Effect of timing and size of photoperiod change on plasma FSH concentration and the correlation between FSH and age at first egg in pullets

1. ISA Brown pullets were transferred at 6, 9, 12, 15, 18 or 20.3 weeks of age from an 8 h photoperiod to an 8, 10, 13 or 16 h photoperiod. Plasma follicle stimulating hormone (FSH) concentration was measured at transfer at 7 and 14 d afterwards, and age at first egg (AFE) was recorded. 2. Plasma FS...

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Bibliographic Details
Published in:British poultry science 1999-07, Vol.40 (3), p.380-384
Main Authors: Lewis, P.D, Perry, G.C, Morris, T.R, Douthwaite, J.A
Format: Article
Language:English
Subjects:
age at first egg
age differences
Aging - metabolism
Animals
blood chemistry
Chickens - blood
Chickens - physiology
Circadian Rhythm - physiology
Female
Follicle Stimulating Hormone - blood
follicle-stimulating hormone
luteinizing hormone
Luteinizing Hormone - blood
Ovulation - physiology
photoperiod
pullets
quantitative analysis
Time Factors
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Summary:1. ISA Brown pullets were transferred at 6, 9, 12, 15, 18 or 20.3 weeks of age from an 8 h photoperiod to an 8, 10, 13 or 16 h photoperiod. Plasma follicle stimulating hormone (FSH) concentration was measured at transfer at 7 and 14 d afterwards, and age at first egg (AFE) was recorded. 2. Plasma FSH concentration in pullets reared on constant 8 h photoperiods generally increased with age but with a trough at 12 weeks. Plasma FSH increased during the first 14 d of photostimulation to a significantly higher concentration, compared with constant 8 h controls, when the photoperiod was increased to 13 or 16 h at 9, 12 or 15 weeks; but for the increase from 8 h to 10 h photoperiods FSH was only significantly higher than controls when the change was made at 12 weeks. 3. The change in plasma FSH concentration 14 d after photostimulation was significantly correlated with mean AFE (reported in Lewis et al., 1997) and appears to be a better predictor of gonadal development than concurrent changes in plasma LH concentration previously reported (Lewis et al., 1994).
ISSN:0007-1668
1466-1799
DOI:10.1080/00071669987485