ONTOGENIA INICIAL E CONSUMO DE VITELO EM EMBRIÕES DE BETTA SPLENDENS

Abstract

Among the ornamental species, the Betta splendens deserve highlights, because of its great commercial interest. The process of ontogeny can be described as the development of the embryo at the time of fertilization, trough embryonic development stage to the hatching or later stages. The study of the embryogenesis of a species is of great importance and is a useful tool in study of the growth of species in their natural environment. This work aimed to describe the initial ontogeny in embryos of specimen B. splendens. It was possible to observe that as time marches on embryogenesis, there was a decrease in the height of the yolk and in its length, mainly in the final third of the embryonic period. The volume of yolk available to the embryo decreased during embryonic development, from 0.19912 mm3 average value of the HPF 12.5 to 0.10262 mm3 moments after the eruption that began with 34.0 HPF. It was possible to observe that the newly-hatched larvae had a residual volume of yolk of 0.01935 mm3 ± 0005, where was still possible to observe drops of oil. The newly hatching larvae observed in this study did not use exogenous food source. The embryo of B. splendens has stages of embryo development comparable to that observed in other species of teleosts. Consumption of yolk is more prominent in the final third of embryonic development, after 15.0 hours post-fertilization, in the period near the hatch and the period immediately after hatching. Through this work we observed and recorded the main stages of the development of the Siamese fighting fish B. splendens, and also verify the rate of consumption of yolk during the stages of embryogenesis until the larvae hatch and the newly-hatched, contributing thus to a better understanding of the biology of the species.