Suda T
Department of Biochemistry, School of Dentistry, Showa University, Tokyo, Japan.
Bone. 1998 May;22(5 Suppl):73S-78S. doi: 10.1016/s8756-3282(98)00021-0.
Thirty fertilized chicken eggs preincubated for 0, 7, and 10 days on earth (10 eggs each) were flown in the space shuttle "Endeavour" and further incubated for 7 days under microgravity. Twenty out of 30 eggs (nine out of ten 10-day-old eggs; 10 out of ten 7-day-old eggs; 1 out of ten 0-day-old eggs) were recovered alive after landing. The only living embryo of the 0-day-old egg died 24 days after launch, and was comparable to a 16-day-old embryo when it died. The high mortality of the 0-day-old eggs appeared to be related to the specific inner structure of the egg. The yolk (specific gravity, 1.029) would not have separated from the albumen (1.040) during space flight. The subtle difference in specific gravity between the yolk and the albumen appeared to play a critical role in early chick embryogenesis. All the tissues, including cartilage and bone, were formed normally in 7- and 10-day-old chicken embryos during space flight. When the 7- and 10-day-old embryos recovered at Kennedy Space Center (KSC) were further incubated on earth, they hatched normally. No appreciable changes were recognized in these chicks. The reason for these unexpected results is not known. Further space experiments are needed to explain the failure of the effects of microgravity on chicken embryogenesis.
30枚在地球上预孵化0天、7天和10天的受精鸡蛋（每种情况10枚）搭载“奋进号”航天飞机飞行，并在微重力环境下进一步孵化7天。30枚鸡蛋中有20枚（10枚10日龄鸡蛋中的9枚；10枚7日龄鸡蛋中的10枚；10枚0日龄鸡蛋中的1枚）在着陆后存活下来。0日龄鸡蛋中唯一存活的胚胎在发射后24天死亡，死亡时相当于16日龄胚胎。0日龄鸡蛋的高死亡率似乎与鸡蛋的特定内部结构有关。蛋黄（比重1.029）在太空飞行期间不会与蛋白（1.040）分离。蛋黄和蛋白之间比重的细微差异似乎在早期雏鸡胚胎发育中起关键作用。在太空飞行期间，7日龄和10日龄鸡胚胎的所有组织，包括软骨和骨骼，都正常形成。当在肯尼迪航天中心（KSC）回收的7日龄和10日龄胚胎在地球上进一步孵化时，它们正常孵化。这些雏鸡没有明显变化。这些意外结果的原因尚不清楚。需要进一步的太空实验来解释微重力对鸡胚胎发育影响的失败情况。
