Download Animal Nutrition Heterotrophic Organisms Animal

Lecture 13
Animal Nutrition
Organisms can be divided into two classes
on the basis of their method of nutrition
Autotrophic Organisms
Heterotrophic Organisms
• bacteria, fungi,
protozoa and animals
• incapable of
manufacturing
organic compounds
from inorganic
nutrients
Nutritional Requirements
• nutrient: substance an
organism needs to remain alive
• food: any material that contains
nutrients
Heterotrophic Organisms
Animal Nutrition
Animals:
• diverse feeding strategies
• are under intense pressure
(natural selection) to use food
efficiently
Nutrients are molecules that serve as:
• sources of metabolic energy
• raw material for growth and tissue repair
• maintenance of body function
• reproduction
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Meeting Basic Needs
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Nutrient Requirements
carbohydrates
proteins
lipids
vitamins
essential elements
electrolytes
Nutrient Requirements
• Carbohydrates,
fats, and proteins
supply animals
with metabolic
energy
Understanding Nutrition
calorie: measure of the
energy content of food
Calorie: unit of energy
calorie: is the amount of heat
needed to raise the
temperature of 1 g of water
1°C
• if a single helping of food contains
150 Calories, then 150 kilocalories
(kcal) of energy is released when the
food is completely oxidized by cells
kilocalorie = Calorie (Cal)
figure 50-02.jpg
Nutrients Provide Energy
Nutrient Requirements
50.2
• Carbohydrates are
stored in liver and
muscle cells as
glycogen
Figure 50.2
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Energy and Exercise
• During exercise, glycogen is
broken down into glucose
• muscle cells use glucose that is
released to manufacture ATP
• glucose from liver enters
bloodstream and is delivered to
cells
Nutrient Requirements
• the most important
form of stored energy
in animals is fat
• fat has more energy
per gram than
glycogen
Nutrient Requirements
• Glycogen reserves are
built up, and then
additional carbohydrates,
proteins, and fats are
converted to body fat
• Some species use seasonal
over-nourishment to
survive periods of food
unavailability
Undernourishment
• an animal with
insufficient caloric
intake
• must metabolize its
stored glycogen, fat
and protein
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figure 50-03.jpg
50.3
Figure 50.3 The Course of Starvation
a starving
animal must
use its own
proteins for
fuel;
Kwashiorkor
syndrome
Figure 50.3
figure 50-04.jpg
Nutrient Requirements
• all animals require
certain basic
organic molecules
that they cannot
synthesize
50.4
Figure 50.4
figure 50-05.jpg
Essential Amino Acids
• humans require 8
essential amino acids
• all are available in
milk, eggs, meat, but
not in all vegetables
50.5
Figure 50.5
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Nutrient Requirements
Essential Fatty Acids
Humans are able to synthesize almost all of
their required lipids, using acetyl groups from
food
Essential fatty acids such as linoleic acid must
be obtained through a dietary source
• Different animals need mineral elements
in different amounts
• Macronutrients: needed in large amounts
• Micronutrients: needed in small amounts
table 50-01a.jpg
50.1
table 50-01b.jpg
50.1
Table 50.1 – Part 1
table 50-02a.jpg
Vitamins
• group of essential
nutrients
• carbon
compounds
required for
normal growth
and metabolism
• required in small
amounts
50.2
Table 50.2 – Part 1
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table 50-02b.jpg
Malnutrition
• results when any essential nutrient is
lacking from the diet
• chronic malnutrition leads to a
characteristic deficiency disease
• pernicious anemia (the failure of red
blood cells to mature), is caused by B12
deficiency
50.2
Adaptations for Feeding
• Heterotrophic organisms can be
classified by how they acquire their
nutrition
Heterotrophic Organisms:
Predators
animals that feed on living organisms
• herbivores - eat
plants
• carnivores - eat
animals
• omnivores - eat
plants and animals
Heterotrophic Organisms:
Saprobes
Other Adaptations for Feeding
Bacteria and Fungi
• saprophytic –
absorb nutrients
from dead organic
matter
Detritivores, (earthworms and crabs)
Filter feeders, (clams and blue whales)
Fluid feeders obtain food from the fluids
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Adaptations for Feeding
• because the energy
content of vegetation is
low, herbivores must
process large amounts
• teeth of herbivorous
vertebrates: evolved to
process coarse plant
matter
Adaptations for Feeding
• behavioral and
anatomical
adaptations reflect
feeding types
• teeth have evolved
to match diet
Natural Selection
• has tightly matched the structure of animal
mouthparts to their function in obtaining food
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