Health benefits of Designer Eggs
SURUCHI SHARMA*1 and SAHIL SHARMA2
1M.V.Sc. Veterinary Biochemistry DGCN COVAS, CSKHPKV, Palampur, 2M.V.Sc. Animal Nutrition DGCN COVAS, CSKHPKV, Palampur
*Corresponding author’s email: suruchis91@gmail.com
Important role is played by diet in maintaining health. Egg provides essential nutrients to the body it is rich in minerals, vitamins, essential amino acids and fatty acids. Designer foods of animal origin are produced either by feeding specific diets or using new techniques like crossbreeding and genetic engineering. Designer eggs are type of functional food. The egg composition can be altered by genetic composition and nutritional manipulations which can be done by modifying lipid profile, fatty acids, amino acids, minerals and cholesterol concentrations and its fractions or through adding therapeutic pharmaceutical molecules. Designer egg provides organic foodstuff which have improved minerals, vitamins, lowers total cholesterol, balanced ratio of omega-3 and omega-6 fatty acids and essential pigments such as carotenoids or designer eggs are those in which the content has been modified from the standard egg in terms of high vitamin and minerals, lower cholesterol, high omega fatty acids and added pharmaceutical compounds.
An avian egg is a highly integrated biological system. The nutritive value and functional properties of an egg makes it an important item in human diet. Eggs and egg products form an integral part of the food chain. It is the only animal protein source in developing countries that is available to the general population. Egg is source of protein, liposoluble vitamins A, D, E, K, vitamin B-complex such as cyanocobalamin, thiamine, riboflavin, niacin and pyridoxine. Among minerals; it contains iron, calcium, potassium, sodium, phosphorous and zinc. Egg is also an important source of dietary cholesterol which increases serum cholesterol that ultimately causes the appearance of coronary diseases. The association of cholesterol with coronary diseases has raised the concerns by the consumer and somewhat lowered its consumption in a certain section of society. The consumption of cholesterol rich food by diabetic patients, cancer carriers and hypercholesterolemia patients can raise the risk of coronary diseases. Egg yolk has a high concentration of lipid. Thus, it will be of interest to develop products derived from or nutrient within eggs through some nutritional manipulations that helps to maintain consumer health. Generally designer eggs are produced by modifications in layer diets and by technological methods. Designer eggs can provide more than 600 mg omega-3 poly unsaturated fatty acid and 6 mg tocopherol.
Low cholesterol
An average sized egg contains 180-200 mg cholesterol. Supplementations of chromium to layer diet at concentration of less than 1 ppm have shown to lower cholesterol. Further, diet rich in protein and fibre fortified with vitamin E can produce eggs lower in cholesterol. Supplementation of Gynura procumbens plant (longevity spinach) in laying hen diets decreased cholesterol by 12% in egg yolk. Diets rich in alfalfa meal (Medicago sativa) reduce the cholesterol by 19%, this plant is effective in decreasing reabsorption of biliary cholesterol in the intestine of birds further decreasing the cholesterol level in egg yolk. Combination of alfalfa and flax seeds can also lower cholesterol in eggs by 9% which affects cholesterol synthesis. Supplementation with a combination of flax seed, spirulina and vitamin E ; fish oil and selenium; flax seed, spirulina and vitamin E + fish oil and selenium decreases egg yolk cholesterol levels by 23.2%, 26.4% and 22.5% respectively. Supplementation of hemp seed also reduced egg yolk cholesterol by 32% due to presence of phytosterol that lower absorption of cholesterol from the intestine and inhibit cholesterol synthesis in liver.
Improved yolk colour and pigments
Colour of egg yolk is an indicator of pigment content which may vary based upon dietary supplementation such as maize, marigold, alfalfa and blue green algae i.e. spirulina. These are carotenoids rich plants. Thus, supplementing poultry diets with such plants increased the concentration of yolk carotenoids. Eggs with highly pigmented yolks are used in preparing mayonnaise, pasta and different bakery products. With supplementation of Phaeodactylum, Nannochloropis and Isochrysis the yolk colour was shifted from yellow to red colour. Yolk colour and carotenoid pigments are correlated positively. Beta carotene has no influence on yolk pigmentation whereas lutein and zeaxanthin are highly active yolk colourants.
Eggs enriched with vitamins and minerals
Manipulation in the diet improves the levels of iodine, selenium and chromium in eggs without affecting calcium and phosphorus levels. Supplementation of chromium reduces yolk cholesterol whereas selenium level in eggs can be increased by incorporating Yeast Se in diet of layers. Designer eggs have 26 times more vitamin E, 16 times more vitamin A and 7 times more selenium which boost human intake of natural antioxidants like folate, vitamin E, lutein, zinc, selenium, carotenoids, pigments, lecithin to enhance immune response. Inclusion of designer eggs in human diets by 12-16 eggs per month increase vitamin E consumption up to levels of 23 mg per day.
Improved fatty acid profile
Ratio of saturated to unsaturated fatty acid can be changed using canola oil in the feed. Designer egg have balanced ratio of Poly unsaturated fatty acid: saturated fatty acid (1:1) or omega-6: omega-3 poly unsaturated fatty acid (1:1). Omega-3 poly unsaturated fatty acid is important in development of nervous system and also modulates immune function, in addition to anti-tumor, anti-inflammatory and cardio-protective effects. These also lower blood platelet aggregation, blood pressure, incidence of thrombosis and artherosclerosis. Omega-3 content in eggs can be increased by dietary supplementation of groundnut oil, fish oil, safflower oil, linseed oil, fish meal or marine algae.
Antibodies and other products
Developing genetically modified chickens will produce eggs with benefits such as insulin for diabetes treatment. Transgenic hens could be used to produce antibodies in egg albumin. Egg yolk antibodies are antigen specific to antibodies in yolk which could be obtained by injecting specific antibody resulting in production of IgY antibodies subcutaneously or intramuscularly. Thus, eggs can be utilized as immunogens source which will improve immune system. These can also be used as antiviral and antibacterial agents in animals as well as humans to treat E. coli infections, corona and rota virus infections. Egg yolk antibodies can also be used as anti-venom against snake poison. Therefore, designer eggs are the source of immunoglobulins that strengthens the immune system.
Enrichment of bioactive compounds
It is one of the most important trends in designer egg. Egg yolk contains less amounts of lutein as compared to spinach but has higher bioavailability. Supplementation of layer diet with alfalfa and flax seeds increased the concentrations of lutein, zeaxanthin and other carotene compounds. Use of the fermented buckwheat extracts in the diet of layers encriched GABA and L-carnitine in the egg yolk. L-carnitine has role in oxidation of mitochondrial fatty acid and GABA which regulates blood pressure, reduce anxiety, enhance immunity and have anti-hypertensive effects.
Significance of designer eggs
Eggs are cheap source of high quality protein along with balanced ratio of vitamins except vitamin C and minerals but due to high content of cholesterol per capita consumption of eggs is low. Normal egg provides 70 Kcal of energy and contributes to platelet inhibition, anti-acetylcholine inhibitors (AchI) and anti-reactive oxygen species (ROS). Egg contains anti-coagulation and anti-inflammation components as well as anti-hypertensive peptides such as ovokinin which helps to protect heart from many diseases. Due to reduction in consumption of eggs there is a direct impact on poultry industry so, efforts are made to manipulate and improve nutritive value of eggs and this improvement is today known as Designer Eggs.
Conclusion
Designer eggs enriched with minerals, vitamins and other nutrients like fatty acid are good nutritional product as well as good vector for transfer of biological products like antibodies for human health. Thus, the future of poultry is not only to produce higher amount of eggs but producing more eggs of right kind. In-spite of all the benefits, human consumers may not easily accept changes in transgenic nature. Due to such attitude the beneficial effects of designer eggs on human diet and health need to be investigated on large level.
