Animal Nutrition

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Animal Nutrition
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Digestion

1. Reduce size of food material to increase surface
   area
2. Kill unwanted microbes
3. Break down macromolecules into subunits
4. Absorb small molecules into the bloodstream

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Types of Digestion

• Mechanical digestion
• Teeth, mouth
• Enzymatic (chemical) digestion
• Mouth
• Stomach
• Small intestine

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Enzymatic Synthesis and Digestion ofOrganic
Polymers
Synthesis
Digestion
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Intracellular Digestion

• Enzymatic digestion
• Inside food vacuole

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Extracellular Digestion

• Allows digestion of larger organisms
• Enzymes are secreted into gastrovascular cavity

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Alimentary Canals

• Specialization
• Increased surface area

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Human Digestive System
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Dentition

• Carnivore
• Grab, cut, crush
• Herbivore
• Grind
• Omnivore

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Tooth Function
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Swallowing
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Stomach

• Mechanical digestion
• Peristaltic contractions
• Enzymatic digestion
• Pepsinogen
• Enzyme precursor
• Converted to active form pepsin by acid
• Digests proteins
• Acid kills unwanted microbes
• Some absorption of nutrients
• Water and alcohol

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Small Intestine

• Neutralization of acid
• Pancreas produces alkaline (basic) secretions
• Enzymatic (chemical) digestion
• Source of enzymes
• Small intestine
• Pancreas
• Emulsification
• Bile salts from liver
• Increases surface area of fat droplets

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Small Intestine

• Absorption of digested molecules
• Structure of small intestine increases surface
  area
• Villi and microvilli
• Intestinal walls are filled with capillaries
• Nutrients pass through intestine wall into
  capillaries and into the blood stream

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Duodenum

• Approximately the first foot of the small
  intestine
• Ducts from pancreas and gall bladder enter here
• Pancreas bicarbonate, hydrolytic enzymes
• Gall Bladder bile

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Pancreas

• Gland
• Bicarbonate neutralizes stomach acids
• Hydrolytic enzymes
• Carbohydrates Amylase, disaccharidases
• Proteins - Trypsin, chymotrypsin, aminopeptidase,
  carboxypeptidase, dipeptidase
• DNA and RNA - Nuclease, neucleosidase
• Fats - Bile salts, lipase

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Carbohydrates
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Protein Structure
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Proteases

• Aminopeptidase
• Trypsin and chymotrypsin
• Carboxypeptidase

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DNA and RNA
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Lipids
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Homeostasis
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Enzyme Activation

• Pancreas secretes enzymes in inactive form
• Enteropeptidase found in small intestine
  activates the enzymes

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Intestinal Wall Structure
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Enzymatic Digestion
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Gastrointestinal Tracts
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Cellulose Digestion

• No multicellular animal can directly digest
  cellulose
• Microorganisms live in specialized intestinal
  cavities to digest cellulose

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RuminationChewing Cud

• Rumen
• Microorganisms digest cellulose
• Some nutrients absorbed through wall of rumen
• Rumination (chewing cud)
• Reticulum and Omasum
• Absorb water
• Slowly pass material from rumen to abomasum
• Abomasum
• True stomach
• Digestion of microorganisms
• Digestion of proteins

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Ruminant Digestive Tract