Animal nutrition involves the ingestion, digestion, absorption and elimination of food. There are four classes of essential nutrients: amino acids, fatty acids, vitamins and minerals. Dietary deficiencies like undernourishment and malnourishment occur when diets lack sufficient energy or essential nutrients and negatively impact animal health and survival. The main stages of food processing are ingestion, digestion, absorption and elimination. Animals have evolved various dental and digestive system adaptations suited to their diets. Overnourishment and obesity can result from consuming more calories than needed.

1. Animal Nutrition
KATIE BELK

2. Basic Terms
 Nutrition: food being taken in, taken apart, and
taken up
 Herbivores: dine mainly on plants or algae
 For example: cattle, parrotfish, and termites
 Carnivores: mostly eat other animals
 For example: sharks, hawks, and spiders
 Omnivores: don’t eat everything, but they do
regularly consume animals as well as plants of algae
 For example: bears

3. Essential Nutrients
 Four classes: essential amino acids, essential fatty
acids, vitamins, and minerals.
 Essential amino acids: cannot be synthesized by animals
and must obtain food in prefabricated form
 Essential fatty acids: ones that cannot be synthesized by
animals(unsaturated fatty acids)
 Vitamins: organic molecules with diverse functions that are
required in diet in very small amounts
 Minerals: inorganic nutrients are usually required in small
amounts-requirements vary among animal species

4. Dietary Deficiencies
 Undernourishment: result of diet that consistently
supplies less chemical energy than the body
requires
 Malnourishment: the long-term absence from the
diet of one or more essential nutrients.
 Both of these dietary deficiencies have negative
impacts on the healthy and survival of animals.

5.  First Stage
Main  Ingestion: actual act of
eating
Stages of
 Second Stage
Food  Digestion: food is broken
Processing down into molecules small
enough for body to absorb
 Third Stage
 Absorption: animal’s cells
take up (absorb) small
molecules such as amino
acids and simple sugars
 Fourth Stage:
 Elimination: completes
process as undigested
material passes out of
digestive system

6. Ingestion Organs
 Sphincters, oral cavity, salivary glands, pharynx,
and esophagus
 Peristalsis, amylase, and bolus help with ingestion
as well.

7. Digestion and Absorption Organs
 Stomach, small
intestine, duodenum, pancreas, liver, gallbladder, vill
i, microvilli, lacteal, large
intestine, colon, cecum, and appendix
 Others that help with digestion and absorption are
gastric juice, chyme, pepsin, mucus, bile, and feces.

8. Dental Adaptations
 Evolutionary
adaptation of teeth for
processing different
kinds of food is one
major reason mammals
have been so
successful
 Example:
poisonous snakes
have fangs to inject
venom into prey
Stomach and Intestinal
Adaptations
 The length and size
(expandable) of the
vertebrate digestive
system is correlated
with diet.
 A longer digestive
tract gives more
time for digestion
and more surface
area for the Adaptations
absorption of
nutrients.

9. Energy Sources and Stores
 Most animals “burn” proteins only after exhausting
their supply of carbohydrates and fats.
 When animals take in more energy-rich molecules,
such as fats, it breaks down and the excess are
converted to storage molecules.

10. Overnourishment and Obesity
 Overnourishment: the
consumption of more calories
then the body needs for
normal metabolism
 Overnourishment also causes
obesity which is the
excessive accumulation of fat
 Obesity contributes to a number
of health problems, including the
most common type of diabetes
(type 2), cancer of the colon and
breast, and the cardiovascular
disease that can lead to heart
attack and strokes.