5 COMMON MYTHS ABOUT EGGS

5 COMMON MYTHS ABOUT EGGS

For World Egg Day and during Tecnozoo Egg Week, we’ve decided to debunk 5 common myths about eggs.

EGG SHELL COLOR DEPENDS ON DIET: FALSE

Eggs come in different shell colors, although the typical consumer is accustomed to the classic light brown or white eggs commonly found in supermarkets.

Some chicken breeds lay eggs that range in color from blue to brown.

The dominant pigment in brown eggshells is protoporphyrin IX, with traces of other porphyrins: biliverdin, coproporphyrin, and uroporphyrin. In blue eggs, the color is determined by biliverdin.

The expression of these pigments—and therefore the eggshell color—is genetically determined. However, color intensity, uniformity, and other aspects can be influenced by the hen’s age, health status, environment, and diet. Since diet does not affect shell color, the nutritional properties of the egg are not linked to it, and it is not true that a brown egg is more nutritious than a white one.

A DARKER YOLK MEANS THE EGG IS MORE NUTRITIOUS: FALSE

Yolk color is an important organoleptic trait for consumers and is often associated with egg quality.

The color of the egg yolk is determined by the type and profile of carotenoids present in the feed, their concentration, and intestinal absorption. Yolk color does not affect the egg’s lipid or protein profile, and therefore does not influence its nutritional characteristics.

It is true that physiological changes in the hen, such as aging, stress, or health conditions, can affect pigment absorption and thus yolk color intensity. However, these variations mainly influence color uniformity from egg to egg within the same group.

The main carotenoids used in poultry nutrition to modulate yolk color are xanthophylls, which give a yellow color (such as zeaxanthin and lutein) or a red color (such as canthaxanthin).

These pigments are mainly synthetic but can also be found in varying concentrations in different feed sources: for example, corn is rich in zeaxanthin, and alfalfa is rich in lutein.

Spices are also an excellent source of natural carotenoids.

A ROOSTER IN THE COOP INCREASES EGG PRODUCTION: FALSE

Roosters are not necessary for egg laying. There is no scientific evidence linking the presence of a rooster to oviposition.

Egg laying is regulated by the number of daylight hours.

L’ attività dell’ ipotalamo è alla base del meccanismo ormonale che porta alla produzione dell’ uovo ed è la stimolazione luminosa a regolarne l’ attività.

14–16 hours of light are sufficient to stimulate full hypothalamic activity. This is why, in non-intensive farming systems (without light programs or environmental management), a decreasing photoperiod (shorter days) often corresponds to a reduction in egg laying.

A rooster is therefore not necessary for egg production. In fact, fertilized eggs are not suitable for commercial consumption, and the product’s shelf life (the time between production and consumption without posing health risks to the consumer) is reduced.

EGG CHOLESTEROL INCREASES THE RISK OF CARDIOVASCULAR DISEASE: FALSE

For many years, the high cholesterol content in eggs was directly linked to increased blood cholesterol levels and, consequently, a higher predisposition to cardiovascular disease.

More recent studies have disproven a direct correlation between dietary cholesterol and blood cholesterol, showing that the mechanisms regulating cholesterol levels are much more complex and multifactorial. Likewise, the development of cardiovascular diseases associated with high cholesterol is complex and influenced by multiple factors.

Studies agree that consuming up to two eggs per day does not significantly affect blood cholesterol in people without specific metabolic issues.

THE WHITE FILAMENTS NEAR THE YOLK ARE A SIGN OF FERTILIZATION: FALSE

The filaments visible near the yolk, in close contact with the vitelline membrane, are called chalazae and are the result of the egg’s rotation in the oviduct. They are protein structures that anchor to the poles of the egg and suspend the yolk in the center.

They are completely normal structures and have nothing to do with fertilization.

It is also important to remember that commercial eggs are not fertilized. 5 COMMON MYTHS ABOUT EGGS

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BIBLIOGRAPHY “5 Common Myths About Eggs”

• Arch. Geflügelk – “Variation of Eggshell Colour in Different Egg-Type Chickens”
• Dr. Ekaitz Maguregui – “The Egg Yolk Color and Pigments”
• Samiullah Khan, J R Roberts, Kapil K Chousalkar – “Eggshell color in brown-egg laying hens — a review”
• P J H Jones – “Dietary cholesterol and the risk of cardiovascular disease in patients: a review of the Harvard Egg Study and other data”
• Silvia Cerolini, Margherita Marzoni Fecia di Cossato, Isabella Romboli – “Poultry and Rabbit Farming”