Effect of the addition of ultraviolet light on broiler growth, fear, and stress response
Gabrielle M. House, Eric B. Sobotik, Jill R. Nelson, Gregory S. Archer
Abstract
The objective of this study was to determine the effects of ultraviolet light supplementation on production parameters, fear responses, and stress susceptibility in broiler chickens. Birds were reared under either light emitting diode (LED) bulbs supplemented with UV light fixtures (UV) or just LEDs (Control). Growth, feed conversion, tonic immobility, inversion, composite asymmetry, plasma corticosterone, heterophil-to-lymphocyte ratio, and humoral immunity were measured to determine treatment differences. No differences were found in body weight or feed conversion (P > 0.05). UV birds righted quicker during tonic immobility (P < 0.05) and had less intense wing flapping (P < 0.05) compared with the Control. UV birds also had lower physical asymmetry (P < 0.05), plasma corticosterone (P < 0.05), and heterophil-to-lymphocyte ratios (P < 0.05) than the Control birds. Treatments did not differ in humoral immunity (P > 0.05). These results suggest broilers reared under ultraviolet light have lower stress susceptibility and fear responses. Ultraviolet light may be critical to maximize broiler welfare.