Feeding Guidelines


In January 2002 the European Zoo Nutrition Centre (EZNC) was established. Some of the targets are to improve communication on zoo animal feeding, expand the availability of information on this topic and to improve the specific knowledge of animal feeding by supporting research projects in EAZA zoos.

By developing feeding guidelines for zoo animals that are approved by the European Zoo Nutrition Research Group (EZNRG), EZNC will provide specific nutrition information that institutions need in order to develop an appropriate feeding program.
EZNC has developed a standard procedure detailing how to develop these guidelines. This standard procedure is based on the Feeding Program Guidelines of the AZA that were developed by the Nutrition Advisory Group (NAG).

These nutrition guidelines should be developed for EEP/TAG and ESB animals in the first place as part of more general husbandry guidelines for these species. They can also be developed for other non-domestic animals, although that group will have a lower priority.
Primarily the standard procedures listed below are meant for the co-ordinators of EEP/TAG and ESB½s, and for individuals who offer their help in setting up nutrition guidelines for animal species.

Recommended Feeding Strategy

  • Aim to provide a nutritionally balanced diet.

  • Provide a diet that reasonably stimulates natural feeding behaviours.

  • Provide a nutritionally balanced diet that the animal consumes consistently.

  • Provide a diet that meets all of the above criteria, and is practical and economical to feed.

  • Aim to provide a nutritionally balanced diet.
    A diet is considered to be “nutritionally balanced” when it provides appropriate levels of known dietary essential nutrients based on current knowledge and information. A nutritionally balanced diet must be provided in a suitable form and correct proportion based on the most appropriate physiological model or models for the species. Nutritional status, natural feeding ecology, gastrointestinal (GI) morphology, and nutrients contained in the diet of free-ranging individuals, and foods/feeds available to the institution should be taken into consideration when formulating a balanced diet. The “diet” is all foods offered and/or accessible to an animal, regardless of purpose. Foods used for enrichment, training programs, and/or treats need to be included in calculations when balancing the total diet. A nutritionally balanced diet provides the animal with all the known nutrients it requires without gross excesses or deficiencies.

    Provide a diet that reasonably stimulates natural feeding behaviours.
    A nutritionally complete diet that stimulates natural feeding behaviours encourages the animals to obtain food in a manner similar to that in the wild. The diet should, whenever reasonably possible, encourage methods of consumption similar to methods in the wild, should be of a form as close to natural as possible, and should allow a similar amount of time spent on feeding.

    Provide a nutritionally balanced diet that the animal consumes consistently.
    Of equal importance to a diet formulated to meet all known nutrient requirements is a diet that is reliably consumed by the animal. If the intended animal(s) does not consume the diet due to poor palatability or inappropriate form and/or presentation, the diet is of no value. Diet intake should periodically be monitored to ensure that the animal(s) are consuming the majority of the diet and not selecting only certain items.

    Provide a diet that meets all of the above criteria and is practical and economical to feed.
    A practical diet is one that can be prepared by the appointed person(s) (commissary and/or animal caretaker) using ingredients that are readily available to the zoo or animal care institution. All institutions have budget guidelines. While meeting the nutritional, behavioural, palatability, and functional needs of each animal, the appropriate diet also will fall within practical budgetary constraints.

    Recommended Diet Formulation

    Diet summary.
    Through collecting fed diets an overview can be obtained about the current diets of the EEP/TAG or ESB species. These diets can be divided into "successful" diets and "less successful" diets. Data should be collected not only on ‘offered’ but also ‘consumed’ diets. In addition, information should be collected on water supply. If possible, information detailing the analyses of the fed foodstuffs and ingredients should be gathered.

    A literature review will help pull together information on a particular species or on an individual animal. For EEP/TAG/ESB animals this review should start with the Husbandry Manual Nutrition Chapter. When working with an animal for which there is no husbandry manual, the literature review should include information on the nutritional, behavioural, and functional needs of the species in the wild and in captivity. Important information includes: the natural diet (accompanying nutrient content, if available) and feeding habits, gastro-intestinal morphology, normal adult weight of males and females, age at maturity, longevity of the species (in captivity and in the wild), and any special physiological needs the animal might have (egg laying, breeding, growth, gestation, etc.). In addition, it is important to include those nutritional requirements for the species (or closely related physiological models) that may be available in the NRC report series on nutrient requirements of domestic or non domestic animals or from other sources for example on growing, non-lactating and lactating animals. Diets from institutions currently working successfully with the species should be evaluated. Historical diets from holding institutions should also be examined. The NAG web site may provide additional information (www.NAGonline.net). Published and anecdotic ally literature should be cited appropriately in any document describing the formulation of the diet.

    Diet Evaluation.
    Diets fed in zoos can be evaluated for nutritional adequacy either by hand calculations or by the advised nutrition computer program “Zootrition”. The nutrient density and nutritional appropriateness of the diet should be determined. If there are no known nutritional requirements available for the species in question, an appropriate domestic animal model can be used (e.g., NRC horse requirements for zebras) as a guideline until information specific to the species has been gathered. Specific TAG/EEP/ESB nutrition recommendations should be included when available. Laboratory analysis of dietary ingredients is recommended as a periodic check on published values, or when no published values exist. The evaluation of husbandry practices as they relate to diet; animal response, condition, and body weights are all essential components of the overall evaluation process.
    The nutritional needs of an animal may change throughout its life. Diets should be adjusted when there is a change in life stage, season, or if the animal’s health status can be aided by a change in diet. Veterinary indication and literature survey should suggest if and when a diet change is necessary. The dietary needs of a group may change as the group changes in configuration. It is important that someone accurately and objectively assesses the dietary acceptance of each animal in the group. Since animal keepers are usually those most closely observing the animals, this responsibility may be theirs.
    Periodically, as part of the feeding record, the total quantity of the diet consumed by the animal and/or group as well as diet items avoided or consumed only in part should be evaluated. Keepers also should inform the appropriate personnel of diet preparation problems or special food preparation requirements for individual animals. Animal weight change and body condition should be monitored and reported. It is important to assess the intake of both the individual and group to ensure that each animal obtains the correct amounts of food.

    Diet Implementation.
    It is crucial that animal care staff provide feedback to the appropriate person or department within the institution regarding animal acceptance of the diet.

    There are several reasons for diet reformulation. Diets may be reformulated based on feedback from animal keepers, veterinarians, curators or animal managers or as newly published research information becomes available. During the process of diet reformulation the information contained in the ‘historical background’ and ‘diet evaluation’ chapters of the husbandry manual should be taken into consideration.

    Recommended Dietary Records

    Record Information.
    Ideally, dietary records should consist of transaction information, dietary information from previous institutions (when provided), all institutional diet information (up-to-date, changes, etc.), and information from daily animal care staff reports (animal weights, abnormal feeding behaviours, keeper comments, evaluations and questions), as well as all other information pertinent to the nutritional health of the animal. Dietary records should be freely available for review by animal care staff. We advise the use of “Zootrition” as the standardised form for this information.

    Record Use.
    The nutrition records should be an integral part of the feeding program. The records will help document thought processes regarding diet formulation and presentation that may prevent repeating past mistakes. There is very little nutritional information available for most captive wild animals. For this reason, every bit of information collected is immensely important. Records should include information associated with feed intake (including food preferences), feeding behaviour, general appearance (weight, coat, eyes, teeth, etc.), change in status (pregnant, lactating, growing, old age, etc.), change in schedule (fasted for veterinary reasons, did not eat because animal did not come into the feeding area, etc.), and animal movement (death, moved house, removed from collection, etc.). These records may be used to track feeding trends, plot appropriate nutrient intake for stage of life, identify variability in nutrient requirements between individuals and species (captive vs. domestic animals), and improve overall management of the captive wild animals in our care.
    A coded system for physical parameters for animals based on a 5 point system developed in Edinburgh zoo can be used.

    Recommended Food Use

    Food Used for Behavioural Enrichment.
    All food used for behavioural enrichment must be calculated into the animal’s diet. Similarly, informed estimates must be made of food provided by the general public, or by local wildlife. Preparation and presentation of the daily diet should aim to ensure appropriate nutritional content and promote natural feeding behaviours. An animal does not need to be consuming its wild diet in order to exhibit natural feeding behaviour. Some foods, such as browse and produce, lend themselves naturally to enrichment. Some commercial diets are more difficult to contend with as enrichment items. Nevertheless, every attempt should be made to feed commercial diets in a manner that promotes natural feeding behaviour. The natural feeding times of animals should be considered (e.g., animals that feed in pre-dawn hours may need to be fed in pre-dawn hours to encourage diet consumption and promote natural behaviours).

    Nutritionally complete feeds.
    It is often recommended to provide a proportion of the nutrients by means of a pelleted, extruded, or canned feed. Often these products are referred to as “nutritionally complete” because they have been formulated by the manufacturer to be nutritionally complete for a particular species. The products are designed to provide all of the required nutrients to the target species. The addition of other foods/feeds may complement these products and not only provide a diet that is nutritionally balanced but also allows ample opportunity for normal feeding behaviours. Alternatively, the use of additional foods in conjunction with nutritionally complete feeds may dilute the nutrients provided, producing a nutrient deficient diet. It also increases the likelihood that animals will sort through the items in their diet, selecting items other than those that provide adequate nutrients. The use of supplements in conjunction with nutritionally complete feeds may potentially produce a diet with excessive nutrients that may pose harm to the animal. Use of a nutritionally complete feed (either commercial or homemade) will help to ensure the animal is consistently being offered a similar level and quality of nutrients. Commercial nutritionally complete feeds have the added benefit of allowing dietary consistency across EEP institutions when animals are moved between institutions. Laboratory analyses of nutritionally complete feeds will be advisable as a quality control check and to provide information to the diet formulation database.

    Public feeding.
    The European Zoo Nutrition Research Centre does not recommend a public feeding program. Public feeding, if allowed, should be supervised and fed items quantified as part of the diet for all animals.

    Food use records.
    In order to improve diets, and for animal well being, propagation, and ultimately survival, knowledge of appropriate feeding and nutrient consumption is essential. Knowledge of the nutrient content of any feed or diet is incomplete without understanding the utilization/digestion/metabolism of these feeds/diets by the target species or group of animals. Food can be considered the vector for the needed chemicals (nutrients). It is important to know the details of the nutrients, not just the foodstuff, consumed. The availability of the nutrients to the species, the presence of secondary or toxic plant compounds, and physiological differences between species, etc. will all affect how an animal utilises the nutrients in the food consumed. This is important because the target nutrient levels in the diets fed are often times based on interpolation and extrapolation of data from related species and on feeding experience with the species in captivity.

    Suggested Chapters for Feeding Guidelines