Pattern of secretion of luteinizing hormone and testosterone in the sexually mature male turkey

Effect of various photoperiods on testicular weight, weekly sperm output and plasma levels of LH and testosterone over the reproductive season in male turkeys

“…Previous studies using commercial breeder turkeys revealed a high degree of sensitivity to photoperiod for TW [10,11], semen output [18], and circulating LH and testosterone concentrations [6][7][8][9]. The present results confirmed previous observations [10,11] that prepubertal male turkeys maintained under constant long days are precocious semen producers (26-29 wk) In .…”

“…In males from previously named species, LH and testosterone are discharged in pulsatile patterns during both the photophase and the scotophase of the nycthemere. Moreover, it appears that in mature male www.journals.elsevierhealth.com/periodicals/the Theriogenology 66 (2006) [851][852][853][854][855][856][857][858][859] turkeys, a pulsatile pattern of testosterone is maintained regardless of its baseline concentration, whereas the pulsatile pattern of LH is maintained only if associated with low plasma concentrations of both LH and testosterone [6,7]. Turkey males in semen production exposed to continuous or intermittent light regimes had minor differences in patterns of LH and testosterone secretion [7,8].…”

Episodic Gonadotropin Secretion in the Mature Fowl: Serial Blood Sampling from Unrestrained Male Broiler Breeders (Gallus domesticus)1

“…The pulsatile pattern of LH secretion has previously been documented in the male fowl [3,4]. However, to our knowledge the present is the first to report pulsatile FSH secretion in avian species.…”

“…In this situation, the pulse frequency ranged from 0.12 to 0.32 pulses/h and occurred during both the photophase and scotophase of the 14L:10D photoperiod [4]. In the male Japanese quail, LH pulse frequency ranged from 0.25 to 0.42 pulses/h during a long day (20L:4D) photoperiod [5].…”

Effect of photoperiod on plasma concentrations of luteinizing hormone and testosterone and on semen output in turkey breeder males

“…Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/terms-and-conditions The effects of different photoperiods on episodic release of luteinizing hormone (LH) and testosterone (T) have already been studied in juvenile and young mature male breeder turkeys (Bacon et al, 1991;Yang et al, 1998) but no study of their relationships over the entire reproductive season has yet been conducted. A total of 120 male turkeys were first placed under decreasing then a short photoperiod up to 21 weeks of age and then maintained under 7 h of light per day (7L:17D) from 21 to 23 weeks of age.…”