Nutrition Research

In 1974, Toronto Zoo was the first zoo in North America to employ a full-time nutritionist and, to date, remains the only zoo in Canada to do so. The Animal Nutrition Centre (ANC) has developed balanced diets to ensure the optimal health and wellbeing of a wide variety of species. Like the Reproductive Physiology Centre, the ANC is also divided into two components that work together seamlessly to improve animal health and care: the Food Production Unit and the Nutrition Research Unit.

On this page:

FORMULATION OF A NEW CRICKET DIET AND DEVELOPMENT OF PROPER FEEDING PROCEDURES FOR FEEDER CRICKETS AT THE TORONTO ZOO

MASS PRODUCING NATIVE INSECTS FOR THE PANAMA FROG RESCUE PROGRAM

AFRICAN ELEPHANTS – Vitamin E

AFRICAN ELEPHANTS - Development and Validation of an Objective Body Condition Index for African Elephants

BROWSE PRESERVATION TO IMPROVE WINTER FEEDING OF BROWSE DEPENDENT ANIMALS AT THE TORONTO ZOO

REINDEER - Testing Remote Camera Recorders on Reindeer

GORILLAS - The Impact of Dietary Change on Undesirable Behaviours and Activity Levels in Western Lowland Gorillas at Toronto Zoo

TOAD - Vitamin A Study

PUERTO RICAN CRESTED TOAD - Hypovitaminosis A in Captive Puerto Rican Crested Toads (Bufo lemur)

FEEDER INSECTS

FUTURE RESEARCH INTO THE NUTRITION OF AMPHIBINS AND REPTILES

FORMULATION OF A NEW CRICKET DIET AND DEVELOPMENT OF PROPER FEEDING PROCEDURES FOR FEEDER CRICKETS AT THE TORONTO ZOO

MASS PRODUCING NATIVE INSECTS FOR THE PANAMA FROG RESCUE PROGRAM

FORMULATION OF A NEW CRICKET DIET AND DEVELOPMENT OF PROPER FEEDING PROCEDURES FOR FEEDER CRICKETS AT THE TORONTO ZOO

This is a two-part study to develop a feeding protocol for crickets used as food at the Toronto Zoo. The first part involved the development of a new diet to feed to the crickets and for use as a dusting powder to improve the nutritive quality of the crickets. The second part of the study involves the examination of different cricket feeding strategies in order to determine which one provides the most nutritious crickets. This strategy will then evolve into a new feeding protocol which will be implemented throughout the Zoo in order to improve the nutritive quality of crickets as they are fed to the collection. The study is expected to be completed for 2011.

MASS PRODUCING NATIVE INSECTS FOR THE PANAMA FROG RESCUE PROGRAM

For several years Toronto Zoo has helped with the Panama Frog Rescue Program run by Houston Zoo. This has involved financial and active aid directly involved with the frogs. In 2007, Lou Perrotti, Manager of Conservation Projects at Roger Williams Park Zoo in Rhode Island found out that EVACC, the El Valle Amphibian Conservation Center in Panama was having to collect insects from the wild to feed the 500 + frogs in their collection. He was asked to develop a system whereby native Panamanian insects could be mass reared to be used as food for the frogs. This would reduce the time taken in procuring the food, provide more consistent food for the frogs and reduce the impact on the insect populations in the wild. In 2008, Lou asked Tom Mason to join him in the program. In two trips to El Valle, the facility has been successful in developing methods of producing 4 species of katydids and taught staff at EVACC how to collect insect species such as termites in an efficient manner. Other invertebrates such as springtails and sow bugs have also been cultured. It is hoped that the systems developed will aid in the maintenance and conservation of the frogs and that what is learned can be transferred to similar conservation programs around the world.

AFRICAN ELEPHANTS – Vitamin E

The elephants at Toronto Zoo receive additional vitamin E in their diet. To try to monitor the efficacy of this supplementation vitamin E is determined in their blood-samples on regular intervals.

AFRICAN ELEPHANTS - Development and Validation of an Objective Body Condition Index for African Elephants

An animal either under- or over-conditioned is potentially at risk for health problems. Obesity has been cited as a problem in zoo elephants and subjectively linked to inadequate diets and reduced physical activity. Assumptions are that poor body condition is linked to a number of current health conditions, such as foot problems, arthritis and abnormal reproductive cycles (Knobil and Neil, 1998, Taylor and Poole, 1998). A recent study reported acyclicity in female African elephants was correlated with a larger body mass index (Freeman et al., 2008). Weight control was suggested as one way to potentially mitigate these estrous cycle problems. Due to the high rates of ovarian acyclicity in the captive African elephant population, there is increased interest in objectively determining if body condition status is a risk factor for poor health and reproduction. Body condition scoring systems based on scientific data need to be developed for use by researchers and animal managers. The goal of this study is to develop an objective body condition scoring system for African elephants, and validate it using serological measures of nutritional status. Indices of body condition will then be correlated to reproductive cyclicity status. The results of this study have the potential to improve management and care of elephants, and may ultimately lead to increased reproductive success.

BROWSE PRESERVATION TO IMPROVE WINTER FEEDING OF BROWSE DEPENDENT ANIMALS AT THE TORONTO ZOO

The purpose of this study is to perfect a technique by which browse can be collected and preserved until the winter months when natural browse is not available. Browsers, or animals that would primarily feed upon leaves and new shoots in the wild, are difficult to feed properly in captivity due to the scarcity of a suitable browse substitute, especially during the winter months.

The ability to store browse for use during the winter would greatly improve the nutritional quality of the overall diet and quality of life for this particular group of animals. The Toronto Zoo has been manually packing and preserving (ensiling) willow and apple browse in drums for 3 years and the numbers of drums preserved restricts research efficacy and improvements. Currently a mobile and hydraulic browse press is made. This press will enable to pack browse faster into drums and to preserve it better. It will enable the ANC to make larger numbers of drums with browse silage which in turn will allow comparative research. The nutrition intern will start with this project in September and is likely to continue until completion of his M.SC-Thesis. In 2010 100+ drums were packed with apple and willow browse. A trial comparing the addition of apples or no apples to browse silage has been prepared and is continuing. Different ways of pruning apple trees to stimulate vegetative growth has been prepared and are continuing. Already good quality browse silage can be made repeatedly at Toronto Zoo.

REINDEER - Testing Remote Camera Recorders on Reindeer

Boreal caribou have distinct habitat requirements at different spatial and temporal scales and these influence diet choice. Caribou use different foods seasonally, and an attempt will be made to quantify caribou diet selection and associated movement patterns throughout the year. The influence of commercial forestry activities on caribou seasonal diets is poorly understood and caribou diet in managed and unmanaged landscapes we will be examined in the presence of high and low predator densities. The general approach will be to estimate nutritional characteristics for specific foods, estimate the degree of preference for those foods by caribou, and then use prevalence of those foods within forest stand types to estimate energetic gain. Collar mounted cameras will be used to directly observe seasonal diet selection by caribou, enclosures placed in high-value food patches to assess the effects of herbivory on plant composition, and cafeteria trials on captive caribou to refine diet selection based on field observations. The usefulness of remote cameras to detect diet in wild caribou and to optimize the placement angle of the equipment were tested on reindeer at the Toronto Zoo prior to being mounted on wild caribou in March 2010.

GORILLAS - The Impact of Dietary Change on Undesirable Behaviours and Activity Levels in Western Lowland Gorillas at Toronto Zoo

Human and non-human primates, like other animals, have evolved adaptations for manipulating and digesting the food available in their natural habitats. In captive environments, however, it can be difficult to nutritionally and functionally re-create these natural diets. In the wild, Western lowland gorillas travel long distances while foraging and consume a diet based primarily on large quantities of green plant material. This diet is high in fiber and low in caloric density. However, in Toronto Zoo gorillas consume a diet that in addition to produce and fruit contains relatively concentrated and fortified feeds like biscuits and gels used to provide a “nutritionally complete” diet). In the summer fresh browse is supplied on an availability basis. This diet appears to reduce the apparent need for gorillas to spend large amounts of time finding and processing foods and thereby contributes to observed low levels of foraging activity as compared to wild gorillas. Concerns are this captive diet along with low levels of activity, may predispose to obesity, medical problems and the undesirable behaviours like regurgitation and re-ingestion of food (R+R). The Toronto Zoo Animal Nutrition Centre can now provide more fresh and ensiled browse. Browse is therefore aimed at replacing the more concentrated foods like fruit and biscuits in winter and summer. The objective of the study is to examine the influence of diet change on activity levels, the occurrence of undesirable behaviours, animal well being and bodyweight of gorillas.

This study is executed in cooperation with the University of Guelph (Animal Behaviour and Welfare and Poultry and Animal Nutrition) and the Cleveland Zoo. Preliminary results from this study in 2010 have confirmed a strong reduction in R+R occurrence when browse is fed and suggest a link between diet and time spend on foraging and processing food. The time spend on eating browse was highest for most gorillas.

TOAD - Vitamin A Study

Current knowledge of amphibian nutrition is minimal. In recent years a number of different species of amphibians kept in captivity have suffered from different clinical syndromes suspected to have been caused by vitamin A deficiency. Bufonids (toads) appear to be at an increased risk of disease from vitamin A deficiency, and the Puerto Rican crested toad housed at the Toronto Zoo is a species which has suffered from a clinical syndrome attributable to vitamin A deficiency.

Suspected differences in vitamin A requirements and signs of deficiency between amphibian species have directed interest in studying vitamin A deficiency in marine toads. This study will investigate the role of vitamin A in this species to define the clinical and pathological signs of vitamin A deficiency and the optimum dietary levels of this vitamin in this and other amphibians.

The results from the study revealed minimal difference between the “deficient” as fed crickets and “normal” as fed crickets (i.e. no dusting) and in the “naked” crickets and the vitamin A “deficient” as fed crickets (i.e. dusted and gut loaded). When marine toads were compared to wild Wyoming toads, the marine toad liver vitamin A levels were extremely low on both the control and deficient diets, yet there were no clinical signs of illness in either group or lesions found on histology. A series of questions will still need to be answered such as normal liver and serum vitamin A levels in wild marine toads.

PUERTO RICAN CRESTED TOAD - Hypovitaminosis A in Captive Puerto Rican Crested Toads (Bufo lemur)

Current knowledge of amphibian nutrition is minimal. In recent years, a number of different species of amphibians kept in captivity have suffered from different clinical syndromes which have been suspected to be due to vitamin A deficiency. However, this has not been proven to date. Bufonids (toads) appear to be at an increased risk. The Puerto Rican crested toad housed at the Toronto Zoo is one species which has suffered from a clinical syndrome attributable to vitamin A deficiency. The proposed trial will determine the effects of feeding a vitamin A deficient diet to young, developing Puerto Rican crested toads. The results will provide valuable information on susceptibility, pathogenesis, clinical signs, diagnosis and treatment of vitamin A deficiency and toxicity in the Puerto Rican crested toad.

FEEDER INSECTS

The purpose of this study is to formulate a Toronto Zoo cricket diet and the evaluate a new cricket diet to be used as a gut loading agent for feeder insects to provide complete nutrition for reptiles and amphibians at the Toronto Zoo. This study is part of a M.Sc. study by thesis through the University of Guelph and experimentation is planned to be completed in 2010.

FUTURE RESEARCH INTO THE NUTRITION OF AMPHIBINS AND REPTILES

Strategies are currently worked out in cooperation with curators and veterinarians for further investigations in the next 10 years. These will include the dynamics of nutrients in feeder insects, the comparison of the nutritional values of a variety of feeder insects and investigations into the diets for tad-poles.

FORMULATION OF A NEW CRICKET DIET AND DEVELOPMENT OF PROPER FEEDING PROCEDURES FOR FEEDER CRICKETS AT THE TORONTO ZOO

This is a two-part study to develop a feeding protocol for crickets used as food at the Toronto Zoo. The first part involved the development of a new diet to feed to the crickets and for use as a dusting powder to improve the nutritive quality of the crickets. The second part of the study involves the examination of different cricket feeding strategies in order to determine which one provides the most nutritious crickets. This strategy will then evolve into a new feeding protocol which will be implemented throughout the Zoo in order to improve the nutritive quality of crickets as they are fed to the collection.

MASS PRODUCING NATIVE INSECTS FOR THE PANAMA FROG RESCUE PROGRAM

For several years Toronto Zoo has helped with the Panama Frog Rescue Program run by Houston Zoo. This has involved financial and active aid directly involved with the frogs. In 2007, Lou Perrotti, Manager of Conservation Projects at Roger Williams Park Zoo in Rhode Island found out that EVACC, the El Valle Amphibian Conservation Center in Panama was having to collect insects from the wild to feed the 500 + frogs in their collection. He was asked to develop a system whereby native Panamanian insects could be mass reared to be used as food for the frogs. This would reduce the time taken in procuring the food, provide more consistent food for the frogs and reduce the impact on the insect populations in the wild. In 2008, Lou asked Tom Mason to join him in the program. In two trips to El Valle, the facility has been successful in developing methods of producing 4 species of katydids and taught staff at EVACC how to collect insect species such as termites in an efficient manner. Other invertebrates such as springtails and sow bugs have also been cultured. It is hoped that the systems developed will aid in the maintenance and conservation of the frogs and that what is learned can be transferred to similar conservation programs around the world.