Pyramiding in Torts

[red bootz]

Hi all,

To all those that think shell pyramiding in tortoises is caused by lack of UV or too much protein, here is some food for thought.


-------- Original Message --------
Subject: [HerpNutrition] New Research on Pyramidal Growth in Tortoises.
28Sep03
Date: Sun, 28 Sep 2003 19:50:43 EDT
From: WalkaboutF@a...
To: HerpNutrition@yahoogroups.com



Hello All

Regarding our emailings on this list, we've had several requests for
reprinting in hard copy and also for forwarding to other lists. Both
are fine and
permitted as long as credit is given to our HerpNutrition list and
Walkabout
Farm. Our goal is simply the dissemination of knowledge in order to
advance the
science of herpetoculture, so it's great to see the information out
there in
other venues.

Those of you with tortoises and turtles are perhaps familiar with the
problem
of pyramidal growth in the carapaces of young captive tortoises. Many
factors have been incriminated --- dietary protein, calcium, vitamin D,
Ca:P, low
UVB, rapid growth from high calorie diets --- but to date our
information has
been strictly observational and anecdotal. One paper published 15 years ago
suggested environmental humidity may play a role in pyramidal growth
(Weser, 1988,
Zur Hockerbildung bei Schildkroten. Sauria 10:23-25). No controlled trials
have been done, until now.

A paper has just been published by nutritionists at the University of
Veterinary Medicine in Vienna (Austria). Fifty hatchling Geochelone
sulcata
(siblings and half-siblings from the same farm) were placed in one of
five groups that
differed in dietary protein and environmental humidity. Protein levels
were
14, 19 and 30% crude protein on a dry matter (DM) bases; the diet form was
soaked pellets mixed with endive. Extra calcium was provided each group.
Humidity groups were arid (24-58%), medium (31-75%) and high (45-99%).
Lighting was
by three different lights, including UVB-emitting Reptisun 5.0 by ZooMed.

Pyramid humps were quantified by means of measuring the depth and
side-lengths of the second and third, and third and fourth central
plates on the
carapace. Ratios were calculated and termed the H-value (H=hump).
Statistical tests
included appropriate non-parametric Kruskal-Wallis test and Mann-Whitney
U-test.

The study lasted 5 months.

The researchers found that growth rates differed significantly with dietary
protein level. Hematocrit and serum levels of calcium and phosphorus
did not
differ between groups. They found that dietary protein had little effect on
pyramidal growth.

However the researchers found that environmental humidity had a significant
effect on pyramidal growth. Sulcata kept in the drier conditions had
significantly greater pyramidal growth, and those kept in the highest
humidity level
had smooth carapaces. Photos accompany the data and statistical analyses.

The authors suggest that under natural conditions, the faster growing
hatchlings would be in the humid areas under growing grasses. In
contrast, those
naturally in dry areas would have no growing grass because of food
scarcity, hence
have lower food intakes. During food scarcity, there is little growth and
probably little bone growth.

Thus the combination of arid conditions and abundant food is abnormal for
young tortoises, yet is commonly found in captivity. However,
correction of the
problem is not through food (calories, protein) restriction, which can
secondarily lead to immune suppression, stunting, debilitation from
multiple nutrient
deficiencies, and shortened lifespan, but through increasing humidity.
When
humidity was high, then high food intake, and high dietary protein, did not
lead to pyramidal growth.

The authors hypothesize that during dry conditions, dehydration reduces
both
intra- and inter-cellular pressures on soft cartilage at the areas of bone
growth, which could lead to collapse of the soft tissue and subsequent
ossification in the collapsed position.

The authors conclude the paper by recommending hide areas of 100%
humidity be
available to tortoises at all times.

Further work is needed to replicate these results, determine mineral
balance
(acid-base balance) under dry and humid conditions, and examine the
carapacial
tissue histologically.

For details: Wiesner CS, Iben C. 2003. Influence of environmental humidity
and dietary protein on pyramidal growth of carapaces in African spurred
tortoises (Geochelone sulcata). J Anim Physiol a Anim. Nutr 87:66-74.

cheers,
Sue
Susan Donoghue, VMD, DACVN
Owner, Nutrition Support Services, Inc.
HerpNutrition at Walkabout Farm
www.HerpNutrition.com



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[Wu-Gwei]

I read that already. Humidity is a factor, but cannot deny that protein and overfeeding are other significant contributing factors as well.


Cheers,
JJ

[Linds]

Interesting read! Thanks for sharing

[ReptileHQ]

This really did not sit well with me, so I contacted Andy Highfield of the Tortoise Trust and this is what he had to say:

----------
Hi Chris,

I have seen this. I believe the whole concept is totally flawed and frankly, makes no biological sense. The "study" was far too short in duration, the numbers of animals used inadequate (despite the 'statistcs') and the regimes employed artificial and misleading.

Unfortunately, many are likely to take it seriously.... animals will die.

Any C. Highfield
----------

I tend to fully agree with him in all respects. It's really too bad that misleading information gets out to the public like this after people like Andy devote their whole lives to chelonians and educating the public.

Chris

[red bootz]

This info was being passed around on the redfoot group on Yahoo. I've had this in my files for a bit, now.
I am very interested as to everyones thoughts on this topic. I have heard time and again that high protein diets lead to shell deformities. But I have seen and experienced pyramiding even when no animal proteins are included in their diet.
In an issue of reptiles magazine a while back there was an article by an author who took a trip out to what he called "Redfoot Island". Here on Redfoot Island, In a perfectly natural setting, almost all the redfoots had pyramided shells. With their main foood source on the sparse island being prickly pear cactus, one would be hard pressed to finger animal based protein as the culprit.
Are there any studies that show a correlation between pyramiding and protein intake? Red foots are known in the wild to consume some carrion, so we know that some torts, especially forest dwellers, can handle some protein in their diet. When does this become too much. Are ther any studies that show a relationship between over-feeding and pyramiding? What is over-feeding by the way. How is that measured? If anybody can pass something along it will be greatly appreciated.
I wouldn't go so far as to say it is misinformation. Just something to think about.

[ReptileHQ]

A varied diet is also important, and I doubt there are many edible species of plants on Redfoot Island. Plants which are high in protein can also be a culprit, such as Alfalfa or many types of supermarket produce.

The island is NOT a perfect natural setting for those redfoots. I believe it states in the article that they are not native to that island and probably floated there from the mainland. Also, the sex ratios are very lopsided meaning they will eventually breed themselves out on that island.

Andy Highfield, cosidered by many people in the world as one of the leading authorities of chelonian husbandry, just called it misinformation, I'll go with him on this one....

Chris

[ReptileHQ]

....there were also studies done with red and yellowfoots stating that adults do need a small amount of animal protein in their diet(5-10%). It stated something about problems with rear limb mobility with animals which had no animal protein in their diet. I would imagine that other forest dwellers would be in the same boat. Kinixys homeana and K. erosa do best when kept and fed like a box turtle for example.

Grassland tortoises on the other hand should have a diet void of animal protein.

Chris

[eyespy]

A lot of the torts brought into Penn with pyramiding also have high protein output in the urine and high levels of uric acid in the bloodstream, which are also symptoms of too much protein in the diet. It might just be coincidence, but the vets I work with tend to buy into the too much protein in the diet idea because of those test results.

All living things are made of protein, even plants, so animals fed "grocery greens" rather than grasses can get too much protein. We see a lot of Mediterranean torts that pyramid from a salad-only diet because they need more fiber and less plant proteins. Some of these animals are very well hydrated and have access to soaking dishes 24/7 so I don't think it's a humidity problem. It's more that they get a lot of romaine, collards, fruit, etc. when they should be getting more grasses, weeds and tree leaves.

[Wu-Gwei]

Thank you Chris for Highfield's opinion on the research. I saw the article in Yahoo's Chelonian Nutrition group as well.

Anyho... nothing is changed.


Cheers,
JJ

[Nic]

That is the first time I heard that Protein has nothing to do with pyriamiding. I don't know if I buy it...