Animal Nutrition

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Animal Nutrition
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Nutritional Requirements

• Animals are heterotrophs
• Herbivores, carnivores, omnivores

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Energy Budget
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Energy Storage

• In humans
• Liver and muscles
• Stored as glycogen
• Glycogen reserves full, calorie intakegt calorie
  expenditure excess is stored as fat

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Managing Glucose Levels

• Insulin reduces blood glucose levels
• Glucose rise above set point
• Pancreas secretes insulin
• Promotes transport of
• glucose into cells
• Drops blood glucose levels
• Suppresses appetite

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Managing Glucose Levels

• Glucagon increase blood glucose levels
• Secreted by pancreas
• Promotes breakdown of glycogen
• release glucose into blood

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Appetite-Regulating Hormones

• Leptin in adipose tissue (fat)
• Suppresses appetite as its level increases
• Leptin decreases with body fat ? appetite
  increases
• PYY small intestine after meals
• Appetite suppressant
• Counters appetite stimulant
• ghrelin

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• Gherlin stomach wall
• hungry feeling
• Increases in dieters who lose weight

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Whats in a diet?

• Must meet ATP requirements
• Raw materials for biosynthesis
• Source of N and P ( to make proteins, nucleic
  acids)
• Need complex molecules that cannot be synthesized
  (amino acids, vitamins)
• Need minerals (Iron, Calcium)

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Essential Amino Acids

• 20 required to make proteins
• Most animals synthesize half (if N available)
• Essential amino acids (8) must come from food
• Not enough of these causes protein deficiency
• Sources are meat, eggs, cheese
• What about vegetarians?

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Essential Fatty Acids

• Cannot make unsaturated fatty acids
• Ex. Linoleic acid for cell membranes
• Most human diets furnish ample quantities of
  fatty acids

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Vitamins Minerals

• Vitamins organic molecules
• 13 essential vitamins
• Minerals Inorganic nutrients

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Feeding Adaptations
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Ingestion Mouth, Pharynx, Esophagus

• Mechanical Chemical Digestion
• Trigger reflexive release of saliva
• Contains
• Mucin a protein the protects from abrasion
  lubricates food for easy swallowing
• Buffers- prevent tooth decay by neutralizing acid
• Anti-bacterial agents kill bacteria that enter
  the moth with food
• Amylase-digests starch and glycogen

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Digestion - Stomach

• Holds up to 2L of Food
• Pyloric Sphincter controls amount of chyme into
  small intestine
• Gastric juices secreted by epithelium lining
• HCl (pH of 2)
• Breaks down matrix that binds cells
• Kills bacteria
• Pepsin breaks down proteins
• Mucus- protects stomach lining

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Absorption Small Intestine

• Over 6 m
• Contains villi
• 3 sections
• Doudenum most digestion
• Where acid from stomach mixes with digestive
  juices from the pancreas, liver, gall bladder,
  and glandular cells of intestines
• Jejunum- absorption of nutrients and water
• Ileum absorption of nutrients and water

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Absorption

• Passive
• Fructose
• Active
• Amino acids, small peptides, vitamins, glucose
• Why is active yransport important ?

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Pancreas

• Contains Enzymes
• Produces insulin
• Contains buffers
• Alkaline solution rich in bicarbonate that
  neutralizes the acidic contents coming from the
  stomach

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Liver

• Production of bile
• Bile is stored in gall bladder until needed
• Contains bile salt that act as detergents
• Bile also contains pigments from red blood cells
  that have been destroyed, this is released with
  feces

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Large Intestine (Colon)

• Reclaims water
• 7L of water secreted into the system a day
• 90 is reabsorbed
• Diarrhea insufficient amount reabsorbed
• Constipation too muc reabsorbed

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Flora of Large intestine

• Mostly harmless bacteria
• E. Coli
• Many generate gases as a by product of their
  metabolism including methane and hydrogen sulfide
• Some produce vitamins
• Vitamin K, folic acid, B vitamins, biotin

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Rectum

• Terminal portion of colon
• Feces contain
• Bacteria
• Undigested material
• Cellulose, fiber, roughage
• Salt

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Structural Adaptations

• Dentition
• Length of digestive system
• Number and size of stomachs

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Dentition

• Adaptation to process
• different types of food

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Length of digestive system

• Herbivores Omnivores
• Long digestive system
• Harder to digest cellulose
• Carnivores
• Short digestive system

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How can cows digest cellulose so easily?

• Symbiotic organisms
• Symbiotic protists and bacteria