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ANIMAL NUTRITION

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Animal Nutrition

Nutrients & Diet Digestive System

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Lesson 1Learning Objective1.List the chemical elements which make up carbohydrates,

fats and proteins.2.List the principle sources of, and dietary importance of

carbohydrates, fats, proteins, vitamins (C and D), mineral salts (calcium and iron), fibre (roughage) and water.

Outline Need for food Carbohydrates Fats Proteins

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Need for Food

•To provide energy for vital activities of body•To replace energy lost•To make new cells and tissues•To repair tissues•To maintain healthy body•To prevent deficiency diseases

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7 Classes of Food

•Carbohydrates•Fats•Proteins•Vitamins•Dietary fibre•Mineral Salts•Water

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Ingredients Nutrients presentBread Carbohydrate, vitamins, fibreLettuce Carbohydrate, protein, vitamins, fibre,

minerals, waterTomato Carbohydrate, protein, vitamins, fibre,

minerals, waterBeef Proteins, fats, mineralsCheese Fats, proteins, vitamins, minerals

(calcium)

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Carbohydrate

Sources:

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Carbohydrate

Uses of carbohydrates:• Source of energy (17 kJ/g)• Formation of nucleic acids (DNA)• To be converted to other organic

compounds, e.g. amino acids and fats• Formation of supporting structures, e.g.

cellulose cell wall.

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Carbohydrate

Chemical elements:• Carbon (C)• Hydrogen (H)• Oxygen (O)

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Carbohydrate

Carbohydrate

Monosaccharide PolysaccharideDisaccharide

E.g. glucose, fructose, galactose

E.g. starch,glycogen,cellulose

E.g. maltose, lactose, sucrose

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Monosaccharide

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Disaccharide

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Polysaccharide

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Stored food• In animals, glucose is stored in the form of glycogen.• In plants, glucose is stored in the form of starch.

Why are glycogen and starch suitable as storage materials?

– Easily hydrolysed to glucose when needed– Large molecules and insoluble in water hence they do not

change the osmotic pressure in cells– Structures are compact so they occupy less space

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Fats

Sources:

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Fats

Uses of fats:• Source of energy (37 kJ/g)• Insulating material to prevent

excessive heat loss• Prevent water loss from skin's

surface, by producing oily secretions over the surface.

• A solvent for fat-soluble vitamins and hormones

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Fats

Chemical elements:• Carbon (C)• Hydrogen (H)• Oxygen (O)

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Fats

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Fats

Fats

Saturated Unsaturated

Fats that contain

fatty acid chains

with only single bonds

Fats that contain

fatty acid chains

with doublesingle bonds

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Saturated Fats

• Sources: Meats, dairy products, chips.• Not heart-healthy• Can raise LDL cholesterol (“bad”

cholesterol)

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Unsaturated Fats

• Sources: Nuts, avocadoes, olives• Heart-healthy• Can lower LDL cholesterol (“bad”

cholesterol) and raise HDL cholesterol (“good” cholesterol)

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Proteins

Sources:

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Proteins

Uses of proteins:• Source of energy (17 kJ/g)• Synthesis of new protoplasm• Synthesis of enzyme and hormone• Synthesis of antibodies to combat

diseases

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Proteins

Chemical elements:• Carbon (C)• Hydrogen (H)• Oxygen (O)• Nitrogen (N)• Sulphur (S)• Phosphorus (P)

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Proteins

Proteins are comprised of amino acids linked together.

There are 20 different amino acids used to make proteins.

Amino acids can be broken into 2 types:• Essential amino acids (8)– Amino acids that cannot be synthesised by human body.

• Non-essential amino acids (12)– Amino acids that can be synthesised by human body.

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ProteinsDeficiency:Kwashiorkor

Signs and symptoms:• Swollen abdomen• Enlarged liver• Changes in pigmentation of skin and hair• General drowsiness• Cracked and scaly skin

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Lesson 2Learning Objective1.List the principle sources of, and dietary importance of

carbohydrates, fats, proteins, vitamins (C and D), mineral salts (calcium and iron), fibre (roughage) and water.

2.Describe the deficiency symptoms of vitamins C and D and mineral salts; calcium and iron.

Outline Vitamins Mineral salts Dietary fibre/roughage Water

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Vitamins Organic compounds• Not built in a definite pattern• Not energy providing• Required in small quantities for normal health and

development• 15 or more vitamins– Water-soluble

• Cannot be stored in the body

– Fat-soluble• Can be stored in the body

• Lack of vitamins leads to vitamin-deficiency disease

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Vitamin C Water-soluble vitamin Easily destroyed by heat, excess is

excreted by body Sources: Fresh citrus fruits, fresh green

vegetables, tomatoes, papaya. Importances:

Promotes healthy gums and teeth Maintenance of healthy epithelial tissue Aids in iron absorption Aids in healing wound

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Vitamin C Deficiency: Scurvy

Signs and symptoms Bleeding under skin Swollen of joints Swollen, bleeding gums Poor healing of wounds

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Vitamin D Fat-soluble vitamin Sources: Fish liver oils, egg yolk, liver,

butter, milk, cheese, uv rays in sunlight (ergosterol in skin vitamin D

Importances: Promotes strong, healthy bones and

teeth Aids in the absorption of calcium and

phosphorus from intestine.

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Vitamin D Deficiency: Rickets– Poor teeth and bone formation– Soft weak bones– Bowed legs and knock knees– Osteoporosis

Excess: Calcification of soft tissues in arteries, kidneys, lungs and brain.

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Mineral Salts Inorganic salts. Do not provide energy. Required in small quantities. Examples are calcium and iron.

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Calcium Sources: Milk, cheese, cereals, bread, eggs,

lean meat, green vegetables. Importances:

Bones and teeth formation Blood clotting Muscle contraction Pregnancy and lactation

Deficiency: Rickets Brittle bones and teeth Inability to clot

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Iron Sources: Liver, egg yolk, meat, bread, flour

and green vegetables Importances:

Formation of protein haemoglobin in red blood cells

Formation of protein myoglobin in muscle cells

Deficiency: Nutritional Anemia Tiredness Breathlessness

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Dietary Fibre/Roughage Indigestible fibrous materials present in

diet, e.g. cellulose Sources: Fruits, vegetables, barley, brown

rice and whole-meal bread. Importances:

Helps peristalsis and prevent constipation Provides bulk to intestinal contents

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Water Essential component of protoplasm Importances:

Acts as a medium for chemical and metabolic reactions to occur

Transporting agent for digested food substances, excretory products, and hormones

Acts as a medium for transport of dissolved food substances and nitrogenous wastes in blood

Helps regulate body temperature Essential component of digestive juice, blood and

lubricant found in joints.

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Lesson 3Learning Objectives1.Understand the concept of a balanced diet.2.Explain why diet especially energy intake, should be related to age, sex and

activity of an Individual3.State the effects of malnutrition in relation to : starvation, heart disease,

constipation and obesity.4.Discuss the problems that contribute to famine (unequal distribution of food,

drought and flooding, increasing population).

Outline Balanced diet Factors affecting diet Effects of malnutrition Famine

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Balanced Diet

A balanced diet is a

type of diet which

consists of all food at the correct amount.

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Factors Affecting Diet1. Age

Teenagers need more energy than young children or adults. This is because they are actively growing and therefore needs energy for growth.

2. GenderMen use up more energy than women. This is because men have more muscle tissue than women (muscle tissue uses up more energy)

3. Physical ActivityThe more active a person is, the more energy he needs.

Can you think of any more factors?

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Malnutrition

• Unbalanced diet.• It is caused by

1. eating too much of one or more food types.

2. eating too little of a particular food.

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Eating too much of one or more food types

1. Obesity The state of being extremely overweight.

This is because of eating too much carbohydrates and fats. Excess carbohydrates are converted to fats and stored in the body.

Being overweight / obese often lead to: Hypertension (high blood pressure) Diabetes (high blood sugar) Coronary heart disease

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2. Coronary Heart Disease Fats deposited on the inside walls of coronary

arteries reduce or prevent blood flow to heart muscles (artherosclerosis), thus the heart muscles cannot get enough oxygen. Heart muscles stop contracting, leading to chest pain (angina) and heart attacks.

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Eating too little of a particular food

1. Vitamin and mineral deficiency diseases are examples of this type of malnutrition.

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2.Constipation● Constipation is a condition in which a person

finds it difficult to remove the waste matter (faeces) from the large intestine (colon).

● This is due to eating too little fibre. ● It may stimulate cancer growths (colon cancer)

in the long term.3.Starvation

● Severe reduction in food intake for an extended period of time.

● It can cause permanent organ damage and can be fatal.

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Famine

• Famine is the widespread scarcity of food.• Hundreds of millions of people suffer from

famine.• This is caused by several factors:

– Drought and flooding– Unequal distribution of food– Overpopulation