Influence of Microgravity on the Concentration of Circulating Primordial Germ Cells in Silky Chicken Offspring

This study was performed to examine the implications of microgravity on circulating primordial germ cells (PGCs) of the offspring of silky chickens at stages 13 to 17. China's ShenZhou-3 unmanned spaceship was launched on March 25, 2002, at 22: 00 Beijing time ( 14: 00 GMT). The spaceship carried nine fertilized silky chicken eggs (F0) to test the reliability of the life-support system in the space environment. One female and two male chickens were born front these eggs. The three chickens mated naturally and F1 fertilized eggs were collected. Blood was collected from the dorsal aorta or the marginal vein of the embryos at stages 13 to 17, and the number of circulating PGCs of F1 offspring was counted. A similar experimental protocol was performed for the control group (Cl and C2 group). No differences were observed except at stage 15, when the F1 offspring of the flight group (170 group) showed higher PGC concentrations than the other treatment groups. These results indicated that microgravity may have little effect on the migration and concentration of PGCs in F1 offspring, perhaps because the flight chickens were raised to maturity on Earth under a gravity of 1 Xg and had sufficient time to recover. Thus, microgravity appeared to have little effect on the PGC concentrations of F1 offspring of silky chickens during circulating stages 13 to 17.