It's called like an egg to an egg, whenesto hen inaye can have a variety of colours, shapes and sizes. This from Grandma's malso egg yolks "somehow yellower than the stores" and the neighbor's behind the fence seem bigger. But it's not just a first glance, eggs can also differ in tom, what's under shell - in its composition.
The Czech golden-spotted hen and the oravka hen are Czech and Slovak national breeds that have been bred and raised for centuries. And it is these two breeds that scientists have chosen for their research. They compared how breed, housing and age of the hen can affect the quality of the eggs laid. For example, they were interested in the weight and shape of the egg, the strength and colour of the shell, the ratio of yolk to white, as well as blood parameters such as total cholesterol and protein content.
The researchers evaluated eggs from 34-, 42- and 50-week-old hens raised in so-called enriched cages and those from litter-breeders. A total of 132 animals were used in the study and 60 eggs were collected from each breed during the study period. In addition, blood samples were taken from the laying hens themselves. The hens were sampled between seven and eight o'clock in the morning from the wing vein.
And what did the results show? For example, the researchers found significant differences in blood cholesterol levels, which were higher in hens kept in enriched cages. Differences in total protein content were related to the age of the hens, with younger hens having higher levels in their blood. With regard to egg quality, shell colour was mainly influenced by breed, while housing system had an effect on weight, surface, thickness and shell strength. The results obtained present an interesting comparison of changes in blood biochemical parameters and egg quality. These factors certainly need to be further investigated, especially in other breeds where such data are unfortunately often lacking for the time being.
The original work can be found here:
www.sciencedirect.com/science/article/pii/S0032579120307926
Kraus, A., Zita, L., Krunt, O., Härtlová, H., & Chmelíková, E. (2021). Determination of selected biochemical parameters in blood serum and egg quality of Czech and Slovak native hens depending on the housing system and hen age. Poultry Science, 100(2), 1142-1153.
Ing. Adam Kraus
After completing her Master's degree with a focus on Quality and Processing of Agricultural Products, she has been continuing her PhD studies at the Department of Animal Husbandry since 2018. At the faculty, she is involved in teaching meat processing technology. In 2019, he participated in a foreign internship at the National Research Institute of Animal Production in Krakow. He actively publishes and participates in conferences focusing on performance and quality of hen production.
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