Effect of genotype and hens' starting body fat content on the changes in the body fat content of the hens and on the weight and composition of the eggs produced in the first egg laying period
Main Article Content
Abstract
The aim of this study was to examine the effect of genotype and hens’ starting body fat content on the
changes in the body fat content of the hens and on the weight and composition of the eggs produced in the
first egg laying period. The experiment was carried out with altogether 30 hens (15 TETRA SL brown egg
layers and 15 TETRA BLANCA white egg layers), which were chosen from altogether 45 TETRA SL and
45 TETRA BLANCA hens based on their CT (computer tomography) predicted body fat content at 20 weeks
of age (hens with the highest (n=5), hens with the lowest (n=5) and hens with average (n=5) body fat content
in both genotype). For the in vivo determination of changes in the body composition of these hens, computer
tomography (CT) measurements were carried out at every fourth week between the 20th and 72nd week of
age. During the CT measurements hens were fixed with belts in a special plexiglass container without using
any anaesthetics. The measurements covered the whole body of the hens using overlapping 10 mm slice
thickness on a Siemens Somatom Emotion 6 multislice CT scanner. After collecting, weighing and breaking
the eggs produced by the experimental birds on the days of the CT measurements their yolk ratio was
determined. Based on the results, it was established that the body fat content of the hens increased
continuously in both of the genotypes in the first phase of the experimental period, while it did not change
further in the second phase of the experiment. It was also observed at all examination days, that the body fat
content of the white egg layers was higher than that of the brown egg layers. Hens with the highest starting
body fat content had the highest body fat content in both genotypes during the whole egg laying period. The
egg production of the hens was not influenced by the body fat content of the birds, but it was affected by the
genotype. The TETRA SL hens produced significantly more eggs than the TETRA BLANCA hens. The hens
with average body fat content produced lighter eggs than the hens with low or high body fat content.
changes in the body fat content of the hens and on the weight and composition of the eggs produced in the
first egg laying period. The experiment was carried out with altogether 30 hens (15 TETRA SL brown egg
layers and 15 TETRA BLANCA white egg layers), which were chosen from altogether 45 TETRA SL and
45 TETRA BLANCA hens based on their CT (computer tomography) predicted body fat content at 20 weeks
of age (hens with the highest (n=5), hens with the lowest (n=5) and hens with average (n=5) body fat content
in both genotype). For the in vivo determination of changes in the body composition of these hens, computer
tomography (CT) measurements were carried out at every fourth week between the 20th and 72nd week of
age. During the CT measurements hens were fixed with belts in a special plexiglass container without using
any anaesthetics. The measurements covered the whole body of the hens using overlapping 10 mm slice
thickness on a Siemens Somatom Emotion 6 multislice CT scanner. After collecting, weighing and breaking
the eggs produced by the experimental birds on the days of the CT measurements their yolk ratio was
determined. Based on the results, it was established that the body fat content of the hens increased
continuously in both of the genotypes in the first phase of the experimental period, while it did not change
further in the second phase of the experiment. It was also observed at all examination days, that the body fat
content of the white egg layers was higher than that of the brown egg layers. Hens with the highest starting
body fat content had the highest body fat content in both genotypes during the whole egg laying period. The
egg production of the hens was not influenced by the body fat content of the birds, but it was affected by the
genotype. The TETRA SL hens produced significantly more eggs than the TETRA BLANCA hens. The hens
with average body fat content produced lighter eggs than the hens with low or high body fat content.
Article Details
How to Cite
Szentirmai, Eszter, Gábor Milisits, Tamás Donkó, Zoltán Sütő, A. Orbán, József Újvári, O. Pőcze, and Imre Repa. 2012. “Effect of Genotype and hens’ Starting Body Fat Content on the Changes in the Body Fat Content of the Hens and on the Weight and Composition of the Eggs Produced in the First Egg Laying Period”. Review on Agriculture and Rural Development 1 (1. suppl.):440-45. https://analecta.hu/index.php/rard/article/view/13247.
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