Date of Graduation

2014

Document Type

Dissertation

Degree Type

PhD

College

Davis College of Agriculture, Natural Resources and Design

Department

Animal and Nutritional Sciences

Committee Chair

Joseph S Moritz

Committee Co-Chair

Deborah Boone

Committee Member

Stacy Gartin

Committee Member

Marie Krause

Committee Member

Robert Taylor

Abstract

In the poultry industry, feed and feed manufacture account for 60 to 70% of production costs. Because of this, integrators are continually seeking ways to decrease costs while maintaining pellet quality and bird performance. The research presented in this dissertation offer several novel feed ingredients that have the potential to replace costly feed ingredients, increase pellet quality, improve bird growth and performance, and improve nutrient digestibility. In Chapter 2, four experimental phytase enzymes (A -- D) were examined for thermostability during pelleting, as well as efficacy in vivo. Phytase activity post-pelleting demonstrated high variability between phytases, ranging from 120 to 1,300 FTU/kg. Bird performance revealed the most consistency with enzymes A and D, with enzyme A resulting in the highest phosphorus sparing. The take home message in Chapter 2 is that high efficacy in vitro may not translate to high efficacy in vivo, and both experiments must be completed prior to phytase commercialization. In Chapter 3, the efficacy of two enzyme cocktails (Allzyme SSF and VegPro) was assessed in diets containing meat and bone meal. Birds were fed diets containing SSF and VegPro separately or in combination; the enzymes, both separately or in combination, demonstrated improvement over the negative control for ending bird weight, live weight gain, and feed conversion ratio. The combination of enzymes demonstrated improved ileal amino acid digestibility compared to the negative control, while the enzymes separately demonstrated improved true amino acid digestibility for several amino acids. The digestibility of meat and bone meal did not improve with enzyme supplementation, likely due to the enzyme's target substrate being vegetable in origin. In Chapter 4, the effects of algae biomass were examined. The nutrient digestibility of algae was determined and these data were used to formulate a practical broiler starter diet containing 21% algae, and the effects of diets containing incrementally increasing levels of algae on performance and amino acid digestibility were assessed. Algae biomass energy and digestible amino acid content was determined to be most similar to soybean meal and was used as a replacement for this ingredient in diet formulation. The 21% algae diet increased pellet durability, suggesting algae as a pellet binder. Diets containing up to 16% algae resulted in similar performance and amino acid digestibility as the 0% algae diet. The two appendices represent research conducted to assess poultry litter biochar as a replacement for rock phosphates. In Appendix A, biochar was found to improve pelleting characteristics. Performance benefits were not observed, potentially due to arsenic contamination. However, some bone mineralization was observed. The biochar used in Appendix B was found to contain a lower level of arsenic. Pellet durability was again increased with dietary biochar inclusion and performance was improved. Performance was most improved with dietary inclusions of both biochar and phytase. No differences were observed for digesta viscosity. Amino acid digestibility and bone mineralization are currently being examined for this experiment.

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