Animal Nutrition And Modes Of Nutrition
All animals feed on ready-made food. This food is made up of several groups of substances. Before these food substances can be absorbed into the animal's body, they are acted on by digestive enzymes. Animal nutrition, therefore, involves the study of food substances, balanced diets and digestive enzymes.
In this section we shall also study the different modes of nutrition. Living organisms exhibit either autotrophic or heterotrophic modes of nutrition. Generally, green plants and certain microorganism exhibit an autotrophic mode of nutrition, while the other organisms exhibit a heterotrophic mode of nutrition.
FOOD SUBSTANCES:
All food taken in by animal can be divide into six groups of food substances or nutrients.
They are carbohydrates, proteins, fats and oils, (or lipids), mineral salts, vitamins, and water.
Carbohydrates, protein, fats and oils, and water are known as primary food substances because they are necessary for the maintenance of life. The first three, together with nucleic acids, are the basic chemical building - blocks of an organism. Mineral salts and vitamins are know as welfare food substances because they are essential for the well- being of the individual.
CARBOHYDRATE:
Carbohydrates are made up of carbon, hydrogen and oxygen. There are different types of carbohydrates. There are different types of carbohydrates. Some example are sugars, starch and cellulose .
Carbohydrates are the main source of energy inthe body. In addition, they are used to build certain body parts (e.g. exoskeletons of arthropods). Mucus, an important lubricant in our bodies, is composed of carbohydrates.
SIMPLE SUGARS. The common sugars found in organisms are the hexose (six-carbon) sugars. They are the most important energy-storage molecules in organism. Examples are Glucose, Fructose, and Galactose. Ribose and Deoxyribose are Pentose (five-carbon) sugars used in the formation of nucleic acids.
COMPLEX SUGARS. These are formed by the joining or condensation of two simple sugar molecules. example are Sucrose, Maltose, Lactose....
NOTE: Condensation is a reaction in which two or more molecules join to form a large molecules, with the removal of a molecule of water or some other simple molecule.....