Concentration of mineral substances in the tibiotarsus of the Japanese quail in weightlessness

The concentrations of Ca, P, Mg, and Na were studied in the tibiotarsus of 17-day-old embryos of Japanese quail, in quail 2-4 days of post-embryonic development in the MIR orbital station, and in adult birds of both sexes exposed to 7 days of weightlessness. In addition, Ca, P, Mg levels were determined in shells of eggs from which the quail hatched during the orbital flight. Differences between Ca and P levels were found in quail of different sex. In the male bird, the Ca concentration decreased during the flight. In the female quail this did not happen due to interrupted ovulation. These results are probably associated with the intensity of reabsorption of the elements from the bone tissue in dependence on egg formation. In the control experiment, the level of Mg in female quail was found to be lower. It is probably also associated with Mg reabsorption from the bones, necessary for the regulation of the intensity processes of egg calcification in the uterus.