Date of Graduation


Document Type


Degree Type



Davis College of Agriculture, Natural Resources and Design


Animal and Nutritional Sciences

Committee Chair

Joseph S Moritz

Committee Co-Chair

Gerard E D'Souza

Committee Member

Jacek Jaczynski


Experiments were conducted to determine the effects of different ingredients and manufacture techniques on the quality of pellets being produced as well as to examine how broiler performance will be affected by the dose of phytase product included in the diet. Chapter 3 explores the effects of a manipulation of either feed ingredient or manufacture technique (referred to as concern areas) on manufacture and pellet quality variables. Treatments included high or low mixer-added fat (2.5 vs. 0.5%), high or low distillers dried grains with solubles (DDGS) (8 vs. 2%), high or low dicalcium phosphate (1.63 vs. 0.31%), and high or low steam conditioning temperature (71 vs. 79°C). The high concern treatments for the mixer-added fat and dicalcium phosphate treatments demonstrated negative effects on pellet quality variables. However, the high concern treatments for DDGS and steam conditioning temperature did not produce similar negative effects. In chapter 4, different doses of phytase products were examined to determine an effective dosage level of each product on bird performance and tibia mineralization. Feed formulations were based on the phytase activity provided by the manufacturer and provided a calculated activity of 500, 1,500, and 6,000 FTU/kg for each phytase product. In addition, a positive and negative control diet based on non-phytate phosphorus level were formulated. Pellets were crumbled to a similar size and fed to 12 replicate pens of 10 straight-run Hubbard x Cobb broiler chicks for 21-d. Positive and negative control formulations produced relative differences in live weight gain, ending bird weight, and feed conversion ratio as expected. Main effects of dose and phytase product significantly affected live weight gain, ending bird weight, and feed conversion ratio. The granulated bacterial phytase was superior to the transgenic phytase corn product and the 6,000 FTU/kg dose was superior to the 500 and 1,500 FTU/kg doses.