Evaluation of the Effect of Lighting Technology on Broiler Performance, Stress, and Gene Expression

Broiler production and management has become highly specialized over the years to optimize bird performance.  Recent research has focused on the effect of light on bird growth and health, specifically regarding the intensity, duration, and wavelength of light provided to the birds.  This project evaluates the impact of different lighting technologies including cold cathode fluorescent (CCFL), light emitting diode (LED), and incandescent lamps on broiler performance, welfare and gene expression.  Live performance for each technology was evaluated using live broiler body weight, weight gain, feed conversion, and mortality.  Birds were removed from each house at days 7, 14, 35, and 42 to be humanely euthanized, weighed, and harvested for tissues for transcriptome analysis.  Blood collection via cardiac puncture for heterophil:lymphocyte (H:L) ratios was performed to evaluate environmental stress.  Results indicate that incandescent and LED lamps provide better growth with low feed conversion ratios, while CCFL lamps yield poor performance.  An evaluation of heterophil to lymphocyte ratios shows strong correlations between age, seasonality, and technology.  Transcriptome studies were conducted to compare gene expression patterns in the retina and pineal gland of the birds under different lighting technologies.