Patterns of diurnal change in respiration rate, heart rate and cecal motility of broiler chickens were determined by radio-telemetry. Observations were also made on diurnal sleep-wakefulness cycles and eating rhythm. All the observed parameters clearly synchronized with a photoperiod of 14 hours illumination (0500-1900 hrs.) and 10 hours darkness.Respiration rate, heart rate and cecal motility maintained high levels during the light period and decreased sharply on transition from the light to the dark period. The mean values of respiration and heart rates per minute were 35.6 and 335 in the light period and 23.1 and 278 in the dark period. The mean cecal motility, expressed as the number of contractions per hour reached a peak value of 51.6 between 1800 and 1900 hrs., and then decreased sharply to the lowest level of 29.0 after "lights-off." The extent of the appearance of EEG fast waves also decreased to the lowest level at the onset of dark period and increased gradually during the last half of the dark period.

Godet, J., D. Schiirch and V. Nigon, 1970b. Caracterisation et evolution des hemoglobines dans le cours du developpement postembryonnaire chez la poule. J. Embry. Exp. Morph. 23: 153-167. Konitzer, K., and K. Michalke, 1965. Der eisenstoffweschel der weissen Mous Ausscheichung und organ verterlung einen Fe 59 tracer dosis. Acta Biol. Med. Germ. 14: 489-495. Ramsay, W. N. M., 1966. The incorporation of iron into hemoglobin in the domestic fowl. Quat. J. Exp. Physiol. 51: 221-228. Rusov, C, 1965. Recherches sur la ferrocinetique des volailles normales par Fe 59 . Med. Landbow. Opzechugs Genet. 30: 787-795. ABSTRACTEffects of different photoperiods on the appearance of EEG slow waves were examined in freely-moving chickens by a radio telemetry system. The experiments were performed under 14L10D, 18L6D, 21L3D and 24L. It was clear that the EEG components were strictly synchronized to light-dark cycles. Continuous illumination exerted a dampening effect on the appearance of the slow wave diurnal rhythms. Chickens exposed to light-dark cycles of 14L10D and 18L6D maintained a constant daily level of slow wave activity. These levels are regarded as a normal amount of slow wave activity in male chickens. The daily amount of slow wave activity under 21L3D and 24L is probably regulated in a way different from that under 14L10D and 18L6D. The illumination seems to exert a strong effect on the mechanism controlling the appearance of the EEG in chickens when compared to mammals.

No abstract