Faculty of Veterinary Science
Department of Veterinary Anatomy and Physiology
Selected Highlights from Research Findings
Microrecanalization is a rare phenomenon in occluded or damaged ducts, and may be responsible for pregnancies attributed to some men who had been vasectomized. As part of their studies on the reproductive biology of birds, researchers launched a research project entitled: Microrecanalization of efferent ducts of the testis following their occlusion in the quail. Their findings indicate that microrecanalization occurred in several efferent ducts of vasectomized domestic fowls and Japanese quails as well as carbendazim-exposed quails.
The process was limited to ducts that were blocked by inspissated masses of spermatozoa or elongated spermatids.
These are germ cells that are stabilized by -S-S bridges, and are therefore more difficult to remove than earlier germ cell series by the phagocytic process of the duct epithelial lining. Several micro canals developed from the original duct and surrounded the granulomata that were provoked by the degenerating spermatozoa.
Some of the neo-canals contained spermatozoa, although, within the confines of these studies, it was not possible to determine whether or not these new canals made any contact with patent segments of the efferent duct, proximal or distal to the occlusion.
Microrecanalization has not been reported previously in the efferent ducts of any vasectomized animal, including man. This phenomenon in the efferent ducts in birds that were subjected to two different procedures may be part of the means by which the male reproductive tract circumvents occlusions in any/some of the excurrent ducts of the testis. The quail is an excellent model for further studies of this phenomenon in animals.
Prof TA Aire
Veterinary Anatomy and Physiology
+ 27 (0) 12 529 8428
Although the ostrich industry in South Africa has been a major contributor to the economy for many decades, relatively little research has been done on this proverbial “goose that lays the golden eggs”. The lack of research can mainly be attributed to the fact that up until recently, the industry has been dominated by farmers who consider themselves experts and allowed researchers little if any input.
It is only recently that farmers have been increasingly turning to researchers to help them find solutions to the many problems that the industry faces. One of the major problems is the low fertility rate amongst ostriches.
The aim of one of the studies undertaken at Onderstepoort entitled: A Morphological and Immunohistochemical Study of Healthy and Atretic Follicles in the Ovary of the Sexually Immature Ostrich (Struthio camelus), was to find answers to questions about the reproductive biology of the sexually immature ostrich.
The study found that morphological and immunohistochemical changes do occur in the ovarian follicles of these birds – contradictory to what was previously believed.
The findings indicate that ovarian follicles in the sexually immature ostrich undergo a cycle of growth and degeneration, which is similar to that reported in sexually mature birds of other avian species.
Furthermore, the results of the immunohistochemical study have shown that the distribution and immunostaining of intermediate filaments change during follicular development and regression.
The findings of the study will help researchers focusing on Parenteology to devise new strategies aimed at improving the fertility rate of this bird. Dr M-CN Madekurozwa
Veterinary Anatomy and Physiology
+27 (0) 12 529 8417
madex@0p.up.ac.za
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