Short-term night lighting disrupts lipid and glucose metabolism in Zebra Finches: Implication for urban stopover birds

Night lighting has been shown to affect wild animals. To date, the effects of night lighting on the metabolic homeostasis of birds that spend short time in urban environments remain unclear. Using model bird species Zebra Finch (Taeniopygia guttata), we investigated the effects of short-term night lighting on liver transcriptome, blood glucose, triglyceride, and thyroxine (T4 and T3) levels in birds exposed to two different night lighting duration periods (three days and six days). After three days of night lighting exposure, the expression of genes involved in fat synthesis in the liver was upregulated while the expression of genes involved in fatty acid oxidation and triglyceride decomposition was downregulated. There was also a reduction in blood triglyceride, glucose, and T3 concentrations. However, after six days of night lighting, the expression of genes associated with fatty acid decomposition and hyperglycemia in the liver was upregulated, while the expression of genes involved in fat synthesis was downregulated. Simultaneously, blood glucose levels and T3 concentration increased. These findings indicate that short-term exposure to night lighting can disrupt the lipid and glucose metabolism of small passerine birds, and longer stopovers in urban area with intense night lighting may cause birds to consume more lipid energy.