ABSTRACT
As serpentes pertencem ao segundo maior grupo dentro dos répteis, podendo apresentar sazonalidade quanto à espermatogênese, com produção descontínua ou contínua. O presente trabalho tem como objetivo caracterizar aspectos da biologia reprodutiva de Boa constrictor constrictor com base nos achados histológicos dos testículos nos períodos de máxima atividade (período de gametogênese) e quiescência. Os testículos de dois espécimes de Boa c. constrictor (7767 e 11752) foram cortados a uma espessura de 3µm em micrótomo, corados com azul de toluidina 1%, fotodocumentados e descritos. A presença de espermatozoides na luz do túbulo seminífero no indivíduo 7767 indica um período de máxima gametogênese, enquanto o lúmen dos túbulos seminíferos pouco evidentes, sem a presença de espermatozoides e de células gaméticas em divisão, caracteriza o indivíduo 11752 em período quiescente. Mediante os achados histológicos descritos no presente estudo, concluiu-se que Boa c. constrictor apresenta sazonalidade em relação à gametogênese, sendo esse padrão de sazonalidade associado ao período de cópulas relatado em literatura característico de serpentes com padrão pré-nupcial.(AU)
These snakes belong to the second largest group within the reptiles, being able to present seasonality regarding spermatogenesis, with discontinuous or continuous production. The present study aims to characterize Boa constrictor constrictor reproductive biology aspects from histological findings in testicles during periods of maximum activity (period of gametogenesis) and quiescence. The testicles of two specimens of Boa c. constrictor (7767 and 11752) were cut to a thickness of 3µm in microtome, stained with 1% toluidine blue, photodocumented and described. The spermatozoa presence in the seminiferous tubule lumen in individual 7767 indicates a period of maximum gametogenesis, whereas the seminiferous tubules lumen is not very evident without spermatozoa and the absence of dividing gametic cells characterizes individual 11752 in the quiescent period. Through the histological findings we concluded that Boa c. constrictor presents seasonality in relation to gametogenesis, and the pattern of reproductive seasonality observed along with the period of copulas reported in the literature resembles the pre-nuptial pattern.(AU)
Subject(s)
Animals , Seasons , Sexual Behavior, Animal , Spermatogenesis/physiology , Boidae/growth & development , Boidae/physiology , Boidae/genetics , Gametogenesis/physiologyABSTRACT
The anaconda Eunectes murinus (Linnaeus, 1758) inhabits large hydrographic basins in tropical America and figures among the world's largest snakes, attaining a length of 12 m. This study analyzed the growth of three female anaconda siblings, with records from their birth in captivity up to around 14 months of age. The snakes were kept in a controlled environment with constant temperature and data related to biometry, feeding and skin shedding were recorded. At the end of these 445 days, the siblings had grown on average 2.6 times their initial length and increased their initial weight by 3830.lOg, incorporating about 43.5% of total food ingested to their body mass. They showed a total of 0.69 skin sheddings per month in that period, and did not exhibit significant differences in shedding intervals, nor in body growth (weight and length), when compared among themselves. Food was refused at times, coinciding with the days that preceded the ecdyses. Sheddings do not seem to be explained by feeding or growth, which suggests a relation to other endogenous factors. A more detailed study of this species is needed to better understand its growth to the adult phase and its hormonal levels during growth.
La anaconda Eunectes murinus (Linnaeus, 1758) se encuentra en una ampia área hidrográfica de América tropical y figura entre las más grandes serpientes del mundo, alcanzando una longitud de 12 metros. Este estudio analizó el crecimiento de tres anacondas hembras hermanas, con registros de su nacimiento en cautiverio hasta alrededor de 14 meses de edad. Las serpientes fueron mantenidas en un medio controlado con temperatura constante y se obtuvieron registros relacionados con su biometría, alimentación y mudas de piel. Al final de 445 días, las hermanas crecieron en promedio 2,6 veces su longitud inicial e incrementaron su peso inicial en 3810,1 g, incorporando a su masa corporal alrededor de 43,5% del alimento ingerido. Ellas tuvieron un total de 0,69 mudas de piel por mes en ese periodo y no hubo diferencias significativas en los intervalos de mudas, ni en el crecimiento corporal (peso y longitud), cuando comparadas entre ellas. La comida, a veces, fue rechazada coincidiendo con los días que precedían al cambio de piel. Las mudas de piel parecen no tener relación con la alimentación o crecimiento, lo cual sugiere que puede deberse a otros factores endógenos. Es necesario un estudio más detallado de esta especie para comprender mejor su crecimiento en la fase adulta y sus niveles hormonales durante el crecimiento.