Effect of melatonin supplementation on the sexual development in European quail (Coturnix coturnix).
At the end of their wintering phase, male European quails were exposed to a stimulation photoperiod of light/dark 12:12 h for 10 days to induce sexual development. A daily oral melatonin supplementation was then given to one group of treated males (N=11) and the alcohol solvent was given to a control group of males (N=10). These solutions were provided during the final 3 h of the photophase for 28 days, then during the final 4 h for 18 days. There were no significant differences between the two groups with respect to fat levels. However, 3 weeks after the beginning of melatonin supplementation, the sexual development of the treated birds slowed down. The importance of this decline varied to a greater or lesser degree between individual birds. When melatonin supplementation stopped, sexual development resumed. Activity recordings revealed a decrease in feeding activity when melatonin supplementation was provided. However, this response showed important interindividual variability. The birds that produced the most marked responses to melatonin during the first 3 weeks of supplementation were those that also showed the most obvious decline in sexual development. It seems that, in European quail, a wild migratory species that always shows a natural biological annual rhythm, a melatonin signal could play a role in regulating reproduction.
Guyomarc'h
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C
UMR CNRS 6552 Ethologie-Evolution-Ecologie, Université des Sciences de Rennes I, 35042 cedex, Rennes, France
Lumineau
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S
Vivien-Roels
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B
Richard
J -P.
J
Deregnaucourt
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S