Spermatogenesis in goats with and without scrotum bipartition.
The objective of the present research was to quantify the seminiferous epithelium cells, spermatogenesis efficiency and characterize the ultrastrucure of Sertoli cells in goats. Eighteen goats were used and divided into three groups: Group I - goats without bipartition of the scrotum; Group II - animals with bipartition of the scrotum in up to 50% of the testicular length; Group III - goats with bipartition of the scrotum in more than 50% of the testicular length. The goat testes in Group III had a greater number of primary spermatocytes (25.37 ± 4.55 cells per cross sections), spermatids (112 ± 15.12 cells per cross sections), and Sertoli cells (9.46 ± 1.74 cells per cross sections) than the animals in Groups I and II (P<0.05). The spermatogenic mitotic, meiotic, and general efficiency were greater in animals in Group III (1.25 ± 0.28; 5.12 ± 1.63; 6.44 ± 1.96) when compared to those in Groups I and II. Sheet-like processes originated from the Sertoli cell body as simple and smooth structures which involved almost all the surface of germ cells. Slender cord-like processes originated from Sertoli cells and also from the sheet-like processes. The relative frequency of the cycle stages showed differences among the groups of goats studied, and the highest frequency was in Stage 3 (20.68% for goats in Group I, 21.15% for those in Group II, and 16.89% for the animals in Group III). In conclusion, goats with bipartition of the scrotum have a greater number of germ and Sertoli cells per cross section of seminiferous tubule, that indicated a greater sperm production when compared to the other groups, and the ultrastructure of the Sertoli cell process did not present any relationship with bipartition of the scrotum.
Cytology of germ cells in the scrotal testes of naturally unilate­ral cryptorchid West African dwarf goats
The present study compares the light and ultrastructure of germ cells between testes of normal bucks and the scrotal testes of unilateral cryptorchid bucks using light, electron microscopic and immunohistochemistry techniques. Both testes showed evidence of normal spermatogenesis characterised by presence of complete germ line. In the two groups studied, types A and B spermatogonia were lying close to the basal lamina and exhibited their respective typical morphology. The spermatocytes were of two main types, primary and secondary. The spermatocytes were round and distributed from the basal to the luminal compartments. The primary spermatocytes were in various stages of meiotic divisions. Secondary spermatocytes were observed only at stage 4 of the seminiferous epithelial cycle. Spermatids exhibited complex morphological configuration suggestive of normal spermiogenesis. Evidence of spermiation, characterised by the presence of mature spermatozoa in the lumen of the seminiferous tubule was observed in testes of normal and scrotal testes of unilateral cryptorchid bucks. Eight stages of the seminiferous epithelia cycle were observed in the scrotal testes of the cryptorchid and testes of the normal bucks. Also, cellular composition of each stage was similar in the normal and scrotal testes of the cryptorchid bucks. Similar immunoreactivity expression for vimectin, vascular endothelial growth factor, estrogen and fibroblast growth factor respectively, were recorded in the two groups studied. The findings in the present study suggest the presence of morphologically normal germ cells and normal cell associations in the scrotal testes of naturally unilateral cryptorchid West African Dwarf bucks.
The relation of food quantity to rumination behavior.
Preliminary work suggested that the quantity of food ingested by retarded individuals who usually ruminated following meals was related to the frequency and duration of ruminating responses. This possible relation was experimentally examined by systematically varying food quantity from regular portions to satiation levels for three retarded individuals who exhibited high levels of ruminating. A clear functional relation of food quantity to ruminating emerged, with satiation procedures producing rapid and large decreases in the relatively high frequencies and durations of ruminating characteristic of baseline food quantity conditions.