Intermittent Photoperiod Schedule does not Influence Brain and Serum Melatonin and Selected Serum Antioxidant Enzymes Activity in Broiler Chickens

This study evaluated the effect of the intermittent light program on serum and brain melatonin concentrations, antioxidant enzyme activities, and homocysteine concentration in broiler chickens. A total of 60 one-day-old broiler chickens (Cobb 500) were distributed in three light-proof controlled rooms (20 chicks per room). All birds were reared in continuous light until 3 days of age. Then, chicks were treated as follows: 1) intermittent lighting program (1L: 3D cycles), 2) continuous lighting program (24L), and 3) nonintermittent restricted lighting program (8L: 16D). At day 42 of age, sera and brains were collected from all chicks of each group (at the end of the dark phase for groups 1 and 3). Serum and brain melatonin concentrations were not affected by the different photoperiod schedules. Serum glutathione reductase, glucose-6-phosphate dehydrogenase, superoxide dismutase, and glutathione peroxidase activity as well as homocysteine concentration were also similar between different treatment groups. In conclusion, intermittent lighting program during the rearing period does not affect serum and brain melatonin levels as well as antioxidant status at the end of the dark phase in broilers.