Nutrition in Zoos Flashcards
What role did nutrition play 30 years ago in zoos?
25% of captive zoos animals died because of inadequate nutrition
the knowledge about animals diets were limited
improving and understanding nutrition of captive animals is paramount to their continued survival
Is the diets in zoo identical to what is in the wild?
No
What are the constituents of food that we need to apply to animal food to have a well-balance diet?
- carbohydrates
- lipids
- proteins
4.fibre - viamines
- Minerals
- water
What is the importants of carbohydrates?
Act primarily as a n immediate energy source during cellular metabolism but if they are present in excess, they are stored in cells as glycogen
What is the primary energy source for animals?
Glucose, absorbed from digestion of starch into maltose, then into glucose by enzymes
What are lipids and the purpose?
fats, cholesterols, and phospholipids
Type of fat is determined by fatty acids
fats are stored as adipose tissue, act as long term energy reserves and insulation.
omega 6 (bad) and omega 3 (linolenic acid - good)
Can animals produce all the fatty acids they need?
No, Animals synthesis majority of the fatty acids they need, some essential fatty acids cannot be produced for themselves and must be present in the diet
What are proteins?
Constructed from the DNA contained in the chromosomes, they are have variety of functions;
- enzymes and control the metabolic activity
- hormones or antibodies
- form most structural components in cells - collagen for strengthening skin, actin,myosin, and muscle
What are vitamins?
are organic molecules - essential in the diet
function in enzymes regulation, or act as hormones. Essential for growth, health and reproduction
Lipid Soluble vitamins (A,D,E and K) can be stored in the body fat and used for periods of dietary inadequacy
Water soluble vitamins must be ingested frequently - passes through urine as they cannot be stored
What happens if an animals consumed too much Vitamins A, D, E and K?
They are lipid soluble vitamins, excess amount of these vitamins may be harmful as they store in the body thus accumating
Why do captive animals have vitamin deficiencies?
because their diet is very restricted or because the naturally occurring vitamins have been destroyed by food preparation techniques
What animals required/need vitamines C? and why is it important?
Ascorbic acid
bat and anthropoid primates, amphibians, reptiles and many birds and mammals can synthesis it
important for metabolic reactions and in the synthesis of collagen in cartilage
symptoms - joint pain, dry skin, digestive disorders, dry hairs
what are signs of vitamin B deficiency?
CNS problems, resulting in convulsions and lack of coordination, diarrhoea, anaemia and impaired growth
What is Vitamin B1deficiency?
Lack of vitamin B1 is rare but occurs in pinnipeds that consume raw fish, they contain enzymes that will destroy thiamine
a sudden loss in righting reflex in saltwater crocodiles hatchlings
What types of minerals are there?
Macro, micro, and ultratrace minerals
Iron, silicon, calcium
vertebrates need calcium for their skeletons and birds for their egg shell production
reptiles - adequate exposure to UV light in order to promote the absorption of calcium and the synthesis of vitamin D
What is the importance of energy in animals and is it a nutrient?
not a nutrient but derived from nutrients
chemical energy is found in the nutrients, and functions of the body including maintenance, growth and reproduction and lactation.
how is energy supplied to animals?
energy for activity , growth, and reproduction
Do endotherms or ectotherms require more energy?
endotherms (mammals and birds) need more energy per unit of mass than ectotherms to maintain a constant body temperature
What is secondary production?
the rate at which animals in a food chain accumulate dry mass (biomass) or energy within the mass/growth of unit area, per unit time
the way the food is ingested - food goes through -
1. cell respiration = heat loss
2. secondary production = growth
3. excretion (urine) = faeces are released
utilisation energy is different depending what environment the animals is in -
What is the impact of moving a tropical mammal or endotherms animal to different environment?
Energetic cost of maintaining a constant body temperature are large
Tropical mammals kept outside in zoos in temperate regions may need additional food in order to cope with the energetic demands of heat loss.
Endotherms have high respiration rates and must keep their body temperatures high. This makes them poor converters of food into biomass compared with ectotherms.
What is the issue that arises to sedentary animals?
Sedentary animals need less
energy from their food than
active animals or they put on
weight
Obesity is a problem in some
zoo animals because they do
not need to expend energy
searching for food; for
example, some zoo elephants
are considered to be obese
compared with their wild
counterparts (Harris et al.,
2008)
What is gross assimilation efficiency?
is a measure of how well an animal utilises it food
Assimilation efficiency (%) = (Food ingested/ faeces egested) × 100
What’s the difference between the gross assimilation efficiency of carnivores vs herbivores? and how do elephants differ?
Carnivores - high protein, easily digested and absorbed diets - assimilate > 80% of dietary energy
Herbivores - very inefficient guts and must eat a great deal of food to compensate for this Diets contain large amounts of cellulose from plant cell walls – symbiotic relationship with gut microbiota aids digestion and metabolism = assimilate < 40% of dietary energy
Elephants are not ruminants and their guts are much less efficient. African elephants (Loxodonta africana) have a GAE of approximately 22% (Rees, 1982a). In other words, about 78% of what they eat passes out as faeces
What is browse eating? and an example of an animal
Refers to the vegetation provided for browsing
animals:
Branches containing leafy material
Acts as an enrichment, especially if it is
located at the level at which it would normally
occur in the wild, eg. suspended at height for
giraffes.
Many browsers will spend a great deal of time
obtaining food from branches, even when
other food, such as hay, is provided at the
same time.
Elephants will spend hours using their toe
nails to break small pieces of bark from tree
trunks provided as food and enrichment.
What is the difference between grass vs browsers?
Main difference - whats in it
Grasses
type - monocots
cell wall - thick high cellulose/hemicellulose
plant defence compounds - silica
Broweses
type - herbaceous and woody dicots (forbs, shrub leaves and stems)
Phenolics – tannins
Terpenes
Alkaloids
What are the anatomical differences between grazers and browers?
Grazers
* Larger, more muscular, subdivided
rumen/reticulum
* Smaller opening between reticulum and
omasum
Browsers
* Narrow muzzles
* More mobile lips and tongues - wrap around and grab leaves
* Larger salivary gland - combat antinutritional factors - deactivate antinutritional enzymes
* Smaller rumen
* Large abomasum and hindgut (cecum and
colon)
How do relative size of organs differ with diets of birds?
the more grass the longer the digestive tract is
Carnivorous - small crop and caeca, simple digestive tract
Omnivorous -
Herbivorous expanded foregut - large microbial fermentations
long midgut
Large colon
How is the Mongastric Hindgut fermenters (herbivores) digestive tract designed to assist them in their diet?
Mongastric Hindgut fermenters (herbivores)
Enlarged hindgut, preceded by a simple - stomach and intestine
Maximises utilisation of fibre rich diets
How are koala’s digestive tract adapted for eating eucalyptus?
Monogastric hind gut fermenter
Enlarged caecum (2 m in length) and colon
Diet of eucalyptus leaves (~200-250 g of leaves / day)
- Mature leaves are highly fibrous - consume immature leaves
- High tannin and volatile oil content, toxic to other animals
Very slow metabolic rate → long retention time to maximise amount of energy extracted
- Solutes and fine feed particles are retained in the caecum/proximal colon for ~200 hours
- Large particles are retained for < 20 hours
- Only absorbs 25% of ingested fibre
Water is absorbed from leaves – low
requirement to drink
How is a kangaroo specialised in its digestive tract?
Monogastric – foregut fermenters
BUT it has TWO enlarged pre-gastric
chambers:
1) Sacciform - sacklike front chamber
contains an abundance of bacteria,
fungi and protozoa that begin the
fermentation process. Food may
remain here for many hours until
fermentation begins
2) Tubiform – after fermentation begins
food passes into the second stomach
chamber, where acids and enzymes
finish digestion.
What is the difference between foregut and hindgut fermentation?
Foregut
fermentation prior to enzymatic digestion and absorption:
use of bacterial protein, bacterial products (b-vitamins)
Bacterial detoxification
loss of easily digestible substrates and bacterial modification
Hindgut fermentation (orangutan)
fermentation after enzymatic digestion and absorption
loss of bacterial protein bacterial productions (b-vitamins?)
(coprophagy can be retain nutrients - regaining some protein)
Use of easily digestible substrates - sugars, proteins use them more efficiently
What is the intake and passage rate in hindgut and foregut animals such as primates?
Intake and passage rate in primates - dictates how time the digestive tract has to absorb nutrients from feed.
high or low intake
hindgut fermenters can either have high or low intake and short or longs ingesta retention
nonruminant - limited to a low food intake and hence long ingesta retention
SEE LECTURE SLIDES
What is the compared effects of feeding high-sugar/starch diets in colobus monkey and orangutan?
Foregut - easily digestible - nutrients enters the fermentation chamber = malfermentation
low food intake laminitis, liver abscess, reduced lifespan, diarrhoea, orial stereotypies
= thin/skinny monkey
Hindgut -easily digestible nutrients absorbed in small intestine which can lead to obesity
only excessive amount can lead to caecum acidosis, diarrhoea, laminitis
= obese
What is the minimum required supplement for carnivores and why?
- A supplement containing at a minimum
calcium, vitamin A, iodine, taurine, and
some B vitamins should be added to the
meat diet. - reduces incidence of nutritional
problems in captive exotic carnivores;
however, such a diet regularly causes fecal
problems
How to exotic felines diet differ?
- Exotic feline diets are usually higher
than canine diets in fat, protein, and
vitamin A.
Why do zoos use frozen and canned cat foods?
- Frozen and canned cat foods usually
are more palatable than dry ones to
exotic cats. - Many zoos prefer to use frozen diets
over canned products, because generally
they are less expensive and large
quantities are easier to feed.
What is the issue with soft-hamburger consistency of commercial diets? and what is recommended for those who do recieve this diet?
can result in excess calculus deposits and periodontal disease if hard or unprocessed items are not also provided.
- All cats fed a soft diet should receive
bones with some meat intact twice
weekly.
What was the traditional approach to zoo nutrition? and what are the benefits vs negatives to this.
“Do as we always did”
based on experience of what is been working - this means mistakes have been made for a long time
“imitate the natural diet”
best approach - depends on what we know about the natural diet
Two ways to approach this
1. Ratcliffe and wackernagel - a complete feed for each animal (group)
Pelleted/extruded - atypical physical structure. But some nutrients are difficult to limit and behaviour deficits (obtaining the food)
- Hediger
‘natural’ feeds (forages, fruits/
vegetables), that resemble the
natural diet
Selective feeding possible
Available feeds differ in nutrient
content from the natural diet
“use a suitable domestic species as a model”
scientific compromise - huge amount of knowledge exists but species-specific peculiarities are easily overlooked.
“Based on studies in zoo animals”
Scientific approach - financially and logistically challenging, difficulty in summarizing knowledge
What are nutritional problems faced in zoos with carnivores, primates, Fish-eater, and herbivore?
carnivore - red meat = calcium deficiency
primate - fruit and veggies = calcium deficiency
fish-eater - thawed fish = sodium and vitamin B deficiency
Herbivore - hay and grains = acidosis, vitamin E- and calcium deficiency
Wild VS ZOO
LOOK AT SLIDES
What is the issue with researching in a zoo setting? and how are issues prevented
Studies only allowed if of no risk to the zoo animals
‘Risk-free’ options for nutritional studies include:
- Inventories
- Epidemiological studies
- Measuring digestibility
- Measuring digesta passage
on used diets
What do you do with novel species or those new to captivity?
- Identify species feeding strategy and nutritional ecology
*Determine if herbivore, carnivore or
omnivore
* Is the animal a browsing herbivore,
selective insectivore etc. - Gastrointestinal tract morphology
* Including anatomy of oral cavity
(why?) - indication into how and what
it eats, leafs, trees, etc - Known and/or extrapolated species requirements
* Model from data for domesticated
species with similar GIT and feeding
strategies
* Consider energy requirements of
domestic animals are often based on
performance criteria (growth,
lactation etc.) which may not apply to
zoo animals. - Foods available and their cost
* Foods available in the wild are not
always available in captivity – use
harvested forages, fruit and
vegetables, meat and dairy products.* Choices should be made on the basis of nutrients foods bring to the total diet, not an attempt to substitute what one perceives to be analogous food ‘types’
