KATIE BELK

Animal Nutrition

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

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

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.

Main Stages of Food Processing

First Stage Ingestion: actual act of

eating

Second Stage Digestion: food is broken

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

Ingestion Organs

Sphincters, oral cavity, salivary glands, pharynx, and esophagus

Peristalsis, amylase, and bolus help with ingestion as well.

Digestion and Absorption Organs

Stomach, small intestine, duodenum, pancreas, liver, gallbladder, villi, microvilli, lacteal, large intestine, colon, cecum, and appendix

Others that help with digestion and absorption are gastric juice, chyme, pepsin, mucus, bile, and feces.

Adaptations

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 absorption of nutrients.

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.

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.