Effect Of Lighting Schedules On Growth, Metabolism, Immune Function And Carcass Traits Of Yellow Feather Broilers

One experiment was conducted to investigate the effects of lighting schedule on growth performance, nutrient metabolism, immune function and carcass trait of yellow feathered broilers with a completely randomized design. A total of3600-day-old maleLingnan yellow feathered broilers were randomly allocated to4treatments with eachtreatment having6replicates of15birds. The4lighting schedules were continuous (23L∶1D)(group1),16L∶8D(group2),12L∶3D∶2L∶3D∶2L∶2D(group3) and simulated natural lighting(group4). All groups received23-hr lighting for the first three days, after which lighting schedule were initiated according to experiment design. The lighting cycle started at06:00h everyday. The lighting continuing time of group4was based on the sunrise and sunset time in Lanzhou.(Lighting time started from5:48on first day to6:25on last day and the end time was from20:22to19:54).The experiment lasted for63days. Light intensity was kept20Lx through the whole periods.The results were as follows: Body weight and feed intake of broilers in group4werelower than those in group1, group2and group3at7d (P<0.05). There producedsome changing tendency for other performance：Thymus index and ANAE positive percentage response in group3increased19.89%(P=0.057) and16.14%(P=0.086) than those in group4at21d. ANAE positive percentage response in group3increased10.0%(P=0.062) than which in group1at42d and CK content decreased37.70%(P=0.094) in group4than under group1at42d. Bursa of fabricius index and T-AOC activity in group4was higher31.01%(P=0.059) and31.84%(P=0.083) than those in group4at63d. Newcastle disease antibody titer in group4was increased17.65%å'Œ15.47%(P=0.073) than group1and group3at63d. There was a trend (P=0.080) fora greater percentage of eviscerated carcass in the short lighting group and intermittentshort lighting group than the natural lighting group. Other indexes on each stage show no differ significantly between lighting schedules (P>0.05).These results showed that yellow feathered broilers can get the same performance undersimulated natural lighting condition compared to continuous and long lighting condition inLanzhou. And simulated natural lighting schedule can avoid the trouble of adjusting lightingprogram, save the cost and benefit broiler’s welfare.