It’s astonishing, but the shell of guinea fowl eggs exceeds in strength that of all other eggs in the world, including ostrich eggs, the largest.
Scientists do not explain the reasons for this difference. When the guinea fowl first appeared in Guinea, it was undoubtedly necessary for nature to organize a particular resistance of the egg, to protect the chicks in gestation, germs, shocks or perhaps also from the heat.
All this remains quite mysterious but the observation remains that a chicken egg can withstand a pressure of 5 kg, explains Joël Gautron, research director at the National Research Institute for Agriculture, Food and the Environment ( Inrae), while a guinea fowl egg will support 8 kg while having a shell barely thicker.
The work carried out by researchers from INRAE from the center of Val-de-Loire showed that guinea fowl eggs have the particularity of being formed of two layers, two shell thicknesses which have a different structure and that is it. which creates exceptional solidity. One of the layers contains very small columns of calcite arranged vertically and the other is formed of micro crystals of calcites smaller and nested in each other in all directions. It is this double structure that makes the propagation of cracks more difficult.
In France, guinea fowl eggs are not eaten. But scientists are interested in it for several reasons. First of all because by studying the genes which allow the guinea fowl to lay such solid eggs, we can have indications to find among the hens, genes which also favor the laying of eggs with the more resistant shell and that it is interesting for the food industry, it would limit breakage during transport. Then, there is a technological interest because by taking as a starting point the double structure of the eggshell of guinea fowl, the engineers hope to develop ultra-resistant materials for our phones, our cars, our houses, even for medical prostheses. .
Finally, the chemical reactions that allow the guinea fowl to make its shell are of great interest to researchers, because the shell is a bit like ceramic. However, when trying to artificially manufacture this type of material, high temperatures, pressure and a lot of energy are needed. How can the body of a guinea fowl build these kinds of chemical structures at low temperature without being energetically depleted? It is a vast subject. Guinea fowl definitely have cutting edge techniques in materials science.