The "bulging back" of tortoises has always been a matter of controversy and concern, especially for novices, which is a word that is both "often heard" but also "fresh".
Find such a highly professional article to share with you, I hope to help everyone's cognition.
The "Ekopolytic Syndrome" includes complex physical and biological mechanisms, and the study of its correct formation mechanism requires considerable effort.
We began to study this topic in the 1990s, but it was not until around 2004 that our efforts yielded some results. We have conducted a large number of experiments on this topic, and conducted autopsies and laboratory studies on normal and sick individuals through diagnostic imaging technology. I want to emphasize that not a single animal was injured or killed in the process, and the individuals we studied were "natural" dead individuals caused by other causes of death.
The main objective of this study is to examine the theories in dispute, clarify the theoretical basis obtained by citing incomplete or erroneous data, and thus establish the correct mechanism for influencing the morphological variation of the backlift. The goal for the future is to develop viable methods to reduce or prevent the occurrence of backlift variation.
This article is an excerpt from our forthcoming Comprehensive Scholarly Review (1), which incorporates a large amount of experimental data and cites references. Hopefully, this article will make it easy for the average owner to gain access to and understand about the tortoise boomerback phenomenon.
The two main arguments of this article are:
Abnormal hyperplasia is caused by incorrect foods, especially feeds that are high in protein, high in calories and calcium;
Abnormal hyperplasia is caused by an overly dry environment or (and) dehydration.
This article will show that the above factors are important causes of the phenomenon of backlift.
One of the main factors we call "humidity theory" has not yet been properly explained biologically, and some of the claims do not correspond to the known physiological knowledge, only proposing vague concepts of "cell dehydration" and "tissue collapse"; other similar theories are not feasible. However, many breeders have observed the effects of environmental humidity and even changes in ambient humidity on tortoises, and one of our main challenges is to try to understand the real effects of humidity.
First of all, we must know that the body composition of turtles is exactly the same as that of most animals, and their bones have different appearances, but their chemical composition is the same as that of other animals. Under this premise, the outer stratum corneal scales are mainly composed of β-keratin, of which there are a small number of α-keratin cells, both of which have been extensively studied, but tortoises (and turtles) are unique in that they cover the bones of the body and the outer stratum corneum, so damage to this layer of bone or stratum corneum will have a serious impact.
If we first examine the skeletal structure, we can see that it is as fragile as a defect in a dog, horse, or human. There is nothing unusual or unique about the development of tortoise bones and the stresses they can withstand, and the development process is fully consistent with the known knowledge of biology and nutrition.
The basic trace elements (the main components of calcium and phosphorus) needed for bone making are obtained from food and transported by the blood, and the quantity and proportion of these trace elements must be correct to allow the bones to develop normally. In addition, in order to transport these substances, the animal's vitamin D3 must be normally metabolized; it must be supplied with osteogenetic elements or Vit. Abnormal transport of D3 can result in a bone that lacks normal density and toughness. Reptile breeders mostly call this condition metabolic osteopathy or MBD (Metabolic Bone Diease).
Bones that lack proper density are extremely vulnerable to physical stress, as in rickets, where the long bones of the legs are bent by gravity and muscle pull. If we examine the skeletal structure of a patient with rickets, we find that the condition is very similar to that of tortoise bones with MBD and the "bulging back" variant; compared to the hard, thin, and densely textured normal bones, the diseased bones are fibrotic, thicker, and more porous, and this bone is extremely prone to deformation under constant stress. For tortoises, one of the sources of stress is the strong muscles connecting the limbs, and tortoises with MBD or dorsal bulges usually do not have a sunken pelvic region due to muscle tension; their upper body may also appear bulging due to the expansion and contraction of the lungs themselves and the action of the associated muscles.
Bones are the most malleable during growth, so the effect on bones is more severe at this time-
The faster it grows, the more likely it is to produce absolute or relative defects – in all animals and humans.
Tortoises caught on artificial feed are difficult to have good bone density, especially in herbivorous tortoises; fast-growing individuals have difficulty in having healthy bone density (in fact, this case has never been observed). All of our fast-growing individuals, with or without external symptoms, suffer from some degree of MBD. This can be demonstrated by the dissection of dead individuals or by comparing X-ray images of wild tortoises with captive individuals.
Every tortoise breeder knows that after the eggs hatch into turtles, the bones are very soft and elastic, and then gradually harden over time, but they do not harden to the point of losing elasticity. Stresses applied over long periods of time can cause changes in bones, and even weak stresses can have serious effects.
Tortoises differ from most aquatic turtles from other animals in that their bodies are mostly covered by bones. The outside of the skeleton is covered with stratum corneum or scales. Keratin has many unique properties and is one of the toughest biomaterials, and is also able to absorb or release moisture to stabilize the environment of the tortoiseshell (just as our nails become softer after bathing and hard and brittle when dry).
We have a fairly good idea of the properties of α- and β-keratin (keratin) at different water content and ambient humidity, how keratin changes its hardness due to the humidity in the environment is a very important property, its hardness changes are very drastic, can be measured and quantified, and at relative humidity of more than 80%, the toughness and resistance of squamous keratin is only half of that of the relative humidity of 50%. When the relative humidity reaches 90-100%, the keratin becomes very soft because it absorbs water too quickly, with little tension to the bones that cover it; conversely, at extremely low relative humidity (about 25%), the keratin loses water and becomes very hard and strong, in which case the stratum corneum can exert sufficient physical stress on the bones underneath it. As a result of previous tests, the design of the tortoise ecosystem is mostly maintained at extremely low relative humidity (12%).
Recent experimental results have also shown that the basking lamp has an excellent drying effect, in its direct exposure area, the water molecules in the shell of the shell are released and the relative humidity of the surface can be rapidly reduced to less than 20%, so that the strength of keratin increases, but also enhances the stress of the stratum corneum on the underlying bone.
There are many people who think of wild young turtles
(e.g. Testudo graeca, a European tortoise) mostly lives in humid environments with a relative humidity of 90-100%. This is a completely incorrect message.
Part of our study made thousands of measurements of the natural habitat of young turtles, using mini-automated recording devices to take measurements over 12 months in several major habitats to collect highly accurate temperature and humidity data, and 18,000 humidity detailed data points were obtained through recorders installed on tortoises. Our findings show that young turtles live in little significantly different environments from adult turtles, with relative humidity between 34 and 60%. Very few exceptions to relative humidity exceeding 90% are recorded in storms or showers.
In the semi-arid regions of southern Europe's Ameria and Murcia regions (similar to most semi-arid regions in North Africa), rainfall is unattainable even during peak periods of tortoise activity. The recording time of the data covers all tortoise activity (including dormancy), the tortoises are active at high humidity (>80%) for only 2% of all recorded time, the relative humidity of the tortoises during the foraging period can be as low as 20%, but most of the growth period after that will return to the relative humidity of 45-50%, the collected data are consistent with previous records in Morocco, Turkey and Tunisia (not exactly consistent), and other workers record data also includes the North American desert tortoise (Desert). tortoise) in the cave humidity record, this data can not show 90-100% relative humidity suitable for young turtle growth.
In fact, desert tortoises
(Gopherus agasssizii) is located in the dry desert region of Arizona, where the relative humidity is even lower than in the Ameria and Murcia regions. If the main reason why wild tortoises in dry areas do not have a back bump is that they use caves or vegetation to provide a secluded environment of 90-100% relative humidity, then the local European tortoises in Spain (Testudo graeca graeca) will produce many morphological variations due to the absence of this environment, which is a semi-dry area with an average annual rainfall of only 226 mm (the average rainfall in the UK is about 600 mm), which is the least annual rainfall in Europe.
I would encourage all tortoise breeders to pay special attention to the "average" relative humidity chart of the tortoise habitat provided by the meteorological website, where only the meteorological data collected from the height of the tortoise habitat is meaningful and reliable information. The temperature and humidity vary greatly from altitude to altitude, and the climate in inland and coastal areas is also very different. Tortoises are mostly only very single organisms, and the reasons behind them must also explore the climatic information of their individual habitats (rather than the average information of all habitats).
Another major property of keratin is the ability to alter physical stress on bones and how it proliferates in turtles and turtles, in two main patterns. When tortoises rely only on cell proliferation, new material accumulates on the edges of the scales, thus forming a tree-like structure; while most water turtle cells are flat hyperplasia, and each cell grows under the old cells at the same rate, many aquatic turtles lack "historical growth rings", and the old scales eventually fall off and are replaced by the new scales. Tortoises do not have scales shedding , and their stratum corneum increases in a vertically proliferative fashion.
This expanding pattern of vertical cell hyperplasia exerts upward stress on the bones, which can have a serious effect when any degree of MBD occurs, and the bones conform to the growth of scales, which is the main reason for the tortoise's backlift, but in aquatic turtles, it does not occur because of the different growth directions of the scales.
Backlifts are more pronounced when:
1. Keratin is overly hard due to extremely dry environments
2. Abnormal thickening of keratin
Over-proliferating and thickened stratum corneum is a common feature of individuals with severely bulging-backed tortoises. Compared with healthy wild individuals, abnormal hyperplasia can be quickly judged by the difference in the color of the stratum corneum; individuals with excessive hyperplasia are generally densely textured and dark in the stratum corneum.
Most individuals with this phenomenon grow up in similar environments: in breeding sites that mimic the natural environment, the intake of water that contains insulated lamps and limits moisture is controlled. We have found that many feeding sites adjust environmental humidity to extremely low, even lower than in arid habitats. The effect of the ceiling insulation lamp on tortoises has not been carefully explored, but it is certain that it will cause a large amount of water evapotranspiration. Tortoises in this environment may also have other health problems associated with dehydration: bladder stones, gout, and kidney disease.
After laboratory research work, an interesting phenomenon was confirmed: when turtles and tortoises go through a long period of dehydration, their outer skin tissue thickens in an attempt to reduce the evapotranspiration of moisture from the skin, and the thickened outer skin affects the epidermis of the limbs and causes the proliferation of β-keratin.
When the animal is dehydrated, the scales will accelerate and thicken, but the growth of the bones does not accelerate with it, and the thickened dry stratum corneum thus produces a huge force on the bone; but under normal circumstances, the force of the stratum corneum on the bone is very weak. The accelerated growth rate coupled with MBD and the overly dry environment will cause the muscle tension to pull each other with the tension caused by the excessive hyperplasia of the keratinous scales, resulting in the deformation of the tortoiseshell.
Another important point is that in the wild, tortoise shells are constantly worn out by rough plants, stones, wind-blown sand and the tortoises themselves. Even during the dormant period, the tortoise remains partially active, and the microorganisms in the cave soil will decompose the material of the outer layer of the tortoiseshell, so the outer layer of the tortoiseshell is constantly worn out and thinned. In most captive rearing environments (especially indoor rearing environments), the care of the breeder will mostly eliminate the factors that make the turtle shell wear out, even if the humidity is properly controlled, the stratum corneum will continue to accumulate, and if the environment is dry, there will be a bonus effect.
If the stratum corneum is thicker (and drier), the more pronounced the phenomenon becomes, not only from the nature of the stratum corneum itself, but also from the strong physical stresses that the stratum corneum exerts on the bones underneath it.
In order to alleviate the severe backlift phenomenon, some breeders raise the environmental humidity of tortoises to more than 90% for a long time and increase the temperature, the effect of which is only to soften the stratum corneum and reduce the stress added to the bones, but it does not improve MBD and exposes tortoises at high risk of fungal and bacterial infections. The moist and softened stratum corneum is difficult to resist the invasion of microorganisms, and it also lacks structural strength and is easily damaged. Although the visible backlift phenomenon may be alleviated or disappeared in this extreme environment, it is only a palliative measure.
I think it is a grave mistake to address the problems arising from the unnatural environment. To improve morphological variation, try to improve the causes of back booms, rather than focusing on suppressing obvious extrinsic symptoms.
Therefore, the arguments to be made are:
The bone density of captive tortoises is similar to that of healthy wild individuals, and regular measurements are tracked. Healthy bone density reduces the chance of morphological variation.
Ensure that the feeding environment can provide the right temperature and humidity. Reference detailed environmental factors to the species' natural habitat to establish an appropriate safe range of temperature and humidity, rather than speculation or rough meteorological data.
Improve the feeding environment so that the tortoise shell can have normal wear and tear to avoid the continuous thickening of the stratum corneum.
It is still somewhat difficult to meet these requirements. It is obvious that the current breeding environment needs to be improved, and although the insulation lamp is a necessary facility, it will also cause serious problems. In the non-natural environment, it is difficult for the breeder to control the environmental humidity within the safe range, and the turtles and turtles are also difficult to achieve healthy bone density and growth under artificial feeding. Wild tortoises must be periodically active and foraging and dormant for long periods of time, so the environmental factors they are exposed to change with the seasons. Possible solutions to these problems are not nonsense, and may be a major advance in turtle and turtle feeding, especially for the breeding of species that are not easy to reproduce or are endangered.
Thanks to Ed Pirog for his many wonderful discussions, discussions and comments on this topic over the past 20 years, he has continued to devote considerable effort to this topic. Through his observations, he confirmed that the changes in the stratum corneum with humidity, temperature and its degree of water absorption are important factors in the development of the phenomenon of backlift. From Ed's observations, I began to do detailed experiments and measurements on the properties of keratin in different environmental conditions. Here, for the first time, we publish the above research results.
Original title:
The causes of “Pyramiding” deformity in tortoises: a summary of a lecture given to the Sociedad Herpetologica Velenciana Congreso Tortugas on October 30 2010
作者：A. C . Highfield - Tortoise Trust
The original article was first published on November 1, 2010 at the following URL:
http://www.tortoisetrust.org/articles/pyramiding.html
postscript:
The above article is only the author's point of view, M note pulled out and shared with you, after reading such a long paper, is it a brain hole, was the "wall cracked" science popularization?
M Ji personally believes that to achieve the perfect round back armor, it is still more difficult, slight or acceptable, if long into the "mountain", it is obviously sub-healthy, sick. Of course, as a breeder, I also hope to provide a better environment and breeding for the turtle as much as possible, so that it can grow healthily.