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As a contribution to the project "Development of endothermy of avian embryo"
(DFG Tö 181-1) the effect of a short term hypothermia on the heart rate and
the inner egg temperature of chick embryos of different ages was examined. The
purposes was to verify the effect of manipulations on the embryo outside of
The physilogical parameters of the heart rate (HR) and inner egg temperatur
(IET) served as measurements. As the temperature regulation, among others, is
dependent upon cardiovascular conditions, the HR was capable of being a
sensitively reacting and easily measurable parameter to determine the
reactionary ability of the embryo. The IET reflects the influence of the
ambient temperature as well as the influence of the heat production on the
embryo. It is thereby well suited to a complete estimation of the response to
To detect the HR, a semiinvasive method of the electrocardiogram charting was
used. In order to mesure the IET, an invasive methode was developed, with
which the temperatur near the embryo could be measured over a long time,
without substantially influencing the embryo.
The response of the HR and the IET of chick embryos at the 14th, 17th and 20th
day of incubation during the cooling of the room temperature (21 °C) from 5 to
25 minutes was examined. A comparison between egg with live embryos and egg
with dead embryos underlines the influence of blood circulation and metabolism
on the IET.
The resulting decline of the HR and IET during the cooling of the room
temperature was dependent on the duration and the age of the embryos.
During the rewarming under incubation conditions (37,4 °C), the HR and IET
rose logarithmic. During a two hour rewarming, 86% of the examined embryos
reached their original HR level and 64% reached their initial IET again. It
can therefore be concluded that the adaptation time for embryos after
treatment should be least two, if not four hours.
The high linear correlation between HR and IET during the cooling and during
the rewarming in all three age stage permit the conclusion from one parameter
to the others and makes it possible to narrow the scope of future experiments.
600 Technik, Medizin, angewandte Wissenschaften::630 Landwirtschaft::630 Landwirtschaft und verwandte Bereiche
Der Einfluß einer kurzzeitigen Hypothermie auf die Herzfrequenz und die
Eiinnentemperatur von Hühnerembryonen unterschiedlichen Alters
Univ.-Prof. Dr. H. Tönhardt
Univ.-Prof. Dr. G. Monreal
Prof. Dr. Horst Skarabis, Prof. Dr. Werner Müller-
The effect of a short term hypothermia on the heart rate and the inner egg
temperature of chick embryos of different ages