Nutrition Considerations in Zoo Animal Husbandry

  • Zoo Animal Nutrition and Feeding - Discipline

    • How much of each nutrient is required in a healthful diet

    • How nutrients can/should be provided

    • How the animal's body acquires and uses nutrients for different physiological processes

 

  • Animal Nutrition Considerations

    • Ecological and behavioral aspects of diet composition

    • Physiological parameters (e.g., dentition, serum values, etc.)

    • Gastrointestinal (GI) tract anatomy and physiology

    • Nutritional requirements and composition

 

  • Ecological Feeding Categories

    • Carnivores

      • Eats other animals or animal parts

        • Insectivore - insects

        • Vermivore - worms, annelids

        • Piscivore - fish

    • Herbivores

      • Eats plants and plant materials

        • Folivore - leaves

        • Frugivore - fruit

        • Granivore - grain and seeds

    • Omnivores

      • Eats plants and animals

    • Generalists = eat a wide variety of foods more or less equally

    • Specialists = rely on one(ish) food source, excluding others

 

  • Dentition: Tooth Physiology

    • Heterodont = teeth differentiated in form, function, and shape

    • Homodont = teeth similar in shape and function (size may vary)

    • Edentulous = lacking teeth

    • Diastema = Naturally occurring gap between teeth of different function

 

  • Dentition: Heterodont Differentiation

    • Incisor = cutting and securing food

    • Canine = seizing and piercing prey, fighting

    • Cheek Teeth:

      • Premolar = deciduous and permanent

      • Molar = permanent only

    • Dental Formula (front to back, only on one side)

    • Written as: tooth type top#/bottom#

 

  • GI Tract: Basic Physiology

    • Generally, 3 "Regions":

      • Foregut (mouth → stomach entry)

      • Midgut (stomach → small intestine)

      • Hindgut (cecum, colon → rectum)

    • Four Main Functions (in order):

      • Ingestion and mechanical breakdown (mouth/esophagus)

      • Chemical breakdown (i.e. digestion) via enzymes (stomach)

      • Neutralize acid and regulate food intake (duodenum), absorption of nutrients (jejunum), and of B12 and bile salts (ileum)

      • Absorption of water and electrolytes, egestion (colon, cecum, rectum)

 

  • GI Tract Anatomy: Herbivores

    • GI tracts generally more complex in comparison

    • Challenge = breaking down cellulose (lack cellulase enzyme)

    • Many digest via fermentation with a complex ecosystem of symbiotic microorganisms in the gut and intestine (microflora)

 

  • GI Tract Anatomy: Monogastric Herbivores

    • Stomach = single chambered

    • Ferment cellulose in an enlarged cecum = pouch at the beginning of the large intestine

    • Fermentation occurs after stomach = hindgut fermenter

    • Often coprophagic, why?

    • Ex - lagomorphs, equids, rodents

 

  • GI Tract Anatomy: Ruminant Herbivores

    • Rumination = regurgitating and rechewing to break down cellulose

    • Stomach = complex, multi-chambered

      • Rumen (microflora)

      • Reticulum (regurgitated)

      • Omasum (filtering)

      • Abomasum (Enzymatic Stomach)

    • Fermentation occurs before/at stomach = foregut fermenter

    • Ex - cervids, bovids, giraffes, etc.

 

  • GI Tract Anatomy: Birds

    • Bill/beak vs. teeth

    • Crop = diverticulum of the esophagus, stores food

    • Two Stomachs:

      • Proventriculus = glandular, secretes mucus and receives food

      • Gizzard = muscular, crushes and churns food (may contain stones)

    • Cloaca = common opening for digestive, reproductive, and urinary tracts

 

  • Animal Nutrition Considerations

    • Ecological and behavioral aspects of diet composition

    • Physiological parameters (e.g., dentition, serum values, etc.)

    • Gastrointestinal (GI) tract anatomy and physiology

    • Nutritional requirements and composition

 

  • The Major Challenge of Zoo Animal Diets

    • Nutrient requirements of most wild animals still unknown

    • Often use domestics as a comparative model, but only provides so much

    • Nutrient requirements affected by physiological stages (growth, reproduction, lactation, geriatrics, disease, etc.)

 

  • Metabolism and Energy Assimilation

    • Metabolism = series of chemical changes that take place in an animal, through which nutrients are used and processed, and waste materials eliminated

    • C=P+R+U+F

    • C = gross energy in food

    • P = basal metabolism = energy used to support basic life processes (growth, assimilation, storage, etc.)

    • R = energy lost as heat

    • U = energy lost as urine

    • F = energy lost as feces

 

  • Essential Nutrients in Animal Diets

    • Nutrients = chemical substances the animal's body uses as sources of energy or as metabolism drivers, essential for carrying out life processes

    • Organic (contain carbon molecules)

      • Carbohydrates

      • Proteins

      • Fats (lipids)

      • Vitamins

    • Inorganic (lack carbon molecules)

      • Water

      • Macrominerals

      • Microminerals

 

  • Organic Nutrients - Proteins and Lipids

    • Proteins

      • Initiate chemical reactions, help rebuild tissues

      • Provides amino acids (AA) necessary for bodily function

      • 22 AA total. ~10 essential (cannot be synthesized)

    • Lipids/Fats

      • Carriers of fat-soluble vitamins

      • Energy, growth, hormone regulation, and inflammation

 

  • Organic Nutrients - Carbohydrates

    • Carbohydrates

      • Ex. sugar, starches, and fiber

      • Largest part of animal's food supply

      • Base energy source in diet, helps with general bodily function and digestion

      • Produced in plants via photosynthesis

 

  • Organic Nutrients - Vitamins

    • Fulfill a variety of metabolic roles, differ chemically based on physiological function (presence can be environmentally impacted)

    • Fat Soluble

      • Stored in fat and liver, can be toxic

      • A, D, E, K

    • Water Soluble

      • Enter via bloodstream, excess excreted

      • C (ascorbic acid)

      • B-vitamins (B)

 

  • Organic Nutrients - Fat Soluble Vitamins

    • A = development of skin, fertility, immuno-response, vision

      • Fish oil, milk, alfalfa

    • D = bone growth (Ca, P)

      • Egg yolk, fish meal, when skin exposed to UV light

    • E = muscle activity and development, aids in reproduction

      • Hays, browse, cereals, etc.

    • K = coagulation of blood

      • Green forage, most synthesize in GI tract

 

  • Organic Nutrients - Water Soluble Vitamins

    • B Vitamins = various metabolic and reproductive roles in assimilating other nutrients

      • Most animal-derived foods (meats, organs, milk, eggs, fish, etc.)

    • C (ascorbic acid) = cellular and tissue respiration, Fe absorption, metabolism

      • Citrus, leafy  veg, some fruits

      • Required = primates, guinea pigs, certain fish, and many inverts

      • Not required = amphibians, reptiles, most birds

 

  • Inorganic Nutrients - Water

    • Transport hormones and nutrients (blood)

    • Internal temperature

    • Lubricating joints

    • Some animals need continuous supply, others obtain from food

    • All zoo animals should have access to fresh, reliable water

 

  • Inorganic Nutrients - Minerals

    • Exist in soil or water and assimilated into plants/animals; Aid in skeletal structure, enzyme/hormone constituents, osmotic homeostasis; classified as macro- (large amounts) or micro- (small amounts)

    • Potassium = extra-cellular fluid component, osmatic balance within cells, acid-balance (via forages, KCI, etc.)

    • Sodium = extra-cellular fluid component, osmatic balance within cells, cell permeability (via salt, NaCL)

 

  • Inorganic Nutrients - Minerals

    • Exist in soil or water and assimilated into plants/animals; Aid in skeletal structure, enzyme/hormone constituents, osmotic homeostasis; classified as macro- (large amounts)

    • Calcium = bone/teeth formation, nerve function (via bone meal, lime, shells, etc.)

    • Phosphorous = bone/teeth formation, component of RNA, DNA, and enzymes (via bone meal, cereal grains, etc.)