Effect of photoperiod length and light intensity on some welfare criteria, carcass, and meat quality characteristics in broilers

ABSTRACT - The objective of this study was to investigate the effects of photoperiod length and light intensity on leg and eye health, tonic immobility, some blood parameters, carcass, and meat quality characteristics in broilers. A total of 272 one-day-old male broiler chicks (Ross 308) were randomly assigned to four treatment groups based on the photoperiod length (23L:1D or increasing duration of light) and light intensity (20 lux vs. dim light) with four replicates. In this study, photoperiod lenght had no effect on incidence of foot pad and hock burn. On the other hand, the effect of photoperiod lenght had significantinfluenceonthegaitscore.Theincidencesofgaitscore(3+4+5)inbrightanddimlightgroupswasfoundas21.4and41.0%in broilers, respectively. In addition, the effect of light intensity had statistical significanceongaitscore.Thetonicimmobilityduration in 20 lux and dim light groups were 271.53 and 226.78 s, respectively, and tonic immobility duration was unaffected by light intensity. All the blood parameters, except for triglyceride, were not affected by light intensity. The dim light had a negative effect on broiler welfare as demonstrated by increased eye weight and dimensions. Cold carcass yield and whole breast and wing yields were lower in the dim light group than in 20 lux light intensity. The broilers kept with dim light had lower breast meat ultimate pH (6.19) and L* values (54.30) than those reared with 20 lux. These findingshavealotofimplicationsonthe use of increasing photoperiod and bright light to improve leg an eye health benefitsforthebroilerwelfareinbroilers.Key Words: carcass quality, corticosterone, eye and leg health, lighting