No abstract

No abstract

No abstract

No abstract

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.