Effect of Light Spectrum on Stress Susceptibility and Salmonella Status of Laying Hens
Abstract
Background and Objectives: Light-emitting diode (LED) light bulbs are becoming more prevalent in layer production and there is discussion on whether the spectrum of light that is produced by the bulb can affect stress and health of laying hens. To investigate if differences between how different wavelengths of light affect these factors we raised hens under either bulbs that produced mainly blue light (BLUE), or mainly red light (RED) or mainly a white light (WHITE). Methodology: Each treatment consisted of 30 white leghorn hens and the experiment was replicated twice. Stress susceptibility was measured using bilateral asymmetry (ASYM), plasma corticosterone concentrations (CORT) and secondary antibody production to I.M. KLH injection (KLH). The birds were also subjected to a Salmonella challenged. Hens were broken into groups that were Unvaccinated/unchallenged (UVUC), Salmonella enteritidis (SE) vaccinated/unchallenged (VUC), Unvaccinated/ SE challenged (UVC) and SE vaccinated/SE challenged (VC). The ceca were enumerated. Results: RED birds had lower ASYM (1.43±0.12 mm) than both BLUE (1.85±0.14 mm, p = 0.03) and YELLOW (1.86±0.13 mm, p = 0.03). RED (13.8±1.7 ng mL–1, p = 0.03) and YELLOW (12.7±1.7 ng mL–1, p = 0.01) birds had lower CORT than BLUE (21.1±1.8 ng mL–1). RED birds (401562±22013 U mL–1) had higher KLH titers both BLUE (338312±18272 U mL–1, p = 0.03) and YELLOW (333814±18790 U mL–1, p = 0.03). Lighting did not affect ceca counts or serum titers in either trial (p>0.05). Differences were observed in the Salmonella titers between the vaccinated versus unvaccinated groups (p<0.05). Conclusion: The results indicate that spectrum of LED light can affect the stress susceptibility and but not Salmonella status.
Keywords:
Layers, LED light, lighting, light stimulation, Salmonella, stressArticle Metrics
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