D3 Question

[Nobody]

I've read that if a Sulcata tortoise is housed outdoors and gets sunlight,it doesn't need to be givent any D3 supplementation.My question is what if a Sulcata tortoise gets sunlight everyday,would it still be safe to give him a D3 supplement?Shall there be any side effects or harm done to it?
Thanks.

 

[t_mclellan]

Google is a great thing!

http://www.anapsid.org/uvd3.html

This is from Melissa Kaplan's
"Musings on D3 & UV"
Vitamin D3
My article on Metabolic Bone Disease goes into the natural development of D3 in the body as a result of the previtamin D formed through exposure of the skin to ultraviolet B wavelengths, so I won't repeat it here. If you are unfamiliar with the process, or the numerous disorders clustered under the MBD umbrella term, please read that article.
D3 is formed naturally in the body through exposure to UVB wavelengths (290-320 namometer, or nm). These wavelengths are produced by the sun, but are filtered out by regular glass and plastic; even fine-mesh screen can filter out significant amounts. (The windows in our house block out the UV wavelengths - otherwise all fabrics within range of the window would fade out within just a few years. Glass used in constructing commercial aquariums/terrariums is also made from plain window glass.) Thus an animal needs to be exposed to direct sunlight. It doesn't take much for an organism to get the amount of UV needed to metabolize adequate amounts of D3 when (again, this bears repeating), the environment and diet are right. Human needs are satisfied by 45 minutes exposure to the sun a week. Reptile veterinarian and researcher Dr. Alison Alberts states that 30 minutes exposure to the sun a day is sufficient for green iguanas.
Carnivorous and omnivorous animals get D3 not only by their body manufacturing it through exposure to sunlight (even nocturnal snakes come out at dusk to bask a bit), but through eating healthy prey. Prey that is not healthy, prey that is fed a marginal diet or one lacking in proper nutrition, or is composed of old or sick animals, will result in malnutrition, including adversely impacting the predator's ability to properly metabolize and process the nutrients its digestive system extracted from the prey.
Plants, however, do not contain D3, cholecalciferol. Plants contain D2, ergocalciferol. Ergocalciferol has been found to be much less efficient in calcium metabolism than cholecalciferol. Herbivorous reptiles maintained on plant diets who are not given adequate amounts of UVB were found to develop MBD. Since no one knows how much D3 an herbivorous reptile needs, it can be a dangerous proposition to rely on supplementing D3 through use of oral vitamins. How much is enough? How much is too much? Unfortunately, more is not better. Too much D3 causes the same thing as not enough D3 - metabolic bone disease. How then can we assure that our herbivores and omnivores are getting adequate D3, but not too much?

 

[Maggie Cummings]

Google is a great thing!

http://www.anapsid.org/uvd3.html

This is from Melissa Kaplan's
"Musings on D3 & UV"
Vitamin D3
My article on Metabolic Bone Disease goes into the natural development of D3 in the body as a result of the previtamin D formed through exposure of the skin to ultraviolet B wavelengths, so I won't repeat it here. If you are unfamiliar with the process, or the numerous disorders clustered under the MBD umbrella term, please read that article.
D3 is formed naturally in the body through exposure to UVB wavelengths (290-320 namometer, or nm). These wavelengths are produced by the sun, but are filtered out by regular glass and plastic; even fine-mesh screen can filter out significant amounts. (The windows in our house block out the UV wavelengths - otherwise all fabrics within range of the window would fade out within just a few years. Glass used in constructing commercial aquariums/terrariums is also made from plain window glass.) Thus an animal needs to be exposed to direct sunlight. It doesn't take much for an organism to get the amount of UV needed to metabolize adequate amounts of D3 when (again, this bears repeating), the environment and diet are right. Human needs are satisfied by 45 minutes exposure to the sun a week. Reptile veterinarian and researcher Dr. Alison Alberts states that 30 minutes exposure to the sun a day is sufficient for green iguanas.
Carnivorous and omnivorous animals get D3 not only by their body manufacturing it through exposure to sunlight (even nocturnal snakes come out at dusk to bask a bit), but through eating healthy prey. Prey that is not healthy, prey that is fed a marginal diet or one lacking in proper nutrition, or is composed of old or sick animals, will result in malnutrition, including adversely impacting the predator's ability to properly metabolize and process the nutrients its digestive system extracted from the prey.
Plants, however, do not contain D3, cholecalciferol. Plants contain D2, ergocalciferol. Ergocalciferol has been found to be much less efficient in calcium metabolism than cholecalciferol. Herbivorous reptiles maintained on plant diets who are not given adequate amounts of UVB were found to develop MBD. Since no one knows how much D3 an herbivorous reptile needs, it can be a dangerous proposition to rely on supplementing D3 through use of oral vitamins. How much is enough? How much is too much? Unfortunately, more is not better. Too much D3 causes the same thing as not enough D3 - metabolic bone disease. How then can we assure that our herbivores and omnivores are getting adequate D3, but not too much?

This hasn't been updated since 2002, I think opinions have changed since then...

 

[chadk]

Basically if the tort gets sufficient UVB, you should not be supplementing with D3. Stick with calcium powder that does not have D3...

But in places like the PNW, where my torts get very little sun exposure in the winter, it may be reasonable to suppliment with D3 during that time.

 

[Tom]

I've read that if a Sulcata tortoise is housed outdoors and gets sunlight,it doesn't need to be givent any D3 supplementation.My question is what if a Sulcata tortoise gets sunlight everyday,would it still be safe to give him a D3 supplement?Shall there be any side effects or harm done to it?
Thanks.

I've been doing it, IN MODERATION, since the nineties, with no ill effect.

 

[t_mclellan]

I think the problem that occurs with D-3 is that is FAT soluble NOT water soluble .
It builds up over time.
All tortoises will eat protein when & if the opportunity arises, Even a Sulcata. In the wild they will eat carrion if they stumble upon it. The periodic increase in D-3 is not the a problem. The problem is the intake of more D-3 than the animal can use before it gets more.
Sources of D-3 as we all know are sunlight & animal matter. How many of you know that some plants produce D-3 also? Some plants produce D-3 in there flowers & fruit.
Tomatoes are just 1 example.

I don't know the amounts of D-3 needed for proper growth verses toxicity. The numbers in this example I'm just pulling out of the air for an example.
Say a 50# Sulcata needs average 50mg. of D-3 a day for normal function. (1mg. per Lb.)
It gets 40mg. a day from sunlight, 5mg. from plant matter, That is 45mg.
Sometimes they will find less suitable plants & maybe receive 0mg. from plant matter & 35mg. from sunlight. They have a total of 35mg.
Another day they receive 50mg. from sunlight, 0mg. from plants & 20mg. from carrion.
Total 70mg. but an average of 49.95mg D-3.
Basically some days they get more than they need & the body stores the excess for days that they receive less.
There is a window of acceptable intake. For example; Extended periods below 30mg. a day would produce deficiency problems. Also extended periods with more than 70mg. would produce excess problems. While bouncing around within the acceptable zone would produce normal function. Sometimes problems from Deficiency OR excess can take years to surface.

This is how I think it works. I will be looking into it just to make sure.
I'll ask my Vet. while she runs the yearly fecals for me.