caa a22 4500 397567472 CHVBK 20180308164832.0 cr unu---uuuuu 161202e199612 xx s 000 0 eng 10.3382/ps.0751579 doi (NATIONALLICENCE)oxford-10.3382/ps.0751579 Secretion of Luteinizing Hormone During a Forced Molt in Turkey Hens [Elektronische Daten] [WAYNE L. BACON, DAVID W. LONG] 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 the 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 d 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 concentrations 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. © 1996 Poultry Science Association, Inc. Physiology and Reproduction nationallicence turkey nationallicence female nationallicence luteinizing hormone nationallicence photostimulation nationallicence forced molt nationallicence BACON WAYNE L. aut LONG DAVID W. aut Poultry Science Oxford University Press 75/12(1996-12), 1579-1586 0032-5791 75:12<1579 1996 75 ps https://doi.org/10.3382/ps.0751579 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.3382/ps.0751579 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- BACON WAYNE L. aut NATIONALLICENCE 700 1- LONG DAVID W. aut NATIONALLICENCE 773 0- Poultry Science Oxford University Press 75/12(1996-12), 1579-1586 0032-5791 75:12<1579 1996 75 ps Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford