Date of Graduation


Document Type


Degree Name

Doctor of Philosophy in Poultry Science (PhD)

Degree Level



Poultry Science


Craig N. Coon

Committee Member

Ricardo Ekmay

Second Committee Member

Malea Frank

Third Committee Member

Charles Maxwell


Amino Acid Requirements, Body Composition, Broiler Breeders, Poultry Science, Protein Turnover


Amino acids (AA) are commonly referred to as the building blocks of protein due to their role in the synthesis of proteins. Considering these nutrients are involved in growth and metabolism, much emphasis is placed on determining the dietary requirements of amino acids. Therefore, an experiment was conducted to evaluate the amino acid requirements of performance parameters such as egg weights, egg production, egg mass, feed conversion ratios, and body weight gain in two age groups of broiler breeders. In this experiment, 648 Cobb 700 broiler breeder hens were placed in individual cages to determine the amino acid requirements of arginine, glutamic acid, lysine, methionine and cystine, threonine, tryptophan, isoleucine, and valine. Birds were fed for a period of seven weeks, which included two weeks of adaptation and five weeks of testing. The testing period was divided into two phases to examine the amino acid requirements on two age groups. Phase I lasted from wks 30 through 37, while Phase II occurred from wks 44 through 51. From the data, ideal profiles for egg weights, egg production, egg mass, feed conversion ratios, and body weight change were developed. Additionally, the body composition and protein turnover of broiler breeder hens were evaluated for hens fed diets containing deficient, adequate, and excess levels of the amino acids of interest. Findings showed that ideal profiles for parameters should be used in tandem, depending on the production goal and life stage. Furthermore, feeding deficient and excess levels of amino acids to hens results in differences in lean mass and protein turnover. Fractional degradation rates were significantly lower for hens fed deficient levels of branched-chain amino acids such as valine and isoleucine (P < 0.05) as compared to adequate and excess levels. The described studies emphasize the need to conduct amino acid studies on broiler breeders and the effect of performance on requirements, body composition, and protein turnover.

Available for download on Monday, February 17, 2025