Effects of Exposure to Monochromatic Light on Pigeon Squab Performance and Growth-Related Hormones

Abstract

The objective of this study was to investigate the effects of the exposure to monochromatic light on growth performance, and on the growth hormone (GH) and insulin-like growth factor 1 (IGF-1) concentrations in growing Pigeons ( Columba livia). A total of 144 paired adult White King Pigeons were randomly divided into 12 compartments forming groups of 12 pairs. Then, three compartments were exposed to blue LED (BL), green LED (GL), red LED (RL), and white LED (WL). Allocation of light colours was done within blocks of four compartments. The pigeons were kept under WL for a two week adaptation period before the study began. Body weight (BW) and body weight gain (BWG) were evaluated weekly. Two pigeons from each replicate group were randomly selected for blood collection to determine the hormone concentrations at 1 day, 7 days, 14 days, 21 days, and 28 days of age. The results indicated that there were no between-treatment differences in the final BWs ( P = 0.570), but the squabs exposed to RL had greater BWGs between 7 and 14 days of age ( P = 0.009, P = 0.049, respectively). The correlation trend lines for the body weight and growth hormone comparisons were inverted U-shaped, which corresponded to the birds’ growth cycle. The results indicated that monochromatic red light had potential effects on growth performance during the early phase of production. Growth performance was closely related to the blood plasma concentrations of GH and IGF-1.