ever been reported in dart frogs?


Just wondering if a calcium salt might be less problematic or at least used to lower the total carbonate intake of frogs. Any thoughts?
 

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In insectivores, calcium supplementation is largely used to balance the inadequate ratio of calcium to phosphorus in nearly all commercially produced feeder insects. One important route of action for this is that Ca outcompetes P in the gut, in part through the formation of insoluble phosphorus compounds with carbonate or hydroxide (as in human phosphate binding medications). Other calcium formulations will not form these compounds, and so won't function as intended, though some (e.g. calcium gluconate) are used for short term therapy for hypocalcemia.

In captive herbivorous herps, kidney stones seem to be moderately common (though I haven't looked up hard data), which stands to reason since they don't have the same base diet that needs correction.

FWIW, CaCO3 is a salt.
 

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Discussion Starter · #3 ·
I meant a non-carbonate salt, non- buffering salt, like chloride. I know that metal oxides are very poorly absorbed, and that many easily cultures live foods for frogs have too much phosphorus for their calcium content. I'm trying to see if I can get a Grindal worm culture going to see if dart frogs will take those because analids have favorable Ca:p ratios. But as I thought about it calcium carbonate is even a more alkaline buffer than sodium bicarbonate if I remember my chemistry correctly and I know for medical school and numerous nutrition and biochemistry courses that too alkaline buffer intake can be harmful to both humans and other mammals, so more than likely all vertebrates as well. So I was wondering 1. If such problems have been encountered in dart frogs and 2. Would supplementation with a combination mixture of carbonate, chloride, gluconate and oxide would be better in that it would still increase dietary Ca but reduce the overall fraction. Does that make sense? I do have CaCl but if I add that to my supplement, it would also reduce the active D3 fraction of the formation.

Bottom line is, first is it a problem? If it ain't broke don't fix it. But if it is a problem, and you all have more experience with dart frogs, then it's fair simple to change the formulation of dietary supplements by current manufacturers. So I thought I'd raise the issue and start the discussion. Does that make sense?
 

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Mantella baroni, Dendrobates auratus, Afrixalus dorsalis, Theloderma corticale
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I meant a non-carbonate salt, non- buffering salt, like chloride. I know that metal oxides are very poorly absorbed, and that many easily cultures live foods for frogs have too much phosphorus for their calcium content. I'm trying to see if I can get a Grindal worm culture going to see if dart frogs will take those because analids have favorable Ca:p ratios. But as I thought about it calcium carbonate is even a more alkaline buffer than sodium bicarbonate if I remember my chemistry correctly and I know for medical school and numerous nutrition and biochemistry courses that too alkaline buffer intake can be harmful to both humans and other mammals, so more than likely all vertebrates as well. So I was wondering 1. If such problems have been encountered in dart frogs and 2. Would supplementation with a combination mixture of carbonate, chloride, gluconate and oxide would be better in that it would still increase dietary Ca but reduce the overall fraction. Does that make sense? I do have CaCl but if I add that to my supplement, it would also reduce the active D3 fraction of the formation.

Bottom line is, first is it a problem? If it ain't broke don't fix it. But if it is a problem, and you all have more experience with dart frogs, then it's fair simple to change the formulation of dietary supplements by current manufacturers. So I thought I'd raise the issue and start the discussion. Does that make sense?
Although calcium carbonate is indeed an alkaline buffer, it is also the form in which frogs in the wild will mostly encounter their calcium (and magnesium for that matter). Isopod exoskeletons have calcium carbonate in them (and magnesium calcite), as do mites and other invertebrates. The high calcium found in black soldier fly larvae for example is also mostly calcium carbonate. Granted, the pure form we use for dusting is in a slightly different form due to not being in an organic matrix, but what we're essentially doing is turning a fruit fly into an isopod (or similar) in terms of calcium. This correction is not perfectly balanced, which is likely why we see some deposits in kidneys.

I do wonder if these kidney deposits are perhaps also due to a slight but chronic vitamin D imbalance.

Favourable calcium ratios can be found in isopods, amphipods, most soil mites, black soldier fly larvae and firebrats (although I can't relocate the source for this last one). I have not seen a full nutrient analysis on springtails, but judging from literature showing the presence of calcium carbonate deposits in cells and the midgut in wild springtail populations, there is a good chance that springtails also have a good calcium ratio when fed properly.

Edit: relocated the source for positive calcium/phosphorous ratios in firebrats. Breeding Silverfish as Feeders for Small Geckos - Gecko Time
 

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Discussion Starter · #5 ·
You may add to your list of Ca:p balances live foods annelids as well. Feeding captive insectivorous animals: nutritional aspects of insects as food • AZA Nutrition Advisory Group

I'm going to be trying to raise Grindal worms for that very reason and see if dart frogs will accept those. They are very easily cultured.

Thanks for that bit of information regarding to form of Ca in invertebrate Ca. I guess that didn't dawn on me that it's mostly in the form of carbonates as well. I guess I was thinking that most of it would have been free ionic Ca or bound to proteins. Still I wonder whether CaCl salt mixed with carbonate might be a better form in that at least it would cut down on the total carbonate fraction. That and perhaps a little Ca oxide as well, even though I know that it's poorly absorbed through the gut.
 

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I do wonder if these kidney deposits are perhaps also due to a slight but chronic vitamin D imbalance.
Mader (Mader's Reptile and Amphibian Medicine and Surgery) has no references to urinary calculi in amphibians that I could find. It states that in reptiles, they are typically constituted of uric acid deposits (though are occasionally have calcium components) and are caused primarily by chronic dehydration. I could find no reference there to diet or supplementation being a risk factor except for excess protein in the diet of herbivores.

There is no reference there in the nutrition chapter to any danger from calcium carbonate or any other supplement. CaCO3 is recommended there as a supplement since other calcium compounds have less calcium per gram, and would be difficult or impossible to use to rectify the Ca/P balance of prey items as it would be impossible to get enough of the compound to stick to or be ingested by the prey item.

I recently had a yearling snake die for reasons unknown after a long period of something like "failure to thrive"; necropsy showed severe renal calculi, but also noted good body conformation and no evidence at all of dehydration, and noted that the presence of the calculi was quite unusual given the overall condition. So, there are some (probably rare, given the prevalence of dehydration and incorrect herbivore diets) ideopathic cases in herps as well.

A quick web search turns up a handful of NIH articles that seem to agree that the link between Vit D and urinary deposits in humans, anyway, is completely unclear.
 
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