Date of Graduation


Document Type


Degree Name

Doctor of Philosophy in Poultry Science (PhD)

Degree Level



Poultry Science


Michael T. Kidd

Committee Member

Samuel Rochell

Second Committee Member

Lawton Nalley

Third Committee Member

Sara Orlowski

Fourth Committee Member

Roy Brister


broiler, microalgae, nutrition, poultry, spirulina


Spirulina (Arthrospira platensis) is a cyanobacteria microalgae that has potential as an animal feed ingredient. Five experiments were conducted to further assess its ability to serve as a protein source in broiler diets. Experiment 1 consisted of an amino acid digestibility and apparent metabolizable energy assay. The results indicated that the standardized ileal amino acid levels of spirulina are comparable with typical soybean meal. Experiment 2 assessed the performance and processing parameters of broilers fed 10% spirulina in low crude protein diets, using published digestibility coefficients. Spirulina inclusion improved footpad quality and increased redness and yellowness of the breast, skin on thigh, and skinless thigh. Experiment 3 utilized whole blood and liver samples from experiment 2. Results indicate that spirulina reduces systemic inflammation- and bacterial translocation-induced by low protein diet and could be a promising alternative protein source in poultry diets. Experiment 4 examined the growth performance, carcass characteristics, woody breast myopathies, and breast fillet pigmentation during the grower and finisher phase. Spirulina was included up to 10% from 15 to 35 d and 5% from 34 to 49 d in standard corn/soybean meal diets. Results indicated no significant differences on any performance and carcass yields; validating digestibility values from experiment 1. Pigment deposition responded strongly to spirulina inclusion. Experiment 5 assessed spirulina inclusion of 2.5% and dietary CP level in a 2x2 factorial. Performance parameters, water consumption, processing yields, litter quality, and litter flux measurements were recorded. Crude protein reductions inhibited performance parameters and processing yields, while reducing water consumption and carbon dioxide flux. Spirulina inclusion reduced carcass and breast yield through decreased feed utilization.