Relationships between broodiness expression laying persistency and concentrations of hormones during the first productive period in turkey hens (Meleagris gallopavo)

Guemene, Daniel D.; Williams, JB

doi:10.1051/rnd:19940409

Cited by 20 publications

(12 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The overall and baseline concentrations of LH were relatively low at the end of the > 40-wk reproductive period, in agreement with Guemene and Williams (1994). After forced molting and 6 d of the short-day photoperiod no further decline in baseline or total LH concentrations were detected, indicating that this treatment does not affect overall or baseline secretion of LH in laying hens.…”

Section: Discussionsupporting

confidence: 81%

“…At the end of reproduction, the baseline concentration of LH in laying hens is not greatly different than in nonlaying hens of the same age (Guemene and Williams, 1994).…”

Section: Introductionmentioning

confidence: 81%

“…In turkey hens, baseline concentrations of LH have been shown to decline during a 26-wk egg production period (Guemene and Williams, 1994), with most of the decline occurring during the first half of the production period. At the end of reproduction, the baseline concentration of LH in laying hens is not greatly different than in nonlaying hens of the same age (Guemene and Williams, 1994).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Secretion of Luteinizing Hormone During a Forced Molt in Turkey Hens

Bacon

Long

1996

Poultry Science

View full text Add to dashboard Cite

The secretory pattern of luteinizing hormone (LH) was determined in turkey hens during a forced molt induced by water (1 d) and feed (5 d) restriction and switching the photoschedule from 14 h light (L):10 h dark (D) (long-day) to 6L:18D (short-day), the 1st d of feed and water restriction. Serial blood samples were collected from six hens (every 10 min for 6 h, then every 4 min for 2 h) at four different times during the trial. The first serial bleeding was done at the end of egg laying and 1 d before forced molting was initiated; the second 7 d after start of forced molting and short-day lighting; the third after 49 d of short-day lighting, and the fourth after 56 d of short-day lighting and 2 day after returning the hens to long-day lighting. Egg production stopped by 5 d after initiation of forced molting. Egg production reinitiated by 34 d (range 22 to 34 d) after returning to long-day lighting. Overall and baseline concentration of LH were low at the end of egg laying and 7 d after the start of forced molting. Number and amplitude of pulses of LH were also low at these times. Overall and baseline concentrations of LH remained low after 49 d of short-day lighting, with no change in number of LH pulses per 8 h. However, the amplitude of LH pulses was increased at this time in comparison to just after initiation of forced molting. At 2 d after switching to long-day lighting, increases in overall, baseline, and number of pulses of LH were detected. Peak amplitude did not change 2 d after switching to the long-day photoperiod. It was concluded that in turkey hens at the end of a relatively long laying period, baseline LH is low and does not decrease during a forced molt and subsequent reconditioning period. Relatively large increases in circulating LH are induced by exposing the reconditioned hens to the long-day photoperiod of 14L:10D, and this increase was associated with an increase in overall and baseline LH concentrations and LH pulse frequency.

show abstract

Section: Discussionsupporting

confidence: 81%

“…At the end of reproduction, the baseline concentration of LH in laying hens is not greatly different than in nonlaying hens of the same age (Guemene and Williams, 1994).…”

Section: Introductionmentioning

confidence: 81%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Secretion of Luteinizing Hormone During a Forced Molt in Turkey Hens

Bacon

Long

1996

Poultry Science

View full text Add to dashboard Cite

show abstract

“…Baseline levels of LH increase after switching turkey hens from short-day lighting to long-day lighting and reach a maximum about 2 wk before the start of egg production [39]. The baseline level then declines gradually until it reaches a relatively low but constant level after a few weeks of laying [10,18,28,40]. Plasma concentrations of LH also declined late in the laying period in chicken hens, coincident with advancing age, decreasing egg production, and increasing egg size [41].…”

Section: Discussionmentioning

confidence: 99%

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

Liu¹,

Long²,

Bacon³

2002

Biology of Reproduction

View full text Add to dashboard Cite

In turkey hens, the egg production rate is relatively high early during a reproductive period, but declines as the period progresses. Among lines with different egg production potential, the interval between preovulatory surges of LH is the primary determinant of the egg production rate. The main objective of this study was to determine whether the decline in egg production rate late during an egg production period is also associated with a difference in the interval between LH preovulatory surges. A group of photosensitive turkey hens (Early) were photostimulated with continuous light (24L:0D) at 40 wk of age to induce egg laying, and serial blood samples were collected after about 3 wk of egg production. A second group of hens (Late) were housed in floor pens and photostimulated with 14L:10D at 40 wk of age for a normal 36-wk reproduction period and were then switched to 24L:0D lighting for 2 wk before collection of serial blood samples. Continuous light photostimulation was used for at least 2 wk before and during serial blood sampling to avoid potential masking effects of diurnal lighting on the interval between LH surges. The Early (n = 12) and Late (n = 16) hens were cannulated 3 days before being serially bled hourly for 10 days. The mean interval between preovulatory surges of LH was shorter in the Early hens than in the Late hens (26.1 +/- 2.5 h and 34.7 +/- 3.9 h, respectively). The intra-hen LH surge interval coefficient of variation was lower in the Early hens than in the Late hens (7.2% and 18.6%, respectively). The inter-hen LH surge interval coefficient of variation was similar in the Early and Late hens (9.5% and 11.2%, respectively). The incidence of blind surges of LH (those not retrospectively associated with ovipositions) was not different between Early and Late laying hens (8.4% +/- 15.2% and 7.3% +/- 14.6%, respectively). In conclusion, in turkey hens, longer intervals and greater intra-hen variation between LH surges were associated with a poorer rate of egg production late in the reproductive period relative to early in the reproductive period.

show abstract

“…Marrone et al [31] and Reddy et al [52], have been brought about by increased peripheral prolactin concentration. On the other hand, estradiol in conjunction with progesterone primes the release of LH [15]. The increase in oestradiol-17b levels after inhibiting the high levels of prolactin suggests that prolactin levels may be interfering with oestradiol synthesis [52].…”

Section: Discussionmentioning

confidence: 99%

Patterns of folliculogenesis in ducks following the administration of a gonadotropin-releasing hormone 1 (GnRH) analogue

Zoheir

Ahmed

2012

Journal of Genetic Engineering and Biotechnology

View full text Add to dashboard Cite

The efficacy of synthetic gonadotrophin-releasing hormone (GnRH) analogue in improving the folliculogenesis of ducks has not been established. The aim of the study was to investigate the effect of oral administration of GnRH analogue as luteinizing hormone releasing hormone A 2 (LHRH-A 2 ) on expression of relevant genes, egg production, changes of hormone levels and an ovarian follicle development in ducks. Five hundred ducks at 220 days old were randomly allotted to five groups, where each bird received daily in food 0, 5, 10, 15, or 20 lg LHRH-A 2 for 60 days. In all treated groups, a non-significant increase in the level of GnRH receptor was noticed as compared to the corresponding control. Interestingly, the egg product in the 10 and 15 lg LHRH-A 2 groups was profoundly increased (P < 0.05) if compared to 0 and 5 lg LHRH-A 2 groups or control. A reduction in circulating prolactin (PRL) levels occurs concurrently with an increase in progesterone (P 4 ) and estradiol (E 2 ) particularly in 5, 10 and 15 lg LHRH-A 2 groups. Maximal apoptotic percentage for the granulosa cells was obtained in 20 lg LHRH-A 2 group as compared to control or 5, 10 and 15 lg treatment groups. Finally, these data suggest that the oral administration of 10 and 15 lg LHRH-A 2 may induce ovarian cycle and play vital gonadotrope role during the folliculogenesis process in ducks. This study also demonstrated a need to concentrate further research on the potential effect of GnRH during the early period to improve the reproductive performance.

show abstract

Relationships between broodiness expression laying persistency and concentrations of hormones during the first productive period in turkey hens (Meleagris gallopavo)

Cited by 20 publications

References 31 publications

Secretion of Luteinizing Hormone During a Forced Molt in Turkey Hens

Secretion of Luteinizing Hormone During a Forced Molt in Turkey Hens

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

Patterns of folliculogenesis in ducks following the administration of a gonadotropin-releasing hormone 1 (GnRH) analogue

Contact Info

Product

Resources

About