M. Hassanzadeh et al., Effect of intermittent lighting schedules during the natural scotoperiod on T-3-induced ascites in broiler chickens, AVIAN PATH, 29(5), 2000, pp. 433-439
The influence of an intermittent lighting programme during the 12 h of the
dark period on the incidence of ascites and on metabolic parameters of broi
ler chickens was examined. A group of 336 1-day-old male broiler chickens m
ere randomly allocated to two open rooms At 5 days of age, an intermittent
lighting schedule of 3 h of dark alternating with 1 h of light was introduc
ed during the night in one room, while in the second room the schedule cons
isted of 23 h of light alternating with 1 h of dark. One-half of the birds
in each room were fed a diet supplemented with 1.5 ppm 3, 3', 5-triiodothyr
onine (T-3), while the other half received a control diet. Mortality associ
ated with ascites was significantly higher in birds fed the T-3-supplemente
d diet, but was significantly lower in birds in the room receiving the inte
rmittent lighting schedule. The intermittent lighting programme was also as
sociated with a temporary reduction in growth rate, packed cell volume and
plasma T-3 concentrations, suggesting reduced oxygen utilization. However,
final body weights were not significantly affected by the lighting programm
e. It was concluded that imposing 12 h of intermittent lighting during scot
operiod reduces the incidence of ascite mortality.