ANIMAL NUTRITION Chapter 41

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ANIMAL NUTRITIONChapter 41
Animals are heterotrophs
Nutrition is not only the need for food, but
also the need for specific food components.
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• Require food for
• fuel (chemical energy)
• carbon for its own molecules
• essential nutrients

FUEL - ATP
BIOSYNTHESIS
ENERGY STORAGE
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Food Processing
Ingestion
Digestion
Absorption
Elimination
Act of eating
Process of breaking food down into molecules
small enough for the body to absorb
Take up small molecules from the digestive
compartment
Undigested material passes out of the digestive
compartment
Intracellular
Extracellular
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Dietary Categories (represents the kind of food
the animal usually eats)
Herbivores
Carnivores
Omnivores
Consume animals as well as plants or algae
Mainly eat plants and algae
Eat other animals
Gorillas Cows Hares Snails
Sharks Hawks Spiders Snakes
Cockroaches Crows Bears Raccoons Humans
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Most animals are opportunistic Eating foods
that are outside their main dietary category
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Feeding Mechanisms
Suspension (filter) feeders
Substate feeders
Fluid feeders
Bulk feeders
Sift small food particles from the water
Live in or on their food source
Suck nutrient rich fluids from a living host
Eat relatively large pieces of food
Clams Oysters Baleen whales
Maggots Earthworms
Mosguitos Leeches Hummingbirds Bees
Most animals
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Feeding Mechanisms
Suspension (filter) feeders
Sift small food particles from the water
Sponges Clams Oysters Baleen whales
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Feeding Mechanisms
Substate feeders
Live in or on their food source
Maggots Earthworms
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Feeding Mechanisms
Fluid feeders
Suck nutrient rich fluids from a living host
Mosguitos Leeches Hummingbirds Bees
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Feeding Mechanisms
Bulk feeders
Eat relatively large pieces of food
Most animals
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Food Processing
Ingestion
Digestion
Absorption
Elimination
Act of eating
Process of breaking food down into molecules
small enough for the body to absorb
Take up small molecules from the digestive
compartment
Undigested material passes out of the digestive
compartment
Intracellular
Extracellular
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Virtually all food, whether of plant or animal
origin, consists of highly complex compounds
that cannot be used without first being broken
down to simpler compounds digestion.
CHOs, fats and proteins can all be used as fuel.
Campbell Fig. 9.19
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Net Energy Value of Foods 4 kcal per gram for
protein 4 kcal per gram for CHO 9 kcal per
gram for lipid
Amino acids
Simple sugars
Fatty acids
Campbell Fig.40.10
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If the food intake exceeds the energy used, most
animals store the surplus as fat, irrespective
of the nature of the food.
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Net Energy Value of Foods 4 kcal per gram for
CHO ? Fast ? Aerobic or anaerobic ? Storing
glycogen also requires storing water 9 kcal per
gram for lipid ? Slower ? Aerobic
Simple sugars
Fatty acids
Campbell Fig.40.10
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Glucose

• Human body regulates the use and storage of
  glucose.

STIMULUS Blood glucose level rises after eating.
Homeostasis 90 mg glucose/ 100 mL blood
STIMULUS Blood glucose level drops below set
point.
Figure 41.3
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Stores of glycogen and fat are used up so what
is left?
Undernourished calorie deficient
Overnourished calorie excess
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Neuropeptide Y
Hypothalamic feeding center
Negative feedback
? Food intake
? Fat stores   
? Leptin secretion   
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Neuropeptide Y
Hypothalamic feeding center
X
Negative feedback
? Food intake
? Fat stores   
X
? Leptin secretion   
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Hormones and Appetite
Figure 41.5
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Malnourished diet is missing one or
more essential nutrients
Materials that must be obtained in their
preassembled form because animal cells cannot
make them from any raw material
Osteophagia bone eating
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Essential Nutrients
Essential amino acids
Essential fatty acids
Vitamins
Minerals
In order for protein synthesis to occur in human
adults, eight amino acids must be available
simultaneously and in the correct relative amounts
Important for phospholipid membrane and
principal storage compound
Organic molecules in small amounts
Inorganic molecules in small amounts
Water soluble
Fat soluble
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Food Processing
Ingestion
Digestion
Absorption
Elimination
Act of eating
Process of breaking food down into molecules
small enough for the body to absorb
Take up small molecules from the digestive
compartment
Undigested material passes out of the digestive
compartment
Intracellular
Extracellular
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Campbell Fig.41.10
Food Processing
Digestion
Process of breaking food down into molecules
small enough for the body to absorb
Intracellular
Extracellular
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Campbell Fig.41.11
Food Processing
Digestion
Process of breaking food down into molecules
small enough for the body to absorb
Intracellular
Extracellular
Gastrovascular cavity
Complete digestive tract or alimentary canal
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Campbell Fig. 33.4
Campbell Fig. 33.10
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Campbell Fig. 41.13
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Campbell Fig.41.12a
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Campbell Fig.41.12b
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? Highly reliant on digestive system to remain
healthy ? Cannot afford to store heavy
materials in body for lengthy period
Campbell Fig.41.12c
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• Mouth usually
• relatively simple

• Esophagus may be widened at
• midpoint to form crop (storage area)

• Proventriculus glandular
• stomach which is highly acidic

4. Gizzard thick muscular walls and sandpaper
like surface
stomach
5. Small intestine food digestion and absorption

• Caecum bacterial breakdown
• of cellulose

7. Large intestine
8. Cloaca final holding area
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Proctor and Lynch Manual of Ornithology
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EVOLUTIONARY ADAPTATIONS OF VERTEBRATE
DIGESTIVE SYSTEMS

• Length of digestive system
• Accessory structures (such as)
• Crop
• Gizzard
• Liver
• Caeca

Campbell Fig. 41.21
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Carnivorous Bird Herbivorous Bird Herbivorous Bird
Carnivorous Bird Grain Fruits and Berries
Gizzard Substantial Substantial Reduced in size
Small intestine Shorter, less complex Longer, more complex Shorter, less complex
Caeca Small or absent Well developed Less well developed
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EVOLUTIONARY ADAPTATIONS OF VERTEBRATE
DIGESTIVE SYSTEMS
Dentition
Many kinds of animals have toothlike
structures, but only vertebrates have true teeth,
with an ultra-hard layer of ENAMEL on the outside
and softer DENTINE on the inside.
Campbell Fig. 41.20
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The incisors in blue (cutting plant food) The
canines in red (slicing and tearing meat) The
molars in green (grinding grass and other plants)
http//www.oum.ox.ac.uk/children/animals/nuteeth.h
tm
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http//animaldiversity.ummz.umich.edu/site/topics/
mammal_anatomy/kinds_of_teeth.html
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Examples of modified incisors
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EVOLUTIONARY ADAPTATIONS OF VERTEBRATE
DIGESTIVE SYSTEMS
Use of Symbiotic Microorganisms
Campbell Fig. 41.22
X
cellulase
cellulose
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Campbell Fig.41.22
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Four compartment stomach

• Reticulum form
• food bolus and initiate
• regurgitation

Reticular epithelium honeycomb lining
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Four compartment stomach

• Reticulum form
• food bolus and initiate
• regurgitation

Rumen Interior

• Rumen digestive
• and fermentation vat
• containing anaerobic
• microbes and site
• of fatty acid absorption

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http//www.borderouge.com/photos/chai.jpg
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Four compartment stomach

• Reticulum form
• food bolus and initiate
• regurgitation

• Rumen digestive
• and fermentation vat,
• contains anaerobic
• microbes, site
• of fatty acid absorption

3. Omasum lined by muscular folds, reduces
particle size, absorbs water (and any leftover
fatty acids)
Omasum epithelium
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Four compartment stomach

• Reticulum form
• food bolus and initiate
• regurgitation

• Rumen digestive
• and fermentation vat,
• contains anaerobic microbes,
• site of fatty acid absorption

• Omasum lined by muscular
• folds, reduces particle size,
• absorbs water (and any
• leftover fatty acids)

• Abomasum true
• glandular stomach where
• bacteria and pathogens
• are killed

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What do the microbes provide to the ruminants?
Symbiotic Microorganisms
1. Digestion of cellulose
2. Provision of organic acids
3. Provision of protein
4. Provision of B vitamins
5. Detoxify compounds
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What do the ruminants provide to the microbes?
Symbiotic Microorganisms
1. Housing with reliable heat
2. Adequate nutrition
3. Garbage removal
4. Neutral environment
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EVOLUTIONARY ADAPTATIONS OF VERTEBRATE
DIGESTIVE SYSTEMS

• Foregut fermenters
• a. Cows, sheep, goats
• Hindgut fermenters
• Horses, rodents, rabbits
• Coprophagy
• Using feces as a nutritional resource
• Food passes through entire digestive tract a
  second time

Campbell Fig. 41.21