Age-related Morphology of the Ostrich Oviduct (isthmus, Uterus and Vagina)

Ostrich fertility is a very important measure of their reproductive efficiency, hence our interest in studying the ostrich oviduct. In our study, we found in fully mature birds a thin walled region between magnum and isthmus free of glands and considered as an area of transition called zona translucent. Also, the uterus was formed from a cranial short tubal part followed by a caudal large sac-like pouch. The mucosal folds of uterus are called uterine lamellae. The free borders of these lamellae were smooth, while their both sides were wrinkled. Most of these lamellae were directed longitudinally and converged towards the vagina. In pre-laying birds (3–3.5 years of age) a well developed membrane was found between the vagina and the urodeum. Afterwards in the laying hens we could not found this membrane. Histologically, the glandular buds were found to appear in lamina propria of the isthmus and uterus but not in the vagina of immature ostrich chicks and to become tubular branched glands in pre-laying hens and active, more branched, filled with secretory materials in laying ostrich hens. The cores of the mucosal folds in isthmus and uterus were filled with glands and free of glands in the vagina. Histochemically, in laying ostrich hens the isthmian and vaginal epithelium were reacted positively to PAS staining, while some individual PAS-positive secretory granules were present within the cytoplasm of the apical part of the uterine epithelium.