[Embryonic development of guppies in weightlessness].

The program of the Cosmos-1514 flight included an experiment the purpose of which was to study the effect of weightlessness on the embryonic development of the live-bearing guppy fish: three pregnant females were flown for 5 days. Prelaunch their embryos were at the stage of cerebral vesicle differentiation and somite formation; this implies that the basic stages of organogenesis developed in weightlessness. One female was fixed in Bouin's fluid two days postflight and the second fish was fixed nine days postflight. Fourteen days after flight the third female gave birth to 25 normal fry. Thereafter that fish was mated 6 times more, each time delivering normal offspring. In addition, the offspring of the second generation was normal. Histological analysis of the embryos that were developing in weightlessness revealed no abnormalities. It can be concluded that weightlessness produced no effect on the fish development, beginning with the stage of the axial complex formation.