The testicular capsule was studied histologically, morphometrically, ultrastructurally and immunohistochemically in the Japanese quail, domestic fowl, turkey and duck (all members of the Galloanserae). The testicular capsule was, relative to mammals, thin, being 81.5 ± 13.7 µ m in the quail, 91.7 ± 6.2 µ m in the domestic fowl, 104.

The testicular capsule and peritubular boundary tissue of the emu and ostrich, as typical representatives of ratite birds, were studied in sexually mature and active birds. The testicular capsule was much thicker (578.1±73.4 m for the free surface of the ostrich testis, and 176.2±57.5 mfor the emu) than those of members of the Galloanserae. The cellular composition of both testicular capsule and peritubular tissue was similar generally to that of members of the previously studied Galloanserae and of mammals. The tunica albuginea of the testicular capsule mainly comprised smooth-musclelike or myoid cells mostly running in one direction and occurring in one main mass. Unlike the Galloanserae, the tunica albuginea contained more collagen fibres than smooth muscle cells, especially in the ostrich. Peritubular tissue was similarly composed of smooth-muscle-like cells distributed in several layers. Actin microfilaments and desmin and vimentin intermediate filaments were variably immunoexpressed in these two tissue types in both birds, with a clear dichotomy in the peritubular tissue. Thus, taken together with studies of some members of the Galloanserae, avian testes clearly contain a morphological mechanism that is represented partly by the smooth muscle cells of the testicular capsule and peritubular tissue for transporting the testicular fluid, which is usually copious in birds, and its cellular content from the testis into the excurrent duct system; thismechanism is similar to that found in mammals.

: The presence, location and degree of immunoexpression of various microfilament (MF) and intermediate filament (IF) systems (actin, cytokeratins, desmin, vimentin) were studied in the excurrent ducts of the testis in sexually mature and active galliform (Japanese quail, domestic fowl, turkey) and anseriform (duck) birds. These proteins were variably expressed between the epithelia and periductal tissue (periductal smooth muscle cell layer and interductal connective tissue) types and between species. Variable heterogeneous co-expression of filament systems was also found in the various duct epithelia and periductal tissue types: co-expression of filament systems was the rule rather than the exception. In the duck, neither vimentin nor cytokeratin was present in any of the tissues, whereas actin and desmin (absent in the rete testis) were co-expressed in the efferent ducts and epididymal duct unit (comprising the ductus conjugens, ductus epididymidis and ductus deferens). Actin, desmin and vimentin were generally co-expressed in the rete testis, efferent ducts and epididymal duct unit of the quail, domestic fowl and turkey, with vimentin being more strongly immunoreactive than actin and desmin in the epididymal duct unit, but more weakly immunoexpressed in the efferent ducts. Cytokeratin was present and co-expressed with actin, desmin and vimentin in the rete testis, efferent ducts and epididymal duct unit of the domestic fowl and turkey, but not in the quail and duck. The periductal smooth muscle cell layer and interductal tissue co-expressed actin, desmin and vimentin variably in all birds. Luminal spermatozoa of both the turkey and duck were immunonegative for all protein systems, whereas those of the quail and domestic fowl co-expressed actin, desmin and vimentin moderately or strongly. The tissues of the reproductive tract of male birds thus contain cytoskeletal protein systems that are variably but mostly co-expressed and whose contractile ability appears necessary and sufficient for transportation through the various excurent ducts of the voluminous testicular fluid and its high sperm content, characteristic features of male avian reproduction.

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One billion erythrocytes lysate samples obtained from pregnant (28-day old)

The efferent duct of the ostrich consists of two segments, the proximal efferent duct (PED) and the distal efferent duct (DED) that are continuous, as in some other birds. Both segments of the duct possess an epithelium comprising non-ciliated and ciliated cells in varying proportions between the two segments. The non-ciliated cell (type I) of the PED contains a well-developed, subapical endocytic apparatus of apical tubules and endocytic vacuoles, a solitary, large, heterogeneous lipid droplet, and numerous, oval, dense bodies in the supranuclear region of the cell. Mitochondria tend to concentrate in the basal part of the cell. Intercellular spaces between the non-ciliated cells are enlarged, especially in the basal half of the epithelium. Together, these morphological features confer on the PED an efficient fluid absorption capability. The DED epithelium displays the type II non-ciliated cell whose poorly developed subapical endocytic apparatus as well as the absence of dilated basal intercellular spaces indicate its limited fluid absorptive capacity.

The fate of the proximal centriole in passeridan birds is an area of controversy and relative lack of knowledge in avian spermatogenesis and spermatology. This study examines, for the first time, spatiotemporal changes in the centriolar complex in various phases of spermiogenesis in a passerine bird, the Masked weaver (Ploceus velatus). It also describes the configuration of the centriolar complex and the relationship between it and the granular body in both intra-and extra-testicular spermatozoa. It is shown that the proximal centriole is retained and attaches, at its free end, to the granular body of spermatids in every step of spermiogenesis, as well as in mature intra-testicular and post-testicular spermatozoa, including those in the lumen of the seminal glomus. As the centriolar complex, along with its attached granular body, approaches the nucleus in the early spermatid, the proximal centriole articulates with the distal centriole at an acute angle of about 45⁰, and thereafter, both centrioles, still maintaining this conformation, implant, by means of their articulating proximal ends, at the implantation fossa of the nucleus.In the mature spermatid and spermatozoon, the granular body winds itself helically around the centriolar complex in the neck/midpiece region of the cell, and, thus, becomes the granular 2 helix. The significance of this observation must await future studies, including possible phylogenetic re-evaluation and classification of birds.

The cellular composition of the testicular capsule, seminiferous peritubular tissue, the epithelia as well as periductal muscle cell layers of the excurrent ducts was studied, in sexually mature and active Masked Weaver (Ploceus velatus) b i r d s o f t h e p a s s e r i n e f a m i l y , P l o c e i d a e .Ultrastructure of the contractile cells in the testicular capsule, peritubular and periductal tissues showed that these cells were smooth muscles of typical morphological characteristics. Variability in the immunohistochemical co-expression of microfilaments and intermediate filaments in the different tissues was evident. Actin and desmin proteins were co-expressed 2 immunohistochemically in the testicular capsule and seminiferous peritubular smooth muscle layer. Actin was singly and very weakly expressed in the rete testis epithelium while cytokeratins and desmin were co-expressed in the epithelium of the excurrent ducts. The periductal muscle layer of all ducts of the epididymis, the ductus deferens as well as the seminal glomus, strongly co-expressed actin and desmin. Vimentin was absent in all cells and tissue types studied. There is clear evidence that the tissues of the male gonad and its excurrent ducts in the Masked Weaver, as has been reported for members of the Galloanserae and Ratitae, contain well-formed contractile tissues whose function would include the transportation of luminal through-flow from the testis into, and through, its excurrent ducts. The microtubule helix in the head and of the mid-piece, of elongating spermatids, as well as of the mature spermatozoa in the various excurrent ducts, including some spermatozoa in the seminal glomus, also co-expressed these three proteins.