Tips on how to evaluate the internal quality of the egg

The internal quality of the egg is a topic of greater interest in poultry farming, both in layers and in breeders, because, in the first mentioned, the internal quality defines the nutritional qualities and the acceptance of the egg by the consumer.


With this article, the Zucami technical team intends to present TIPS that help our clients to know the most relevant characteristics and aspects related to the internal quality of the egg.

Albumen, indicator of egg freshness.

Along with the height of the air chamber, the consistency of the albumen is one of the indicators of the freshness of the egg.
After oviposition, the consistency of the albumens decreases over time:
Micrómetro

This occurs due to an increase in pH, which leads to the degradation of the binding of the proteins ovomucin and lysozyme, which make the albumen more and more fluid.

The quality of the albumen also decreases significantly with the age of the birds, as well as with the appearance of outbreaks of certain diseases such as infectious bronchitis or Newcastle disease.

Proper storage of the egg, together with genetic improvement, allow the height of the albumen to be maintained over time

Stains of blood and meat

Blood stains are inclusions that can sometimes be found in the egg, usually in the yolk, and are often the result of a small hemorrhage in the ovary or oviduct or as a consequence of the rupture of small capillaries in the process of rupture of the follicular wall during ovulation.
Traces of pigment may also be found in brown-colored egg layers that can be mistaken for bloodstains. Meat stains are usually found in the egg white.
Flesh spots are due to shedding of dead cellular tissue.
White Eggs: the frequency of meat stains is very low.
Brown Eggs: The incidence of meat stains can be around 3-5% in the case of stains greater than 2-3mm.

Yolk colour.

The color of the yolk is mainly due to the carotenoids provided through the feeding of the hens. For this reason, depending on market preferences regarding the color of the yolk, we can adjust its incorporation into the diet of the birds.

The most widespread method to measure the color of the yolk is the use of the Roche Scale:
It consists of contrasting the color of the yolk with a range of colors made up of 15 pre-established values, which go on an increasing scale from pale yellow to reddish orange.

Double yolk eggs.

Especially at the beginning of laying it is not uncommon to find eggs with two yolks.

The incidence of double yolk eggs increases if an early stimulation is carried out, either by light or due to a premature change to laying food, with a high calcium content.

In genetic improvement programs, by counting only salable eggs in the selection nuclei, selection is being made indirectly to reduce the incidence of double-yolked eggs, since birds with a high productive potential have a lower tendency to have double-yolked eggs.

Fresh egg.

Egg freshness is a quality factor.
It is related, in addition to the characteristics of category A eggs in the EU marketing standard (quality of the shell, white and yolk), with the processes that the egg undergoes after the moment of laying.

An egg is at its highest quality (and freshness) at the time of laying. Over time, changes occur that affect its structure and make it possible to differentiate a fresher egg from another that is not so fresh.

Without a doubt, the egg is one of the most balanced foods for the human diet and is a very high quality protein.

It contains essential amino acids in proportions similar to human requirements and has an important contribution of a wide range of vitamins.

It is one of the foods of animal origin with less unsaturated fats.

Fatty acids account for about 4 g, of which 65% are unsaturated and 35% saturated (Instituto de Estudios del Huevo, 2009).