Ozkan, S.Yalcin, S.Babacanoglu, E.Uysal, S.Karadas, F.Kozanoglu, H.2025-05-102025-05-1020120032-57911525-317110.3382/ps.2012-024272-s2.0-84868087379https://doi.org/10.3382/ps.2012-02427https://hdl.handle.net/20.500.14720/1593Uysal, Sezer/0000-0002-1117-0625Photoperiodic incubation lighting might improve bird adaptation to a novel environment at hatching for a better start in early posthatching development. We evaluated the effect of 16L:8D lighting for either the whole incubation period (Inc(0-21d)) or the last week of incubation (Inc(14-21d) on early posthatching growth, blood melatonin, and corticosterone at 6 d as well as malondialdehyde levels in brain tissue, relative asymmetry, and overall broiler performance as an interaction with the posthatching lighting programs. Dark incubation conditions (Inc(Dark)) served as control. There were 3 incubation batches in the experiment. Chicks from 2 of 3 batches were reared either at 16L:8D or under continuous lighting (24 h) through 6 d posthatching. Batch 3 chicks were reared to 35 d under either 16L:8D or 23L:1D. The main finding was a significant incubation x posthatching lighting interaction for 35-d BW in broilers. Although groups had similar BW under continuous lighting, Inc(0-21d) and Inc(14-21d) broilers were respectively 94 and 78 g heavier than Inc(Dark) birds under 16L:8D at 35 d. Lighted incubation groups increased 0 to 6 d of gain and had higher d-6 breast muscle weights with no effect on other traits measured. Posthatching 16L:8D reduced the gain and d-6 breast muscle. Significant incubation x posthatching lighting and posthatching lighting x sampling time interactions for blood melatonin may indicate that Inc(0-21d) affects melatonin diurnal rhythms even at 6 d under continuous light. Lower blood corticosterone levels on d 6 in Inc(0-21d) chicks reared under 16L:8D posthatching may support our hypothesis that incubation lighting can modify the bird stress response, probably affecting the hypothalamic-pituitary-adrenal axis during ontogeny, and may improve adaptation to a similar environment posthatching. The lower malondialdehyde concentration in brain tissue of Inc(0-21d) birds on d 6 may indicate lower lipid peroxidation and thus lower oxidative stress compared with Inc(Dark). These results provide further evidence that Inc(0-21d) may improve both bird adaptation to a similar photoperiodic environment and growth, probably through early entrainment of circadian physiology.eninfo:eu-repo/semantics/openAccessIncubation LightingPosthatching LightingPhysiologyStressBroiler PerformanceArticle9111Q1Q12922293023091151WOS:000310421000027