CHAPTER 41 ANIMAL NUTRITION

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CHAPTER 41 ANIMAL NUTRITION
LEPTIN apetite suppressor (hormone produced by
fat cells)
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The four main stages of food processing are
ingestion, digestion, absorption, and elimination
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Why Eat?
C6H12O6 6O2 -gt 6CO2 6H2O Energy (ATP heat)

• FUEL
• BIOSYNTHESIS
• ESSENTIAL NUTRIENTS

ATP (Cell Respiration)
Organic Macromolecules
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Why Eat?

• Everything you eat gets DIGESTED into glucose,
  amino acids, and glycerol fatty acids
• These 3 digestion products enter cell respiration
  (glycolysis and Krebs cycle)
• Products of cell respiration CO2, NH3, H2O, ATP
• These end products can be used for cellular work
  (movement), generating heat, and BIOSYNTHESIS
• Excess gets converted to GLYCOGEN or FAT!

CO2, other simple compounds

• FUEL
• BIOSYNTHESIS
• ESSENTIAL NUTRIENTS

ATP
Organic Macromolecules
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Why Eat?
Carbon Skeletons, and other simple products of
cell respiration

• FUEL
• BIOSYNTHESIS
• ESSENTIAL NUTRIENTS

ATP
BIOSYNTHESIS ANABOLIC PATHWAY
Biosynthesis Making of New Proteins,
Carbohydrates, Fats, Nucleic Acids needed by the
body using the energy and raw material derived
from food
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How much energy do you get from food?

• Carbohydrates 4 kcal/gm
• Proteins 4 kcal/gm
• Fats 9 kcal/gm
• Calorie heat required to raise the temperature
  of water by 10c
• Kcal 1000cal
• Cell Respiration process that burns food
• Carbs quick energy release
• Fats, proteins slow to release energy

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What happens to excess carbs?

• Gets stored as glycogen in liver and muscle
• Too much carb? -Gets converted into fat!!!!
• Glycogen can be released quickly during exercise
• Disadvantge less energy (4 kcal/gm)
• Fats more energy (9kcal/gm), takes time to
  release

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How is glucose regulated?

• Insulin (produced by the Islets of Langerhans -
  in pancreas) decreases blood sugar by ?
• Glucagon (pancreas) increases blood sugar by ?

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How is glucose regulated?
2 places to find glucose - blood or cells stored
as glycogen A) Glycogen synthesis in muscle and
liver using free glucose in cells B) Glycogen
breakdown to release glucose into the cells C)
Increased movement of glucose into blood from
cells D) Decreased movement of glucose into blood
from cells E) Increased uptake or movement of
glucose from blood into cells F) Decreased uptake
or movement of glucose from blood into cells G)
Glucose utilization in cells - cell resp. H)
Glucose synthesis in cells

• Insulin (produced by the Islets of Langerhans -
  in pancreas) decreases blood sugar by A,D,E,G
• Glucagon (pancreas) increases blood sugar by ?
  B,D,F,H

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Why Eat?

• FUEL
• BIOSYNTHESIS
• ESSENTIAL NUTRIENTS

Essential nutrients body cannot make it so,
it must be provided preassembled in the food.
Example Vitamins, essential amino acids,
essential fatty acids, minerals


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• An animal whose diet is missing one or more
  essential nutrients is said to be malnourished.

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• Animals require 20 amino acids to make proteins.
• Essential amino acids must be obtained from food
  in prefabricated form. (eight)

Protein Deficiency - Kwashiorkar
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• Essential fatty acids.
• Certain unsaturated fatty acids, including
  linoleic acids required by humans.
• Deficiencies are rare.

Mahatma Gandhi once said, "Where ever flaxseeds
become a regular food item among the people,
there will be better health".
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• Vitamins -organic molecules required in the diet
  in very small quantities (upto 100 mg)

Fat Soluble Vitamins Water Soluble Vitamins
A, D, E, K C, B, Niacin, Folic acid, Biotin
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Fat Soluble Vitamin Function Deficiency
A Vision, maintain healthy skin Vision problems, dry skin
D Absorption of Calcium and phosphorous helps bone growth Rickets (bone deformities)
E Antioxidant maintains cell membrane
K Blood clotting Clotting problems, Anemia
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Water Soluble Vitamin Function Deficiency
C Detoxification, antioxidant, collagen synthesis (gums) Scurvy (skin, teeth, blood vessel degenration)
B (1,2,6,12) Coenzyme component FAD, amino acid and nucleic acid metabolism, B1 Beriberi (nerve disorder, anemia)
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• Minerals are simple inorganic nutrients, usually
  required in small amounts - from less than 1 mg
  to about 2,500 mg per day.

Mineral Function Deficiency
Calcium Bone and tooth formation, nerve and muscle function Retarded growth, osteoporosis
Iron Hemoglobin component - cofactor Anemia
Sodium Acid- base balance, water balance, nerve function Too much high blood pressure
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Feeder types

• Herbivores- eat autotrophs (plants, algae).
• Carnivores - eat other animals.
• Omnivores eat animal and plant/algal matter

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Feeding mechanisms

• Suspension-feeders that sift small food particles
  from the water.ex. Baleen whales, clam

Fig. 41.6
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• Substrate-feeders live in or on their food
  source, eating their way through the food.
• For example, maggots burrow into animal
  carcasses and leaf miners tunnel through the
  interior of leaves.

Fig. 41.7
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• Deposit-feeders, like earthworms, eat their way
  through dirt or sediments and extract partially
  decayed organic material consumed along with the
  soil or sediments.

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• Fluid-feeders make their living sucking
  nutrient-rich fluids from a living host and are
  often considered parasites.
• Mosquitoes and leaches suck blood from animals.

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• Most animals are bulk-feeders that eat relatively
  large pieces of food.

Fig. 41.9
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Human Digestive System

• Alimentary canal accessory glands that secrete
  digestive juices into the canal through ducts.
• Peristalsis rhythmic waves- push food along.
• Sphincters muscular ringlike valves, regulate
  the passage of food
• Accessory glands - salivary glands, the pancreas,
  the liver, and the gallbladder.

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• When does the lunch you had today complete its
  passage through your digestive system?

Mouth Seconds Esophagus Seconds
Stomach 2-6 hours Small Intestine 5-6 hrs.
Large Intestine 12- 24 Hours TOTAL 19 36
hrs!!
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Fig. 41.13
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The journey begins

• Physical chewing -Increases surface area of food
• Saliva - Moistens Kills bacteria Buffer
• Chemical digestion Enzyme
• Salivary Amylase Acts on AMYLOSE - long
  straings of glucose found in starch/glycogen
• (starch glycogen) -gt (smaller polysaccharides
  maltose)

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• Pharynx (throat) - opens to esophagus and the
  trachea (windpipe).
• Epiglottis - cartilaginous flap prevents food
  going into the windpipe

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Epiglottitis
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Fig. 41.14
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The stomach

• Muscular Organ peristalisis -chyme - mixture of
  gastric juicefood
• Gastric juice - glands
• Parietal cells - HCl pH 2!! -kills bacteria
  converts pepsinogen -gt pepsin (inactive)-gt(active)
  
• Chief cells - Pepsin action proteins -gt
  polypeptides amino acids
• Mucous cells - Mucous prevents eating away of
  stomach lining

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• Pyloric Sphincter-prevents back flow of food!

   
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Small intestine is the major organ of digestion
and absorption

• 6 m long
• First section duodenum
• LOTS OF ENZYMES FROM ACCESSORY GLANDS
• Pancreas makes 1)pancreatic amylase - acts on
  polysachcharides -gt tri, di saccharides
  2)bicarbonate - changes pH to make it basic so
  enzymes can act on the food 3)trypsin,
  chymotrypsin - act on polypeptides -gttri
  dipeptides , 4)lipase - acts on fats -gt fatty
  acid and glycerol, 5)nucleases act on DNA and RNA
  -gt nucleotides
• Liver makes bile gall bladder stores bile
  bile emulsifies fats
• Lining of intestine other enzymes (intestinal
  juice) convert to monomers

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• .

Fig. 41.18
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• Jejunum, ileum sections of small intestine
  absorption of nutrients into lymph/blood - see
  notes in powerpoint slide for details

Active transport glucose, amino acid, vitamins
Passive transport - fructose
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Hormones help regulate digestion

• Hormones released by wall of the stomach and
  duodenum
• Ensure that digestive secretions are present only
  when needed.
• Stomach wall - hormone gastrin (stimulates
  gastric juice)
• Duodenum hormone Secritin (pancrease releases
  bicarbonate)
• Duodenum hormone Cholecystokinin (CCK)-
  gallbladder releases bile

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Reclaiming water is a major function of the large
intestine

• Cecum- very mall in humans - appendix

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Fig. 41.12
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Structural adaptations of digestive systems are
often associated with diet
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• (1)

Fig. 41.22