Effect of Light Color during Incubation on Post-hatch Serotonin and Corticosterone Concentration in Gerze Turkish Indigenous Chickens

Exposing broiler chicken eggs to light during incubation can influence hatchability, stress levels, and overall chick welfare after hatching. Therefore, this study aimed to determine the effect of different-colored lights applied during incubation on serotonin and corticosterone hormone concentrations related to post-hatch chicken welfare. Gerze Turkish Indigenous chicken eggs were incubated under no light (dark; n: 108), green light (n: 114), red light (n: 114), and white (n: 114) light for 18 days. All chicks from each treatment group were fed for 120 days. Plasma corticosterone levels were evaluated using a commercially available ELISA kit (detection range 0.1-40 ng/mL, Chicken Corticosterone ELISA ^{BT LAB}). Plasma 5-HT levels were also measured using a commercially available ELISA kit (analytic range 0.5-150ng/mL, 5-HT BT LAB Chicken Serotonin ELISA Kit), following the standard procedures. Red-light-incubated chicks had the lowest (P<0.05) plasma corticosterone. Dark-incubated chicks had higher (P<0.05) plasma serotonin concentrations than green- and white-incubated chicks. However, green-incubated chicks had lower (P<0.05) plasma serotonin concentrations than red- and dark-incubated chicks. These results indicate that different-colored light applications during incubation altered post-hatch serotonin and corticosterone concentrations. This work was supported by the Ondokuz Mayis University (Project no: BAP04-A-2024-4803) Scientific Research Coordination Unit.