Quantificação de células dos túbulos seminíferos e rendimento da espermatogênese em cutias (Dasyprocta aguti) criadas em cativeiros

Reproductive characteristics of wild boar males (Sus scrofa) under different environmental conditions

The wild boar population has been on a permanent increase over the last decades, causing conflicts with the requirements of modern human society. Existing effort to stabilize wild boar numbers generally fails with one of the causes being the high reproductive potential of wild boar. The aim of this study was to assess the onset of sexual maturity in wild boar males with regard to age, physical frame and environmental conditions on the basis of testicle development and sperm production. This study assessed the dimensions of gonads and the occurrence of sperm in boars caught during common hunts. Environmental conditions were found as an important factor for growth and sexual maturity of wild boar males. The body weight was a more important factor for sperm production than the age of young wild boar males. The weight threshold for sperm production in the testes was 29 kg of live weight, which corresponds to 6 months of age on average. This study has proven that environmental conditions are a significant factor affecting the physical development of male wild boars, more specifically the growth rate of their body frames and the onset of sexual maturity. In a better quality environment boars grow faster and enter puberty at an earlier age. Poor food supply and/or high hunting pressure result in slower body and testicular growth, as well as the production of sperm at a later age (approx. 2-3 months later).

Análise morfológica e funcional do processo espermatogênico em cobaios (Cavia porcellus) da pré-puberdade até a pós-puberdade

Este estudo descreveu as análises morfológica e funcional do processo espermatogênico em cobaios (Cavia porcellus) de cinco (S5); seis (S6); nove (S9) e onze (S11) semanas de idade (N=5/grupo). Os aspectos analisados incluíram a contagem das populações celulares presentes no estádio 1 do ciclo do epitélio seminífero (CES), eficiência das mitoses espermatogoniais (RMi), produção meiótica (RMe), rendimento geral da espermatogênese (RGE), índice de células de Sertoli (ICS) e capacidade de suporte das células de Sertoli (CSCS). Os resultados mostraram que número médio de espermatogônias A, espermatócitos primários em pré-leptóteno/leptóteno, espermatócitos primários em paquíteno, células espermatogênicas totais e células de Sertoli mostraram variações numéricas em função da idade, entretanto, não detectadas estatisticamente, enquanto espermátides arredondadas aumentaram significativamente na puberdade e depois se estabilizaram. A produção espermatogênica de cobaios de 5 a 11 semanas não atingiu o ponto de estabilização e o RMi, RMe, RGE, ICS e CSCS mostraram variação numérica significativa em função da idade. Os resultados demonstraram que Cavia porcellus na pós-puberdade 2 são um modelo experimental vantajoso para estudos de processos de reconhecimento homólogos, alinhamento, e sinapses durante a prófase meiótica; o rendimento intrínseco da espermatogênese em cobaios é semelhante ao relatado para ratos Wistar, pacas e cutias (Dasyprocta sp.) e menor do que em preás, enquanto que a eficiência funcional das células de Sertoli é superior a de cutias e ratos Wistar e inferior à de pacas, rato espinhoso e catetos. Concluiu-se que em cobaios a espermatogênese está completamente estabelecida na semana 6 de idade, indicando a fase púbere do desenvolvimento sexual, e até a semana 11 eles não atingiram a produção espermática diária máxima e, portanto, a maturidade sexual.

Proliferation of seminiferous epithelium cells during the postnatal development in goats

The objective of this research study was to evaluate the proliferation of somatic and germ cells in the seminiferous epithelium of Alpine goats. A total of 47 goats reared in semi-intensive conditions were used, divided into age groups from birth up to 12 months of age. Following castration, testis fragments were included in plastic resin and were mounted in Entellan(®) for histometric evaluations. In general, the total number of germ cells per seminiferous cord transverse section was low until 4 months of age. An increase was observed between 4 and 5 months, lasting until 9 months of age. From that age on, this number tended to stabilize, until 12 months. The population of support cells (undifferentiated support cells and Sertoli cells) remained constant from birth to the first month, when it peaked. This was followed by a reduction until the fifth month of age. From that age on, there was differentiation in mature Sertoli cells, and its population remained constant until 12 months of age. It can be concluded that Alpine goats were in the impuberal phase from birth to 3 months of age, prepuberal phase during the fourth month, reached puberty at 5 months of age, postpuberal phase from 6 to 8 months, and reached sexual maturity at 9 months of age. Overall yield of spermatogenesis and Sertoli cell index increased from puberty up to the 12th month of age.

Development of spermatogenesis in captive-bred Spix's yellow-toothed cavy (Galea spixii)

The aim of this study was to evaluate the phases of sexual development and spermatogenesis of Spix’s yellow-toothed cavy (Galea spixii) based on analyses of the structural components of the testes. The testes of animals from 0 to 150 days of age were collected by orchiectomy, weighed, and processed for analysis by light microscopy. At 45 days of age, spermatozoa were seen in the tubular lumen. Spermatogenesis was not established in animals from 45 to 150 days of age. The stages of sexual development may be classified into the following phases: from birth to the age of 15 days (immature); 30 days of age (prepubertal); 45–105 days of age (pubertal); and 120 and 150 days of age (postpubertal). This is the first study to address the male reproductive biology of Spix’s yellow-toothed cavy.

Morphology of the male agouti accessory genital glands (Dasyprocta prymnolopha Wagler, 1831)

The morphology of the accessory genital glands of the male agouti was studied in twenty-three animals that were raised in captivity. Twenty animals had their genital glands dissected in situ for macroscopic description. The samples of each gland were recovered, embedded in paraffin, sliced and stained by Hematoxylin-Eosin technique. It was founded four pairs of glands: the vesicular glands, the coagulating glands, the prostate and the bulbourethral glands. Histological characteristics of the vesicular, coagulating and prostate glands showed similar morphology, within the pseudostratified columnar epithelium. The tubulo-alveolar type of the bulbourethral glands showed a lack of connective tissue among the tubules, a small amount of red stained presented it the cytoplasm, and the presence of vacuoles in the tissue. This study concluded that the agouti showed to have similar morphological aspect described in the others species of rodents.

Somatic and germ cell proliferation during post-natal development of the testis in the wild boar (Sus scrofa scrofa)

This study aimed to investigate the proliferation of cells in the seminiferous epithelium, the intrinsic rate of spermatogenesis and Sertoli cell index in wild boars, during the period from birth to 12 months of age. A total of 52 animals raised in captivity were assigned to 13 experimental groups. After unilateral orchidectomy, fragments of the testes were embedded in plastic resin and used to prepare slides for histometric analysis. Variables assessed in each age group included the characterization of cell populations in the seminiferous epithelium, the intrinsic rate of spermatogenesis, Sertoli cell index and the stages of testicular development in each animal. Gonocytes were in greater numbers in newborn animals, and by the fourth month were no longer identified. The population of spermatogonias increased from 3 to 9 months, after that showed a tendency to stabilization. Primary spermatocytes in pre-leptotene/leptotene were first seen in 8-month-old animals. Primary spermatocytes in pachytene, and round spermatids increase gradually in frequency in animals from 9 to 12 months of age. Undifferentiated support cells were very frequent at birth to 7 months and increased between 7 and 8 months, after that there was a tendency for no further increase in this cell type. We conclude that the Sertoli cell population stabilized in the pre-pubertal phase and germ cell population increased after puberty. The overall yield of spermatogenesis and Sertoli cell index were greater in animals around 12 months of age.