2012 Annual Report 1a.Objectives (from AD-416): The objective of this cooperative research project is to improve broiler production efficiency and meat yield of heavy broiler chickens fed low-energy diets or diets varying in amino acid levels and to evaluate production efficiency and physiological responses of heavy broiler chickens as a function of light intensity. 1b.Approach (from AD-416): Day old broiler chickens will be obtained from a commercial hatchery and reared and fed low energy diets including strategies to increase the inclusion of distillers dried grains with solubles (DDG/S) in broiler diets. In addition, dietary amino acids will be investigated throughout the production cycle. Production efficiency and meat yield will be characterized. Studies on varying light intensities will be conducted in light controlled chambers. Blood samples will be obtained for analyses of selected blood gases, electrolytes, and indicators of stress as well as evaluation of immune stress. Also, neuropeptides associated with proopiomelanocortin release will be determined by obtaining brain samples from the thalamic region. Specific dissected areas will be extracted and component neuropeptides will be fractionated according to molecular size. Peptide identification will be performed by liquid chromatography and mass spectrometry. 3.Progress Report: Nutritional studies are being conducted in heavy broilers assessing alternative ingredients and their potential commercial acceptability. Efforts are being made in the area of in ovo technology with the aim of improving embryo and chick nutrition in an effort to improve the integrity of the growing broiler.