Document Detail

Exogenous melatonin modifies rate of sexual maturation in domestic pullets.
MedLine Citation:
PMID:  16493954     Owner:  NLM     Status:  MEDLINE    
Growing pullets were maintained on 14-h photoperiods and given diets supplemented with 25 mg of melatonin (MEL)/kg during the final 7 h of the photo-period to investigate the role of MEL in sexual development. Melatonin diets were fed to 70 d (to mimic a transfer from 7 to 14 h at 70 d), from 105 d onward (to mimic a transfer from 14 to 7 h at 105 d), or throughout the trial (to mimic constant 7-h photoperiods). Control birds, which were fed normal diets, were maintained on 7 or 14 h, transferred from 7 to 14 h at 70 d, or transferred from 14 to 7 h at 105 d. The MEL groups matured 6 to 11 d later than the constant 14-h controls. The group mimicking a transfer from 7 to 14 h matured 35 d later than photostimulated controls, the group mimicking a 14 to 7-h change at 105 d matured 41 d earlier than birds given a decrease in day length; the third group matured 13 d earlier than constant 7-h controls. Although these data suggest that the birds did not perceive the final 7 h of the photoperiod as being part of the night, when given MEL diets, residual plasma MEL during the first 7 h of the photoperiod was atypically high, possibly preventing an interpretation of day and night. However, continuously high plasma MEL did not result in birds responding as if in constant darkness, because birds transferred from darkness to 14 h at 70 d would not have matured at a similar time to birds changed from 14 h to darkness at 105 d. Plasma LH concentrations for birds mimicking a 7 to 14 h change at 70 d were not significantly different from constant 7-h controls after the transfer to normal diets. The later maturity of the experimental groups, compared with constant 14-h controls, clearly indicated that MEL had some influence over hypothalamic activity and gonadal development.
P D Lewis; B A Middleton; R M Gous
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Publication Detail:
Type:  Controlled Clinical Trial; Journal Article    
Journal Detail:
Title:  Poultry science     Volume:  85     ISSN:  0032-5791     ISO Abbreviation:  Poult. Sci.     Publication Date:  2006 Jan 
Date Detail:
Created Date:  2006-02-23     Completed Date:  2006-04-21     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0401150     Medline TA:  Poult Sci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  117-22     Citation Subset:  IM    
Animal and Poultry Science, School of Agricultural Sciences and Agribusiness, University of KwaZulu-Natal, Scottsville, South Africa.
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MeSH Terms
Chickens / growth & development*
Drug Administration Schedule
Melatonin / blood,  pharmacology*
Oviposition / drug effects
Sexual Maturation / drug effects*
Reg. No./Substance:

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