Submitted to: Feedinfo News Service
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/25/2011
Publication Date: 11/12/2011
Citation: Olanrewaju, H.A., Branton, S.L. 2011. Influence of environmental temperature and light intensity on growth performance and blood physiological parameters of broilers grown to heavy weight. Feedinfo News Service. 6:1-4. Interpretive Summary: Exposure of chicks to ambient temperatures (Low=15.5, Moderate=21.1, and High=26.7 °C) from day 21 to 56 day of age concurrently with differing light-intensities (0.5, 3.0, and 20 lx) from day 8 to 56 day of age on growth performance, blood physiological variables, and their involvement on welfare in broiler chicken were examined. Result indicated that the effects of ambient temperatures were predominantly pronounced than that of light-intensity on growth performance and blood physiological variables and the conditions worsened as the level of ambient temperatures increased. In addition, the high ambient temperature and light intensity that we used in this study apparently did not act together or separately to affect plasma corticosterone that is a measure of well-being. It was concluded that exposure of modern heavy weight broilers to high ambient temperature of 26.7 °C in comparison with low and moderate ambient temperatures may have a negative effect on broiler live performance and some blood physiological variables without inducing stress in broilers grown to heavy weights. The results of this study show the positive impact of reducing microenvironmental factors (temperature and light intensity), suggesting that modern heavy broilers need to be grown under lower ambient temperature than previously reported due to their body weight size and metabolic rates.
Technical Abstract: In a study of temperature and light intensity, 9 treatments consisted of 3 levels (Low=15.6, Moderate=21.1, High=26.7 °C) of temperatures and 3 levels (0.5, 3.0, 20 lx) of light intensities from d 8 to 56 d of age. Across all light levels at d 56, broilers subjected to high temperature significantly (P = 0.05) had poorer BW, BWG, FI, and higher FCR compared with values observed at low and moderate temperatures. Furthermore, venous blood samples were collected on d 56. High temperature significantly (P = 0.05) reduced partial pressure of CO2 (pCO2), bicarbonate, hematocrit, hemoglobin, K+, and Na+ while significantly (P = 0.05) elevating pH level, glucose, osmolality, and Cl- levels. Partial pressure of O2 (pO2) was slightly increased when related to ambient temperature. There was no effect of light-intensity on most of the examined variables, except for glucose. Acid-base regulation during high ambient temperature and light intensity exposure had not deteriorated despite lower pCO2 that consequently increased blood pH, due to a compensatory decrease in HCO3- concentration. Plasma corticosterone was not affected by temperature, light intensity or their interaction, suggesting an absence of physiological stress. These results indicate that moderate temperatures and light-intensities improve broiler live performance, while high temperature and high light-intensity may have a negative effect on broiler live performance and some blood physiological variables without inducing stress in broilers.