Page 107 - Agriculture_Form_Three

Agriculture for Secondary Schools

Proteins
Proteins contain carbon, hydrogen, oxygen, nitrogen and some sulphur atoms.
Proteins are compounds which are formed by joining several molecules of amino
acids linked together by peptide bonds. They differ in their type, arrangement and
number of amino acids involved. Proteins are essential in the diets of animals for
tissue formation, growth and repair and in supporting various metabolic processes in
the body. The nutritional value of a protein source is judged by the content of its amino
acids. There are two main categories of amino acids: essential, and non-essential
amino acids. The essential amino acids are those that are absolutely necessary to
be provided in the diet because they cannot be synthesised by the animal body. The
non-essential amino acids are acids that are synthesised in the body of the animal
and therefore do not have to be supplied in the diet. The major sources of protein in
animal feeds are feeds of animal origin, oil cakes and leguminous forages.

Fats and oils
Fats and oils are organic compounds that are made up of fatty acids. They are
insoluble in water. They are high in energy at about 2.25 times that obtained from
carbohydrate. Feeds rich in fats and oils include oil seeds and their by-products as
well as some animal and fish products.
Vitamins and minerals

Vitamins and minerals are dietary elements that are required by animals in relatively
small quantities to support proper functioning of metabolic processes. When vitamins
and minerals are not supplied in adequate amounts, animals may develop serious
deficiency conditions some of which can be fatal. Most of the vitamins cannot be
synthesised by the animal’s body and therefore they have to be supplied through
diet. Vitamins are classified into two groups on the basis of their solubility, that
is, fat-soluble and water-soluble vitamins. Fat soluble vitamins are vitamins that
can dissolve in fats and oils. They include vitamin A, D, E, and K. Water soluble
vitamins are those vitamins which are soluble in water. They include vitamin C and
eight B vitamins that form the B-complex, that is Thiamine (B1), Riboflavin (B2),
Niacin (B3), Pantothenic acid (B5), Pyridoxine (B6) Biotin (B7), Folic acid (B9),
and Cobalamin (B12). Water soluble vitamins cannot be stored in the body with the
exception of Vitamin B12 which is stored in the liver. Excess water-soluble vitamins
are removed from the body through the urine. Problems with water soluble vitamins
are seen more among monogastric farm animals as ruminants can synthesise most
of the water-soluble vitamins particularly B-complex.

There are 15 mineral nutrient elements that are required by farm animals and they
are grouped into two: macro-elements and micro-elements. On one hand, macro-

Student’s Book Form Three
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AGRICULTURE FORM 3 9.11.2022.indd 96 10/01/2025 12:31