ANIMAL NUTRITION

ANIMAL NUTRITION (FOOD SUBSTANCES)

Food is a complex energy-rich organic matter which living organism feed on to obtain nutrients and substances necessary for life. Food substances are classified to six groups

Table of Contents

(i) Carbohydrate (ii) Protein (iii) Fat and oils (iv) Mineral salts (v) Vitamins (vi) Water and roughages.

Carbohydrates

These are made up of carbon, hydrogen and oxygen. They have general formula (C_xH₂O)y. carbohydrate consists of simple sugar, starches, cellulose and glycogen. They are grouped into simple sugar or monosaccharide, double sugar/disaccharides and poly saccharide. The common sources include yam, cassava, potatoes, bread, cereals e.g. rice, maize e.t.c.

Simple sugar or Monosaccharide

These are the simplest sugar which consists of one molecule of simple sugars. They have general formula C₆H₁₀O₆. Examples are glucose, fructose and ribose (C₅H₁₀O₅) or galactose

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Disaccharide/Reducing sugar

These are sugars which consist of two molecules of simple sugar which formed by condensation with the general formula C₁₂H₂₂O₁₁. Examples are sucrose, maltose and lactose

Sucrose: It is a non-reducing sugar which is formed from a molecule of glucose and a molecule of glucose is the main source

Maltose: This is obtained from the condensation of two molecules of simple sugar. It is reducing sugar

Lactose (milk-sugar): It is a reducing sugar. It is obtained from the condensation of a molecule of glucose and a molecule of galactose

Polysaccharide

These are complex carbohydrates. Examples are starch, cellulose, chitin and inulin.

Starch: It has the formula C₆H₁₀O₅)n where n represent a large number. It is formed from the condensation of numerous molecules of simple sugar. Examples of the sources of starch are yam, cereals, cassava and bread
Cellulose: This is composed of several condensed unit of monosaccharides. It makes the cell wall of plant source of cellulose include whole meal bread, cereals, fresh fruit and vegetables.

iii. Glycogen (Animal starch): This is the form which animals store their carbohydrate usually in the muscle or liver

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Importance of Carbohydrate

It provides energy required by animals for their daily activities
It provides heat during it oxidation used in maintain the body temperature

iii. It forms certain body part of arthropods (exoskeleton)

The mucus which is an important lubricant in the body is formed carbohydrate

PROTEIN

Proteins are complex molecules and are made of smaller unit called amino acids. Proteins have to be digested to amino acids before they are absorbed in the body of animal. The breakdown of proteins during digestion takes place in the following

Protein Peptone Polypeptide Amino acid

Protein is composed of carbon, hydrogen, oxygen, phosphorus and sulphur

Sources of protein include both animal source and plant source

The animal source includes milk, egg, fish, cheese, meat and chicken while the Plant sources are beans, groundnut, soya beans and melon.

Importance of Protein

Protein is needed for growth of young ones
It is used for the repair of worn out tissues or cells

iii. It aids reproduction

It is used for the production of enzymes
It is needed for the production of hormone
It is needed for body building57

FATS AND OIL

Fat and oils are also called lipids. They consist of only carbon, hydrogen and oxygen. However, the amount of oxygen in each lipid is very little e.g. tristearin, is C₅₇H₁₀O₆. Fats are solid lipid at room temperature. Plant sources of oil include groundnut, palm oil, soya beans oil; coconut oil and melon oil white animal sources of fat include butter, fish or cod oil.

Fat and oil are hydrolysed during digestion to fatty acid and glycerol

Importance of Fat and Oil

Fat and oil provides more energy to animal than carbohydrate
Fat supplies essential fatty acid to animal

iii. Fat and oil act as solvent for fat soluble vitamins

They help in the maintenance of body temperature
They act as insulator to animal which help them to conserve heat

MINERAL SALT

Mineral salts are food substances that are required in traces for vital body process. They are taken in their ionic forms. Animal takes in their elements mainly by feeding on plants or their products except a few of them such as sodium chloride (table salt). Lack of mineral salts will result in nutritional deficiency. These mineral elements or salts include phosphorus, calcium, iodine, manganese, fluorine, copper and cobalt.

MINERAL	SOURCE	FUNCTIONS	DEFICIENCY SYMPTOMS
CALCIUM	Milk, Cheese, Egg and Fish	(i) Bone and teeth formation and development (ii) Needed for blood clotting (iii) Normal Functioning of the heart, nervous system and muscle	(i) Rickets (ii) Osteomalacia (iii) Tooth decay
PHOSPHORUS	Milk, cheese, egg, fish and wheat	(i) For strong development of teeth and bone (ii) It forms part of DNA and RNA (iii) Needed for respiration	i) Rickets (ii) Osteomalacia (iii) Tooth decay
MAGNESSIUM	Green, vegetables, milk, meat	(i) For muscle contraction (ii) Needed for utilization of iron (iii) Needed for teeth and bone	Nervous disorder
POTASSIUM	Fruits and other Natural food	(i) Needed for functioning of the muscles (ii) For transmission of impulses in nerves	It leads to muscle paralysis
SULPHUR	Beans, fish, meat & egg	Constituent of proteins, amino acids and vitamin B	Poor growth
SODIUM & CHLORINE	Table salt, fish fruit	(i) Transmission of impulses (ii) Maintenance of osmotic balance of the cell	(i) Dehydration (ii) Muscle cramp
IRON	Eggs, liver, kidneys, beans, vegetables	(i) Formation of haemoglobin in red blood cell	Anaemia
IODINE	Sea foods	(i) Required by the thyroid gland to make thyroxine	Goitre
MARGANESE	Egg, Milk, Meat	(i) Required for normal growth (ii) Acts as co-factors in some enzymatic reactions
COPPER	Green vegetables, eggs, milk, meat	(i) It catalyses the use of iron (ii) For proper respiration in some aerobic organisms	Anaemia

VITAMINS

Vitamins are organic food substances which are needed in small quantities or traces for body normal growth and healthy development in man and other animals. Absence or insufficiency of vitamin supply in diet may lead to deficiency diseases

Groups of Vitamins

(i) Fat Soluble Vitamins: These are vitamins that are soluble only in fat e.g. vitamins A,D, E and K

(ii) Water Soluble Vitamins: These are vitamins that are soluble in water e.g. vitamins B-complex and vitamin C. some members of vitamin B₂(Riboflavin), B3 (Niacin), b5 (Pantothenic) B6 (Pyridoxine), B12, (cyanocobalamine), Folic acid e.t.c.

VITAMIN	SOURCE	FUNCTION	DEFICIENCY/SYMPTOMS
VITAMIN A (Retino)	Liver, eggs, fish, milk, palm oil, fresh vegetables	(i) Required for normal growth of cells and skin (ii) For proper vision of the eye	(i) Night blindness (ii) Reduced resistance to diseases
VITAMIN B₁	Yeast, unpolished rice, milk, beans, palm wine	(i) Required for normal growth (ii) Formation of co-enzymes involved in cellular respiration	(i) Slow growth (ii) Dermatitis
VITAMIN B₂	Yeast, soya beans, egg, milk, green vegetables	(i) Required for growth healthy skin and proper functioning of the eyes (ii) Formation or co-enzymes involved in cellular respiration	(i) Slow growth (ii) Dermatitis
VITAMIN B₃	Yeast, beans, milk, palm wine, yam, vegetables	Needed for cellular respiration	Pellagra ( a skin disease and digestive problem
VITAMIN B₁₂	Kidney, liver, fish, milk	Formation of red blood cells	Pernicious anaemia
VITAMIN C (Ascorbic acid)	Fresh fruits e.g. Orange and green vegetables	(i) Aids wound healing (ii) Helps to resist infection	Scurvy (characteristic by bleeding gum, poor healing of wood an low resistance of infection)
VITAMIN D Calciferol	Fish, milk, egg, liver, form in the skin by light	Needed for strong bone and teeth formation and development	Ricket, osteomalacia
VITAMIN E (Ergo sterol)	Green vegetable, butter, liver	Promotion of fertility in animals	Reproductive failure e.g. sterility and pre mature abortion
VITAMIN K Phylloquinone	Fresh green vegetable/cabbage spinach	Aids blood clothing	Haemorrhage

WATER

Water is composed of two elements hydrogen and oxygen. Source of water available to animals include metabolic water from food, drinking water from rivers, rain, pond e.t.c.

Importance of Water

(i) It is required for metabolic activities in the body

(ii) Water is necessary for digestion of food

(iii) It can be used for maintenance of body temperature

(iv) It is served as a medium of transportation of nutrients

(v) It helps in excretion of metabolic waste products from the body e.g. urine

(vi) It is the basis of body secretion from endocrine gland

(vii) It helps in the maintenance of the osmotic content of the body

BALANCED DIET

This is a diet containing the correct proportion or the right amount of all six food substances required by an organism. The balanced diet must contain the six food classes such as carbohydrate, proteins, fats and oil, minerals, vitamins and water

DIGESTIVE ENZYMES

These are organic catalyst which are complex protein substances that are manufactured by living cells. They accelerate metabolic reactions without changing their composition in the process. Enzymes are produced by both plants and animals. Enzymes may be named according to the process in which they are involved processes like photosynthesis, respiration and digestion and enzymatic in nature.

Characteristics of Enzymes

(i) Enzymes are specific in their actions

(ii) Only small quantity of an enzyme is required to catalyse a reaction

(iii) Enzymes have a specific temperature range above or below which they work become inactive or denatured. They work best at about 37⁰c

(iv) Enzymes do not lose their chemical composition at the end of a reaction

(v) Enzymes are affected by the acidity and alkalinity (PH) of a medium. An enzyme which is active in an acidic medium e.g. pepsin become inactive in alkaline medium and vice versa.

(vi) Enzymes are usually involved in reversible reaction

(vii) Enzymes are produced by glands of the system that require that activities e.g. digestive enzymes are produced by various gland of digestive system

(viii) Substance called inhibitor can stop the activities of enzymes

(ix) The activities of enzymes can be enhanced when they are joined to a co-enzymes e.g inorganic subsistence such as phosphorus.

CLASSES OF ENZYMES

PROTEASES– These are protein digesting enzymes. They are present in the stomach e.g Renin and Pepsin and also in the duodenum (Trypsin) and ileum (Erepsin). They all digest protein and break them into smaller unit.
AMYLASE- They are enzymes which digest starches and sugars and convert them to glucose. Ptyalin or Salivary amylase is produced by salivary gland in the mouth. It can converts starch to maltose.

Pancreatic amylase is produced in the pancreas. It converts starch to maltose, sucrose and lactose. It also converts these double sugars to their final products. Maltose to glucose, sucrose to fructose and glucose and lactose to galactose and glucose.

LIPASES– These are enzymes which convert and oils to fatty acid and glycerol. They are produced in the pancreas and ileum.

Digestive enzymes and functions

Enzymes	Sources	Location	Substrate acted upon	Effect/product
Ptyalin	Salivary gland	Mouth	Starch	Partial hydrolysis of starch to maltose
Renin	Gastric gland	Stomach	Proteins	It coagulate or curdle milk
Pepsin	Gastric gland	Stomach	Proteins	It convert solid protein to peptones
Pancreatic Lipase	Pancreas	Duodenum	Fat and oils	It converts fat and oils to fatty acid and glycerol
Amylase	Pancreas	Duodenum	Starch	It converts starch to maltose
Trypsin	Pancreas	Duodenum	Proteins or peptones	It converts proteins or peptones to polypeptide
Erepsin	Succus entricus	Small intestine	Poly peptide	It converts polypeptide to amino acid

ASSIGNMENT

1a. Define enzyme

State 5 characteristics of enzymes