Animal Nutrition | Carbohydrates, Proteins, Fats and Oils, Mineral Salts, Vitamins, Water and Roughages.

Animal Nutrition (Food Substances) Food is a complex, energy-rich organic matter that living organisms consume to obtain essential nutrients for life. These nutrients are classified into six groups: (i) Carbohydrates (ii) Proteins (iii) Fats and Oils (iv) Mineral Salts (v) Vitamins (vi) Water and Roughages.   Carbohydrates: Carbohydrates are composed of carbon, hydrogen, and oxygen […]

Animal Nutrition (Food Substances)

Food is a complex, energy-rich organic matter that living organisms consume to obtain essential nutrients for life. These nutrients are classified into six groups:

(i) Carbohydrates

(ii) Proteins

(iii) Fats and Oils

(iv) Mineral Salts

(v) Vitamins

(vi) Water and Roughages.



Carbohydrates are composed of carbon, hydrogen, and oxygen with the general formula (CxH2O)y. They include simple sugars, starches, cellulose, and glycogen, categorized into monosaccharides, disaccharides, and polysaccharides. Common sources are yam, cassava, potatoes, bread, and cereals like rice and maize.

  1. Monosaccharides: Simple sugars with the formula C6H10O6, such as glucose, fructose, and ribose.
  2. Disaccharides: Double sugars with the formula C12H22O11, including sucrose, maltose, and lactose.


  1. Sucrose is a non-reducing sugar formed from glucose and fructose.
  2. Maltose is a reducing sugar obtained from the condensation of two simple sugar molecules.
  3. Lactose (milk sugar) is a reducing sugar formed from glucose and galactose.


– Polysaccharides: Complex carbohydrates like starch, cellulose, chitin, and inulin.

  1. Starch (C6H10O5)n is derived from the condensation of numerous simple sugar molecules found in yam, cereals, cassava, and bread.
  2. Cellulose, present in whole meal bread, cereals, fresh fruit, and vegetables, forms the plant cell wall.
  3. Glycogen (animal starch) is the form in which animals store carbohydrates, usually in muscles or the liver.


Importance of Carbohydrates:

  1. Provides energy for daily activities.
  2. Generates heat during oxidation, maintaining body temperature.
  3. Contributes to specific body parts, such as the exoskeleton in arthropods.
  4. Forms mucus, a crucial lubricant in the body.



Proteins are complex molecules composed of amino acids. They need to be digested into amino acids before absorption in the animal’s body. The breakdown during digestion proceeds as follows:

Protein → Peptone → Polypeptide → Amino Acid

Proteins consist of carbon, hydrogen, oxygen, phosphorus, and sulfur. Sources include animal products (milk, eggs, fish, cheese, meat, and chicken) and plant products (beans, groundnut, soya beans, and melon).


Importance of Protein:

  1. Essential for the growth of young organisms.
  2. Used in the repair of worn-out tissues or cells.
  3. Aids in reproduction.
  4. Necessary for enzyme production.
  5. Required for hormone production.
  6. Contributes to bodybuilding.


Fats and Oils:

Fats and oils, also known as lipids, consist of carbon, hydrogen, and oxygen. They are hydrolyzed into fatty acids and glycerol during digestion. Plant sources include groundnut, palm oil, soya beans oil, coconut oil, and melon oil, while animal sources include butter, fish, or cod oil.


Importance of Fats and Oils:

  1. Provide more energy to animals than carbohydrates.
  2. Supply essential fatty acids.
  3. Act as solvents for fat-soluble vitamins.
  4. Assist in maintaining body temperature.
  5. Act as insulation, helping animals conserve heat.


Mineral Salts:

Mineral salts are vital substances required in trace amounts for essential body processes. Animals mainly obtain them by feeding on plants or plant products, except for some, like sodium chloride (table salt). Lack of these minerals can lead to nutritional deficiencies.


Common Mineral Salts, Sources, Functions, and Deficiency Symptoms:

  1. Calcium: Milk, cheese, egg, fish; vital for bone and teeth formation, blood clotting, and normal functioning of the heart, nervous system, and muscles. Deficiency symptoms include rickets, osteomalacia, and tooth decay.
  2. Phosphorus: Milk, cheese, egg, fish, wheat; essential for strong teeth and bone development, DNA and RNA formation, and respiration. Deficiency symptoms mirror those of calcium deficiency.
  3. Magnesium: Green vegetables, milk, meat; crucial for muscle contraction, iron utilization, teeth, and bone health. Deficiency leads to nervous disorders.
  4. Potassium: Fruits and natural foods; needed for muscle function and nerve impulse transmission. Deficiency results in muscle paralysis.
  5. Sulphur: Beans, fish, meat, egg; a constituent of proteins, amino acids, and vitamin B. Deficiency leads to poor growth.
  6. Sodium & Chlorine: Table salt, fish, fruit; essential for impulse transmission and maintaining cell osmotic balance. Deficiency causes dehydration and muscle cramps.
  7. Iron: Eggs, liver, kidneys, beans, vegetables; required for hemoglobin formation in red blood cells. Deficiency results in anemia.
  8. Iodine: Seafoods; necessary for the thyroid gland to produce thyroxine. Deficiency leads to goiter.
  9. Manganese: Egg, milk, meat; necessary for normal growth and acts as a co-factor in enzymatic reactions.
  10. Copper: Green vegetables, eggs, milk, meat; catalyzes iron use and aids proper respiration. Deficiency leads to anemia.



Vitamins are essential organic food substances required in small quantities for normal growth and healthy development in humans and animals. Inadequate vitamin supply in the diet can result in deficiency diseases.


Groups of Vitamins:

(i) Fat Soluble Vitamins: Soluble only in fat, including vitamins A, D, E, and K.

(ii) Water Soluble Vitamins: Soluble in water, encompassing vitamins B-complex and C, such as B2 (Riboflavin), B3 (Niacin), B5 (Pantothenic), B6 (Pyridoxine), B12 (Cyanocobalamin), and Folic acid, among others.

Vitamin A (Retino): This essential vitamin is found in various sources such as liver, eggs, fish, milk, palm oil, and fresh vegetables. Its functions include supporting the normal growth of cells and skin, as well as contributing to proper vision. A deficiency in Vitamin A may manifest as night blindness and reduced resistance to diseases.


Vitamin B1: Present in yeast, unpolished rice, milk, beans, and palm wine, Vitamin B1 plays a crucial role in normal growth and the formation of co-enzymes involved in cellular respiration. A deficiency in Vitamin B1 can result in slow growth and dermatitis.


Vitamin B2: Yeast, soya beans, egg, milk, and green vegetables are rich sources of Vitamin B2. This vitamin is essential for growth, maintaining healthy skin, and proper functioning of the eyes. Similar to Vitamin B1, a deficiency in Vitamin B2 can lead to slow growth and dermatitis.


Vitamin B3: Found in yeast, beans, milk, palm wine, yam, and various vegetables, Vitamin B3 is necessary for cellular respiration. A deficiency in this vitamin can result in pellagra, characterized by skin problems and digestive issues.


Vitamin B12: Abundant in kidney, liver, fish, and milk, Vitamin B12 is crucial for the formation of red blood cells. A deficiency may lead to pernicious anemia.


Vitamin C (Ascorbic acid): Derived from fresh fruits like oranges and green vegetables, Vitamin C aids in wound healing and helps resist infections. A deficiency can result in scurvy, characterized by bleeding gums, poor wound healing, and low resistance to infection.


Vitamin D (Calciferol): Found in fish, milk, eggs, and liver, Vitamin D is also produced in the skin when exposed to light. It is necessary for the formation of strong bones and teeth. Deficiency may cause conditions such as rickets and osteomalacia.


Vitamin E (Ergo sterol): Present in green vegetables, butter, and liver, Vitamin E is associated with the promotion of fertility in animals. A deficiency can lead to reproductive failure, including issues like sterility and premature abortion.


Vitamin K (Phylloquinone): Found in fresh green vegetables, cabbage, and spinach, Vitamin K aids in blood clotting. A deficiency in Vitamin K may result in hemorrhage.



Water is composed of hydrogen and oxygen. Sources of water include metabolic water from food, drinking water from various sources like rivers, rain, and ponds.


Importance of Water:

(i) Required for metabolic activities in the body

(ii) Necessary for digestion of food

(iii) Used for maintaining body temperature

(iv) Serves as a medium for transporting nutrients

(v) Assists in excretion of metabolic waste products (e.g., urine)

(vi) Basis for body secretion from endocrine glands

(vii) Maintains the osmotic content of the body


Balanced Diet

A balanced diet contains the correct proportion of all six essential food substances: carbohydrates, proteins, fats and oils, minerals, vitamins, and water.


Digestive Enzymes

Digestive enzymes are organic catalysts, complex protein substances produced by living cells. They accelerate metabolic reactions without altering their composition.


Characteristics of Enzymes:

(i) Specific in their actions

(ii) Only small quantities required for catalyzing a reaction

(iii) Have a specific temperature range for optimal activity

(iv) Do not lose their chemical composition after a reaction

(v) Affected by acidity and alkalinity (pH) of the medium

(vi) Involved in reversible reactions

(vii) Produced by glands specific to the system they support

(viii) Activities can be inhibited by certain substances

(ix) Enhanced by co-enzymes, such as inorganic substances like phosphorus.


Classes of Enzymes:

Proteases – Protein-digesting enzymes found in the stomach (Renin, Pepsin) and small intestine (Trypsin, Erepsin).


Amylase – Enzymes digesting starches and sugars, including Ptyalin (Salivary amylase) in the mouth and Pancreatic amylase in the pancreas.


Lipases – Enzymes converting oils to fatty acids and glycerol, produced in the pancreas and ileum.


Related Posts:

Nutrient Cycling In Nature | Carbon Cycle, Water Cycle & Their Importance

Plant Nutrition

Organization of Life

Characteristics Of Living Things

Living Things And Non-Living Things

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