Tarcízio Antônio Rego de Paula

Espermatogênese de catetos (Tayassu tajacu)

The aim of this study was to analyze morphologically and functionally the spermatogenesis in adult collared peccary. Fifteen testes provided by a commercial wild animal abattoir were used. The stages of the seminiferous epithelium cycle, the cellular number of the seminiferous tubules, the intrinsic efficiency of spermatogenesis, the Sertoli cells, the mean diameter of the seminiferous tubules and the volumetric proportion of testicular parenchyma components were analyzed. The mitosis efficiency coefficient in collared peccary was 22.54, the meiotic profile, 1:2.7, and spermatogenesis general profile was 1:64. It was concluded that spermatogenesis in peccary is very similar to that in pigs.

Histomorphometric evaluation of the neotropical brown brocket deer Mazama gouazoubira testis, with an emphasis on cell population indexes of spermatogenic yield

Information on the reproductive biology of neotropical cervids is scarce. Therefore, the aim of this study was to perform biometric, histologic and stereologic analyses of the brown brocket deer Mazama gouazoubira testis, with an emphasis on the intrinsic yield and the Sertoli cell index. Seven adult males kept in captivity were used. The animals were immobilized; anesthetized and testicle fragments were obtained by biopsy incision. The material was fixed, processed and examined by routine histological methods for light microscopy. The average body weight was 17.2kg, from which 0.40% were allocated in gonads and 0.33% in seminiferous tubules, which represented 85.9% of the testis parenchyma. The mean albuginea width and volume were 345.7μm and 3.5mL (5.3% of the testicular weight), respectively. The mean mediastinum volume of both testicles was 1.0mL (1.5% of the testicular weight) and the testicular parenchyma volume corresponded to 93.1% of total testicular weight (64.9g). The seminiferous tubules diameter was 224.4μm, while the epithelium height was 69.6μm. On average, an adult brown brocket deer showed a total of 1418m of seminiferous tubules in both testicles (21.5m per gram of testis). Each stage I seminiferous tubular cross section contained 1.10 type A spermatogonia, 13.4 primary spermatocytes in pre-leptotene/leptotene, 13.7 spermatocytes in pachytene, 48.8 round spermatids and 3.7 Sertoli cells. The general yield of spermatogenesis was 44.7 cells and the Sertoli cell index was 13.2. The qualitative and quantitative description of testicular histology of brown brocket deer help to understand its spermatogenic process and to establish parameters for the reproductive biology of this wild species. Furthermore, the data from the present research will help further studies using other species of Brazilian cervids, especially endangered ones, making an additional effort to the species preservation.

Maturação sexual e parâmetros reprodutivos em touros da raça Nelore criados em sistema extensivo

The objective of this study was to verify the stage of sexual maturity, occurrence of the testicular format and the relationship among reproductive characteristics. Data were used from 5903 Nellore bulls averaging 21 months submitted to the soundness evaluation from 1999 to 2003. At the time of the evaluation, the following characteristics were recorded: scrotal circumference at soundness evaluation (31.99 ± 2.23 cm), left testicular length (11.21 ± 0.98 cm) and right testicular length (11.26 ± 0.97 cm), left testicular width (5.92 ± 0.44 cm) and right testicular width (5.97 ± 0.46 cm), testicular format (1.72 ± 0.46), testicular volume (632.21 ± 132.72 cm3), individual motility (69.56 ± 12.31%), vigor (2.87 ± 0.61), as well as total defects (22.19 ± 11.13%) and major defects (15.86 ± 10.45%) of the spermatozoa. The frequencies of the testicular formats were long (30.80%), long-moderate (66.19%), long-oval (2.49%), oval-spherical (0.02%) and spherical (0.04%). Correlations between the scrotal circumference and the reproductive traits were positive. Scrotal circumference is a good trait for selection of young Nellore bulls. More than 70% of the animals studied are sexually mature at 21 months old.

Morphometry of testis and seminiferous tubules of the adult crab-eating fox (Cerdocyon thous, Linnaeus, 1766)

Body and testicular biometric parameters are very important for establishing reproductive patterns and, consequently, the development of protocols for assisted reproduction in different species. A direct correlation between the testis weight and the sperm population was observed in other studied species, because the testis size primarily reflects the total volume of the seminiferous tubule, its main component. The objective of this study was to determine the testicular volume parameters and correlate data from morphometry of testis and seminiferous tubules with body mass in six adult crab-eating foxes. The mean body weight of the crab-eating foxes in this study was 6.53 kg, with approximately 0.068% allocated to the testicular mass and 0.042% specifically to seminiferous tubules, which represented 87.5% of the testicular parenchyma. The albuginea comprised 12.5% of the testicular mass. The mean diameter of seminiferous tubules was 236 μm, and the mean thickness of the seminiferous epithelium was 62.9 μm. Values of tubular parameters indicate a sperm productivity close to those observed in previously studied carnivores.

Evaluation of the Cell Population of the Seminiferous Epithelium and Spermatic Indexes of the Bat Sturnira lilium (Chiroptera: Phyllostomidae)

Due to the scarcity of information about patterns of spermatogenesis in bats, this study aimed to provide information on the testicular activity of the bat Sturnira lilium along the annual seasons. Thus, a series of morphometrical and stereological analyses were made using the testes of adult S. lilium in order to achieve a better understanding of the sperm production dynamics. Light and transmission electron microscopy analyses were performed in testicular fragments of animals captured during dry and rainy seasons. The testes followed the pattern of organization described for other mammals, and there were no morphological differences between organs collected either in dry or in rainy seasons. Each tubular cross-section in stage 1 was made of 0.5 type-A spermatogonia, 4.4 primary spermatocytes in preleptotene/leptotene, 3.7 in zygotene, 11.9 in pachytene, 35.6 round spermatids and 8.5 Sertoli cells. The mitotic and meiotic indexes were 15.4 and 2.9 cells, respectively, while the spermatogenesis yield was 68.7 cells. The testicular sperm reserves was 37.61×106 cells, and daily sperm production per gram of testis averaged 209.68×106 cells, both highest averages occurring in the rainy season. S. lilium male bats have a continuous reproductive pattern, high spermatogenesis yield and low support capacity by the Sertoli cells.

Histomorphometric evaluation of the Molossus molossus (Chiroptera, Molossidae) testis: The tubular compartment and indices of sperm production

Insectivorous bats play a very important role in the regulation of tropical ecosystems, but information about their reproductive cycle is lacking. Thus, male Molossus molossus were captured over the four seasons, and morphometric analyses of their testes were conducted to infer on the gonadal dynamics and the reproductive capacity of the species. Testes were immersed in Karnovsky fixative, and fragments were embedded in methacrylate and paraplast for morphometric and TUNEL assay respectively. The least gonadosomatic index (0.3%), tubulesomatic index (0.2%) and tubular diameter (133.2μm) occurred in summer. An adult M. molossus showed a total average of 48.9m of seminiferous tubules per gram of testis. Primary spermatocytes were observed in the zygotene at Stage 1 of the seminiferous epithelium cycle. The greatest meiotic index was obtained in winter (3.8 cells), and the general yield of spermatogenesis was higher in winter (64.5 cells) than in summer (19.1 cells). There was no difference in the apoptotic cells count among seasons. The Sertoli cell index was less in summer (5.9) than in fall (11.6), while the number of Sertoli cells per gram of testis did not vary significantly among the seasons (28.0×10(7)). The spermatic reserve per gram of testis was greater in the fall (63.9×10(7)) and winter (69.8×10(7)) than summer (37.1×10(7)). We conclude that M. molossus males show a continuous reproductive cycle, featuring greater spermatogenic activity during the fall and winter, a tubular length above the average of other mammals and a less support capacity of the Sertoli cells.

Organization and seasonal quantification of the intertubular compartment in the bat Molossus molossus (Pallas, 1776) testis

Environmental factors can influence the reproductive rates in bats, and since morphometric information of bats testis is scarce, we aimed to compare the organization and quantification of the intertubular components in the testes of the bat Molossus molossus, collected in different seasons. Testicular histological sections were evaluated using light and electron microscopy. The intertubular compartment occupied an average 10% of the testes, being predominately constituted of Leydig cells (LC). The percentages of the testes occupied by the intertubular compartment and by LC were significantly higher in summer, while the other intertubular components did not vary significantly among the seasons. As suspected under light microscopy, the ultrastructural analysis confirmed the existence of multinucleated LC during winter. The increase in the nuclear percentage of LC in winter seems to have caused the decrease of the cytoplasmatic measurements in that season, as well as in the volume of LC. The highest cytoplasmatic values and volume of LC registered in the spring, summer, and fall can be related to greater activity of this cell in these seasons. The higher investment in intertubular tissue and in LC observed in summer, compared to winter; suggest an increase in the steroidogenic capacity of this bat during summer. The analyses correlating testicular morphometry and abiotic environmental factors in this study confirm the influence of climatic factors on the reproduction of M. molossus. Microsc. Res. Tech., 2013.

Stages and duration of the seminiferous epithelium cycle in the bat Sturnira lilium

Knowledge of the stages that compose the seminiferous epithelium cycle (SEC) and determination of the duration of spermatogenic processes are fundamental for the accurate quantification of the dynamics of spermatogenesis. The aim of this study was to characterize the stages that compose the SEC of the bat Sturnira lilium, including evaluation of the average frequency of each of these stages throughout the year and calculation of the duration of the spermatogenic process. An ultrastructural characterization of the formation of the acrosomal cap was also performed. Testicular fragments were processed for morphological and immunohistochemical analysis as well as ultrastructural analysis using transmission electron microscopy. According to the tubular morphology method, the SEC in S. lilium is divided into eight stages, following the pattern found in other mammals. Primary spermatocytes were found at zygotene in stage 1 of the cycle. There was no variation in frequency of each of the stages over the seasons, with stage 1 being the most frequent, and stage 7 the least frequent. The duration of one seminiferous epithelium cycle was 3.45 days, and approximately 15.52 days were required for the development of sperm from spermatogonia. Ultrastructural characterization allowed the formation of the acrosomal cap in round spermatids to be monitored. In conclusion, the stages that compose the SEC in S. lilium are generally similar to those described for other mammals, but the duration of the spermatogenic process is shorter than previously recorded for mammals. The presence of primary spermatocytes at zygotene in stage 1 of the cycle is probably due to the longer duration of this stage.

Stages and duration of the cycle of the seminiferous epithelium in oncilla (Leopardus tigrinus, Schreber, 1775)

Six adult Leopardus tigrinus (oncilla) were studied to characterize stages of the seminiferous epithelium cycle and its relative frequency and duration, as well as morphometric parameters of the testes. Testicular fragments were obtained (incisional biopsy), embedded (glycol methacrylate), and histologic sections examined with light microscopy. The cycle of the seminiferous epithelium was categorized into eight stages (based on the tubular morphology method). The duration of one seminiferous epithelium cycle was 9.19 d, and approximately 41.37 d were required for development of sperm from spermatogonia. On average, diameter of the seminiferous tubules was 228.29 μm, epithelium height was 78.86 μm, and there were 16.99 m of testicular tubules per gram of testis. Body weight averaged 2.589 kg, of which 0.06 and 0.04% were attributed to the testis and seminiferous tubules, respectively. In conclusion, there were eight distinct stages in the seminiferous epithelium, the length of the seminiferous epithelium cycle was close to that in domestic cats and cougars, and testicular and somatic indexes were similar to those of other carnivores of similar size.

Cycle of the seminiferous epithelium of the bat Molossus molossus, characterized by tubular morphology and acrosomal development

Abstract Objective To describe the seminiferous epithelium cycle (SEC) by tubular morphology method, and the acrosomal development of individualizing spermatids, and to explore the distinction of the stages between two generations of spermatids. Methods Testicular fragments were fixed in Karnovsky, embedded in glycol methacrylate and examined under light microscopy and transmission electron microscopy. Sections in 3 μm thickness were stained with toluidine blue for the characterization of the stages of the SEC by the tubular morphology method, or submitted to the PAS reaction for the visualization of the acrosomal formation. Additional details on the acrosomal formation were observed under transmission electron microscopy. Results Through the eight stages described by tubular morphology method, 10 steps of acrosomal formation were observed in the spermatid development, called acrosomal steps. As the spermatids were produced in stage V of the tubular morphology method, it was at this stage from which began the steps of acrosomal development. Conclusions We propose association of the acrosomal steps for the first time, with the different stages by tubular morphology method. This method presents an alternative to the existent Methods, allowing interspecific comparisons of the SEC, not only among different species of bats, but also among the other mammals.