Main effects of light sources, photoperiods, and genetic strains on blood physiological variables of broilers grown to heavy weights.

Abstract

Effects of light sources, photoperiods, and genetic strains on blood physiological variables of broilers grown to heavy weights were investigated in 2 trials. The experimental design was a 4 × 2 × 2 factorial consisting of 4 light sources [incandescent (ICD, standard), compact fluorescent (CFL), neutral light emitting diode (Neutral‐LED), and cool poultry specific filtered LED (Cool‐PSF‐LED)], 2 photoperiods (Regular/intermittent [2L:2D], and Short [8L:16D], and 2 genetic strains (Ross × Ross 708, Cobb 700). In each trial, 480 (240 males/240 females) 1‐d‐old chicks of each strain from different commercial hatcheries were equally and randomly distributed into 16 environmental control rooms (30 males + 30 females/room) at 50% RH. Each room was randomly assigned one of 16 treatments from d 1 to 56 d of age. Birds were provided similar diets. Feed and water were provided ad libitum. Venous blood samples were collected on d 14, 28, 42, and d 56 of age and analyzed immediately. Cool‐PSF‐LED light sources had significant (P ≤ 0.05) effects on BW, Hb, Hct, electrolytes, angap, and mOsm in comparison with birds reared under ICD, but all these changes were still within the normal acid‐base homeostasis and physiological ranges. Also, the short photoperiod significantly (P ≤ 0.05) reduced BW, pH level, pO2, sO2, and Ca2+, with significantly (P ≤ 0.05) elevated pCO2, Hct, Hb, and McHc concentrations. Acid‐base regulation during short photoperiod exposure had not deteriorated despite higher pCO2 that consequently decreased blood pH due to a respiratory acidosis. In addition, Cobb 700 had significantly (P ≤ 0.05) increased BW, pCO2, Hct, Hb, Ca2+, Cl−, McHc, and angap along with significantly (P ≤ 0.05) reduced pH level, pO2, HCO3−, and glucose in comparison with Ross × Ross 708. Plasma corticosterone was not affected by light sources, photoperiod, genetic strain or their interaction, indicating that exposure of broiler chickens to the short photoperiod markedly affects some physiological blood variables without inducing stress in modern broilers grown to heavy weights. It was concluded that the 3 LED light bulbs evaluated may be suitable for replacement of ICD along with the regular/intermittent photoperiod for commercial poultry facilities to reduce energy costs and optimize production efficiency without compromising the welfare of broilers grown to heavy weights.Support or Funding InformationNoneThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.