Animal Nutrition

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Chapter 41

• Animal Nutrition

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3 main categories of feeding

• Herbivores Plants algae
• Carnivores Meat
• Omnivores Both

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3 needs

• Fuel (ATP)
• Organic matter for biosynthesis
• Essential nutrients - vitamins

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 Four Main Feeding Mechanisms of Animals
SUSPENSION FEEDERS
SUBSTRATE FEEDERS
Feces
Baleen
Caterpillar
FLUID FEEDERS
BULK FEEDERS
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Feeders

• Suspension Sift food from H20 (strainer)
• Substrate Live in or on food
• Fluid Suck nutrients from host
• Bulk Large pieces

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Glucose regulation

• Liver and muscle cells store energy in the form
  of glycogen (extra stored as fat)
• Regulation Negative feedback
• Thermostat in house

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Glucagon promotes the breakdown of glycogen in
the liver and there lease of Glucose into the
blood,increasing blood glucose level.
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41.2 Animals diets must supply carbon skeleton
and essential nutrients

• Make Carbohydrates, Proteins and lipids from
  sugar and nitrogen.
• Essential nutrients cant make must get from
  food pre-made
• Amino acids 20 (meat, cheese, animal products)
• Fatty acids unsaturated easily attained in diet
  
• Vitamins 13 essential H20 soluble fat
  soluble
• C, A, D, E , K
• Minerals - Inorganic nutrients Calcium,
  Phosphate, Iron, Zinc

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Obtaining essential nutrients
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Essential amino acids from a vegetarian diet
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41.3 Stages of food processing

• Organic material in food fats, proteins, and
  carbohydrates
• Steps of digestion
• 1. Ingestion Eating
• 2. Digestion Breaking down food into molecules
  small enough for the body to absorb

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The four stages of food processing
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• 3. Absorption Cells take up small molecules
• 4. Elimination Undigested material passes

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Risk of digesting ones self?

• No Specialized compartments
• Intracellular One cell/Sponges
• Extracellular Breaking down food outside cells

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 Digestion in a hydra
Gastrovascular Cavity - Sac with a single
opening Hydras, Jellies flatworms
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 Variation in alimentary canals
Crop
Gizzard

1. Earthworm. The digestive tract ofan earthworm
   includes a muscular pharynx that sucks food in
   through themouth. Food passes through the
   esophagus and is stored and moistened in the
   crop. The muscular gizzard, whichcontains small
   bits of sand and gravel, pulverizes the food.
   Digestion and absorption occur in the intestine,
   which has a dorsal fold, the typhlosole, that
   increases the surface area for nutrient
   absorption.

Esophagus
Intestine
Pharynx
Mouth
Typhlosole
Lumen of intestine
Foregut
Midgut
Hindgut
(b) Grasshopper. A grasshopper has several
digestive chambers grouped into three main
regions a foregut, with an esophagus and crop
a midgut and a hindgut. Food is moistened and
stored in the crop, but most digestion occurs in
the midgut. Gastric ceca, pouches extending from
the midgut, absorb nutrients.
Esophagus
Rectum
Mouth
Crop
Esophagus
Gizzard
(c) Bird. Many birds have three separate
chambersthe crop, stomach, and gizzardwhere
food is pulverized and churned before passing
into the intestine. A birds crop and gizzard
function very much like those of an earthworm.
In most birds, chemical digestion and absorption
of nutrients occur in the intestine.
Mouth
Intestine
Stomach
Anus
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• Complete digestive system or alimentary canal
• Nematodes, annelids, mollusks, arthropods,
  echinoderms chordates
• Mouth Anus
• Specialized compartments

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 The human digestive system
Parotid gland
Sublingual gland
Submandibular gland
Stomach
Rectum
A schematic diagram of the human digestive system
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Peristalsis rhythmic waves of contraction and
relaxation

• Smooth Muscles pushes the food along the tract
• Sphincters Regulate the passage of material
  between chambers (Drawstring)

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 From mouth to stomach the swallowing reflex and
esophageal peristalsis
Epiglottisup
Tongue
Glottisdown and open
Pharynx
Esophageal sphinctercontracted
Esophageal sphinctercontracted
When a person is not swallowing, the
esophageal sphincter muscle is contracted, the
epiglottis is up, and the glottis is open,
allowing air to flow through the trachea to the
lungs.
The swallowing reflex is triggered when a
bolus of food reaches the pharynx.
Stomach
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Accessory Glands

• Salivary Glands Deliver saliva with salivary
  amylase to begin chemical digestion
• Pancreas Digestive juices that mix with chyme
  in the small intestine
• Liver Produces bile. Bile salts aid in the
  break down of fats
• Gall Bladder Bile is stored here until needed

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 The stomach and its secretions
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Stomach

• Stores food and does preliminary digestion.
• Coating of mucus to not self digest.
• Mixing makes acid chyme. Every 20 seconds due to
  smooth muscles.
• Pyloric sphincter squirts the acid chyme to the
  small intestines. 2 to 6 hours for a meal to
  empty.

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The duodenum
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Flowchart of enzymatic digestion in the human
digestive system
Carbohydrate digestion
Protein digestion
Nucleic acid digestion
Fat digestion
Oral cavity, pharynx, esophagus
Polysaccharides (starch, glycogen)
Disaccharides (sucrose, lactose)
Salivary amylase
Smaller polysaccharides, maltose
Stomach
Proteins
Pepsin
Small polypeptides
Lumen of small intes- tine
Fat globules (Insoluble in water, fats aggregate
as globules.)
Polypeptides
Polysaccharides
DNA, RNA
Pancreatic amylases
Pancreatic trypsin and chymotrypsin (These
proteases cleave bonds adjacent to certain amino
acids.)
Pancreatic nucleases
Bile salts
Maltose and other disaccharides
Fat droplets (A coating of bile salts prevents
small drop- lets from coalescing into larger
globules, increasing exposure to lipase.)
Nucleotides
Smaller polypeptides
Pancreatic carboxypeptidase
Pancreatic lipase
Amino acids
Glycerol, fatty acids, glycerides
Epithelium of small intestine (brush border)
Small peptides
Nucleotidases
Nucleosides
Dipeptidases, carboxypeptidase, and
aminopeptidase (These proteases split off one
amino acid at a time, working from opposite ends
of a polypeptide.)
Disaccharidases
Nucleosidases and phosphatases
Monosaccharides
Nitrogenous bases, sugars, phosphates
Amino acids
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Small Intestine

• Absorption of nutrients takes place
• 6 meters
• Duodenum - beginning of S.I.
• Chyme
• Villi increases SA for more absorption

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The structure of the small intestine
Microvilli(brush border)
Vein carrying blood to hepatic portal vessel
Bloodcapillaries
Epithelialcells
Epithelial cells
Largecircularfolds
Lacteal
Villi
Key
Lymph vessel
Villi
Nutrientabsorption
Intestinal wall
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Large Intestine (Colon)

• Recover water that has entered the alimentary
  canal
• Feces (waste) becomes more solid as it moves
  through
• Flora of bacteria E. Coli
• Colon bacteria secrete methane and hydrogen
  sulfide

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41.5 Modifications

• Teeth Structural variation reflecting diets
• Fangs modified teeth unhinged jaw

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 Dentition and diet
Incisors
Canines
Molars
(a) Carnivore
Premolars
(b) Herbivore
(c) Omnivore
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The digestive tracts of a carnivore (coyote) and
herbivore (koala) compared
Stomach Expandable - Carnivores Length of
alimentary canal Herbivores longer
Carnivore
Herbivore