|Purswell, Joseph - Jody|
Submitted to: International Journal of Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/30/2010
Publication Date: 9/15/2010
Citation: Olanrewaju, H.A., Purswell, J.L., Collier, S.D., Branton, S.L. 2010. Effect of Ambient Temperature and Light Intensity on Growth Performance and Carcass Characteristics of Heavy Broiler Chickens at 56 days of age. International Journal of Poultry Science. 9(8):720-725.
Interpretive Summary: The genetic potential of modern heavy broilers (2.5 kg and above) breeds for high productivity will not be fully realized until microenvironmental constraints (temperature, humidity, light intensity, air velocity, etc) have been fully addressed. Although many studies have been conducted to evaluate the effect of the microenvironmental factors on growth performance and production in broilers, still more studies are necessary to examine the interaction of temperature and light intensity and its effects on growth performance and carcass characteristics of modern heavy broilers. The effects of ambient temperatures of 15.5, 21.1, and 26.7 °C, concurrently with differing light-intensities (0.5, 3.0, and 20 lx) on growth performance, carcass characteristics and the resultant welfare of modern heavy broilers were examined. Results indicated that the effects of ambient temperatures were more pronounced than that of light-intensity on growth performance and carcass characteristics. In addition, the conditions were worsened as the level of ambient temperatures increased. However, the high ambient temperature of 26.7 °C and light intensity that we used in this study did not act together or separately to affect plasma corticosterone, suggesting that these factors may not pose as stressors to the modern heavy broiler chickens. It was concluded that exposure of modern heavy weight broilers to high ambient conditions of 26.7 °C in comparison with 15.5 and 21.1 °C has a negative effect on growth performance and carcass characteristics, suggesting that they need to be grown under lower ambient temperature than previously reported due to their higher body weight and metabolic rates. The results of this study show the positive impact of reducing microenvironmental factors (temperature and light intensity), in that they may reduce energy cost, optimize the environment in broiler houses, aid in maximizing the genetic potential of broilers and reduce production costs.
Technical Abstract: The effects of ambient temperature, light intensity and their interaction on growth performance and carcass characteristics of broilers were investigated in 2 trials. The experiment was consisted of a factorial arrangement of treatments in a randomized complete block design. The 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 21 to 56 d of age at 50% RH. Five hundred and forty Ross 708 chicks were randomly distributed into 9 environmentally controlled chambers (30 males and 30 females chicks/chamber) at 1 d of age. Feed and water were provided ad libitum. Birds were provided a four phase-feeding program (starter: 1 to 14, grower: 15 to 28 d, finisher: 29 to 42 d, and withdrawal: 43 to 56 d). At 56 d of age, both feed intake and birds’ weight were recorded for the growth performance. Also, 20 (10 males and 10 females) birds from each chamber were processed to determine weights and yields. Broilers subjected to high ambient temperature had significantly (P = 0.05) lower BW, BWG, FI, carcass weight, and pectoralis major and minor weights along with a significant (P = 0.05) increased in FCR when compared with low and moderate ambient temperatures broilers. Plasma corticosterone concentrations were not statistically affected by temperature, light intensity or their interaction, suggesting an absence of stress. These results indicate that exposure of modern heavy weight broilers to high ambient temperature of 26.7 °C in comparison with low and moderate ambient temperatures has a negative effect on growth performance and carcass characteristics, suggesting that they need to be grown under lower ambient temperature than previously reported.