Date of Graduation


Document Type


Degree Name

Master of Science in Poultry Science (MS)

Degree Level



Poultry Science


Samuel J. Rochell

Committee Member

Michael T. Kidd

Second Committee Member

Casey M. Owens


Amino Acid, Broiler, Energy, Myopathies, Nutrition, Performance


As new broiler crosses are introduced to the industry, it is of paramount importance to understand their nutritional digressions from previous and other modern broilers. In particular, amino acids (AA) and dietary energy have been identified as key drivers of live performance and carcass composition. In addition, increased nutrient density in broiler diets have been linked to an increase in breast muscle myopathies such as white striping and woody breast. Therefore, a series of trials were conducted to determine the responsiveness of live performance, carcass characteristics, and breast muscle myopathies of Cobb MV × 700 broilers to dietary AA and energy density.

Experiment 1 served to identify the responsiveness to varying AA densities. Live performance responses were detected at 28 d of age, identifying a starting point for AA density modification in Cobb MV × 700 broiler diets. Experiment 2 attempted to identify key time points in the Cobb MV × 700 broiler growout where changes in AA density would be most beneficial for live performance and processing efficiency. It was determined that body weight gain (BWG) and feed intake (FI) responses to AA density were evident at 28 d but diminishing effects were observed by 35 d. Experiment 3 intended to determine the responsiveness of Cobb MV × 700 broilers to commercially viable changes in energy concentration but found no response in BWG, FCR, or processing parameters. In an attempt to increase marginal AA density responses in live performance and processing, Experiment 4 assessed potential interactions between dietary energy and AA density in the latter phases of growout where AA effects had previously diminished. This experiment determined that energy is not a limiting factor for AA responses in Cobb MV × 700 broilers. Woody breast and white striping results were inconsistent throughout Experiments 2 through 4 and a definitive conclusion could not be drawn as to how these myopathies are linked to broiler nutrition.