Influence of Lighting Schedule and Nutrient Density in Broiler Chickens: Effect on Growth Performance, Carcass Traits and Meat Quality

The study was conducted to evaluate the effect of lighting schedule and nutrient density on growth performance, carcass traits and meat quality of broiler chickens. A total of 576 day old Arbor Acre male chickens was used with a 4x2 factorial arrangement. The four lighting schedules were continuous (23 L:1 D, CL), 20 L:4 D (12 L:2 D:8 L:2 D), 16 L:8 D (12 L:3 D:2 L:3 D: 2 L:2 D) and 12 L:12 D (9 L:3 D:1 L:3 D:1 L:3 D:1 L:3 D) and provided by incandescent bulbs. The two nutrient densities were high (H, starter diet: 13.39 MJ/kg apparent metabolisable energy (AME), 23.00% crude protein (CP); finisher diet: 13.39 MJ AME/kg, 19.70% CP) and low energy and protein level (L, starter diet: 12.03 MJ AME/kg, 20.80% CP; finisher diet: 12.14 MJ AME/kg, 18.30% CP). Houses with dark curtains and solid sidewalls were used. Chickens were randomly allocated to the 8 treatments with each treatment comprising 6 replicates of 12 chickens. Feed and water were available ad libitum. Lighting schedules showed no difference (p > 0.05) in growth performance at the end of the experiment. 12 L:12 D significantly reduced (p < 0.05) the concentration of malondialdehyde (MDA) compared to 23 L:1 D treatment. Intermittent lighting (IL) schedules produced higher protein content (p < 0.001) in breast meat. Birds on high density diets had higher body weight (BW), feed intake (FI) (p < 0.001), and feed conversion ratio (FCR) (p < 0.00I) throughout the experiment with the exception of 36 to 42 d. High nutrient density increased (p < 0.05) abdominal fat, decreased (p < 0.05) the moisture loss of meat, and reduced percentage of wings and legs. There was a significant lighting schedulexdiet interaction (p < 0.001) on FCR for days 8 to 14 and 15 to 21. Results indicated that IL can give similar growth performance in comparison with CL, meanwhile with positive effects on meat quality by increasing protein content and decreasing the concentration of MDA. High nutrient density resulted in greater growth performance.