ABSTRACT
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.
Subject(s)
Animals , Polymorphism, Genetic , TurtlesABSTRACT
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.
Subject(s)
Animals , Artiodactyla/anatomy & histology , Testis/anatomy & histology , Sperm Retrieval/veterinary , Semen Analysis/veterinary , Seasons , Biometry , Animals, WildABSTRACT
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.