The Comparasion of Some AgNOR Parameters of Purkinje Cells in The Laying and Broiler Chicks Exposed to Daily Cyclic Lighting During The Embryonic Period

Lighting, in modern poultry breeding, is one of the most important factors affecting the physiology of birds, including reproduction, growth, body temperature, feed consumption and digestion, also plays an impressive role in metabolic events in the body. Changes caused by lighting occur as a result of physiological events associated with the nervous system and the endocrine system. Purkinje cells are one of the largest cells of the central nervous system. In the early days of the chicken embryo, these cells migrate to the cerebellum cortex and form their own cell layer. The regions of DNA that contain rRNA-synthesizing genes and form the nucleolus called Nucleolar Organizer Regions (NOR). During the staining of actively transcribing regions of NORs with the silvering method (AgNOR), the rRNA regions are also stained and appear as small, dark spots under light microscope. This study aimed to determine the effect of 16 h light:8 h dark lighting during incubation on histology, nucleus diameter, areas of these cells and NOR areas of the Purkinje cells of the cerebellum of chicks to provide basic data for similar studies to be carried out in the future. The results showed that lighted incubation increased nucleus areas and NOR areas of the Purkinje cells of the broiler chicks compared to control and increased nucleus diameters of laying chicks. It was concluded that, lighting during incubation increased protein synthesis in the Purkinje cells of broiler chicks and the amount of protein in their cytoplasm resulting in an increase in nucleus area.