ByZaib-Ur-Rehman

Lecturer Department of Poultry Science

PMAS, Arid Agriculture University, Rawalpindi, Pakistan

To get balanced nutrition it is not necessary to eat expensive food. Apart from being inexpensive, egg is a wholesome food which contains balanced amount of essential nutrients like protein, vitamins and minerals. All these nutrients are in highly protected form. Nature has provide the protection to egg, from deterioration, by egg shell then by shell membranes and finally by the antibodies present in the egg.

Nutritional Composition of an EggNutrient (unit)

WholeEgg

Weight 60gWater (percentage) 65-68.5Calories (kcal) 70Protein (g) 6.3Carbohydrate (g) 0.36Total fat (g) 4.8Polyunsaturated fat (g) 1Monounsaturated fat (g) 1.8Saturated fat (g) 1.6Cholesterol (mg) 185Choline (mg) 126Vitamin A (IU) 270Vitamin D (IU) 41Vitamin E (mg) 0.5

Chicken egg is one of the most common foods all over the world

Eggs have biological value of 93.79 % comparable values are 84.5 % for milk, 76 % for fish and 74.3 % for beef

Eggs really are the best protein that can be bought by spending money, and it has all those other valuable vitamins and minerals too

Its major parts for human consumption are albumin and yolk

Albumen also known as egg white, Albumen accounts for most of an egg's liquid weight, about 67%

Albumen comprises more than half the egg's total protein, niacin, riboflavin, chlorine, magnesium, potassium, sodium and sulfur

The albumen encompasses four alternating layers of thick and thin consistencies

From the yolk to external, they are designated as the inner thick or chalaziferous white, the inner thin white, the outer thick white and the outer thin white. Egg white tends to thin out as an egg ages because its protein changes in character.

Yolk or yellow portion makes up about 33% of the liquid weight of the egg

It contains all of the fat in the egg and a little less than half of the protein

With the exception of riboflavin and niacin, the yolk contains a higher proportion of the egg's vitamins than the white

All of the egg's vitamins A, D and E are in the yolk Egg yolks are one of the few foods naturally containing

vitamin D The yolk also contains more phosphorus, manganese, iron,

iodine, copper, and calcium than the white, and it contains all of the zinc.

The yolk of a large egg contains about 59 calories

Yolk fatty acids have a central role in egg nutritionalproperties evaluation

The yolk weight of a typical chicken 60g egg is 20g, ofwhich 50% is solid matter and 50% is water; it contains6g of lipids and 3g of proteins

Egg lipid classes are: Triacylglycerol’s (65%),Phospholipids (28.3%), Free Cholesterol (5.2%),Cholesterol ester and free fatty acids (traces).

The term “cholesterol” refers to a group of chemicals containing both protein and fat components (lipoproteins) that are present in every living cell and perform following functions. Aids in hormone production.

Essential for brain and nerve development.

Starting material from which the liver produces bile acids, necessary for digestion of fats.

Key substances in the wall of every cell.

Precursor for production of steroid hormones by the adrenal glands and gonads.

They are an essential component of all cells in the body of chickens, humans and all animals

They do not occur in plants

Cholesterol content of eggs became an important issue for consumers in the 1970's and 1980's when it was discovered that, among the human population, those with high cholesterol levels in their blood (usually referred to as “serum cholesterol”) were at greater risk of heart attacks and/or atherosclerosis

While this statistical connection is an important one in terms of human health, there have been decisive slipups in its explanation. There is effectively no link between the cholesterol most people consume in their diets, and their serum cholesterol levels (Hu et al., 1999).

There are two types of cholesterol, Low density lipoproteins (LDL) and High density lipoproteins (HDL)

Low density lipoproteins also called bad cholesterol carry most of the cholesterol in the blood. The cholesterol and fat from the LDLs are the chief source of dangerous build up and obstruction in the arteries. Thus, the more LDL cholesterol in the blood causes the greater chance of heart diseases

Nature has provided good cholesterol (HDL) in the egg yolk, it is in minute quantity but very effective

High density lipoproteins also named as good cholesterol, this cholesterol goes back to liver, which leads to its removal from the body so HDLs help to keep cholesterol from building up in the walls of arteries, if level of good cholesterol is low, risk of heart diseases is greater

Egg yolk consist of 68 percent LDL and 16 percent HDL.

The commonly used drugs to lower blood pressure stop the production of the hormone angiotensin to narrowing the body's blood vessels

The scientists identified several different peptides in boiled and fried eggs that act as potent Angiotensin Converting Enzyme (ACE) inhibitors

The scientists showed that enzymes in the stomach and small intestine produce these peptides from eggs

The protein produced by stomach enzymes after coming in contact with eggs acts in the same way as blood pressure lowering drugs

In conclusion eggs do not have any side effect on heart, blood pressure and serum cholesterol; and are safe in every aspect.

Chicken eggs are abundant in antibodies such as IgY which can treat human rotavirus, Escherichia coli, streptococcus, pseudomonas, staphylococcus and salmonella infections.

The nutritionally balanced, high biological value of the egg is an excellent growth promoter in children

It is the best natural nutritional support for convalescents, especially those with tuberculosis or AIDS related infections. Lipoprotein and other high biological value proteins in the egg act as excellent growth promoters in children and animals.

Egg albumen can be used as an remedy in cases, where certain toxins and irritants may have been accidentally consumed. It protects the mucous membranes of the stomach and intestine, and prevents ulcer formation.

Studies carried out at Japan's Kyoto University have revealed that egg contain the two substances—Lumiflavin and Lumichrome. These two substances, along with sulphoraphane, have the ability to restrict the multiplication of cancer-inducing viruses and also prevent the change of normal to cancerous cells. These compounds are also natural antioxidants.

The Gl-globulin lysozyme, the G2 and G3-globulins, ovomacroglobulin, antibody "IgY" as well as other natural antimicrobials and immunostimulants in the egg may prolong the lives of those with AIDS, not only due to their high nutritional value but also because of their antimicrobial properties.

Egg yolk and albumen chalaza are rich sources of "sialic acid,” which has powerful antimicrobial, anti-inflammatory and antiviral properties, and hence is used in the cure of Helicobacter pylori and other microbial infections causing ulcers, colon cancer, gastritis and enteritis.

Lutein and zeaxanthin from eggs helps in maintaining the eye health and reducing the risks of age-related macular degeneration, a major cause of irreversible blindness.

Vitamin E, organic selenium and other antioxidants in functional eggs prevent oxidation, ageing, and formation of plaques in arteries.

The high-quality protein in eggs helps you to feel (prolong a feeling of fullness) full longer and stay energized, which contributes to maintaining a healthy weight.

A single egg contains 50 % of your daily required intake of Choline which is essential for normal functioning of all cells, including those involved with metabolism, brain and nerve function, memory, and the transportation of nutrients throughout the body. Choline also helps to prevent birth defects, as well as helps promote brain and memory development in infants.

Different vitamins and minerals play a very important role in the body which are as follows

Riboflavin: Helps to produce energy in all the cells of the body

Pantothenic Acid: Helps to breakdown food and assists body cells in producing energy.

Phosphorus: Essential for healthy bones, teeth and cell membranes. Phosphorus is also required for energy production in the body. It is also essential for healthy bones, teeth and cell membranes. Phosphorus is also required for energy production in the body.

Vitamin D: Works with calcium to strengthen bones and teeth.

Calcium: Helps to build and maintain strong bones and teeth. This mineral also plays an important role in nerve function, muscle contraction and blood clotting.

Importance of Egg Hen eggs are an important source of nutrients and a major

source of active molecules

Modification of the nutrient content of the egg bymodifying the diet of the hen has led to “ designer eggs ”that serve as functional foods and nutraceuticals

With a hen laying more than 300 eggs per year, and withthe vast infrastructure of the layer industry housing morethan 100,000 hens, the hen holds great promise as a low -cost, high - yield bioreactor of active molecules usable bythe food, pharmaceutical, and cosmetic industries.

Importance of Egg Eggs from all species of poultry consist of 52 – 58%

albumen, 32 – 35% yolk, and 9 – 14% shell and itssupporting membranes

The egg contains all the essential components, such asproteins, lipids, vitamins, minerals, carbohydrates, andgrowth factors required by the developing embryo

Egg components have been attributed diversebiological activities, including antimicrobial andantiviral activity, protease inhibitory action, vitamin -binding properties, anticancer activity, andimmunomodulatory activity

Importance of Egg Albumen proteins identified to date belong to several functional

protein families, including serpin, transferrin, protease inhibitors Kazal, glycosyl hydrolases, lipocalin, bacterial permeability - increasing protein, clusterin, cysteine protease inhibitor, VMO - 1, and uPAR/CD59/Ly6/snake neurotoxin folatereceptor (Gu é rin - Dubiard et al. 2006 ).

Proteins in the egg white occur both as free and conjugated forms. The latter are formed when the protein is modified by prosthetic groups such as lipids and carbohydrates to yield lipoproteins and glycoproteins, respectively (Kovacs - Nolan et al. 2005 )

The major egg white proteins include ovalbumin, ovotransferrin(conalbumin), ovomucoid, and ovomucin. Other egg white proteins include lysozyme, ovoinhibitor, ovomacroglobulin(ovostatin), cystatin, and avidin (Sugino et al. 1997 )

Biological Activities of Egg White Components