Date of Award


Degree Type


Degree Name

Master of Science - Agriculture



First Advisor

Dr. Joey Bray



The objectives of this study were to determine the effects of protease supplementation on commercial broiler performance, carcass yield, and nitrogen retention in fecal matter and litter. Total of 4,800 female (Ross 708) birds split into 96 floor pens, and randomly assigned to one of four treatment groups. Birds were placed within 96, 5’x10’ floor pens in a randomized-block design at the SFASU Poultry Research Center. Birds were randomly divided among the pens at a stocking density of 1.00 ft2/bird (50 birds/pen*24 pens/treatment=1200 birds/treatment), and reared for 49 days on used pine shavings. The target average weight for the birds was 6.25lbs. Dietary treatments consisted of: treatment #1 positive control (PC) Pilgrim’s Standard Diet (Basal diet), treatment # 2 negative control (NC) Pilgrim’s Diet with Protease Matrix removed (only the amino acids’ credit – no energy credit), treatment # 3 (PC+ Protease) Pilgrim’s Diet (Basal diet) + Protease "on top", and treatment # 4 (NC+ Protease) Pilgrim’s Diet with Protease Matrix removed + Protease "on place". groups were analyzed for bird performance, carcass yield, and Nitrogen retention in fecal matter and litter. A yield study was completed at the end of the study to determine meat yield for all retail cuts. Results indicated that the protease addition on top of protein matrix in treatment 3 had significant effect on live body weight at day 49, and had no significant effect on feed conversion ratio (FCR) & adjusted feed conversion ratio (AFCR). Also, the protease had no significant effect on carcass yield. However, the inclusion of protease on low protein diet (NC+ Protease, Tx4) lowered the nitrogen retention in fecal matter.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.



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