Light Spectrum Requirements for Egg Production
Gobbles, 70 (4), 6-8, a publication of the Minnesota Turkey Growers Association.
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Several studies have been carried out in my laboratory to investigate light spectrum requirements for the enhancement of breeder hen turkeys’ reproductive performance (El Halawani, 2004, 2005, 2006 turkey research reviews CD-ROM; El Halawani, Gobbles 66 (4): 4, 2009). The results showed that the 630 nm wavelength in the red band of the spectrum was superior to the 600, 680 and the 720 nm wavelengths for improving egg production.
The findings that light intensity is an important determinant of breeder hen turkeys’ reproductive performance and the red 630 nm wavelength is proven superior to any other wavelength influencing egg production, we investigated the influence of light intensity provided by the 630 nm wavelength on egg production. The results from this study showed egg production to be essentially similar 4.05, 4.40, 3.95 and 4.28 eggs/hen/week among the four light intensities tested that included 0.5, 3.0, 6.0 and 18.0 foot candles (FC; El Halawani, Gobbles 66 (4): 4, 2009), respectively. Recently, we have identified a group of light sensitive dopamine-melatonin neurons in the turkey brain that appear to be the site of photoperiodic time measurement for reproductive stimulation (Kang et. al., Neuroscience 150: 223, 2007; Leclerc et al., Poultry Science 88 (Suppl.1): 127, 2009; Leclerc et al., J Neuroendocrinol 22: 119, 2010,).
More recently, we also found the photopigment melanopsin to be localized within these neurons (Kang et al., Neuroscience 170: 210, 2010). Melanopsin is a non-visual, blue light (460- 480 nm of the spectrum) photopigment that mediates photo information concerning neuroendocrine and circadian, responses in mammals (i.e. seasonal reproduction, Provencio et al., J Neurosci 20:600, 2000). We hypothesized that the non-visual blue photopigment melanopsin expressed in the turkey brain is concerned with mediating light information related to female turkey reproduction as well as enhancing the stimulatory effects of the long wavelength red light (630 nm) on the reproductive hormone system.
In the present application we propose to refine the blue light wavelength and its relationship to the 630 nm red band on egg production, and to compare these with light spectra programmable light bulbs from Once Innovations, Inc.