Nutritional Sciences

Nutritional Sciences

Nutritional Sciences

The nutrition program at Omaha’s Henry Doorly Zoo and Aquarium consists of a nutrition laboratory, a centralized diet kitchen and a browse team. Both components work hand in hand to ensure the nutritional adequacy and safety of all animal diets at the Zoo.

The nutrition laboratory continually monitors and evaluates animal diets for various nutrients. This ensures optimal health and longevity of our zoo animals. Diet formulation for exotic animals can be complicated. Little is known about the nutrient requirements of most exotic species.  Diets are developed and formulated based on a species’ known natural history and diet in the wild, along with specifics regarding digestive anatomy and physiology. This information is then extrapolated with known requirements established for domestic species including cats, dogs, horses, cattle, swine and poultry. As a result of these complexities and unknowns, substantial scientific inquiry is needed to further promote and develop optimal zoo animal diets. The nutrition laboratory here at Omaha’s Henry Doorly Zoo and Aquarium is considered a leader in comparative nutrition research throughout AZA institutions and contributes to the knowledge base in this extremely important area of animal management.

While the nutrition laboratory evaluates the nutritional adequacy of diets, a dedicated full time staff and volunteers are necessary to produce the Zoo’s animal diets on a daily basis. The animals must be fed 365 days a year and the incredible staff of the diet kitchen are responsible for ordering and managing all of the ingredients for animal diets. Our centralized diet kitchen manages all types of feed ingredients including dry forages such as alfalfa hay, fresh produce, fresh meat, custom commercial products, dietary supplements and whole prey ingredients such as fish and rodents for carnivores. These ingredients are carefully managed, weighed and prepared for individual animal diets daily.

Nutrition Lab

In the summer of 2006, new analytical equipment began to arrive in the Zoo's new nutrition lab at the time. The nutrition lab was developed with the capacity to conduct meaningful research with any species residing at Omaha's Henry Doorly Zoo and Aquariumn from fish to primates. In addition, collaborative efforts with other zoos, feed companies, and universities are allowing Omaha's Henry Doorly Zoo and Aquarium to be one of the leaders in exotic animal nutrition research.

Little is known about the nutrient requirements of most exotic species. Diets are developed and formulated based on known requirements established for domestic species including cats, dogs, horses, cattle, swine and poultry.

Improvements in animals nutritional status can improve reproduction and longevity of endangered species in captive and wild populations.  In addition, proper nutrition and advances in nutrition research provide us with tools to more effectively manage their habitat in the wild, thereby improving survival.

The nutrition lab consists of state of the art analytical equipment that measure specific nutrients including water, protein, fat, fatty acids and dietary fibers.  Some of the specialized laboratory equipment includes a gas chromatograph for fatty acid analysis, a LECO FP528 protein analyzer, a fat extraction unit and a bomb calorimeter. The nutrition lab specializes in dietary fiber analyses, including total, soluble and insoluble dietary fiber analyses.

The nutrition lab monitors the nutritional quality of Zoo animal diets on a regular basis and makes necessary changes to diets as needed based on results from analytical procedures.  In addition, many nutrition experiments are conducted in the lab mainly focus on how digestible formulated diets are for any given species. The lab concentrates on digestibility experiments that focus on energy, fat, fatty acids, minerals and protein.

Research Projects


With the growing concern regarding the status of amphibians globally, efforts are underway to conserve as many threatened amphibian species as possible. As a result, deeper understanding of their unique nutritional requirements is paramount.

In order to understand the requirements of amphibians, it is first necessary to understand the nutrient quality of the food they eat, insects. Omaha's Henry Doorly Zoo and Aquarium's Department of Comparative Nutrition continues to conduct numerous experiments in order to determine the effects that various types of diets and ingredients have on the overall nutrient quality of feeder insects that ultimately are fed to amphibians. Data and results from these experiments are assisting nutritionists globally in the development of better diets for amphibians and reptiles.


The Butterfly and Insect Pavilion opened in the spring of 2008 and the nutrition lab works closely with the keepers who care for the different species to provide optimal nutrition for the new butterflies. Research has shown that added amino acids and protein in the form of pollen provide healthful benefits to butterflies. One of the most important benefits is an observed increase in life span.


Very little information was known about fossa (Cryptoprocta ferox) nutrient digestibility and passage rates. Because of this, as with all exotic animals, nutritional needs are based on the use of a suitable model species. Domestic cats have been assumed to be the most reasonable model for most carnivores due to shared similarities in digestive tract anatomy.

In 2007, a Papillion La Vista South High School junior, Nichole Johnson, along with Omaha's Henry Doorly Zoo and Aquarium's Zoo's Comparative Nutrition Department designed a series of experiments to determine nutrient digestibility and passage rates of fossa. Nichole presented and competed with this project at the regional science fair, winning top honors. She progressed to present the project at the National Science Fair in Boston, MA, in February, 2008. In addition, the Comparative Nutrition Department presented the research nationally, in order to disseminate the important findings to other zoo nutritionists globally.


In 2005, the giraffe herd at Omaha's Henry Doorly Zoo and Aquarium became the subjects of a longitudinal study addressing the effects of a newly developed diet.

Every six months from 2005 to 2008, blood was drawn from each giraffe to determine the effects of this diet on blood nutrients including fatty acids, calcium and phosphorus. To conduct a study such as this, the Comparative Nutrition Department worked closely with the Conservation Medicine Department and with the keepers that care for the giraffe daily. Data from this study have been presented in the United States and Internationally in an effort to promote a more healthy giraffe diet.

Insectivore Diets

In addition to understanding insect nutritional profiles for amphibian nutrition, the information is also being used to develop more appropriate diets for insectivorous mammals such as tamandua and hedgehogs.

Commercial insectivore diets, much like those for domestic dogs and cats, contain significant concentrations of grain products, in addition to being highly processed. Studies are being conducted to determine the digestibility of nutrients of a newly developed experimental insectivore diet being made at Omaha's Henry Doorly Zoo and Aquarium's Comparative Nutrition Department.

Large Cat Nutrition

Although decades of research have given nutritionists a solid foundation for developing companion cat diets, much is needed in the field of exotic cat nutrition. Most zoos feed exotic cats a raw beef-based diet, regardless of species. These raw meat diets do contain additional ingredients and supplements to meet domestic cat requirements; however, little is known how exotic cats utilize the specific nutrients in various meats.

In 2006, the Comparative Nutrition Department at Omaha's Henry Doorly Zoo and Aquarium along with researchers in the Department of Animal Sciences at the University of Illinois at Urbana-Champaign, began studying how various cat species digest the nutrients from a variety of different meat-based diets including beef, bison and elk. These studies have been replicated in domestic cats in order to determine the similarities and differences that exist between the species.

Additionally, further studies are being conducted to determine the specific energy requirements of individual exotic cat species in order to maintain ideal and healthy body condition. The results of all of the large cat nutrition research will be presented to other AZA institutions, in addition to publication in nutrition journals.

Small Cat Nutrition

Many small exotic cat species including black footed cats, servals, bobcats, fishing cats, African wildcats and caracals reside at Omaha's Henry Doorly Zoo and Aquarium. In addition, species such as Pallas cats, ocelots, sand cats and Canada lynx are found in AZA institutions throughout North America. Many of these species develop health concerns thought to be nutritionally related.

The Comparative Nutrition Department at Omaha's Henry Doorly Zoo and Aquarium has been conducting studies with small cats fed grain-free domestic cat foods, raw beef based diets, or whole prey (in the form of rodents or fish) to determine nutrient digestibility, blood parameters and gastrointestinal tract health. These results will be used by Omaha's Henry Doorly Zoo and Aquarium to develop the best diets possible for these small cat species.

Student Opportunities

Student internships are available in the nutrition department year-round.  Two types of internships are available to college students:

  • Nutrition Research: This experience will include opportunities in both the nutrition laboratory and the diet kitchen, working directly with the scientists and staff of the department. These are competitive internships and typically fill quickly. One to two positions are available per semester (fall, spring and summer) depending on current research needs. Due to the research focus, shorter internships are not available for nutrition and run a minimum of eight weeks.
  • Diet Preparation: This experience will focus on animal diet preparation and large quantity animal food production working in our centralized diet kitchen. One to four positions are available per semester (fall, spring and summer). Shorter internships are available for diet preparation, such as over Spring or Winter Break.
  • Shadowing: Opportunities for high school and college students to shadow our nutrition staff are available.


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