Birds possess retinal photoreceptors responsible for vision, and non-visual photoreceptors (extra-retinal) responsible for detecting photoperiod and synchronizing their physiology to the environment. These photoreceptors are located in three main organs: the retina of the eye, the pineal gland and the hypothalamus. As the majority of commercial poultry operations rely on controlled environments in which artificial lighting is used to manage birds, light quantity (number of photons delivered) and quality (spectral composition) can significantly impact production. Incandescent lights have a broad spectral output mimicking sunlight and have been the primary source used by the North American poultry industry. However, these bulbs are energy inefficient and producers have been pushed to find alternatives. With new lighting technologies and the advancement in genetic selection of domestic poultry, there is often conflicting evidence as to the effects of light wavelength (and thus type of light bulb) on reproduction. However, we and others have shown that light from the red spectrum is critical to adequately stimulate the reproductive axis, and this effect is mediated primarily via deep-brain photoreceptors. Over the last 5 years, we have translated basic scientific data to develop an LED bulb that promotes reproduction and thus egg production. This was achieved by comparing the effects of light wavelength on production parameters in commercial layers maintained under different environmental conditions, designing a bulb with a defined spectral output, and validating the effectiveness and durability of this bulb under commercial settings (harsh barn environment, industrial cleaning and disinfection). Results confirmed that light from the red spectrum is most efficient at stimulating the hypothalamo-pituitary-gonadal axis. However, results also showed that intensive selection of modern commercial strain of layers has resulted in a shift in the relative importance of photoperiod in initiating sexual maturation, and other cues such as metabolic status and body condition may have become the primary drive highlighting the importance of pullet management. On a practical level, we showed that using the right LED bulb for the right application can improve productivity while reducing cost. Thus, we propose that “spectrum” lighting is the most appropriate technology for the future of the poultry industry.
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