Abstract Myomorphic and hystricomorphic rodents are vital for maintaining various ecosystems around the planet. This review enables a better understanding of how these rodents respond to environmental factors and adapt to climate adversities. Innumerable factors, such as photoperiod, rainfall, and temperature, can impair or contribute to the quality of rodent reproductive parameters. Prolonged animal exposure to high ambient temperatures alters thermoregulation mechanisms and causes testicular and ovarian tissue degeneration and hormonal deregulation. Photoperiod influences the biological circannual rhythm and reproductive cycles of rodents because it strongly regulates melatonin secretion by the pineal gland, which modulates gonadotropic hormone secretion. Rainfall quantity directly regulates the abundance of fruits in an ecosystem, which modulates the reproductive seasonality of species which are most dependent on a seasonal fruit-based diet. Species with a more diversified fruit diet have smaller reproductive seasonality. As such, habitats are chosen by animals for various reasons, including the availability of food, sexual partners, intra-and inter-specific competition, and predation. This knowledge allows us to monitor and establish management plans to aid in conservation strategies for wild rodent species.

Foram avaliados os efeitos da centrifugação associada ao uso de dois diluentes na manutenção da viabilidade espermática em tatus-peba (Euphractus sexcinctus) ao longo do teste de termorresistência (TTR). Amostras de sêmen (n=12), oriundas de 04 machos adultos coletados por eletroejaculação, foram divididas em quatro alíquotas, sendo duas imediatamente diluídas em Tris ou água de coco em pó (ACP-119(r)), e as outras duas centrifugadas (800g10min-1) previamente à diluição. As amostras foram incubadas a 34°C por 3h, e os parâmetros seminais avaliados em intervalos de 1h. Em termos gerais, verificou-se uma redução da viscosidade espermática imediata à diluição em ambos os diluentes, independente do uso da centrifugação. Aos 60 minutos, verificou-se uma redução dos parâmetros avaliados (P<0,05), embora o Tris tenha promovido uma melhor preservação deles (P<0,05), quando comparado ao ACP-119(r) até os 120 minutos de avaliação. Após este período, os dois diluentes se equipararam (P>0,05). Ainda, verificou-se um efeito deletério da centrifugação sobre a qualidade do sêmen de tatus-peba durante todo o teste de termorresistência. Nas condições do presente estudo, conclui-se que o diluente Tris mostrou-se superior ao ACP-119(r) para a manutenção da viabilidade do sêmen de tatus-peba, sendo desnecessária a realização de centrifugação prévia à diluição.

The effects of the centrifugation associated to the use of two extenders on the viability of six-banded armadillo's (Euphractus sexcinctus) sperm were evaluated during a thermo resistance test (TRT). Semen samples (n=12) derived from 04 stud males collected by electroejaculation were divided in four aliquots; two of that were immediately diluted in Tris or powdered coconut water (ACP-119(r)); the two others were centrifuged (800g10min-1) prior to the dilution. Samples were incubated at 34ºC per 3h, and the semen parameters were evaluated at each hour. In general, dilution promoted a reduction in semen viscosity in the use of both diluents using centrifugation or not. At 60min, a decrease was verified for all semen parameters (P<0.05), however they were better preserved in the use of Tris when compared to ACP-119(r) (P<0.05) up to 120min. After that, both diluents equated. In addition, centrifugation procedure presented a deleterious effect on the armadillo's semen quality during all the thermoresistance test. In the present conditions, conclude that Tris extender is more efficient than ACP-119(r) for the preservation of six-banded armadillo semen viability, and the previous centrifugation is unnecessary.

The objective of this study was to analyze interactions between different straw sizes and thawing rates on the post-thaw goat semen parameters. Twenty-one ejaculates (seven per animal) were collected from three stud bucks by using an artificial vagina. After evaluation, the semen was extended in Tris-egg yolk-glycerol and packed in 0.25 and 0.50 mL straws, followed by storage in liquid nitrogen. Thawing was performed using two different rates: 37 ºC/1 min and 55 ºC/7 s. The interaction between the 0.5-mL straw and the thawing rate of 55 ºC/7 s promoted higher progressive motility. When the effect of straws alone was analyzed, it was verified that the use of the 0.50 mL straw promoted better conservation than the 0.25 mL one for progressive motility and acrosomal integrity, after the frozen-thawing procedures. Optimal results for progressive motility were achieved when goat semen was frozen in 0.5 mL straws and thawed in water at 55 ºC/7 s.