# So what's the deal with D3?



## fbaker8 (Jul 26, 2012)

So, I know that I've been told by several sources to not use calcium powder that has D3 in it. But, the closest pet store to me seems to only sell it with D3. So, my question is, why is it such a big deal to have it/not have it? Does it do any actual harm to the animal, or just found unnecessary? Links to articles or just a brief explanation would be very helpful. Thanks.


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## Diablo (Jul 26, 2012)

I seem to remember that too much of it causes some sort of problem. Ive heard different people using some d3 every other day and some people avoid it altogether. Can't remember exactly why though all I know is too much causes some health issue.


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## Murkve (Jul 26, 2012)

Vitamin D3 is fat soluble. This means that if the body receives too much it cannot easily get rid of it, as the vitamin is stored in the body fat. This happens with a lot of vitamins, but D3 is unique.

A reptile needs D3 in order to correctly manage Calcium - which is water soluble, extra Calcium is excreted in the urine. When a reptile does not receive enough Calcium _or_ D3, a disease called MBD presents. The bones become weak, and needed Calcium is razed from organs.

As already stated, too much Calcium does not present much of a problem. Too much D3 does, and in fact the symptoms look remarkably like MBD. As the body tries to use the excess D3, it calcifies the bones and joints further, leading to an immobile and weak animal. The uninformed keeper, thinking it is a Calcium deficiency, will boost their Calcium dose, which often is in powder form with D3 in it - the culprit in this whole mess. Inevitably, the animal gets worse and dies, and the incident is chalked up as another tragic case of MBD.


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## Jeremyxb12 (Jul 27, 2012)

i guess that means a trip to petco i must go lol. is reptivite with d3 ok? or no? if not then both are going back


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## laurarfl (Jul 27, 2012)

It is rare to have a D3 overload with reptical alone. A lot of this discussion came up when owners began feeding liver and supplementing with cod liver oil as well. 

Here's the word from Dr. Mader and info from the Tortoise Forum:
UVB regulates the synthesis of VitD to prevent overdose in a way that dietary supplementation does not

"A commonly seen comment is that we should be careful with vitamin D supplements to avoid overdoses. I found a reference in Mader's "Reptile Medicine and Surgery" that gives us a guideline for the dosage. (Please note that Mader is clear about this being a guideline, not the result of careful research!)

The target range is 200-2000 International Units (IU) per kilogram of tortoise a day. That would be roughly 100-1000 IU per pound for those who do not understand that metric is the superior system for this sort of thing .

(Note- for the purposes of this article, figure that a kilogram, or 1000 grams is about 2 pounds, and 100 grams is about 3.5 ounces)

The danger zone is about 5000 IU/kg) a day. Overdoses can have nasty consequences, but to hit the danger zone, you would really have to work at it- although something like a high-dose vitamin D table for a very young tortoise would probably do it. The main symptoms of an overdose are hard to see and include things like calcification of soft tissues.

I cannot figure the dosage you get from the sun because there are far too many variables, but if your tortoise has free access to sunlight strong enough to give you a good tan, then you don't need to worry about this. If you live so far north that it is hard to tan in the winter, you may need to supplement with either UVB light or vitamins.

UVB light is a HUGE question mark right now- what is the best way to offer general UVA for vision and behaviors, and UVB-295nm range for D3 fabrication? Heck if I know. I would suggest that if you are using UVB lighting in your set-up (and you should, for several reasons), then you may STILL want to offer some supplemental vitamin D, but probably at the lower dosage end.

Most reptile products are oddly quiet about the dosages in their products, but some numbers I can find for common sources are:

IU's of Vitamin D in 100 grams of food:
- Cod liver oil- 8840 IU (or about 74 IU per drop, but may also be high in mercury)
- Fresh mushrooms- 14 IU
- Fresh mushrooms exposed to UV- 500 IU (note that this is vitamin D2, a less potent or effective version of the vitamin. It may only count as about 1/4th to 1/3rd as useful)
- Mazuri Tortoise Diet- 299 IU 
- Canned tuna in oil- 235 IU
- Beef liver- 15 IU

Some other options are-
- Whole egg- about 20 IU in a medium egg
- One a Day Vitamin Tablets- 400 IU per tablet, or about 10-40 IU in a pinch of a crushed tablet (a common serving size for tortoises)
- Reptical with D3- 13.7 IU per gram of powder

Comments about 'forest-dwelling tortoises get all the D they need in the diet' are obviously inaccurate- unless there is a wild source of D that we do not know about. A half-pound (500gram) tortoise would need to eat the equivalent of 2 pounds of beef liver a day to get the recommended dose of D in the diet! (Granted, some Hinge-backs eat fish, and all forest species eat some mushrooms, but enough to completely satisfy the dose. There is also a lot of solar UV hitting them as well that close to the equator.)

Some vitamins are washed out of the body daily and need constant replenishment- B, C, K, etc. Vitamins A, D, and E are stored in the fat and used as needed. Since they are needed every day by a growing or active tortoise, we do not want the fat reserves to get too low, so need to help ensure an on-going dosage.

(Note that the flip side of this is that the tortoise needs a healthy amount of body fat to store energy in as well! A good argument for making sure they get enough food.)

As you think about vitamin D supplements, remember that 'wet' is better than 'dry'. Vitamin D in powder or dry tablet form is less effective than it is in actual food or in a oil base, like gel-caps. Some sources even suggest that 'dry' D does not count. The supplements in Mazuri, cat food, etc. are often stored in a oily base, but they will loose effectiveness over time, which is one reason for expiration dates on them.

DOSAGE SUGGESTION:
I think the most convenient version would be liquid vitamin D, which comes in 500 IU to 5000 IU strengths, usually taking 5 drops to accomplish. This lets you drizzle it fairly easily over the meal.

For the dosing, I would aim for-
- 1000 IU per kilogram for tortoises without supplemental UVB
- 500 IU per kilogram for tortoises with UVB lighting

BOTTOM LINE:
A good balance of calcium and D (and, of course, some other stuff) are vital to a tortoises health, especially in the early years. There is no reason to be afraid to offer supplemental calcium and vitamin D to give our tortoises the best chances for success.

Like any good thing, you can go too far. If you are giving a tiny tortoise an entire high-dose (2000 IU) D gel cap every day, you may be overdoing it. Short of that, we should be OK.



SOURCES:
Vitamin D in Wikipedia
Dr. Douglas Mader's "Reptile Medicine and Surgery"
http://www.uvguide.co.uk
and a note of thanks to EgyptianDan for the inspiration!

Read more: http://www.tortoiseforum.org/Thread-Vitamin-D-supplements-dosage-info#ixzz21p5xlEg1"


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## Dana C (Jul 27, 2012)

Once again, I worship at the feet of the knowledge Goddess.
Thank you Laura!


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## laurarfl (Jul 27, 2012)

Dana, you are silly. You add quite a lot of info yourself, you know!


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## Jan Paul (Aug 1, 2012)

Maybe i can help a litle bit, here in Holland we work a lot with UVB lighting. We always say, when you give the animals UVB lighting (Good UVB light like the powersuns, not a exo terra energie saver) ore regular sunlight. You must not give them also D3 in the suplements, then they get it from both way's and that can cause kidney failure on long term. There are also already been tests showing that this vitamin had virtually no effect and cause more harm than good , the vitamin must be produced by the body using external UVB light. You can also using sheddings and good UVB meter reading how an animal's skin let UVB thought. So, you can weather the proper lighting for each species in question to find this out what kind of lighting you need for this kind of animal to get a proper UVB. Renske has done some testing and i wil ask here to put those down in this topic. 

I always say, no man can live on pills and Mac Donalds, including animals. We humans needs to have a good diet and natural sunlight (Ore in this case good UVB lightings), otherwise we get depressed and weak.


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## laurarfl (Aug 1, 2012)

That is a good point, Jan Paul.

Vit D synthesized from UVB will be regulated by the body and not overdosed. There are a lot of variables in UVB lights including output and placement. The issue before is how tegus produce and utilize Vit D AND how much they require. I have not seen any studies such as these. Many herbivores such as iguanas do not utilize dietary Vit D very efficiently and monitors seem to utilize dietary D quite effectively.

I also worry about kidney disease in older animals, but it seems that so many young ones are being lost before they ever reach that point. Or they are suffering from secondary nutritional hyperparathyrodism ("MBD") early in life.


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## Renske (Aug 1, 2012)

hello,

I did som uvb test with reptile skins. I'm still working on it, but I can't rib off there skin.


Latin name: Pogona vitticeps
English name: Bearded dragon
Age: 9 years
Sex: female
UVB lighting: Solar raptor
Captive bred: yes
Skin: Back

Uvb through skin: 1% 









Latin name: Dracaena guianensis
English name: Caiman Lizard
Age: 5 years
Sex: male
UVB lighting: Solar raptor
Captive bred: no
Skin: Back

Uvb through skin: 2,5%









Latin name: Physignathus cocincinus
English name: Chinese Waterdragon
Age: 2,5 years
Sex: male
UVB lighting: Solar raptor
Captive bred: yes
Skin: Back

Uvb through skin: 10%









Latin name: Tupinambis merianae
English name: Argetine Black and White Tegu
Age: 3 years
Sex: female
UVB lighting: Solar raptor
Captive bred: probable not
Skin: Back

Uvb through skin: 1,75%









Tegus need a very good uvb spot. I see a lot of people use uvb lights like exo terra and low energy lightbulb like that... But they give almost no uvb... Its pointles... That why a lot of tegus get MBD or die. If you can have them outside your tegus are lucky.
Vitamine 3D suplement will have not a good effect on uvb needed reptiles. It can only make them very ill. 
I did some test on uvb lighting:
On the left side you see number. It is the space in cm..
in the middle you see the uw/cm2.
5cm = 0,16 feet
10cm = 0,32 feet
20cm = 0,66 feet
30cm = 0,99 feet
40cm = 1,31 feet
50cm = 1,64 feet
60cm = 1,97 feet




exo terra repti glo






Powersun (In the past powesun was al lot beter. I don't know why the quality has got this bad. But still its better than a lot uvb lighting.)






Bright sun uvb (realy good uvb. They say you have to chance them every 6 months, but after 10 months they still gave enough uvb.)





Solar Raptor (The best uvb in europe... and is closest to nature light. Australia where you find bearded dragons the sun gives around 300 to 500uw/cm2. )



You can see with bearded dragons that they are realy mest up... In wild bearded dragons get almost 90cm (3 feet) long. In captivety they only get 40 or 50cm (1,3/1,6 feet) long. Wild bearded dragons lay around 10/15 eggs. Caprive bred bearded dragons 20 to 30 eggs... 
Its becouse of years of inbreeding and bad uv...
Thats what we are doing with al lot of reptiles. 

I had a bad uvb light with my first tegu. I gave him lots of vitamine and good food, but she got shacking back leggs. So i went to the fed and we took some blood. They could see she did not get enough 3D. So I desided to buy a uvb meter. When I got it I wacht with terror... Becouse my Solar Glo (exo terra) only 2 months old. Gave no uvb. And the other 2 Solar Glo I had also gave no uvb... So I bought a bright sun uv and she got better. Her 3D came back. And after 1 year I bought the Solar raptor and that made her so shiny. I am happy I always used Powersun and mega ray for my other animals...

I hope you guys understand wath I mean... UVB is very inportant.


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## Jan Paul (Aug 2, 2012)

laurarfl said:


> That is a good point, Jan Paul.
> 
> Vit D synthesized from UVB will be regulated by the body and not overdosed. There are a lot of variables in UVB lights including output and placement. The issue before is how tegus produce and utilize Vit D AND how much they require. I have not seen any studies such as these. Many herbivores such as iguanas do not utilize dietary Vit D very efficiently and monitors seem to utilize dietary D quite effectively.
> 
> I also worry about kidney disease in older animals, but it seems that so many young ones are being lost before they ever reach that point. Or they are suffering from secondary nutritional hyperparathyrodism ("MBD") early in life.



I don't know how Tegu's do this, but what i know is a lot sick Tegu's in captivity. This is not comparable with Monitors i think... 

Also the D3 in suplements is verry easy to o.d. this and happent a lot becouse you not see this before its already to late (And people give this to much, every meal is not good, just calcium is oke but not the D3), rodents are a lot better but these wear a small amount of D3 and is at most enough for night active animal which need less for the same result, and also to fat for every time and therefor not enough D3 . I think people need to be careful with synthetic D3 suplements, there is too little known about. When i have the pdf file i put it down in this topic, it is also in English i thought...


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