Effects of Monochromatic Light on the Development of Immune Organs, Antioxidant Capacity and Immune Response of Thymus and Bursal of Fabricius in Yangzhou Geese.

Light color is a key environmental factor regulating poultry immunity, but research data on geese remains limited. This study aimed to evaluate the effects of monochromatic light on the development of immune organs, antioxidant capacity, and immune response in Yangzhou geese. In this study, 240 male Yangzhou geese (4 replicates × 15 birds) were randomly assigned to white (400-700 nm), green (560 nm), blue (480 nm), or red (660 nm) light treatments for 70 days. In comparison to the white light (WL), both green light (GL) and blue light (BL) significantly enhanced the indices of thymus and bursa of Fabricius and upregulated proliferating cell nuclear antigen (PCNA) expression. These treatments also resulted in elevated serum levels of the anti-inflammatory factor IL-10 and immunoglobulins, while concurrently suppressing pro-inflammatory cytokines. Moreover, exposure to GL and BL significantly upregulated the mRNA expression of melatonin membrane receptors, whereas red light (RL) activated the mRNA expression of nuclear receptors. Furthermore, antioxidant enzyme activities were significantly elevated under GL conditions, along with a decreased malondialdehyde (MDA) content, in comparison to those under WL. These results indicate that GL and BL significantly enhance immune response and antioxidant defense in Yangzhou geese, whereas RL exerts inhibitory effects.