Download Chapter 50 Animal Nutrition

Chapter 50 Animal Nutrition
Biology 102
Tri-County Technical College
Pendleton, SC
Diet and Energy
Requirements
Fuel (chemical energy) needed for
cellular respiration
Raw organic materials for biosynthesis
Essential nutrients MUST be obtained in
prefabricated form
Metabolic rate is measure of overall
energy needs that must be met by
ingestion and digestion of food
Requirements, cont.
BMR (Basal metabolism rate) defined as rate
resulting from all essential physiological
functions of resting person

BMR is about 1300-1500 kcal/day for adult female
and 1600-1800 kcal/day for adult male
Physical activity adds to this requirement
Calorie (c) or Kcalorie (C) used to measure
amounts of energy in foods
Fats (9.5); carbs (4.2), and proteins (4.1)
ISU unit of joule where 1 c = 4.184 joules
But I am really hungry…
Undernourished person or animal is one
whose diet is deficient in calories

This is really iffy…NCTR data now 10
years +
Malnourished person or animal is one
whose diet is missing one or more
essential nutrients

Depending on which nutrient, might be
more damaging than calorie deficiency
Essential Nutrients…and more
Essential amino acids are those that must be
obtained in diet in prefabricated form

In humans, eight are essential; can manufacture
the other 12 given precursors
Protein deficiency results when diet lacks one
or more essential amino acids
Human body CANNOT store essential AAs
Deficiency retards protein synthesis
Essential Nutrients, cont.
Essential fatty acids are those unsaturated
fatty acids that cannot be produced by body

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Linoleic acid is example in humans
Required to produce phospholipids for
membranes
Fatty acid deficiencies are rare
Vitamins are organic molecules required in
diet in much smaller quantities than essential
AAs/Fatty acids
May serve a catalytic function
Vitamin deficiencies may cause very severe
effects
Essential Nutrients, cont.
Water soluble versus fat soluble vitamins
If body of animal can synthesize a certain
compound, it is NOT a vitamin
Minerals are inorganic nutrients required in
diet in small quantities ranging from 1 mg to
2500 mg/daily
Some serve structural/maintenance roles
Calcium and phosphorous
Others serve as parts of enzymes (copper) or
other molecules (iron)
Water, water everywhere…
Water soluble vitamins are NOT stockpiled in
body tissue so excesses excreted in urine
Includes B complex vitamins functioning as
coenzymes in key metabolic processes
Includes vitamin C required for synthesis of
connective tissue/antioxidant
Fat soluble vitamins are stockpiled in body
tissues; excesses NOT excreted by body but
deposited in body fat
Overdoses may result in accumulation to
toxic levels
Vitamins, cont.
Fat soluble vitamins are A, D, E, and K
A incorporated into visual pigments of
eye
D aids in calcium absorption/bone
formation
E is antioxidant for phospholipids
K required for blood clotting
Mineral mine…so to speak
Calcium found in dairy products, dark
green veggies, and legumes
Needed for bone formation, blood
clotting, & nerve and muscle functioning
Phosphorous found in dairy products,
meats, and grains
Needed for bone/tooth formation, acidbase balance, & nucleotide synthesis
Minerals, cont.
Sulfur: proteins from many sources
Is component of certain amino acids
Potassium: meats, dairy products, many fruits
and veggies, and grains
Important in acid-base balance, water
balance, & nerve function
Chlorine found in table salt
Acid-base balance, formation of gastric juice,
nerve function, & osmotic balance
Minerals III
Sodium found in table salt
Acid-base balance, water balance, & nerve
function
Magnesium: whole grains, green, leafy
veggies
Is cofactor and component of ATP
bioenergetics
Iron: meats, eggs, legumes, whole grains,
green, leafy veggies
Hemoglobin, electron carrier in metabolism, &
enzyme cofactor
Animal Adaptations
Animals are chemoheterotrophs (eat plants
and other animals, maybe…)
Herbivores eat autotrophic organisms (plants,
algae, & autotrophic bacteria)
Carnivores eat other animals
Omnivores eat other animals and autotrophs
Animals evolved diversity of adaptations to
exploit, directly/indirectly, resources made
available by autotrophs
Adaptations, cont.
Filter-feeding (suspension): sift small food
particles from the water (clams/oysters;
baleen whales)
Substrate-feeding: live on or in food source
and eat way through food (leaf miners tunnel
through interior of leaves)
Deposit-feeding: type of substrate-feeder that
ingests partially decayed organic materials
along with their substrate (earthworm ingests
soil and digestive system extracts organic
materials
Adaptations, III
Fluid-feeders: suck nutrient-rich fluids
from a living host (aphids ingest phloem
sap; leeches and mosquitoes suck
blood, hummingbirds & bees ingest
nectar
Bulk-feeders: eat relatively large pieces
of food
I can’t believe I ate…
Digestion is process of breaking down food
into small molecules body can absorb
Macromolecules are TOO large
Digestion enzymatically cleaves them into
monomers that can be used by animal
Poly/Disaccharides into simple sugars
Proteins into amino acids
Fats into glycerol and fatty acids
Say what???
Gastrovascular cavity is digestive sac with
single opening; functions in both digestion
and nutrient distribution (Incomplete digestive
tract)
Most animals with simple body plans have
GV cavity
Extracellular digestive cavities are
advantageous because allow ingestion of
larger food items that can be phagocytosed
and digested intracelluarly
Phylum Cnidaria (Hydra) and Phylum
Platyhelminthes (planarians)
Complete Digestive Tract
CDT (alimentary canal) is digestive tube
running between two openings; the mouth
(food ingested) and anus (undigested wastes
eliminated)
Food moves in one direction along tube
Tube can be organized into specialized
regions for digestion and absorption on
nutrients in stepwise fashion
Unidirectional passage of food/specialization
of function makes alimentary canal more
efficient
Phylum Nematoda, Annelida, Mollusca,
Arthropoda, Echinodermata, and Chordata
Tummy growling?
Peristalsis is rhythmic smooth muscle
contractions
Pushes food along alimentary tract
Alimentary tract lined with both circular
and longitudinal muscle bundles
Wow, time for an Estesism
Vertebrate Digestive Tract
Teeth adapted for acquisition/initial
processing of specific types of food
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Tear, shred, grind, and pulverize food
Food chewed and mixed with secretions of
salivary glands
Esophagus is food tube connecting mouth to
stomach
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Peristalsis moves food down esophagus
Esophageal sphincter normally prevents food from
exiting stomach back into esophagus
VDT, cont.
Stomach stores food consumed


Secretions kill most microorganisms and begins
digestion of proteins
Processed into chyme, pyloric sphincter allows
passage into small intestine
Small intestine is major site of digestion

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Protein/carbs continue; fat digestion begins
Absorption of nutrients begins
VDT III
Duodenum site of most digestion; jejunum
and ileum responsible for ~ 90% absorption
of nutrients
Large intestine (colon) absorbs water and
ions
Immense populations bacteria live in colon

Vitamin K, biotin, methane, and hydrogen sulfide
Feces stored in last segment and excreted
Too much water, too little water…oh yeah!!!
VDT IV
Appendix can be source of difficulty
Rectum is terminal portion of large
intestine

Ends at the anus
Site of fecal storage until elimination is
convenient (that’s the hope)
Digestive Enzymes
Macromolecules (protein, carbs, and
fats) must be broken into their
monomers by hydrolytic enzymes
Hydrolysis occurs by adding water
molecules
Digestive enzymes classified according
to substances they hydrolyze
Digestive Enzymes, cont.
carbohydrasescarbs; proteasesprotein;
peptidasespeptides; lipasesfats;
nucleasesnucleic acids
Exo and endo indicate where enzyme
cleaves the molecule
Example: endoprotease hydrolyzes a protein
at an internal site along the polypeptide chain
Salivary Amylase
Secreted with saliva
Begins starch digestion into glucose in
mouth
Bread and crackers begin to taste
“sweet” if held in mouth long enough
Starch digestion continues in duodenum
where pancreatic amylases hydrolyze
starch and glycogen into disaccharides
Pepsin
Major enzyme produced by stomach is
endopeptidase called pepsin
Secreted as zymogen (pepsinogen) by
gastric glands in stomach lining (chief cells)
Along with HCl of stomach, begins protein
digestion
Splits peptide bonds next to some AAs
Begins process of “unwinding” proteins
creating more surface area for other enzymes
to act upon
Pancreatic Enzymes
Pancreas functions as both endocrine
and exocrine gland
Exocrine products delivered to gut via
pancreatic duct
Produces host of digestive enzymes:
Pancreatic amylase, lipase, nuclease,
trypsin, chymotrypsin, and
carboxypeptidase
Stomach tough as nails…
Stomach has pH of about 2
Acidic enough to dissolve iron nails
Function is to disrupt extracellular matrix that
binds cells together in meat and plant
material
Also kills most (but not all) of bacteria that are
swallowed with food
Also produces bicarbonate buffer for
neutralizing acidic chyme as exits stomach
Event Sequencing
Duodenum is first 25 cm of small intestine
>ed delivery of acid chyme to duodenum
stimulates production of secretin by
duodenum wall (enterogastrone)

Secretin simulates bicarbonate release from
pancreas
Gallbladder stores bile produced by liver
Bile does NOT contain digestive enzymes
Sequencing, cont.
Bile does contain bile salts which emulsify fat
Contains pigments (byproducts of destroyed
RBCs)
Cholecystokinin (CCK) produced by
duodenum wall stimulates pancreas to
release pancreatic enzymes into small
intestine & gall bladder to contract and
release bile into small intestine
Sequencing III
Other enterogastrones (secreted by wall
of duodenum) inhibit peristalsis in
stomach
This, in effect, slows food entry into
small intestine
Meanwhile, back at the ranch, it’s a
razing stampede of mugwomps and
widgets…just look at that mess!!!!
Digesting Digestion…what fun
Carbohydrate digestion begins in mouth
and again in duodenum (salivary vs.
pancreatic amylases
Disaccharidases attached to surface of
duodenal epithelium hydrolyze
disaccharies into monosaccharides
Each disaccharide has its own
disaccharidase
DD, cont.
Maltose/maltase; sucrose/sucrase;
lactose/lactase
Occurs in epithelial brush border of
small intestine
Since disaccharides are on surface of
epithelim, final breakdown of carbs
occurs where sugars will be absorbed
Digesting, III
Pepsin begins protein digestion in
stomach
Pancreas secretes enteropeptidase

Converts trypsinogen to trypsin
Chymotrypsin is also produced
Both specific for peptide bonds adjacent
to certain AAs; break large polypeptides
into smaller chains
Digesting IV
Carboxypeptidase (exopeptidase)
splits AAs one at time, off PP end that
has free carboxyl group
Lining of small intestine secretes protein
digesting enzymes
Aminopeptidase splits one AA at time
from PP end that has free amino group
Dipeptidases attached to intestinal
lining split small PPs
Enough of this
digesting..already
Trypsin, chymotrypsin, & carboxypeptidase
are secreted in inactive form by pancreas
Aminopeptidase, dipeptidase, &
enteropeptidase are secreted by lumen of
small intestine
Pepsin secreted by stomach
Trypsin, chymotrypsin, aminopeptidase, &
carboxypeptidase secreted by lumen of small
intestine
Dipeptidases secreted by epithelium of small
intestine (Brush border)
Digesting Nucleic Acids
Also involves teams of enzymes
Nucleases hydrolyze DNA and RNA
into nucleotides

Occurs in lumen of small intestine
Other hydrolytic enzymes
(nucleotidases and nucleosidases)
break nucleotides into nucleosides and
nitrogenous bases, sugars, and
phosphates
Pass the butter, please?
Fat digestion occurs ONLY in lumen of small
intestine
Emulsification produces many small fat
droplets that have large surface area for
digestion
Pancreatic lipase (from duodenum)
hydrolyzes fats into glycerol and fatty acids
Peristalsis moves digestive enzymes-chyme
mixture through the duodenum (poly into
mono)
Bitter as bile…
Bile is produced by liver and store in
gall bladder
Acts as detergent and aids in digestion
and absorption of fats
Also contains pigments that are byproducts of red blood cell destruction in
the liver
“Funny tasting chicken liver…you bet!!!!
And finally, brethren…
Most nutrient absorption occurs in jejunum
and ileum of small intestine
Large folds increase surface available for
absorption
Many villi (projections from surface) increase
SA of small intestine
Villi covered with microscopic microvilli
which > surface area for contact with contents
and absorption (300 m2)
Most water reabsorbed in large intestine
(colon)
Call it like it is…
Feces is wastes of the digestive tract moved
through tract by peristalsis
Intestinal bacteria live on organic material in
feces

Produce some vitamin K (mutualism)
Feces may contain abundance of salts
Stored in rectum and passes through 2
sphincters; 1 voluntary and 1 involuntary to
anus for elimination
Literally…the end