Dr. Pashupathi M1, Dr. Rashmi Mishra 2
1Division of Biochemistry, Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh
2Division of Veterinary Parasitology, Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh
The egg is seen as a naturally occurring chemical store house that delivers very nutrient-dense food in a biological container (the egg shell) that is impervious to adulteration. It is endowed with all the necessary nutrients which can nourish an embryo to a chick. The phrase “Nature’s original functional food” has been used to describe eggs. Of the three dietary essentials – proteins, fats, and carbohydrates, the egg is composed largely of the first two. Due to their great biological value, high protein quality, and low cost and palatability, they are used as food on a global scale. Despite all of its benefits, it is frequently seen as a food high in cholesterol due to the lipid profile of the yolk. Due to this, people who are health conscious have developed a cholesterol phobia, which has resulted in a global decline in egg consumption, particularly in western nations. In light of the aforementioned facts, the idea of the “Designer Egg” has been developed with the intention of reducing the health-harming nutrients (such as cholesterol and triglycerides) and enriching it with the nutrients that are good for you, such as omega-3 fatty acids, antioxidants, vitamins, and minerals.
The nutritional composition of a designer egg may differ from a regular egg in terms of important fatty acids, cholesterol, vitamins, minerals, antioxidants, etc. The simplest way to describe them is as “Nutritionally enhanced, Value added, Supplemental eggs.” The egg is a great vehicle for adding various health-promoting ingredients, therefore the possibilities for designing eggs are endless. By nutritionally manipulating the laying hens’ diet, it would be easy to alter the various nutrients in an egg.A typical designer egg may have six times as much omega-3 fatty acids as compared to a standard egg and up to 40% less cholesterol.
Chromium supplements make it simple to control cholesterol, the biggest egg restriction. The egg and yolk cholesterol will both be markedly reduced by adding chromium supplements from 250-1000 ppb. Copper supplementation is another method of lowering the amount of cholesterol in yolk. When varying amounts of copper were added to the feed of laying hens, the blood and yolk cholesterol levels decreased. Incorporating up to 300 mg/kg of copper into the food of chickens will aid in lowering plasma and yolk cholesterol.
Microbiological feed additive has capacity to improve the host’s health and well being. Effect of probiotic is mediated via improved nutrition utilization, digestive enzyme secretion, appetite stimulation, improvement of gut health, and immune regulation. Additionally, aid in increasing daily feed consumption and retaining calcium and nitrogen. Adding multi-strain probiotics at a rate of 0.5 g/kg of feed to the diet of laying hens can enhance egg production and considerably lower yolk cholesterol. In accordance with the same line, adding probiotics (Rhodobacter capsulatus) in layers at a rate ranging from 0.01 to 0.04% will also lower yolk triglycerides and cholesterol.
Garlic supplementation in the feed of laying hens for more than 16 weeks at various levels, ranging from 0 to 10%, will considerably cut blood and yolk cholesterol. Also, PUFA supplementation in the diet of layers will result in a decrease in cholesterol levels in the diet of layers.
As omega-3 fatty acids are not produced by the human body, they are essential for a variety of bodily processes, including regulating triglyceride, LDL, and HDL levels, preventing cardiovascular disease, lowering blood cholesterol, reducing inflammation, and boosting the immune system. Commercial table eggs contain a high proportion of omega-6 fatty acids but are a poor source of omega-3 fatty acids. Various dietary sources of omega-3 fatty acids are fish and fish oils (salmon, mackerel, menhaden, halibut, and herring), plants (flax seed or linseed, soy and walnut), vegetable oils (canola and safflower oil) as well as marine algae. The richest source out of all is flaxseed oil, which is followed by fish and soybean oil. Eggs from layer birds were markedly enhanced with essential omega-3 fatty acids (ALA, EPA, and DHA) after dietary supplementation of flaxseed oil at various levels of 0%, 1.5%, and 3% and fish oil at rates of 0%, 2%, 3%, and 4%. The organoleptic quality of omega-3 eggs tends to be similar to regular table eggs although in some cases panellists are able to detect fishy taint in eggs, which decreases the overall egg acceptability.
Alteration in pigment content of eggs can be achieved by dietary manipulation. The yolk colour is the indicator of pigment content of egg and varied with dietary supplementation such as plants (marigold, chilli or corn) and blue green algae (Spirulina). These feeds have lutein and zeaxanthin in it which gives the colour to yolk. These compounds will improve eye health by protecting the macula from degenerative, oxidative and photochemical damage. Dietary manipulation makes it possible to improve the level of iodine, selenium, chromium without affecting the calcium and phosphorous level in eggs.
Everyone in today’s world must deal with a lot of stress. These stresses are mediated through oxidative reactions, which produce a lot of free radicals and peroxides inside the body. The best safeguard against such stresses comes from dietary antioxidants. The antioxidant chemicals like vitamin E, vitamin A, selenium have a protective impact against heart diseases as well. A further solution is to design the eggs with a higher antioxidant content.In the layer’s ration, adding vitamin E or fish oil causes a linear, dose-dependent rise in the concentration of α-tocopherol. Supplementing with vitamin E not only boosted the amount of α-tocopherol, but it also maintained the high concentration of ω-3 fatty acids. As a result, eggs now have a superior four-week shelf life and maintain their freshness longer.
A more recent development is the enrichment of bioactive components in eggs. Supplementation of sprouted alfalfa and flax seed increased several plant bioactive compounds, including isolariciresinol, daidzein and equol. Utilizing fermented buckwheat extract in layer diets increased the amount of GABA and L-carnitine in the yolk. L-carnitine is essential for the oxidation of mitochondrial fatty acids, whereas GABA has a number of beneficial impacts on mammalian physiology, such as lowering anxiety, controlling blood pressure, boosting immunity, and having antihypertensive effects.
With the advancement of biotechnology, we can produce genetically modified chickens which then produce the eggs containing the desired compound e.g., insulin for the treatment of diabetic patients and variable antibodies that could be used in treatment of microbial toxins and snake venoms. Antibodies could be produced in the albumin of eggs by transgenic hens. Egg yolk antibodies (EYA) are the antibodies in the yolk and can be generated by injecting hens intramuscularly or subcutaneously with a particular antigen that produces IgY antibodies. Eggs could be used as a source of immunogens to strengthen people’s immune systems, especially those of youngsters, against a variety of diseases.EYA could be employed as an antibacterial and antiviral agent in both humans and animals, as well as to treat rotavirus, corona, and E. coli-related enteric illnesses in calves and pigs and to prevent the spread of rabies.For these reasons, designer eggs can be employed as a source of immunoglobulins that can be used as immunotherapeutic agents to improve immune system capabilities.
However, the efficiency of nutrient transfer from diet to eggs reaches a limit beyond which further enrichment of nutrients in eggs is not possible. Enrichment often has a higher cost of production, so retailers and consumers must pay a higher price for it. As a result, the health benefits of designer eggs must be conveyed through suitable labels on final packaging. Designer eggs are currently gaining popularity on the global market under various trade names, but the Indian market is more encouraging in metropolises and the southern region due to a greater population of non-vegetarian. However, rising public health consciousness and purchasing power offer optimism for the market’s expansion.