Follicular Atresia, Cell Proliferation, and Anti-Mullerian Hormone in Two Neotropical Primates (Aotus nancymae and Sapajus macrocephalus).

This study evaluated the follicular atresia, cell proliferation, and anti-Mullerian hormone action in Aotus nancymae and Sapajus macrocephalus during three sexual phases (follicular, luteal, and gestational). Follicular quantification and immunolocalization of Caspase-3 protein, B-cell lymphoma 2 (BCL-2), proliferating cell nuclear antigen (PCNA), and anti-Mullerian hormone (AMH) were performed. A significant difference in the quantification between preantral and antral follicles, with a progressive decrease in the antrals, was identified. Protein and hormonal markers varied significantly between follicle cell types (A. nancymae p = 0.001; S. macrocephalus, p = 0.002). Immunostaining in the preantral and antral follicles was present in all sexual phases; for Caspase-3, in granulosa cells, oocytes, and stroma; for BCL-2, in granulosa cells, oocytes, and theca; and for PCNA and AMH, in oocytes and granulosa cells. The immunostaining for Caspase-3 was more expressive in the preantral follicles (follicular phase, p < 0.05), while that for BCL-2 and PCNA was more expressive in the antral follicles of the follicular phase. The AMH was more expressive in the primary and antral follicles of nonpregnant females, in both the follicular and luteal phases. Our results contribute to understanding the ovarian follicular selection, recruitment, and degeneration of these species.

Early puberty in short-haired Guinea pigs kept in laboratory animal facilities.

Lab animals, such as Guinea pigs (Cavia porcellus), are crucial for scientific development, as they play an important role in the development and quality control chain of vaccines and drugs distributed by the Brazilian public health system. Investigating their biological and physiological parameters is fundamental to raise and keep these animals, so the handling of the facilities that hold them can be updated whenever new information comes up, with the well-being of the animals and alignment with the 3 Rs in mind. In the search for understanding reproductive aspects of Guinea pigs, the present study had the main goal of studying puberty by means of estrous cycle analysis in short-haired Guinea pigs. Guinea pigs have a vaginal occlusive membrane that covers the vaginal orifice. Its rupture takes place gradually and naturally, moments before labor and during estrus. The present study followed 42 females as for the presentation of the vaginal occlusive membrane. Once the membranes ruptured spontaneously, a swab was collected to study vaginal cytology. Membrane rupture was observed in 39 females; six females showed membrane rupture with less than 21 days of age (17 to 21 days). Twenty-three females were characterized as being in estrus due to cytology showing a prevalence of anucleated superficial cells. One of these females was younger than 21 days old. The opening of the vaginal occlusive membrane took place most frequently in intervals between 17 and 18 days, and the membrane remained open between one and three consecutive days. It was possible to follow three cycles of membrane opening on six females. The present study showed the need to adapt handling guidelines for C. porcellus kept in research animal facilities. The early age of puberty imposes the need of separate the female daughters from their fathers at 16 days old.

Fetal development of the Poeppig's woolly monkey (Lagothrix poeppigii).

The intrauterine development is an evolutionary strategy that prepares the neonate for extra-uterine life, thus providing important information on the life history of species. In this study, we described the external and internal morphology of 25 fetuses of Poeppig's woolly monkeys (Lagothrix poeppigii) by taking advantage of a 10-year participatory collection of biological samples originated from animals hunted for subsistence purposes in the Peruvian Amazon. Logistic regressions estimated the probability of occurrence of each external morphological characteristic in relation to the crown-rump length (CRL). The presence of nails, closed eyelids, differentiated genitalia and formed limbs with separation of the digits were observed in all analyzed fetuses (≥4.2 cm CRL). The other characteristics appeared in the following order: skin with epidermal pigmentation, oral and nasal mucosal pigmentation, tactile pelage and covering pelage. Although advanced fetuses (>15.8 cm CRL) showed most fetal external characteristics, they were not fully developed and no specimen showed tooth eruption or opened eyelids. The growth formula used to determine fetal age was ∛W = 0.042 (t - 45), with a high linear relationship between CRL and gestational age. All associations between the external biometry, absolute volume of internal organs and the CRL had a high coefficient of determination. Advanced fetuses and adults showed similar relative volume of thoracic and abdominal organs, except for thymus and the liver with a higher and lower relative volume, respectively. The relative volume of the tubular gastrointestinal tract and the thymus had a constant increase along fetal development, and the liver showed a significant decrease. This study describes important morphological events for understanding the gestational development in the Lagothrix genus. In addition, these results may be useful to improve imaging techniques, contributing to the in situ and ex situ reproductive management of this highly hunted species in the Amazon.

Embryonic and fetal morphology in the lowland paca (Cuniculus paca): A precocial hystricomorph rodent.

In mammals, the embryonic and fetal development of a species has evolved to maximize neonatal survival. In this study, we use a sample of 132 embryos/fetuses of wild lowland paca (Cuniculus paca), obtained over a period of 15 years through collaborative methods with local hunters in the Amazon to describe the intrauterine development of external and internal morphology of this Neotropical rodent. We also compare the newborn survival strategy in this species with other rodents. The crown-rump length (CRL) ranged between 0.6 and 24.6 cm. External features appeared in the following chronological order: limbs, eyelid buds, fusioned eyelids, genitalia, outer ear, tactile pelage, claws, skin, skin spots, covering pelage, teeth and open eyelids. Fetuses with CRL >19.5 cm presented all external features fully developed. The growth formula of fetal age was calculated as ∛W = 0.082 (t - 37.25), and age was accurately associated with CRL. We described the relationship between CRL and external and internal biometry. The liver declined in proportion within the internal cavity, while the relative volume of tubular gastrointestinal organs increased significantly along the embryo/fetal development. All organs, except the heart and the thymus, had similar relative volumes in advanced fetuses and adults. Our comparison of the intrauterine development in several rodent species indicates that the paca's reproductive strategy is comparable to species that are subject to low natural predation. Given that C. paca is perhaps the most hunted animal in Latin America, sustainable hunting throughout its range must take into account its relative reproductive performance.

Sexual dimorphism in the turtle Kinosternon scorpioides (Testudines: Kinosternidae) from Marajó Island, Brazilian Amazon / Dimorfismo sexual de la tortuga Kinosternon scorpioides (Testudines: Kinosternidae) en la isla de Marajó, Amazonia brasileña

Abstract Introduction: Morphometrics analysis is an efficient and low-cost technique used in studies of sexual dimorphism in turtles. Kinosternon scorpioides scorpioides, scorpion mud turtle, has a wide phenotypic variation, depending on the area of its occurrence. Objective: The objective of this work was to identify the anatomical sexual difference of K. s. scorpioides, adults and hatchlings, through morphometric analysis; and relate the weights of adult animals to environmental factors (temperature and rainfall) in Marajó Island, Brazil. Methods: The sample collection was carried out from March to September 2018, covering both the rainy season (January to July) and the dry season (August to December). For the biometric analysis, 95 adults and 21 hatchlings were used, in which the length and width of the carapace and plastron, height of the shell, and weight were measured (adults only). For the geometric morphometry analysis, 21 adults and 13 hatchlings were used, in which 27 coordinates of anatomical landmarks were inserted in each image of the carapace and 11 in the plastron. Hatchlings were sexed by histology which was enabled by the identification of the ovaries and testicles. Results: The results showed the existence of dimorphism in adults. The plastron and height were higher in females, which had a more rounded carapace than males. This characteristic may be related to the species' sexual strategy, where males impose copulation. Histologically, it was possible to identify the ovaries and testicles in the hatchlings, but there was no anatomical sexual difference, despite the tendency to differentiate in the analysis of carapace PCA. Conclusions: Sexual dimorphism in K. s. scorpioides may play an important role on its reproductive behavior, which is synchronized with environmental events. This fact suggests that the reproductive strategies of this species would be severely affected by changes in the ecosystem.

Resumen Introducción: La morfometría es una técnica eficiente y de bajo costo, utilizada en estudios de dimorfismo sexual en tortugas, mediante el marcado de puntos anatómicos. Este grupo incluye Kinosternon scorpioides scorpioides, con una amplia variedad fenotípica, dependiendo del área en la que se encuentra presente. Objetivo: Este estudio tuvo como objetivo identificar la diferencia sexual entre K. s. scorpioides, adultos y juveniles, a través del análisis morfométrico; y verificar la relación entre las medidas de peso para adultos y los factores ambientales (temperatura y precipitación) en la isla de Marajó, Brasil. Métodos: La recolecta se realizó de marzo a septiembre de 2018, cubriendo tanto la temporada de lluvias (enero a julio) como la estación seca (agosto a diciembre). Para el análisis biométrico, se utilizaron 95 animales adultos y 21 crías, en los que se midió la longitud y el ancho del caparazón y el plastrón, la altura del casco y el peso en adultos. Para la morfometría geométrica, se utilizaron 21 adultos y 13 juveniles, en los que se identificaron 27 coordenadas de puntos de referencia anatómicos en el caparazón y 11 en el plastrón. Los individuos recién eclosionados fueron sexados por histología de rutina, que permite identificar ovarios y testículos. Resultados: Los datos analizados mostraron que existe dimorfismo sexual en adultos. El plastrón y la altura fueron mayores en las hembras, que tenían un caparazón más redondeado que los machos. Esta característica puede estar relacionada con la estrategia sexual de la especie, donde los machos imponen la cópula. En los juveniles recién eclosionados fue posible identificar histológicamente los ovarios y los testículos, pero no hubo diferencias sexuales en relación con la morfometría corporal, a pesar de la tendencia a diferenciarse en el análisis de PCA de caparazón. Conclusiones: El dimorfismo sexual en K. s. scorpioides puede desempeñar un papel importante en su comportamiento reproductivo, que ocurre en sincronía con los eventos ambientales. Este hecho sugiere que las estrategias reproductivas de esta especie se verían gravemente afectadas por los cambios en el ecosistema.

Biometria testicular, eletroejaculação e características seminais de caititus, Tayassu tajacu Linnaeus, 1758 (Mammalia, Artiodactyla, Tayassuidae) mantidos em cativeiro na Amazônia Oriental / Testicular biometry, electroejaculation and seminal features of captive collared peccaries (Tayassu tajacu Linnaeus, 1758, Artiodactyla, Tayassuidae) raised in the Eastern Amazon

Estudos relacionados à obtenção e avaliação de sêmen de Tayassu tajacu são escassos, sendo necessárias pesquisas a respeito. Os objetivos do estudo foram avaliar a biometria testicular de caititus adultos cativos, testar a eficiência da eletroejaculação para obtenção de sêmen e avaliar suas características seminais ao longo do ano. Procedeu-se à eletroejaculação em oito animais adultos e as amostras de sêmen colhidas foram avaliadas quanto às características físicas e morfológicas. Os animais tinham testículo esquerdo com 3,8 ± 0,4 cm X 2,6 ± 0,3 cm e 2,3 ± 0,2 de consistência, e testículo direito com 3,8 ± 0,5 cm X 2,7 ± 0,3 cm e 2,3 ± 0,2 de consistência. A taxa de sucesso nas colheitas foi de 75,21%. O sêmen possuiu: volume 0,81 ± 0,86 mL, concentração 137,44 ± 153 x 106 sptz mL-1, pH 7,92 ± 0,73, motilidade 52,66 ± 28,79%, vigor 2,2 ± 0,8, integridade de membrana plasmática 55,84 ± 28,55%, defeitos maiores 22,87 ± 12,93%, defeitos menores 9,11 ± 5,88% e defeitos totais 31,52 ± 13,81%. Os animais apresentaram simetria testicular, a eletroejaculação se mostrou eficiente para a obtenção de ejaculados em caititus e as flutuações observadas na produção seminal não foram suficientes para caracterizá-los como animais de reprodução sazonal.

Research development in semen collection and sperm evaluation of Tayassu tajacu are necessary. The aims of this research were to evaluate testicular biometry of captive collared peccaries, test electroejaculation for semen collection and evaluate seminal characteristics during the year. Eight animals were submitted to electroejaculation and semen samples were evaluated according their physical and morphological characteristics. Left testicles measured 3.8 ± 0.4 cm X 2.6 ± 0.3 cm and presented 2.3 ± 0.2 of consistence, while right testicles were 3.8 ± 0.5 cm X 2.7 ± 0.3 cm and presented 2.3 ± 0.2 of consistence. Success rate on semen collections achieved 75.21%. Semen presented 0.81 ± 0.86 mL (volume), 137.44 ± 153 x 106 sptz mL-1 (sperm concentration), 7.92 ± 0.73 (pH), 52.66 ± 28.79% (sperm motility), 2.2 ± 0.8 (vigour), 55.84 ± 28.55% (plasmatic membrane integrity), 22.87 ± 12.93% (primary defects), 9.11 ± 5.88% (secondary defects) and 31.52 ± 13.81% (overall defects). Seminal characteristics showed no expressive variation along the year. Testicular symmetry was observed, electroejaculation was an efficient method to semen collection and slight mensal oscillations of seminal quality were not enough to characterize collared peccaries as seasonal reproductive animals.

Características reprodutivas da paca fêmea (Agouti paca) criada em cativeiro / Reprodutive characteristics of the female paca (Agouti paca) raised in captivity

O objetivo do trabalho foi estudar a biologia reprodutiva da Agouti paca criada em cativeiro. Os resultados demonstraram que, a duração média do ciclo estral foi de 32,5 + 3,7 dias e o período gestacional de 148,6 + 4,8 dias. O intervalo entre partos foi de 224,5 + 52,2 dias e o primeiro cio pós-parto foi de 25,6 + 8,8 dias. A maioria (55,6 por cento) das fêmeas apresentou dois partos por ano, com o nascimento de um filhote por parto, sendo 44,7 por cento fêmeas e 55,3 por cento machos. Ao nascer o peso médio das fêmeas foi de 605,9 + 87,5 g e dos machos 736,7 + 108,4 g (P < 0,05). A puberdade das fêmeas ocorreu entre o 8º e 12º mês, porém neste aspecto são necessárias investigações mais detalhadas.

The objective of this paper was to study the reproductive biology of the Agouti paca raised in captivity. It was observed that the estrous cycle average was 32.5 + 3.7 days, gestation length 148.6 + 4.8 days, parturition interval 224.5 + 52.2 days, and the first post-partum 25.6 + 8.8 days. It was also observed that 55.5 percent of the females presented two parturitions per year with one young per parturition, of which 44.7 percent were females and 55.3 percent were males. The birth weight was 605.9 + 87.8 g for females and 736.7 + 108.4 g for males (P<0.05). Puberty in females occurred between 8 to 12 months; for this, however, more detailed investigations are necessary.