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.

1. Ultrastructural changes that take place in the spermatids of the turkey were studied. Twelve steps of spermiogenesis are described. 2. Acrosomal formation is similar to that in the domestic fowl and quail. The perforatorium develops as a dense granule in a tubular invagination of the thickened part of the nuclear membrane during the acrosomal phase of spermatid development. 3. Patchy appearances of the circular (CM) and longitudinal (LM) manchette occur concurrently for a very brief period before the complete disappearance of the former and full establishment of the latter, an indication that the CM reorganises to become the LM. 4. A chromatoid body, as found in mammals, is present in the mid-piece of the turkey spermatid, and glycogen aggregations occur in the spermatid cytoplasm, but not in the mature spermatid or spermatozoon. 5. Mitochondrial alignment around the axoneme in the mid-piece takes place only after the dissolution of the LM, unlike in the Japanese quail. 6. The merits and disadvantages of the 4-phase and step-wise systems of spermatid classification and evaluation are discussed.

Spermiogenesis and cellular associations in the seminiferous epithelium of the guinea fowl were studied and described in "sexually" active adult birds. PAS stain was found to be useful in the recognition of steps of spermatid differentiation only in the first early stages. Nuclear morphological changes were subsequently found to be more reliable in tracing steps of spermiogenesis. It was observed that haematoxylin-eosin stained tissue can be used in the study of spermiogenesis in the bird. Various stages of the seminiferous epithelium were observed in any cross-section of the seminiferous tubules. Distinct cellular associations were observed, but intermix of adjacent germ cells or heterogenous cellular associations were frequently encountered.

The epididymal region of the Japanese quail was studied histologically. The organ consists of the extratesticular portion of the rete testis, the ductuli efferentes proximales and distales, the ducti conjugentes and ductus epididymidis. Distinct tubuli recti link the seminiferous tubules with the rete testis. The non-ciliated cells of the ductuli efferentes proximales and distales show, between them, certain internal structural differences which were highlighted. In 40% of the birds, the ductus deferens showed dark-grey pigments, regarded as melanin. The epididymal region was generally similar in structure to that of the domestic fowl, turkey and duck.

Current knowledge on avian spermiogenesis, including strengths and weaknesses, has been reviewed. Information on avian spermiogenesis considerably lags behind that in mammals because of the paucity of reports in birds. Spermiogenesis in passerine birds has received even much less attention than in non-passerine birds. Mechanisms underlying morphogenesis of the acrosome and nucleus, and roles of microtubular assemblies are poorly understood. The proximal centriole found in non-passerine birds, but hitherto considered to be absent in passerine birds, has recently been described in spermatids and mature spermatozoa of 2 passeridan species, including the Masked weaver for which new and detailed spermiogenetic information is provided in this review. A great deal more studies on spermiogenesis, and spermatogenesis generally, in various avian species are required to considerably enhance knowledge of this phenomenon, contribute to comparative spermatology, provide a basis for appropriate applied studies, and contribute to understanding of phylogeny in this vast order of vertebrates.

Keywords:Di-(n-butyl) phthalate Leydig cell Steroidogenesis Male Japanese quails Endocrine disruptionIn the present study, we have investigated the effects of 30-day dietary (pre-pubertal) exposure to different doses (0 (control), 1, 10, 50, 200 and 400 mg/kg bodyweight/day) of di(n-butyl) phthalate (DBP) on Leydig cells of adult male Japanese quails by quantifying the transcript levels for P450 side-chain cleavage (p450scc), P450c17 (CYP17), and 3β-and 17β-hydroxysteroid dehydrogenase (hsd) using quantitative (real-time) poly-merase chain reaction (qRT-PCR). In addition, the plasma testosterone levels were analysed using radioimmuno-assay (RIA) and testis was examined for evidence of gross pathology and histopathology. Our data showed that pre-pubertal exposure to DBP produced alterations in testicular architecture as evident by poorly developed or misshaped testis, and altered spermatogenesis due to tubular degeneration and atrophy of seminiferous tubules especially in the high DBP dose (200 and 400 mg/ kg) treated groups. In addition, DBP altered several key en-zymes involved in testicular steroidogenesis pathways in an apparent dose-dependent manner. For example, bi-phasic effects of DBP were observed for P450scc and 3β-hsd mRNA, that were generally increasing at low dose 10 mg/kg, and thereafter, an apparent dose-dependent decrease between 50 and 400 mg/kg. The steroidogenic acute regulatory (StAR) protein was at the lowest detectable limits and therefore not quantifiable. These effects did not parallel the non-significant changes observed for plasma testosterone levels. The present data is consis-tent with previous reports showing that DBP modulates Leydig cell steroidogenesis in several species, with a po-tential negative effect on reproduction in those avian species that are vulnerable to endocrine disrupting chemicals.

Carbendazim, a metabolite of benomyl which is widely used as a fungicide, has been found to cause testicular and epididymal damage in laboratory rats, mice and hamsters. No studies of the effects of this chemical on the reproductive organs of birds have been reported previously. This report is that of an investigation on the response of the testis of the Japanese quail to experimental administration of this chemical in sexually mature and active birds. A single dose (400 mg/kg body weight) of carbendazim was administered orally to 20 quails that were sacrificed thereafter at 5 h, 3, 8 and 13 days post-exposure, at five birds spatio-temporally. Five birds acted as control. Testis weights and seminiferous tubular diameter as well as epithelial height decreased significantly from 8 day post-exposure. Epithelial histology was remarkably disrupted, and cessation of spermatogenesis occurred at 13 day post-administration of the chemical. Degenerative changes were uniform in each testis, and not patchy or multi-focal, as previously reported in the rat. The observed histological changes in the testis, due to carbendazim, were capable of causing prolonged infertility in exposed birds.

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.