Gonadal maldevelopment in a flock of Rhode Island Red fowls.

Abstract

SUMMARY In nine fowls with intersexual characteristics from a single hatch of commercial Rhode Island Red pullets, the shanks and tibiae were of female size; plumage and macroscopic post-mortem findings suggested the female type, although two birds had a few masculine saddle feathers. All except one, which had an extensive gonadal tumour, had a single left gonad which was atypical. Behaviour was asexual, except for one animal with masculine aggressiveness. The head appendages were masculine in all cases. In eight of the nine birds the gonads consisted mostly of ovarian-type stroma in which were a few immature and atrophic tubules, some cords of luteal cells, and a few cystic follicles. Oogenesis and spermatogenesis were never seen. Granular medullary cells of the gonadal stroma were quantitatively a most important cellular element, and it is suggested that their secretions may have been of significance in the development of the secondary sexual characters of the birds. Lipids in the gonads were histochemically similar to those of the normal ovary. Gonadal tumours were present in two cases, one tumour being very large, but they did not modify the intersexual appearance and behaviour of the birds. In general histology they resembled human dysgerminomata, and it is suggested that their main cellular component was derived from the germinal epithelium and was similar in origin to the medullary cells. Compared with the gonads, negligible amounts of lipid were present in the tumours. The other gonads were not neoplastic, although they may have had that potentiality.