Dtsch Tierarztl Wochenschr. 1994 Nov;101(11):434-9.

[The problems of spotted breeds of rabbits. 4. Morpho- and histometric findings in the CNS and thyroid glands and the hormone content in blood at slaughter of hybrid rabbits, and estimation of the heterosis effect].

[Article in German]

Flemming K, Kühnel C, Wieberneit D, Wegner W.

Source

Institut für Tierzucht und Vererbungsforschung der Tierärztlichen Hochschule Hannover.

Abstract

Morpho- und histometric investigations of brains, pituitary and thyroid glands as well as thyroid-related functional parameters in the blood of purebred and hybrid rabbits revealed a predisposition to hypothyreotic conditions in homozygous, megacolon-prone genotypes. 

In addition to this also a hypoganglionotic state in different gut wall localizations was confirmed; pituitary traits however did not indicate a primary contribution of this gland to the syndrome, though some alterations were found, which are interpreted as secondary sv. symptomatic. 

Gender influences varied hormonal characteristics and disease manifestations too: 

A dramatic fall in severely diseased does with respect to T3-concentration as well as a seemingly more inactive thyroid gland compared to bucks underline hormonal influences. 

As a consequence of these results it is concluded, that hybridisation within spotted rabbits does not amend the inclination to megacolon in animals homozygous for the K (En) gene, though it may influence its manifestation.