YUMURTA TAVUKLARINDA KULUÇKADA FOTOPERİYODİK AYDINLATMANIN ETKİLERİ: IŞIĞIN ALGILANIŞI, STRES VE DAVRANIŞLARLA İLİŞKİLENDİRİLEN BAZI RESEPTÖR GENLERİN EKSPRESYONU
Project no. 1004 · Status: Kapanmış · 2016
Summary
In this study, the effect of cyclic lighting (16 h light 8 h dark, 16L:8D) during incubation using WHITE and GREEN LED lamps on expression of photoreceptor (red opsin, green opsin, and rhodopsin) and serotonin hormone receptor genes (5HTR1-A, 5HTR1-B) have been investigated in layer chicks at hatching day, before egg production starts (16th week ), and during the egg production (40th week). In relation to animal welfare corticosterone (CORT) as stress hormone in blood, Tonic Immobility (TI) duration as a measure of fear behavior, feather and comb conditions were also studied at 40 week old age. DARK incubation condition has been used as control group. Basal CORT levels of chickens from WHITE and GREEN groups at 40 weeks old age were significantly lower than those incubated in DARK (P?0.05). GREEN group had lowest feather and comb scores indicating better welfare. At hatching, WHITE and GREEN light significantly increased green opsin expression in hypothalamus as compared to DARK. At the age of 40 week, green opsin expression was lower in WHITE group than both of the DARK and GREEN groups. Significantly higher red opsin expression in hypothalamus of 16 week old pullets has been observed in GREEN group than DARK group (fold change 2.08). WHITE group had similar expression level to DARK but 2.08 fold less expression level as compared to GREEN. Expression of serotonin receptors did not differ with the incubation lighting. Under the experimental conditions, our findings suggest that a 16L:8D lighting schedule through the embryonic life resulted in lower stress and better welfare status in a commercial Brown layer genotype. Data related to the changes in expression levels of photo-pigments in photoreceptor cells revealed that lighting during embryo development affected on development of photoreceptors those sensitive to light and specific wavelengths. Key Words: Lighted incubation, laying hen, photoreceptor, serotonin receptors, welfare