| Summary: | 碩士 === 國立中興大學 === 生命科學系所 === 103 === For animals with seasonal reproduction, their gonads are well developed and
producing gametes during breeding season; the gonads undergo atrophy and
apoptosis while entering the non-breeding season. This change is regulated by the
hypothalamic–pituitary–gonadal (HPG) axis such that seasonal breeders experience
annual cycles of reproductive quiescence and renaissance. White Roman gooses are
short-day breeder, they have reproductive activity in winter and gonad regress in
summer. Wild chicken are long-day breeder, their reproductive periods are in
summer and in winter the gonad undergo regression . White Leghorn chicken are
well domesticated breeder with relatively pure genetic background and individual
differences are smaller than other avian species. Therefore, White Leghorn chicken is
an ideal animal model for investigating the genetic and molecular mechanisms of
cellular changes of gonad regression and recrudescence. However White Leghorn
chicken has no seasonal reproduction and will require further comparative analysis
seasonal breeders to ensure proper application.
In our experiments we use forced-molting to change Leghorn rooster gonad
state, and testes were collected in different time point during forced-molting；while
goose testicular tissues are harvested according to their nature annual cycle of
reproduction. The testis size dropped 35% in chicken and dropped 86.5% in goose
and testicular structures were analyzed with IHC，we found both of their somatic
cells and germ cells were decreased during testicular regression and apoptotic cells
were increased in rooster testes. When testes revived, both of their somatic cell and
germ cell were increased and total proliferating cell in testes also expand. According
these results, we concluded that artificial induced gonadal change and naturally
gonadal change have similarly process.
|
|---|
