Date of Graduation


Document Type


Degree Type



Davis College of Agriculture, Natural Resources and Design


Animal and Nutritional Sciences

Committee Chair

Josephh Moritz.


Successful commercial turkey production requires proper genetic strain selection to optimize live performance and profit. In addition, sustainable practices relative to manure disposal are essential due to perceptions that land application of poultry manure is a primary contributor to watershed eutrophication. The objective of our research was to assess genetic strain and finisher diet non-phytate phosphorus (nPP) level effects on large tom performance and litter composition using a research facility that mimics commercial production. Experiments were 2x2 factorial designs utilizing 2 strains (Nicholas and Hybrid) and 2 levels of dietary nPP (normal and low) in finishing diets. Two experiments of similar concept and design were conducted in sequence. In experiment (Exp) 1 Hybrid Converter and Nicholas 88x700 strains were compared, and dietary nPP was reduced during the last finisher diet [calculated percent nPP: normal (0.37) and low (0.31)]. In Exp 2, Hybrid Converter and Nicholas TP5 strains were compared, and dietary nPP was reduced in the last 2 finisher diets [calculated percent nPP: normal (0.58) and low (0.55) in the finisher 1 diet, and normal (0.40) and low (0.38) in the finisher 2 diet]. Live performance measurements were recorded from d 1-136 and from d 1-126 for Exp 1 and 2, respectively. Liver enzyme assays associated with lysine degradation were quantified and litter phosphorus (P) levels were determined. In Exp 1, both strains had similar ending weight (EW). The Hybrid Converter strain had improved feed conversion ratio (FCR) as compared to the Nicholas 88x700 strain. The initial enzyme of the primary pathway of lysine oxidation/degradation, lysine alpha-ketoglutarate reductase (LKR), had greater activity in Nicholas compared to Hybrid toms. Changes in dietary nPP in the finisher diet did not affect performance or litter P, thus indicating potential to decrease feed cost but not environmental impact. In Exp 2, Nicholas TP5 had greater EW but increased FCR as compared to Hybrid Converter toms. However, regression equations that standardized strain EW, predicted a decreased time of production and FCR for Nicholas TP5 toms. Hybrid Converter and Nicholas toms did not differ in LKR activity; although, a decrease in activity over time was observed. Manipulation of dietary nPP level did not affect tom performance. However, the low nPP diet decreased total litter P, thus indicating potential to decrease feed cost and environmental impact.