Growth and Stress Responses in Rats Exposed to Various Light Colours at Night

There is a paucity of knowledge on the effect of artificial light colors on the growth of mammals. This study investigated how different light colors affected the albino rat's growth and stress response. Day-old rats (432) were exposed to blue, green, yellow, red, and white lights. The rats were exposed between 6 pm and 6 am daily for 126 days. Three replicates per treatment per sex and each replicate had 12 rats. The growth indices were calculated from the growth parameters measured. Blood was collected atdays 63 and 126 for the analysis of serum corticosterone. Data were statistically analyzed and level of significance taken at p < 0.05. Weight variation in rats exposed for 28 days revealed that green light had the highest weight (p < 0.05) during the suckling age. The growth of the weanling rats was significantly enhanced under blue light followed by green light. Exposure to yellow light significantly retarded the growth of the rats. The growth indices were significantly higher in the blue-light-exposed rats and in the green-light-exposed rats and much lower in the yellow-light-exposed rats. Corticosterone level was significantly elevated under the light treatments on day 126. Corticosterone reduced with age except in rats exposed to yellow and green lights in male, and yellow and white light in female. The study revealed that various light spectral have effect on the growth and induced stress of rats in age dependent manner