A bright future ahead for Exotic Animal Nutrition

The idea to establish the European Zoo Nutrition Centre was spawned in 1999 at the Zoo Nutrition Congress in Rotterdam Zoo during a meeting with Rotterdam Zoo nutritionist Ing. Joeke Nijboer and Dr. Ir. Walter Jansen, who have completed a Ph.D. in horse nutrition and runs a company specialising in claim consultancy and setting up small businesses in niche markets. The Dutch Zoo Federation (NVD) and the European Association of Zoo and Aquaria (EAZA) had become so convinced of the need for a European Zoo Nutrition Centre to collect and distribute nutritional data, that the NVD offered them free use of an equipped office within NVD ’s headquarters in Amsterdam.
Although there is a wealth of information on the nutrition of exotic species, largely built up through experience at individual zoos and other animal keepers, there is no means by which that information could be shared to everyone ’s benefit. Congresses already provide one platform for discussions, but there is no single collection of data that could be accessed all year round.
The initial project, collecting information on more than 1200 different diets given to Europe ’s 5000-6000 exotic species is now complete and a book of tables and guidelines is available for € 8,95 (excluding postage and handling).

Requirements - a mammoth task
Collecting the data is not easy. The sheer variety of exotic species housed in Europe ’s 1000 or more zoos is only the first hurdle. In Europe, there are not much fulltime nutritionists working in a zoo. The main people responsible for nutrition in zoos are the vets and keepers. The EZNC-team finds that establishing a contact person within each zoo is integral to retrieving information.

Natural feeding
Conservation biologists also have a role to play, but it is more important for the nutritionist to know about the intake and digestive physiology of the animals rather than what different species of plants they would eat in the wild and how long they spend eating. For example, conservation biologists have made reports on how long a wild giraffe spends browsing on each species of acacia tree. So they can plan how many acacia trees of each species there should be per hectare to support a certain number of giraffes, but they have no data on what weight of acacia leaves a giraffe needs to eat every day. That is what interests the zoo nutritionists and what happens to those leaves one they have been eaten. This it seems is no easy task.
The knowledge developed through studying captive animals can be of use in helping maintain wild populations. When the field of zoo nutrition is better developed, it will know what questions should be asked of conservation biologists in order to get the information they need to apply that knowledge back from zoos to the wild. Combining this with breeding programmes-already coordinated by EAZAs in Europe to prevent inbreeding in captive specimens-and this knowledge will be essential to ensuring the survival of wild populations of many species. Therefore, accumulating information on nutrition for breeding animals will become an extremely important. Similar to domestic species, vitamin and mineral nutrition will need to be further investigated to improve breeding performance. Although nutrition research is not a major activity in zoos, it can help in some specific situations. A collaborative study with the University of Wageningen and the “Apenheul ” primate park in the Netherlands to investigate a diabetes mellitus-like disease of woolly monkeys in captivity and in their wild habitat in Brazil. This type of interactive work will become the cornerstone of EZNC ’s existence alongside the information distribution network.

Agricultural studies
In agricultural studies, nutritionists can easily set up a balance trial using large numbers of animals under similar conditions, but with exotic species that just is not possible. Even if there were enough animals of each species across Europe, the conditions in those zoos, with respect to environmental temperature, humidity and housing can be completely different, for example, between Amsterdam and Barcelona. Initial calculations of energy and protein requirements to support basal metabolism can be made based on the weight of an animal, but until data can be collected and compared, real science is not as practical in this respect as experience. Some of the older zoos have built up experience of feeding over perhaps a hundred years, but even now, for some animals there is no experience.

Lack of knowledge
A couple of years ago a consignment of turtles was confiscated in Hong Kong, being exported for consumption. The first problem that nutritionists found was to decide if these turtles are carnivores or herbivores. No one knew. This shows the lack of knowledge in some areas about nutrition for exotic animals. Observing wild animals is not always a practical solution. Furthermore, no one would argue that many of the ingredients used in zoo diets are natural components of the animals’ diets in the wild. Lettuce, for instance is by no means available to wild animals, but it is readily available in Europe, so it is widely used in feed. It is therefore common for estimations from different zoos’ feeding regimes to differ widely, so it is important that users of the EZNC ’s data must be aware of that and not be surprised, as livestock nutritionists might be.

Comparative Nutrition
Zebras and Camels can be compared to horses; exotic fish to commercial species; bears and wolves to domestic dogs. Primates are usually compared to humans, though some species have digestive physiology more in common with horses. Comparing the similarities and differences in digestive physiology and feeding behaviour brings the zoo nutritionist another step closer to satisfying requirements.

From nutrition to feeding
Excessive feeding of healthy animals is not as much of a problem in zoos as it is with livestock or companion animals. Obesity is rare, though it does occur and excess protein is excreted as long as there are no kidney problems. The cost of feed is less of an issue in zoos than it is in agricultural livestock production, reflecting both the embryonic condition of the zoo nutrition field and the aims of zoo animal nutrition itself. Obviously, growth rates are not an issue with zoo animals, but longevity and health are. This gives zoo nutrition more in common with companion animal nutrition, though the life spans of most zoo animals are still not well defined. Further, in common with companion animal nutrition, feeding treats is an integral part of the equation. Elephants, for example, including three kilos of carrots in the diet formulation are an insignificant and, in the nutritionist ’s view, irrelevant as 90%of a carrot is water. However, feeding carrots to elephants is an important part of the bond between keeper and animal-from the keeper ’s viewpoint. Hence, elephants are still fed carrots. In fact, the experience and wisdom of zookeepers is, in the absence of any scientific data to support zoo animal nutrition and feeding practices, vital information and as such is one of the reasons why zoos have little interest in streamlining their feeding costs. One of the other reasons of course is the entertainment value to visitors-whole vegetables are attractive-pelleted feeds and hay is not.

Getting enough
Another challenge is in feeding the right amount. Getting from requirement to diet is not always as simple as it is with farm animals. The pelican outside enclosure is a classic example. Calculation of basal requirements for pelicans would result in a certain weight of fish being given at each feed. In reality, around twice the calculated amount has to be given. This seems excessive without a visit to the pelican enclosure. Zoos are happy to allow water and sea birds native to the Netherlands to share the pelican pond, so ducks, herons, gulls and even cormorants can be seen flying overhead and mingling with the exotics. This means feeding time for the pelicans is a veritable feeding frenzy of different species. To make sure the pelicans meet their dietary requirement, enough has to be given to feed the wild birds as well.

A rapidly developing market?
As the scientific data becomes more available and more trust is gained between the EZNC and individual zoos, feeds feeding will be increasingly based on the animal ’s specific needs, but the other feeding parameters will always have to be taken into account. Hence, zoo animal feeds, though yet underdeveloped, are developing rapidly enough to attract the interest of feed manufacturers. Additives yet are limited to vitamins and minerals, but knowledge of their application in breeding and lactating animals is an area that should develop rapidly enough by pooling information through the EZNC to improve both knowledge and practice. For those with an interest in zoo animal nutrition, the final aspect of EZNC ’s work will involve education. The group is going to begin organising seminars and conferences over the next couple of years, beginning in its home country of the Netherlands and from their it hopes to involve the whole of Europe.