Daily organization of laying in Japanese and European quail: effect of domestication.

In the present study, we aimed to examine the possible effects of domestication on the daily organization of laying in female quail. To achieve this we compared laying patterns in a laboratory strain of Japanese quail with those in European quail originating from a wild population. Under LD 14:10, the same specific laying window was observed, with ovipositions occurring mainly between 7 h and 15 h after lights on. Thus, domestication did not modify the specific daily organization of laying in females laying in the afternoon. Research about the functional value of this temporal organization in the field thus seems justified. At an individual level, two distinct laying profiles were recorded, as in a previous experiment on an industrial Japanese quail strain selected for meat and egg production. However, different frequencies were noted. Whereas stable profile females (laying at the same time each day) were predominant (80.4%, N=102) in the industrial Japanese quail strain, delayed profile females (laying successively later each day) appeared dominant in the European quail (81%, N=22). The Japanese quail from the laboratory strain constituted an intermediate group with a slight dominance of the stable profile (58.8%, N=17). Thus, domestication has changed the frequencies of the laying profiles, favoring stable females, which are the most productive birds. A model involving interaction between one circadian rhythm and one ultradian rhythm can explain the observed laying profiles.