Interval Between Preovulatory Surges of Luteinizing Hormone Increases Late in the Reproductive Period in Turkey Hens1

Liu, H.-K.; Long, David P.; Bacon, Wayne L.

doi:10.1095/biolreprod66.4.1068

Cited by 28 publications

(12 citation statements)

References 45 publications

(90 reference statements)

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“…Also, no long-duration intersequence intervals (intervals Ͼ 30-34 h) ascribed to pauses between sequences [21] were observed in the present experiment. In a longitudinal study using the Egg line of turkeys [19], a slightly longer interval between LH surges (27.9 and 25.7 h, respectively) was found with constant lighting than with 14L:10D diurnal lighting.…”

Section: Hormonecontrasting

confidence: 79%

“…In a previous study with the Egg line of turkeys [21], LH surge amplitude declined further between 3 and 40 wk of egg production, but duration of surges did not change with progression of the reproductive period. Surges of LH are induced by surge secretion of GnRH in birds as in mammals [29].…”

Section: Hormonementioning

confidence: 60%

“…Concentrations of both LH and P 4 return to baseline levels by ovulation, where they remain until initiation of the next preovulatory LH and P 4 surges. Additional intrasequence (intervals between surges of Ͻ30-34 h) and intersequence (intervals between surges of Ͼ30-34 h) preovulatory LH surges continue to occur as the reproductive period progresses [19,20,21].…”

Section: Introductionmentioning

confidence: 99%

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Changes in Plasma Concentrations of Luteinizing Hormone, Progesterone, and Estradiol-17β in Peripubertal Turkey Hens under Constant or Diurnal Lighting1

Bacon

Vizcarra

Morgan

et al. 2002

Biology of Reproduction

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Possible circadian fluctuations and long-term changes in concentrations of reproductive hormones in peripubertal female birds is poorly documented in comparison with mammalian species. Our objective was to document changes in concentrations of several reproductive hormones the several days before and after initial pubertal preovulatory surges of LH in turkey hens photostimulated with either constant (24L:0D) or diurnal (14L:10D) lighting. The hens were cannulated for hourly blood sampling, starting 10 days after photostimulation and continuing until all hens had laid at least two eggs. First eggs were oviposited between 16 and 24 days after photostimulation, and egg production ranged from two to nine eggs/hen during the experimental period. With both lighting treatments, concentrations of LH declined slightly, concentrations of progesterone (P(4)) increased, and concentrations of estradiol-17beta (E(2)) were constant the 3-4 days prior to initial LH surges with no circadian fluctuations in hormone concentrations. Most (10 of 13) initial preovulatory surges of LH were coupled with ovulations, and all LH surges were coupled with P(4) surges. Those LH and P(4) surges not coupled with ovulations (blind surges) occurred with both lighting treatments, but the incidence of blind surges was higher with diurnal lighting. The interval between LH and P(4) surges was longer between the first and second surges than between subsequent surges, when the interval was approximately 26 h. The duration of LH surges (7.4 +/- 3.0 h) was shorter than that of P(4) surges (10.0 +/- 2.0 h). We conclude that, in the peripubertal female turkey, 1) prior to puberty (first LH-P(4) surges), there are no circadian fluctuations in concentrations of LH, P(4), and E(2), 2) 3 days prior to initial LH surges, E(2) concentrations are stable, LH concentrations decline slightly, and P(4) concentrations increase, and 3) surges of LH are coupled to surges of P(4) but LH-P(4) surges are not always coupled to ovipositions (blind surges), possibly because of internal ovulations.

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Section: Hormonecontrasting

confidence: 79%

Section: Hormonementioning

confidence: 60%

Section: Introductionmentioning

confidence: 99%

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Changes in Plasma Concentrations of Luteinizing Hormone, Progesterone, and Estradiol-17β in Peripubertal Turkey Hens under Constant or Diurnal Lighting1

Bacon

Vizcarra

Morgan

et al. 2002

Biology of Reproduction

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“…(Onagbesan et al, 2006). Furthermore, the influential role of LH on egg production was further elucidated by Liu et al (2002;2004) that the intervals between the LH surges are longer in broiler breeder and turkey hens with low egg production rates. In similar vein, the depressed laying rate observed during the non-breeding season was found to parallel low LH secretion and circulation in geese (Shi et al, 2007;Huang et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Influence of high environmental temperature on egg production and shell quality: a review

Oguntunji

Alabi

2010

World's Poultry Science Journal

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In spite of the large amounts of money invested in research, breeding, and the improvement of commercial egg-type strains, high environmental temperature (HET) has been identified as a major non-genetic constraint limiting expression of their full genetic potential. This environmental stressor has been implicated in adverse marked effects on egg production and eggshell quality of hens. Reports have conclusively indicated that poor performance (i.e. drop in egg production and poor eggshell quality) of layers reared in thermally-stressed environments could be adduced to a complex interplay of low feed intake, malfunctioning of the endocrine system, acid-base imbalance and poor physiological functioning of organs and mechanisms connected with the entire egg production process, via follicular recruitment and growth, ovulation, egg formation, shell formation, egg development, oviposition and oviposition interval.

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“…It is suggested that FSH secretion did not change with P 4 treatment, because levels of E 2 did not change during P 4 treatment or development of the PCOF syndrome in experiment 8. For laying hens late in the egg production period, the level of E 2 has been reported to decline [33]; thus, FSH secretion may also be lower at this time. In older hens, a lower rate of FSH secretion may lead to atresia of ovarian follicles during P 4 injection (experiments 2 and 6) instead of ovarian follicle maintenance (experiments 1, 3, 4, and 5) or development of the PCOF syndrome (experiments 7 and 8) subsequent to P 4 injection.…”

Section: Discussionmentioning

confidence: 96%

Progesterone Injection and Egg Production in Turkey Hens1

Bacon

Liu

2004

Biology of Reproduction

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An arrest in laying associated with either a polyovarian follicle (POF) or a polycystic ovarian follicle (PCOF) syndrome has been reported in turkey hens photostimulated at an early age with a constant-light photoperiod. Hens expressing the POF or PCOF syndrome had stopped laying for several weeks, but the ovary contained an increased number of mature-size and larger follicles (POF hens), which were cystic (PCOF) in some of the hens. Hens with the POF or PCOF syndrome had plasma progesterone (P(4)) concentrations that were relatively high and without surges. We hypothesized that high plasma P(4) concentrations may block ovulatory surges of LH but not the growth or maintenance of hierarchical follicles leading to development of the POF or PCOF syndrome in turkey hens. In the first six studies, hens were photostimulated with either a 14L:10D or a 24L:0D photoperiod and, after laying for 1-38 wk, were then injected daily for up to 14 days with P(4) (up to 1.50 mg kg(-1) day(-1)) and necropsied. At all ages, the oviposition rate was reduced at a P(4) dosage of 0.17 mg kg(-1) day(-1). With dosages of 0.33 mg kg(-1) day(-1) or greater, however, ovipositions stopped in most hens within approximately 2 days. For hens laying for less than 15 wk, oviductal weight and number of hierarchical follicles of P(4)-injected hens were not different from control vehicle-injected hens, but the numbers of mature, cystic, and atretic follicles were increased. For hens laying for 38 wk, when treated with P(4), oviductal weight and number of hierarchical follicles decreased, but number of atretic follicles increased. No effect of photoperiod was found on egg production, oviductal weight, or follicle number, and none of the hens developed POF or PCOF syndrome in these experiments. Two additional experiments were conducted with hens early in the reproductive period that had been photostimulated with 14L:10D or 24L:0D and injected with P(4) (0.33 mg kg(-1) day(-1)) for 10 or 12 days but not necropsied until 3 wk after the last injection. Most of the hens photostimulated with the 24L:0D photoperiod and injected with P(4), and a few of the hens photostimulated with the 14L:10D photoperiod and injected with P(4), had developed the PCOF syndrome when necropsied. The hens with the PCOF syndrome had high levels of P(4) when necropsied. From these studies, we concluded that the PCOF syndrome can be induced early in the reproduction period by photostimulating turkey hens with a 24L: 0D photoperiod, injecting them for 10 to 12 days with P(4) at a dosage of 0.33 mg kg(-1) day(-1), and then waiting 3 wk for the PCOF syndrome to develop.

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Interval Between Preovulatory Surges of Luteinizing Hormone Increases Late in the Reproductive Period in Turkey Hens1

Cited by 28 publications

References 45 publications

Changes in Plasma Concentrations of Luteinizing Hormone, Progesterone, and Estradiol-17β in Peripubertal Turkey Hens under Constant or Diurnal Lighting1

Changes in Plasma Concentrations of Luteinizing Hormone, Progesterone, and Estradiol-17β in Peripubertal Turkey Hens under Constant or Diurnal Lighting1

Influence of high environmental temperature on egg production and shell quality: a review

Progesterone Injection and Egg Production in Turkey Hens1

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