General information on feeding tortoises
European and Central-Asian tortoises are quite popular as house pets. As wild animals, they are extremely well adapted to the habitat of their original areas of origin.
Their diet can therefore also be seen as an adaptation to the conditions in the biotope. The European tortoise’s original habitats have mild climates with a dry Mediterranean or continental climate in summer (from May onwards). Only in the spring do the animals have sufficient access to fresh green fodder, comparable to the spring vegetation of a nutrient-poor, Central European meadow. Starting in May, this feed begins to dry up considerably and will contain significantly less protein and fewer easily digestible, energy-rich substances, somewhat comparable to hay. The steppes of Central Asia have similar if more extreme conditions. To be able to live in such a habitat and use the nutritional resources that prevail there, these species have developed special anatomical structures and physiological adaptations.
They have relatively small stomachs which do not expand much, so that they cannot eat large quantities at once. They consume many small quantities of food spread out through the course of a day.
The appendix and large intestine expand to become large fermentation chambers, taking up a majority of the stomach area. In these chambers, crude fibre is broken down by means of controlled fermentation through an extremely efficient and diverse intestinal flora (various bacteria and single-cell organisms) and made digestible. The feed remains in the digestive tract for up to 2 weeks, forming a three-dimensional latticework of raw fibres and providing the intestinal flora with a large surface on which to do their work. However, if there is no structured crude fibre or if it has been replaced by easily digestible material (starch, sugar), this will lead to malfermentation with a severe reduction in the length of time the food remains in the intestine. The intestinal flora may be suppressed or killed off. The tortoise will become dehydrated and may develop diarrhoea or parasitic diseases.
Since water can be very scarce for months in the tortoise's natural habitat, they excrete the end products of protein metabolism as water-insoluble uric acid salts (urates), so that their bodies do not lose water. This adaptation is extremely efficient, as long as their feed does not contain too much protein. Excess urates in the body, resulting from feed that is too high in protein, cannot be excreted. This leads to kidney failure and painful, deadly gout.
Therefore, a feed for European and Asian tortoises should have easily digestible components like sugar, carbohydrates, and a high percentage of structured crude fibre, and be low in protein (5-8%). Use of a variety of plants can partly or wholly cover the animal’s need for fat-soluble vitamins (A and E). They also supply sufficient minerals and trace elements. The animal's need for a balanced ratio of calcium and phosphorus is achieved by processing adult plants and can be supplemented if necessary.
Finally, it should be noted that an optimum body temperature (preferred temperature 35-37°C) is absolutely necessary for adequate digestion of fibre-rich feed. This is achieved through sunning and may need to be simulated in the terrarium by installing a powerful sun lamp to warm the ground temperature to 35-40 °C (however, the animal also needs a cooler place to which to retreat!). Light and warmth will increase the animal’s activity and appetite.
How does the food supply look in the wild?
These currently popular pets place have high maintenance requirements. When keeping and feeding tortoises, it is very important to be aware of their original habitat conditions and to strive to follow them. Although tortoises can reach a very old age, when kept by humans a lifespan of only a few years is unfortunately not uncommon. Appropriate feeding is therefore an essential factor for the successful keeping of tortoises. Improper feeding is the most common cause of illness and death in tortoises.
Their natural habitat consists of barren, dessicated landscapes. In such habitats tortoises find slow-growing plants that are rich in minerals, trace elements, vitamins, crude fibre and roughage. If you can imagine this habitat, it is clear that our lush, protein-rich meadows, fruits, leafy greens and vegetables are not amongst their natural food resources. These foods are too soft and sugary for their digestive systems to properly break down. Even occasional feeding of fruits, leafy greens and vegetables can lead to intestinal imbalances, which in turn can lead to severe diarrhoea. Tortoises are unfortunately unable to discern healthy from unhealthy foods, and will gladly eat tomatoes, leafy greens and vegetables. The result is often gout, constipation, shell deformations, fatty liver or even death.
In the tortoise's natural habitat, both the animal's organism and its feeding instinct have adapted to food that's low in calories and rich in crude fibre. Tortoises must therefore feed continuously throughout the day in order to take in nourishment that’s balanced and adequate. They will have this same instinct even when cared for by humans. They will continue to eat as much as and often as they can, even when presented with real protein bombs in place of low-calorie plants. A high-quality base feed is therefore crucial for the health maintenance of tortoises. The quality of this base feed depends greatly on the starting product.
Pre Alpin Testudo products are healthy, organic-quality feeds adapted to the specific nutritional needs of tortoises. They contain a unique combination of grasses and herbs from organically cultivated meadows located in the Alpine foothills of Bavaria. Expert agricultural engineers regularly inspect these meadows so that they are harvested at the optimum point of maturity. This allows us to produce roughage and base feeds with different protein and crude fibre contents, thus ensuring that we can meet the various seasonal nutritional needs of tortoises.
The plants are gently processed in a modern drying plant with warm air with no added binding agents or flavourings, so that plant structure is maintained. This gentle and weather-independent processing gives the hay a quality exceeding that of any conventionally dried hay. It contains valuable trace elements and vitamin-rich components such as leaves, flowers and seeds. This eliminates losses from crumbling that occur during haymaking, as well as such factors as over-mature starting material and poor processing, which can lead to high germ infestation and mould growth. Through controlled cultivation, timely harvest and gentle processing, Agrobs guarantees a naturally high vital and nutrient content and a high digestibility of the crude fibre contained. By feeding Pre Alpin products, you allow your animal to enjoy the advantages of an original diversity of plant life as it occurs in the Alpine foothills, thus giving it a long life.
By Dr M. Baur and Prof. Dr R. Hoffmann, Zoologisches Institut, Munich