Transcript ANIMAL NUTRITION Chapter 41

ANIMAL
NUTRITION
Chapter 41
Animals are
heterotrophs
Nutrition is not
only the need for food,
but also the need for
specific food
components.
Require food for
2.
1.
fuel (chemical energy)
carbon for its own molecules
3.
essential nutrients
FUEL - ATP
BIOSYNTHESIS
ENERGY STORAGE
Food Processing
Ingestion
Digestion
Absorption
Elimination
Act of
eating
Process of
breaking food
down into
molecules small
enough for the
body to absorb
Take up small
molecules from
the digestive
compartment
Undigested
material
passes out of
the digestive
compartment
Intracellular
Extracellular
Dietary Categories
(represents the kind of food
the animal usually eats)
Herbivores
Carnivores
Omnivores
Mainly eat
plants and
algae
Eat other
animals
Consume
animals as
well as
plants or
algae
Gorillas
Sharks
Cockroaches
Cows
Hawks
Crows
Hares
Spiders
Bears
Snails
Snakes
Raccoons
Humans
Most animals are opportunistic –
Eating foods that are outside
their main dietary category
Feeding Mechanisms
Suspension
(filter)
feeders
Substate
feeders
Fluid
feeders
Bulk feeders
Sift small
food
particles
from the
water
Live in or on
their food
source
Suck
nutrient rich
fluids from
a living host
Eat
relatively
large pieces
of food
Clams
Maggots
Mosguitos
Oysters
Earthworms
Leeches
Most
animals
Baleen
whales
Hummingbirds
Bees
Feeding Mechanisms
Suspension
(filter)
feeders
Sift small
food
particles
from the
water
Sponges
Clams
Oysters
Baleen
whales
Feeding Mechanisms
Substate
feeders
Live in or on
their food
source
Maggots
Earthworms
Feeding Mechanisms
Fluid
feeders
Suck
nutrient rich
fluids from
a living host
Mosguitos
Leeches
Hummingbirds
Bees
Feeding Mechanisms
Bulk feeders
Eat
relatively
large pieces
of food
Most
animals
Food Processing
Ingestion
Digestion
Absorption
Elimination
Act of
eating
Process of
breaking food
down into
molecules small
enough for the
body to absorb
Take up small
molecules from
the digestive
compartment
Undigested
material
passes out of
the digestive
compartment
Intracellular
Extracellular
Virtually all food,
whether of plant or animal origin,
consists of highly complex
compounds that cannot be used
without first being broken down
to simpler compounds =
digestion.
CHOs, fats and
proteins can all
be used as fuel.
Campbell; Fig. 9.19
Net Energy Value of Foods
4 kcal per gram for protein
Amino
acids
4 kcal per gram for CHO
Simple sugars
9 kcal per gram for lipid
Fatty acids
Campbell; Fig.40.10
If the food intake exceeds
the energy used,
most animals store the surplus
as fat,
irrespective of the nature of
the food.
Net Energy Value of Foods
4 kcal per gram for CHO
 Fast
 Aerobic or anaerobic
 Storing glycogen also
requires storing water
Simple sugars
9 kcal per gram for lipid
 Slower
 Aerobic
Fatty acids
Campbell; Fig.40.10
Glucose
• Human body regulates the use and storage of
glucose.
1 When blood glucose
level rises, a gland called
the pancreas secretes insulin,
a hormone, into the blood.
2 Insulin enhances the
transport of glucose into body
cells and stimulates the liver
and muscle cells to store
glucose as glycogen. As a
result, blood glucose level
drops.
STIMULUS:
Blood glucose
level rises
after eating.
Homeostasis:
90 mg glucose/
100 mL blood
Figure 41.3
4 Glucagon promotes
the breakdown of
glycogen in the
liver and the
release of glucose
into the blood,
increasing blood
glucose level.
STIMULUS:
Blood glucose
level drops
below set point.
3 When blood glucose
level drops, the pancreas
secretes the hormone
glucagon, which opposes
the effect of insulin.
Stores of glycogen and
fat are used up – so
what is left?
Undernourished –
calorie deficient
Overnourished –
calorie excess
Hypothalamic feeding center
 Food intake
 Fat stores
 Leptin secretion
Negative feedback
Neuropeptide Y
Hypothalamic feeding center
Negative feedback
Neuropeptide Y
X
 Food intake
 Fat stores
X
 Leptin secretion
Hormones and Appetite
Secreted by the stomach
wall, ghrelin is one of the
signals that triggers feelings
of hunger as mealtimes
approach. In dieters who lose
weight, ghrelin levels increase,
which may be one reason
it’s so hard to stay on a diet.
Produced by adipose (fat)
tissue, leptin suppresses
appetite as its level increases.
When body fat decreases,
leptin levels fall, and appetite
increases.
Ghrelin
Insulin
Figure
The hormone PYY,
secreted by the small
intestine after meals,
acts as an appetite
suppressant that
counters the appetite
41.5 stimulant ghrelin.
Leptin
PYY
A rise in blood sugar level
after a meal stimulates
the pancreas to secrete
insulin (see Figure 41.3).
In addition to its other
functions, insulin suppresses
appetite by acting on the brain.
Malnourished –
diet is missing
one or more
essential nutrients
Materials that must be
obtained in their
preassembled form
because animal cells
cannot make them from
any raw material
Osteophagia –
bone eating
Essential Nutrients
Essential
amino acids
Essential
fatty acids
Vitamins
Minerals
In order for
protein
synthesis to
occur in human
adults, eight
amino acids
must be
available
simultaneously
and in the
correct relative
amounts
Important
for
phospholipid
membrane;
and principal
storage
compound
Organic
molecules in
small amounts
Inorganic
molecules in
small amounts
Water
soluble
Fat
soluble
Food Processing
Ingestion
Digestion
Absorption
Elimination
Act of
eating
Process of
breaking food
down into
molecules small
enough for the
body to absorb
Take up small
molecules from
the digestive
compartment
Undigested
material
passes out of
the digestive
compartment
Intracellular
Extracellular
Food Processing
Digestion
Process of
breaking food
down into
molecules small
enough for the
body to absorb
Intracellular
Extracellular
Campbell; Fig.41.10
Food Processing
Digestion
Process of
breaking food
down into
molecules small
enough for the
body to absorb
Intracellular
Gastrovascular
cavity
Extracellular
Complete digestive tract
or alimentary canal
Campbell; Fig.41.11
Campbell; Fig. 33.4
Campbell; Fig. 33.10
Campbell; Fig. 41.13
Campbell; Fig.41.12a
Campbell; Fig.41.12b
 Highly reliant on digestive
system to remain healthy
 Cannot afford to store
heavy materials in body
for lengthy period
Campbell; Fig.41.12c
1. Mouth – usually
relatively simple
2. Esophagus – may be widened at
midpoint to form crop (storage area)
3. Proventriculus – glandular
stomach which is highly acidic
4.Gizzard – thick muscular walls and
sandpaper like surface
stomach
5.Small intestine – food digestion
and absorption
6. Caecum – bacterial breakdown
of cellulose
7. Large intestine
8. Cloaca – final holding area
Proctor and Lynch; Manual of Ornithology
EVOLUTIONARY
ADAPTATIONS
OF VERTEBRATE
DIGESTIVE SYSTEMS
1. Length of digestive system
2. Accessory structures (such
as)
a. Crop
b. Gizzard
c. Liver
d. Caeca
Campbell; Fig. 41.21
Herbivorous Bird
Carnivorous
Bird
Grain
Fruits and
Berries
Gizzard
Substantial
Substantial
Reduced in
size
Small intestine
Shorter, less
complex
Longer, more
complex
Shorter, less
complex
Caeca
Small or
absent
Well developed
Less well
developed
EVOLUTIONARY
ADAPTATIONS
OF VERTEBRATE
DIGESTIVE SYSTEMS
Dentition
Many kinds of animals
have tooth–like
structures, but only
vertebrates have true
teeth, with an ultrahard layer of
ENAMEL on the
outside and softer
DENTINE on the
inside.
Campbell; Fig. 41.20
The incisors in blue
(cutting plant food)
The canines in red
(slicing and tearing
meat)
The molars in green
(grinding grass and
other plants)
http://www.oum.ox.ac.uk/children/animals/nuteeth.htm
http://animaldiversity.ummz.umich.edu/site/topics/mammal_anatomy/kinds_of_teeth.html
Examples of modified incisors
EVOLUTIONARY
ADAPTATIONS
OF VERTEBRATE
DIGESTIVE SYSTEMS
X
Use of
Symbiotic
Microorganisms
Campbell; Fig. 41.22
Campbell; Fig.41.22
Four compartment
stomach
1. Reticulum – form
food bolus and initiate
regurgitation
Reticular epithelium –
honeycomb lining
Four compartment
stomach
1. Reticulum – form
food bolus and initiate
regurgitation
2. Rumen – digestive
and fermentation vat
containing anaerobic
microbes and site
of fatty acid absorption
Rumen Interior
http://www.borderouge.com/photos/c
hai.jpg
Four compartment
stomach
1. Reticulum – form
food bolus and initiate
regurgitation
2. Rumen – digestive
and fermentation vat,
contains anaerobic
microbes, site
of fatty acid absorption
3. Omasum – lined
by muscular folds, reduces
particle size, absorbs
water (and any
leftover fatty acids)
Omasum
epithelium
Four compartment
stomach
1. Reticulum – form
food bolus and initiate
regurgitation
2. Rumen – digestive
and fermentation vat,
contains anaerobic microbes,
site of fatty acid absorption
3. Omasum – lined by muscular
folds, reduces particle size,
absorbs water (and any
leftover fatty acids)
4. Abomasum – true
glandular stomach where
bacteria and pathogens
are killed
What do the microbes
provide to the ruminants?
Symbiotic
Microorganisms
1. Digestion of cellulose
2. Provision of organic acids
3. Provision of protein
4. Provision of B vitamins
5. Detoxify compounds
What do the ruminants
provide to the microbes?
Symbiotic
Microorganisms
1. Housing with reliable heat
2. Adequate nutrition
3. Garbage removal
4. Neutral environment
EVOLUTIONARY
ADAPTATIONS
OF VERTEBRATE
DIGESTIVE SYSTEMS
1. Foregut fermenters
a. Cows, sheep, goats
2. Hindgut fermenters
a. Horses, rodents, rabbits
b. Coprophagy
a. Using feces as a
nutritional resource
b. Food passes through
entire digestive
tract a second time
Campbell; Fig. 41.21