Download L11: Animal nutrition

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Animal Nutrition
Why do animals eat?
• Chemical energy
• Organic building blocks
• Essential nutrients
• Essential amino acids
• Essential fatty acids
• Vitamins
• Minerals
Animal Nutrition
Lecture 11
Winter 2014
Food Chains
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Energy Requirements
Heterotrophs (consumers)
• Eat other organisms
• Bioenergetics
Autotrophs
(primary producers)
• Use photosynthesis or
chemosynthesis
• plants, algae, cyanobacteria
– Overall flow & transformation of energy
– Determines nutritional needs
– Related to size, activity & environment
• Metabolic rate
– Amount of energy used per unit of time
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Metabolic Rate
Fig. 40.19
• On a per-gram
basis, small
animals have
higher BSR than
large animals
• Needs to eat
more food per
unit of body mass
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Energy Budgets
Fig. 40.20
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Animal Nutrition
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Animal Nutrition
• Three strategies
• Adaptations
Adaptations
Fig. 41.16
Feeding Mechanisms
Fig. 41.17
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Stages of Food Processing
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Fig. 41.6
• Suspension
Feeders
• Substrate
Feeders
• Fluid Feeders
• Bulk Feeders
See Fig. 41.5
Intracellular Digestion
Hydrolysis of food inside vacuoles
• Need to compartmentalize
• Endocytosis
– Phagocytosis (“cellular eating”)
– Pinocytosis (“cellular drinking”)
• Lysosomes
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Extracellular digestion
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• Breakdown of food in
compartments that are
continuous with the
outside of the animal’s
body
• What type of digestive
system do hydras
(Phylum Cnidaria) have?
• Benefits over
intracellular digestion?
Fig. 41.7
Fig. 6.14
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Extracellular digestion
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Mammalian Digestive System
• What type of digestive
system do these
organisms have?
• Benefits over
gastrovascular cavity?
• Alimentary canal
• Peristalsis
– Move food along the digestive tract
• Sphincters (valves)
– Regulate passage of materials
between compartments
• Accessory glands
– Produce, store & secrete digestive
juices
– Salivary glands, pancreas, liver,
gallbladder
Fig. 41.9
Fig. 41.8
The Oral Cavity, Pharynx & Esophagus
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The Oral Cavity, Pharynx & Esophagus
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Oral cavity
• Mechanical digestion
• Chemical digestion
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–
–
–
–
Saliva
Amylase: hydrolysis of starch & glycogen
Mucus: protection & lubrication
Buffers
Antibacterial agents
Fig. 41.10
Fig. 41.10
The Stomach
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• Why doesn’t gastric juice destroy the cells that
produce it?
• Stores & digests food
• Secretes digestive (gastric)
juices
– HCL (hydrochloric acid)
• pH 2
• Disrupts extracellular matrix
of cells
• Kills most bacteria
• Denatures proteins
– Pepsin
• Protease
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The Stomach
Is this a positive or
negative feedback loop?
Fig 41.11
Fig. 41.12
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The Small Intestine
• Churning mixes stomach contents
• Chyme moves to small intestine
– Regulated by sphincter
• The duodenum (~first 25 cm)
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The Small Intestine
• Liver contributes bile (bile salts)
– Emulsifier
– Bile stored in gall bladder
• Pancreas contributes enzymes & bicarbonate
solution
• Most digestion
completed in
this region
– Bicarbonate solution: neutralizes pH of chyme
– Trypsin, chymotrypsin
(proteases)
– Pancreatic amylases,
nucleases, lipases
• Epithelial cells also
contribute enzymes
See Fig. 41.14
See Fig. 41.14
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The Small Intestine
The Small Intestine
Ileum and jejunum
• Absorption of nutrients & water
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• Absorption of fats
– Enter cell and form
triglyceride
– Wrapped in water
soluble coating
• Chylomicron
– Enter lacteal
• lymphatic system
Fig. 41.14
Fig. 41.15
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Enzymes
– Responsible for salivary amylase, pepsin, pancreatic
trypsin and chymotrypsin, amylases, nucleases,
lipases
Fig. 41.12
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The Large Intestine
• Colon
– Recover water for the
body
• Cecum
– Fermentation of plant
material
• Rectum
– Stores feces
Fig. 41.17
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