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HEN EGGS BEYOND THE NUTRITIONAL VALUE Eid, Y. Z. Dept. of poult. Prod., Kafr El-Sheikh Fac Agric. Tanta Univ. 33516 Kafr El-Sheikh Egypt e-mail: [email protected]

Abstract: No doubt that hen eggs consider important source for human feeding. Good taste and numerous applications in preparing a wide variety of foods lead to increase the egg consumption in the world year by year. The egg functional proteins have been recognized as one of the highest quality proteins in digestibility as well as amino acid composition. Hen eggs have been evaluated as a source of essential fatty acids, and several vitamins and minerals thus, daily intake of hen eggs supply nearly the amount recommended of our daily allowance of such materials. These advantages qualify hen eggs to be one of the promising functional foods in the coming decades according to their relation to the human health. Being a functional food has been revealed new trends in egg production like designer eggs and specialty eggs. This article reviews the nutritional and functional properties of the eggs, and throws the light on the new trends of production and uses of hen eggs as nutraceuticals. Key words: hen eggs, human health, functional food, designer eggs, nutraceuticals.

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No doubt that hen eggs consider important source for human feeding. Good taste and numerous applications in preparing a wide variety of foods lead to increase the egg consumption in the world year by year. Egg Nutrition: Hen eggs constitute a rich array of nutrients. High quality protein promoted eggs to be on the top among protein sources. An egg also provides a wide varity of nutrients. This includes fats beside adequate amounts from essential vitamins and minerals which can make a significant contribution to a healthy diet. Egg is economical source of high quality protein, an important component in the diets of the elderly, low-income families, growing children and people limiting calories for weight loss purposes. The chemical composition and the contribution of eggs to the daily recommended allowance are presented in table (1). Easily digested eggs are soft too, so they are a good protein food choice for the very young as well as anyone with chewing problems or ill-fitting dentures. Some egg dishes, such as creamy custards, are especially well suited to those of us who need especially easy-to-swallow foods. One large egg contains:

% of Recommended Daily Intake:

Energy

71 cal

Vitamin A

8%

Protein

6g

Vitamin D

2%

*Fat

5g

Vitamin E

6%

Carbohydrates

0g

Thiamin

2%

Polyunsaturates

0.7 g

Riboflavin

15%

Monounsaturates

2.0 g

Niacin

6%

Saturates

1.5 g

Vitamin B6

2%

Cholesterol

190 mg

* Only 1.5 grams is saturated fat.

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Folate

15%

Vitamin B12

30%

Pantothenic Acid

15%

Phosphorus

6%

Magnesium

2%

Iron

2%

Zinc

5%

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Recently, research has shown that eggs supply significant amounts of carotenoids that may play a role in disease prevention. Eggs are a source of highly bioavailable forms of the carotenoids lutein and zeaxanthin. These antioxidant-like compounds have been shown to help in the prevention of macular degeneration, a leading cause of blindness in the elderly, and have been associated with lower risk of cataract extraction. Consumers may not yet be aware that egg yolks are rich in highly bioavailable forms of both these antioxidants. These antioxidants convey potential health benefits (Elizabeth Applegate, 2000). Another less familiar nutrient in eggs is choline, a compound which is critical for brain and memory development (Subcommittee on the Tenth Edition of the RDAs, 1989). Only recently formal dietary recommendations were made for such nutrient (Institute of Medicine and National Academy of Sciences USA, 1998). Because research on choline is somewhat limited, and study findings have not yet caught the attention of journalists and reporters, consumers know little about choline or its food sources, including eggs (Steven H. Zeisel, 2000) Egg Consumption: Egg consumption averaged 190 eggs per capita in high-income countries, compared with 109 in middle and 31 in lowincome countries in year 2000 (FAO, 2002). Per capita egg consumption rose rapidly in the 1970s in the three income groups (fig. 1). However, from 1980-2000, consumption declined by 14 percent in the high income group this may refer to health fear from egg’s cholesterol and its effect on health, but this assumption is daughtful (Herron and Fernandez, 2004). This trend was basically unchanged in low-income countries, but showed nearly a 10-percent increase in middle-income countries. Egg Consumption in Egypt: During the 1970s and 1980s, egg consumption in Egypt rose on a per capita basis and reached a peak in the late 1980s, due to heavy government subsidies designed to encourage egg and poultry consumption as an inexpensive protein source to people in low-income. However, after the elimination of producer and consumer subsidies, consumption declined sharply, reaching as low as 54 eggs per capita in 1995, then rebounding to 62 eggs (about 3 kilograms) per person in 2000. Currently, Egypt's per capita egg consumption is below the world average and also below levels in many other middle-income countries. In fact, it is closer to low-income countries' average rather than the middle-income countries' average (fig.2). Egg imports have been banned since 1989, except for

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hatching eggs. At their 1982 peak, egg imports amounted to 12,000 tons, about 11 percent of total domestic supply. Imports averaged less than 6 percent of total consumption during the 1980s, before being banned to protect domestic producers. Exports, mostly to neighboring countries, are small, fluctuating between 20 and 145 metric tons per year during the 1990s. Egg Production in Egypt: Egg production made substantial progress during the 1970s, growing by 6.8 percent a year, more than double the 2.9-percent world growth rate. In the 1980s, the annual growth rate of 5.9 percent was still larger than the 3.7-percent world rate, and in the 1990s, both rates were equal at 4 percent annually. The high growth rate of the 1970s was mainly due to government feed subsidies. The government also helped producers by establishing public enterprises with the primary purpose of introducing modern technology and skilled management into the industry. Production peaked in the late 1980s with the benefit of government price subsidies to both producers and consumers. These subsidies were lifted in 1988, however, causing a setback for the egg industry. Egg production rose at a steady rate during the 1990s. In 2000, production climbed back to about 4 billion eggs, still 8 percent below the 1980s peak. Commercial operations supply 70 percent of total output and the backyard Balady operators produce the remaining 30 percent. The number of laying hens was estimated at 17.2 million in 2000, of which 11 million were in the commercial sector and the remainder was mostly in the backyard Balady sector. Each laying hen in a commercial operation lays about 240-270 eggs per year, compared with only 170-180 eggs for the Balady breed. Eggs produced from international breeds weigh 50-56 grams, while Balady eggs average 35-40 grams. Some functional properties of eggs: The functional properties of eggs have been utilized by cooks, chefs, and food manufacturers. The availability of eggs at a reasonable price has been a significant factor in the continued usage of eggs in cookery. The roles of eggs in food preparation are numerous. 1) One of the most common functions of liquid egg is its ability to coagulate or solidify when heated. This ability is of importance in the preparation of cakes, frostings, sauces, hard-cooked eggs, scrambled eggs, and fried eggs. 2) Aeration and structural improvement of the egg when whipped creates foam in products resulting in lighter and airier products like meringues, mousses, and cakes such as sponge food. 3) The emulsifying capacity of the egg yolk is utilized in the preparation of salad dressings

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and sauces. The phospholipids and lipoproteins serve as surface active agents allowing emulsions such as oil and water. These three functions of eggs are generally recognized by most people, but a recently other functions of importance in food preparation have been released (American Egg Board, 1998). These are: 4) adhesive properties used to stick ingredients such as seeds and grains to food products such as health bars, variety breads, and snacks. In the days of bottled soft drinks, the cork liner of the bottle caps was glued in place using egg albumen. 5) Of eggs in food formulation. Eggs improve on the texture and acceptability of products 6) such as microwavable foods that go through a freeze-thaw cycle. Binding by eggs 7) holds food products together as in snack. The binding is really the result of the coagulation of the egg. Clarification of and juices 8) is a commercial application of this property of eggs. The desired brown color of baked products 9) such as rolls, buns, and variety breads is another function of eggs. Eggs are used to contribute color 10), a rich yellow, to baked goods, noodles, and custards. Closely allied to color is the glossy appearance 11) of some baked goods. An egg white wash, either sprayed or brushed on sweet breads, cookies, gives the surface a shine after baking. Flavor 12) of eggs can be modified by feeding of various materials. Eggs carry and meld some flavors, improve others, and impart a desirable egg flavor to custards. The ability of eggs to lock in flavor and aroma by coating of baked goods and snacks is an application in many bakeries. Egg is often an ingredient in batters for deep fat frying of chicken to get the same effect. Eggs hold moisture in variety breads and rolls 13) to help increase the fresh shelf life. Mouth feel is an important characteristic of foods in gaining acceptance. Eggs provide substantial body to a variety of breads, sweet goods, and puddings 14). Eggs act as a pH buffer 15) to maintain a stable pH so that food product formulations won’t be disrupted. Shelf life extension is an important factor in all food distribution. In commercial bread formulations, eggs keep starch molecules moist and fresh 16). From this list, it is readily recognized that the egg industry and the baking industries are partially dependent upon each other (Stadelman, 1999). Functional foods : Background on functional foods: The primary role of diet is to provide sufficient nutrients to meet the nutritional requirements of an individual. There is now increasing scientific evidence to support the hypothesis that some foods and food components have beneficial physiological and psychological effects over and above the provision of

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the basic nutrients. Today, nutrition science has moved on from the classical concepts of avoiding nutrient deficiencies and basic nutritional adequacy to the concept of "positive" or "optimal" nutrition. The research focus has shifted more to the identification of biologically active components in foods that have the potential to optimize physical and mental well being and which may also reduce the risk of disease. Many traditional food products including fruits, vegetables, soya, whole grains, eggs and milk have been found to contain components with potential health benefits. In addition to these foods, new foods are being developed to enhance or incorporate these beneficial components for their health benefits or desirable physiological effects. What are functional foods? The concept of functional foods was born in Japan. In the 1980s, health authorities in Japan recognized that an improved quality of life must accompany increasing life expectancy for the expanding number of elderly people in the population if health care costs were to be controlled. The concept of foods that were developed specifically to promote health or reduce the risk of disease was introduced. Functional foods may be defined as foods or food ingredients that may enhance health through their provision of a physiological benefit beyond traditional nutrients. Examples of functional foods include foods that contain specific minerals, vitamins, fatty acids or dietary fiber, foods with added biologically active substances such as phytochemicals or other antioxidants and probiotics. Why do we need functional foods? Consumer interest in the relationship between diet and health has increased substantially in Europe (Diplock et al., 1999) and all over the world. There is much greater recognition today that people can help themselves and their families to reduce the risk of illness and disease and to maintain their state of health and well being through a healthy lifestyle, including the diet. Ongoing support for the important role of foods such as fruits and vegetables, eggs, milk and wholegrain cereals in disease prevention and the latest research on dietary antioxidants and combinations of protective substances in plants has helped to provide the developments in the functional food market. Trends in population demographics and socio-economic changes also point to the need for foods with added health benefits. An increase in life expectancy, resulting in an increase in the number of elderly and the desire for an improved quality of life, as well as increasing costs of health care, have stimulated governments, researchers, health professionals and the food industry to see how these changes can be

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managed more effectively. There is already a wide range of foods available to today's consumer but now the impetus is to identify those functional foods that have the potential to improve health and wellbeing, reduce the risk from, or delay the onset of, major diseases such as cardiovascular disease, cancer and osteoporosis. Combined with a healthy lifestyle, functional foods can make a positive contribution to health and well being Eggs as functional foods: These eggs are referred to as designer eggs. In the late 1950s a feeding program was developed in the USA to produce eggs with approximately equal levels of saturated, monounsaturated, and polyunsaturated fatty acids. It was likely the first designer egg. More recently, a number of egg producers are offering eggs enriched in n-3 fatty acids (Van Elswyk,, 1998) and vitamin E (Sim, 1998). Docosahexaenoic acid (DHA), a fatty acid generally found in cold water fish, is readily incorporated into egg yolk by the hen when fish oils or other rich sources of DHA are fed. In the human diet, DHA has been claimed to reduce the incidence of coronary problems. This effect is brought about by a significant reduction in collagen-induced platelet aggregation. The DHA in eggs gives benefits to equal levels of DHA from fish oils. Another important role for DHA is in brain and retina development in infants (Hennig and Watkins, 1998). The modification of nutrient content of the egg has led to a number of designer eggs. Government regulations in many countries limit the nutritional or health claims that can be made, as is true in the U.S. The term enriched can only be used in the U.S. if a normal serving will supply 10% more of the recommended daily requirement for the specific nutrient. In recent years, the normal serving was changed from two eggs to one in order to reduce the cholesterol level in a normal serving. The health benefits of supplementary vitamins or minerals has led to a multibillion dollar business in supplying these as pills or enriched drinks. Supplementation of most of these nutrients could be supplied as designer eggs enriched with whatever vitamin or mineral desired, as research reports from around the world have indicated that the level of almost any vitamin or mineral can be influenced by modifying the diet of the hen (Stadelman and Pratt, 1989). A big advantage of this approach is that an overdose is almost impossible, as the hen still produces the egg to reproduce the species and will resist putting toxic levels of any nutrient into the egg. Of course, toxic non nutrient

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materials, such as aflatoxins, may be included in an egg if they are present in the feed. Consider a fluoride-enriched egg for young children to improve tooth structure or a vitamin D-enriched egg for skeletal calcium problems. Designer and Specialty Eggs Designer Eggs: Meeting consumer demands is a constant challenge for the animal food industry. According to the functional foods concepts, many consumers desire somewhat distinct products with respect to safety, healthfulness, freshness, taste, color, etc. To tap into this market, companies have developed several designer and specialty eggs which have appeared on store shelves. The concept of “designer” or “specialty” eggs may be confusing, and often misleading. The coming paragraph is to discuss the types of "new" eggs currently on the market, and some of the misconceptions held by consumers. One of the ways to market a new product is to change the old product. The contents of the chicken egg can be changed in such ways as to be more healthful and appealing to a segment of our consumers who are willing to pay for those changes in the egg. "Designer eggs" are those in which the content has been modified from the standard egg. This modification could be in vitamin content. Designer eggs have been produced that contain higher concentrations of several vitamins. Two vitamins, A and E, are receiving the most interest as components of designer eggs. The vitamin content of the egg is variable and is somewhat dependent on the dietary concentration of any specific vitamin. In addition, the hen does not transfer different vitamins into the egg with equal efficiency. Because of this, the vitamin transfer efficiency and cost of the vitamin must be taken into consideration when determining the economic feasibility of marketing such eggs. Eggs higher in Vitamin E are currently available in stores (Leeson and Caston, 2003). Another modification could be lowered cholesterol. In order for a company to claim a reduce amount of a nutrient the product must have 25 percent less than the normal product standards for that nutrient. A large egg contains approximately 200 - 220 mg of cholesterol. Genetic selection of hens for lowered cholesterol has not been successful in lowering the egg cholesterol content. Research into lowering egg cholesterol has centered mostly on diet and pharmacological drugs. Drugs have been successful in lowering egg cholesterol by as much as 50%. Drugs lower cholesterol in the egg by either inhibiting the

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synthesis of cholesterol in the hen or by inhibiting the transfer of cholesterol from the blood to the developing yolk on the ovary. Today, the drugs which have shown promise in lowering cholesterol are not yet approved for commercial use. Chromium supplementation to laying hen diets at concentrations of less than 1 ppm have been shown to lower egg cholesterol and also improve egg interior quality. Research has also shown that the most effective way to lower egg cholesterol content is to lower the energy consumption of the hen. Another important modification could be fat and fatty acid content. Altering the total fat content in the diet of the hen has little effect on the total fat content of the egg yolk. However, the fatty acid profile (or the ratios of the different types of fatty acids) of egg yolk lipid can easily be changed, simply by changing the type of fat used in the diet. Consumption of polyunsaturated fatty acids has been reported to reduce the risk of atherosclerosis and stroke. Consumption of these fatty acids has also been shown to promote infant growth. Different feeds, such as flaxseed (linseed), safflower oil, marine algae, fish, fish oil, and vegetable oil have been added to chicken feeds to increase the omega-3 fatty acid content in the egg yolk. Omega-3 fatty acid-rich eggs table(2) may provide an alternative food source for enhancing consumer intake of these 'healthy' fatty acids. Evaluation of the eggs during storage indicates that the shelf life of the enriched eggs was comparable to that of typical eggs. There are also designer eggs on the market that contain a lowered saturated to unsaturated fatty acid ratio. Canola oil is commonly used to alter the ratio of saturated to unsaturated fatty acids (Meluzz, et. al., 2003 and Shafey, et. al., 2003). Nutrient values vary depending on the composition of the feed. Note: Changes to the fatty acid profile do not affect the functional properties of the egg.

Modification also could be in mineral content. The shell contains the majority of the minerals in an egg. There are approximately 2,200 mg of calcium and 20 mg of phosphorus in the shell. There has been very little success in changing the calcium and phosphorus content of the albumen and yolk. It is possible, however, to increase the content of selenium, iodine and chromium. This has been done through dietary supplementation of the hen. These three minerals are important in human health. There has been some interest, therefore, in promoting these eggs as designer eggs. Another modification could be pigment content. The color of the yolk is a reflection of its pigment content. In addition, the type of

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pigment in the egg and its concentration are directly influenced by the dietary concentration of any particular pigment. Consumer preferences vary greatly on yolk color, even in the same country. Color is described on the basis of the Roche Color Fan. Yolk colors may be obtained from natural raw materials. Natural sources can be from plants such as marigold, chili, or corn. Recent research has shown that eggs may be beneficial in preventing macular degeneration, a major cause of blindness in the elderly. A recent study indicated that higher intake of carotenoids reduced the risk of age-related macular degeneration. The most effective carotenoids were lutein and zeaxanthin, which are commonly found in dark-green leafy vegetables, such as spinach. Most of the carotenoids in egg yolk are hydroxyl compounds called xanthophylls. Lutein and zeaxanthin are two of the most common xanthophylls found in egg yolk. The egg processing industry has routinely produced highly pigmented yolks for use in bakery products, pasta and mayonnaise. Perhaps there would be a market for eggs having a higher level of lutein and zeaxanthin. Speciality eggs (Jacob and Miles, 2001): Eggs which have a special attribute which makes them attractive to a niche market are known as "speciality" eggs. A number of these eggs are available in stores. The packaging used, however, can often be misleading. (1)-Cage-free or Free-roaming: The majority of commercial egg layers are housed in cages. Caging of hens has benefits for the birds, consumers and producers. The separation of birds from their faeces is advantageous in reducing the risk of disease and parasitic infections. Working conditions for producers are often better with cages than with other systems: automation is possible reducing the amount of physical labor, and dust and ammonia are usually less prevalent. Eggs are laid on the sloping floor of the cage so that there is minimal contact between the egg and the hen. This decreases the possibility of bacterial contamination of the egg. With regard to the welfare of the laying hens, cages have both advantages and disadvantages. While the issue of cages and animal welfare is still being debated, there are some consumers who prefer to purchase eggs produced from hens that are not kept in cages. In order to meet this niche market, some producers raise their birds in a "cage-free" or "free-roaming" system. It is important to note that "cage-free" does not mean that the birds are raised outdoors. Typically the birds are maintained on the floor of a poultry house. The higher production costs associated with this type of management system are reflected in the higher price for the eggs. The price of "cage-free"

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eggs is often twice that of regular eggs. Often the packaging of "cagefree" eggs can mislead the consumer about the product they are purchasing. It is common to see designs on the egg cartons including chickens roaming free outdoors. This is not the case with "cage-free" eggs. The hens are still maintained indoors, just not in cages. (2)-Free-range: "Free-range" eggs are produced from hens that are allowed to graze or roam outdoors. It is not necessary, however, for the hens to be outdoors all the time. Typically, the hens are housed in a poultry house that has access to the outdoors. The hens have the ability to go outdoors during the day, although they can also choose to stay indoors. The flock is usually locked indoors at night to protect the hens from predators. There is no set standard on how much range must be available for the hens.

(3)-Pasture-raised: Pasture rearing of chickens is a modification of the free-range system. The birds remain on pasture all the time, but are confined within a portable pen. The pen is moved daily to give the birds access to fresh pasture. The portable pen usually has a portion covered to protect the hens from the elements. (3)-Organic: Until recently there was no set standard for the production of organic poultry products. The USDA is currently working on developing legal standards. To be certified organic, the eggs must be produced from hens that have been fed certified-organic feed which was produced without synthetic pesticides or herbicides, antibiotics, or genetically-modified crops. In addition, no synthetic pesticides can be used to control external and internal parasites. Typically, organic eggs are also produced from hens in cage-free systems. Nutrient stability in designer egg There are 2 major antioxidant constituents of the egg, vitamin E and lutein, are stable during egg boiling. In the designer eggs a combination of high levels of two antioxidants, vitamin E and lutein, significantly decreased melanoaldehyde MDA formation as a result of Fe-stimulated lipid peroxidation, in spite of the high content of the highly unsaturated DHA in hen's egg. Similarly, egg enrichment by vitamin E and carotenoids decreased cholesterol oxidation in egg lipids exposed to nitrogen oxide (Lai et al, 1996) or during egg powder preparation (Lai et al, 1996a). Vitamin E enrichment of the egg yolk prevents carotenoids from oxidation as well (Lai et al, 1996a). Thus it

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seems likely that the combination of two antioxidants, namely vitamin E and lutein accumulated in egg yolk, may improve the storability of the designer eggs compared to normal table eggs, even in the presence of enhanced levels of DHA. Pharmaceuticals and Nutraceuticals application of eggs The hen, like all animals, produces antibodies to neutralize the antigens (viruses, bacteria, etc.) to which it is exposed to each day. These antibodies circulate throughout her body and are transferred to her egg as protection to the developing chick. Immunologists are taking advantage of the fact that the hen can develop antibodies against a large array of antigens and concentrate them in the egg. Specific antigens are now being selected and injected into the hen that develops antibodies against them. As new biotechnology knowledge is gained in this area, designer eggs in the future may be produced that result in a range of antibodies for treatment against snake venoms to the countering of microorganisms which cause tooth decay. Many of the research studies relating to utilization of the egg as a carrier of special nutrients or using the egg as the source of specific chemicals or pharmaceuticals were reported. The researchers reported on fractionation of the egg into lysozyme, avidin, phosvitin, and other chemicals with known benefits to improve human well-being. Scialic acid and scialoligosaccharides are being isolated from eggs on a commercial scale in Japan (Juneja, 1998). Scialoligosaccharides are a significant constituent of mother’s milk and is likely the first line of defense against pathogens, viruses, and toxins. A preparation of egg yolk scialoligosaccharides was reported to inhibit rotavirus both in vitro and in vivo. Rotavirus is a major pathogen of infectious gastroenteritis of infants. Molecular modification of egg proteins was accomplished. Other possible medical applications are being investigated. The enrichment of the egg yolk with conjugated linolenic acid (CLA), which is an isomeric mixture of C18:2 fatty acids having conjugated double bonds, is an example. CLA isomers occur naturally in dairy and red meat products (Watkins, et. al., 1998). They possess anticarcinogenic properties, including inhibition of stomach cancer in mice, suppression of mammary tumors in rats, and inhibition of cancer cell proliferation. A protein product derived from eggshell membranes that adheres to and enhances growth of human skin fibroblasts and increases the production of Type III collagen, a product rich in the skin of infants. This egg membrane protein is currently being used as a raw material in many cosmetics in Japan. Egg yolk lecithin contains an

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abundance of phosphatidylcholine, which is one of the major phospholipid components of the cellular membrane. Phosphatidylcholine serves as a precursor for acetylcholine, a neurotransmitter that has been implicated in learning and memory. A Japanese research group has reported that phosphatidylcholine, combined with cobalamine (vitamin B12), may slow the progress of or even contribute to the prevention of Alzheimer’s disease. Such a food supplement is being sold in Japan. Finely powdered eggshell is being utilized as a calcium source for humans, especially senior citizens, as the absorption is greater than conventional calcium sources. The finely ground eggshell is being used as a calcium enrichment ingredient in some breads and confections (Sugura, 1998). The possibilities for new developments are limitless. An unidentified worker with transgenic animals has suggested planting a gene in the hen’s chromosomes that could be triggered to inhibit the synthesis of cholesterol by the hen thus producing a cholesterol- “free” egg. The triggering mechanism could be administered by the inclusion of a particular chemical in the feed supply. In this way, normal eggs could be produced for reproduction of the strain when desired and the cholesterol-free egg could be produced when wanted. It might work. With the many new developments, I’m looking forward to the time that the physician recommends to his patient “Eat two designer eggs per day and see me in two months”, rather than the, “Take two aspirin and call me in the morning” (Stadelman, 1999) With the current and future possible nutraceuticals, such a situation might occur. Clearly, an egg has a great potential in terms of improvement of human diet which has been shown in this study. Recently a range of bioactive peptides in the egg has been characterized with antihypertensive, phagocytosis-stimulating and opioid properties which may be beneficial for humans (Kato, 1998). Furthermore, eggs can serve as an important source of nutraceuticals and pharmaceuticals (Stadelman, 1999). In addition, egg consumption may be also of interest in regulating aspects of glucose metabolism (Pelletier et al, 1996). These and other options of egg use in the human diet need further investigation. Upon these data, we can suggest that designer or specialty eggs may play a significant role in improving the human health. In the middle or low income countries, this role could be more significant. Eggs may provide a wide range of nutrients and nutraceuticals which the daily diet is insufficient in it with a relatively cheap price in the

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same time. Rural production and native breeds in such countries may contribute in such projects as its production may reach 30% from the total egg production as in case of Egypt.

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REFERENCES American Egg Board, 1998. Egg Product Reference Guide. American Egg Board, Park Ridge, IL. Diplock A. T., P. J. Aggett, M. Ashwell, F. Bornet, E. B. Fern and M. B. Roberfroid, 1999. Scientifc concepts of functional foods in Europe: Consensus Document. Br. J. Nutr. 81 (Suppl. 1), S1±S27. Elizabeth Applegate (2000) Introduction: Nutritional and Functional Roles of Eggs in the Diet Journal of the American College of Nutrition, Vol. 19, No. 5, 495S–498S (2000) FAO (United Nations Food and Agriculture Organization). 2002. FAO database, http://faostat.fao.org/. Hennig, B., and B. A. Watkins, 1998. Dietary lipid guidelines for infants and children: Considerations for growth and disease risk. Pages 235–251 in: Lipids in Infant Nutrition. Y.-S. Huang and A. J. Sinclair, ed. American Oil Chemists Society Press, Champaign, IL Herron, K. L. and Maria Luz Fernandez, 2004. Are the Current Dietary Guidelines Regarding Egg Consumption Appropriate? J. Nutr. 134: 187–190. Institute of Medicine and National Academy of Sciences USA: ‘Dietary Reference Intakes for Folate, Thiamin, Riboflavin, Niacin, Vitamin B12, Pantothenic Acid, Biotin, and Choline.’ Washington DC: National Academy Press, 1998. Jacqueline Jacob, 2001. Poultry extension coordinator, and Richard Miles, Designer and Specialty Eggs, FACTSHEET PS-51, Institute of Food and Agricultural Sciences, University of Florida. http://edis.ifas.ufl.edu. Juneja, L. R., 1998. Biological characteristics of egg components: Hens egg, store-house of biomedicals, potential applications? Page 36 in: Second International Symposium on Egg Nutrition and Newly Emerging Ovo- Biotechnologies. Banff, AB, Canada. (Abstr.) Kato A. (1998) Chemistry of functional substances in poultry eggs and its applications to human health. Proc. 6th Asian Pacific Poultry Congress, Nagoya, Japan, pp 52-57. Lai Shu-Mei, J.I. Gray, C. Chen and E.A. Grulke, 1996. Nitrogen oxideinitiated cholesterol oxidation and carotenoid degradation in an egg lipid model system. J. Sci. Food Agric. 72: 179-186.

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Lai Shu-Mei, J.I. Gray, J.A. Partridge and C.J. Flegal,1996a. Stability of cholesterol and papirka carotenoids in egg powders as influenced by dietary and processing treatments. J. Sci. Food Agric. 72: 171-178. Leeson S. and L. J. Caston, 2003. Vitamin Enrichment of Eggs. J. Appl. Poult. Res. 12:24–26. Meluzzi A., N. Tallarico, F. Sirri, G. Minelli, A Franchini., 2003. Dietary conjugated linoleic acid supplementation of laying hen: effects on egg fatty acids composition and quality. Ital. J. Anim. Sci. vol. 2, Supplement 1: 456-458. Pelletier X., Thouvenot P., Belbraouet S., Chayvialle J.A., Hanesse B., Mayeux D. and Debry G. (1996) Effect of egg consumption in healthy volunteers: influence of yolk, white or whole-egg on gastric emptying and on glycemic and hormonal responses. Ann. Nutr. Metab. 40: 109-115. Shafey T. M., J. G. Dingle , M. W. McDonald and K. Kostner, 2003. Effect of Type of Grain and Oil Supplement on the Performance, Blood Lipoproteins, Egg Cholesterol and Fatty Acids of Laying Hens. International J. Poultry Science 2 (3): 200-206. Sim, J. S., 1998. Tocopherol-enriched eggs and cholesterol stability. Page 22 in: Second International Symposium on Egg Nutrition and Newly Emerging Ovo-Biotechnologies. Banff, AB, Canada. (Abstr.) Stadelman W. J. 1999, The Incredibly Functional Egg . Poultry Science 78:807–811. Stadelman, W. J., and D. E. Pratt, 1989. Factors influencing composition of the hen’s egg. World’s Poult. Sci. J. 45: 247–266. Steven H. Zeisel, 2000. Choline: Needed for Normal Development of Memory J. American College of Nutr., Vol. 19, No. 5, 528S– 531S. Subcommittee on the Tenth Edition of the RDAs, Food and Nutrition Board, Commission on Life Sciences, National Research Council: ‘Recommended Dietary Allowances,’ 10th ed. Washington, DC National Academy Press, 1989. Sugura, N., 1998. Egg nutraceuticals in the market today, and tomorrow: Bioavailability and commercial use of eggshell calcium, membrane proteins and yolk lecithin products for biomedicals and food additives. Pages 35–36 in: Second International Symposium on Egg Nutrition and Newly Emerging OvoBiotechnologies. Banff, AB, Canada. (Abstr.)

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Taha F. A., 2003. The Poultry Sector in Middle-Income Countries and Its Feed Requirements: The Case of Egypt Economic Research Service/USDA WRS-03-02. www.ers.usda.gov Van Elswyk, M. E., 1998. Eggs as a functional food alternative to fish and supplements for the consumption of docosahexaenoic acid. Page 20 in: Second International Symposium on Egg Nutrition and Newly Emerging Ovo- Biotechnologies. Banff, AB, Canada. (Abstr.) Watkins, B. A., A. A. Devitt and M. A. Latour, 1998. Functions of conjugated linoleic acid (CLA): CLA-enriched eggs, future designer eggs. Page 41 in: Second International Symposium on Egg Nutrition and Newly Emerging Ovo- Biotechnologies. Banff, AB, Canada. (Abstr.)

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Fig. 1

Egg Consumption and production in Egypt (Taha, 2003) Fig. 2

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3rd International Poultry Conference 4 – 7 Apr. 2005 Hurghada - Egypt Table (2): Comparison of Fat Profile* Omega-3 Egg 4.8 g Total Fatty Acids 0.9 g Omega-6 0.4 g Omega-3 2.0 g Monounsaturated 1.5 g Saturated 174 mg Cholesterol

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Classic Egg 5.2 g 1.0 g 0.1 g 2.2 g 1.6 g 183 mg

(Based on 1 whole large egg) * Ferrier et al. Am J Clin Nutr 1995(JUL); 62:81-86. Values are based on 10% flax in the diet.

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