Effect of Simulated Microgravity on Sexual Development of Male Japanese Quail

Hypodynamia can be used to simulate weightlessness in laboratory conditions. The objective of our study was to investigate the effects of chronic hypodynamia on the growth and development of the testes and cloacal gland, and plasma testosterone concentration in Japanese quail. The testis weight in males reared under hypodynamia was significantly lower compared to age-matched control between 21 and 63 days of age (P < 0.05). The cloacal gland area of experimental birds calculated from its width and length was also smaller in comparison with control quail from 35 to 56 days of age (P < 0.05). The foam production was significantly lower in hypodynamia males at age 35, 42, 49 and 63 days (P < 0.05). The plasma testosterone concentration was significantly reduced in hypodynamia birds between 35 and 70 days of age (P < 0.05), with the exception of day 56. These results provide further evidence that although hypodynamia negatively affects the examined variables, the male Japanese quail is able to develop normally under conditions of simulated weightlessness.