Livestock Studies 2010, Vol 50, Num, 2     (Pages: 103-115)

Reproductive hormonal regulation in hens

Çigdem ÇEBİ 1 ,Ergun AKÇAY 1

1 Ankara Üniversitesi, Veteriner Fakültesi, Dölerme ve Sun’i Tohumlama Anabilim dalı, Dışkapı, ANKARA Viewed : 248 - Downloaded : 167 When today's economic conditions and population growth were taken into consideration, poultry farming is the best cover on the animal protein recovery and its most developed subdivision is chicken farming. Poultry sector is attracted attention because of reaching to yield age in a short period of time, high reproductive activity and productivity, growing in small field by reason of low body weight, feed more efficiently than the others, high utilization ability from food. The female poultry`s physiology of reproduction is very different from mammals regarding pregnancy phase, mating season and especially eustrous cycles. Spontaneous ovulation occurs in approximately 24 hours in poultry. Spontaneous ovulation related to the peak of progesteron and LH before ovulation. Making up ovulation by LH is dependent on progesteron released from follicules. Testosteron releasing from primary follicles increases and this event has an inhibitor effect for progesteron. Releasing of testosteron and estrogen from theca cells of mature follicles decreases before ovulation and as a result inhibitor effect of testosterone and estrogen on progesterone synthesis reduces. Thus, production of progesteron from granuloza cells increases for ovulation. Therefore, peak of testosteron before ovulation is necessary for releasing of progesteron which causes the peak of LH from ovary. Keywords : Hen, Reproduction, Hormonal regulation