Investigation regarding the effects of different monochromatic lights on lipid metabolism and immune function in chickens.

Light exposure has significant effects on animal development, metabolism, and immune function; however, few genes regulating these functional changes have been identified. In this study, a total of 160 broilers were randomly housed in 4 groups under different colors of light (white, red, blue, and green, n = 40 each). Body, liver, and spleen weights and serum indices were measured at 56 days, and liver and spleen samples were taken for transcriptomic sequencing. Chicken body, liver, and spleen weights; liver and spleen indices; and serum triglyceride and cholesterol levels significantly increased under blue light. In the spleen, 520, 713, and 733 differentially expressed genes (DEGs), including CRLF2, IFIH1, STAT2, XDH, were found in the red, blue, and green light groups, respectively, compared to the white light group. Compared with those in the white light group, a total of 436, 825, and 596 DEGs, including UPP2, SCD, FASN, were found in the red, blue, and green light groups, respectively. A total of 47 modules were identified by weighted gene coexpression network analysis (WGCNA), the darkolivegreen and royalblue modules of which were significantly positively correlated with blue light exposure and the liver, and the cyan and black modules were positively correlated with blue light exposure and the spleen. KEGG analysis of the hub genes with a |KME| > 0.8 in the module revealed that the effects of blue light on the liver were related mainly to NOD-like receptor signaling and PPAR signaling pathways. The effects of blue light on the spleen were primarily related to NOD-like receptor signaling and RIG-I-like receptor signaling pathways. Expression of UPP2, FASN, and SCD, which promotes hepatic fat accumulation, was upregulated in the blue light group. Moreover, in the blue light group, upregulated XDH, CRLF2, and IFIH1 expression facilitates the immunity of chickens. This study reveals potential pathways through which light affects lipid metabolism and immune function, providing new insights into how light influences animal development and production.