Concentration of Mineral Substances in the Tibiotarsus of the Japanese Quail in Weightlessness

Bod a K., 1. I II e k, V. S abo: Concentrations o/Mineral Substances in the Tibiotarsus o/the Japanese Quail in Weightlessness. Acta vet. Bmo 1996, 65: 33-37. 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. Bone. egg shell. Ca. Mg. P. Na concentrations In weightlessness, demineralization takes place in weight-loaded human bones. This process is dependent on the length of the cosmic flight, the longer the flight the stronger it is (V 0 gel et al. 1974). Osteoporosis also develops in weight-loaded bones of 19-22 dayold rats (J ago d 0 v ski et al. 1976). After 5 days in weightlessness, the concentration ofCa in the proximal epiphysis of the humerus of pregnant rats decreased. The P concentration in bone tissue increased, leading to a lower Ca:P ratio (0 g a nov et al. 1988). Another study revealed that a 14-day period of weightlessness caused are-distribution of Ca, P, Mg and Zn in the bones of the skeleton. The reduction of macroelements was the strongest in the metaepiphyseal part of the tibia (B u r k 0 v s kay a et al. 1991). During chick embryogenesis that took place in the SHUTTLE-Discovery flight experiment (STS-29), the levels of Ca, P and Mg were studied in egg shells of embryos exposed to 6 days of weightlessness, i. e. between days 2 and 7, and between days 9 and 14 of incubation (H est e r et al. 1993). No significant changes were found in concentrations of the studied macroelements. However, no data are available on the concentrations of minerals in egg shells after a complete embryogenesis in weightlessness. In this short paper we present the data on mineral substances in the tibiotarsus of quail embryos, at the beginning of their postembryonic life, further in both male and female adult quail, and in the egg shells, all obtained in the conditions of space flight. Materials and Methods The material was obtained from the experiment Incubator 2A and Incubator 2B of the MIR orbital station (B 0d a et al. 1992). The frrst experiment (Incubator 2A) was carried out between the 4th and 21st March 1990, the second (Incubator 2B) between the 1st and 9th August 1990. Embryogenesis and the 2-4 days of postembryonal development of the Japanese quail was studied in the first experiment. and the sensory-motor and feeding behaviour of adult quail in the second.