2007 Annual Report 1a.Objectives (from AD-416) Phosphorus (P) is a mineral nutrient required for bone growth and many important energetic metabolic processes in animal, plant, and microbial systems. But P, when discharged into surface water can cause significant water pollution. Runoff from the production and feeding facilities, buildings, feed yards, waste storage areas, lagoons, etc. and runoff from land applied manure degrade water quality and diminish its intended value. The addition of phytase enzymes to animal diets has the potential to improve the phytic acid-P utilization by the animal. Phytases enzymes (myo-inositol hexaphosphate phosphohydrolase) catalyze the hydrolysis of feed grain and fiber phytic acid to myo-inositol and phosphate and thereby allow reduction in mineral P supplementation and excretion. The objectives of the collaborative research project between the Institute for Tropical Biology (ITB) and USDA, Agricultural Research Service (ARS) are to evaluate and optimize dietary phytases enzymes production and utilization in animal nutrition under the joint support of the Scientific Cooperation Research Program of USDA, Foreign Agricultural Service and ARS. 1b.Approach (from AD-416) The research approaches will include fermentation studies to identify potential fungal strains of high hydrolytic efficiency. Purification of selected enzyme preparation will be made to isolate high-activity phytic acid-degraders and from commercial Aspergillus preparations. Distinctions will be made between phytases’ activity and that of general phosphatases or hydrolases of inorganic polyphosphates. In controlled experiments, enzyme kinetic parameters will be determined and comparisons of hydrolytic efficiency of the isolates will be validated using selected feed and archived animal manure collections. This work will be carried in the Environmental Management and Byproduct Utilization Laboratory by the cooperating scientist and the experimental results will be prepared for publication in technical journals as well as served as bases for continued research on the use of high activity phytases in diets of Vietnamese poultry strains by FASVM-Nong Lam University scientist in Ho Chi Minh City. 3.Progress Report This report documents research conducted under a reimbursable agreement between ARS and the Institute of Tropical Biology of the Vietnam Academy of Science & Technology and the Faculty of Agricultural Science and Veterinary Medicine of Nong Lam University. Additional details of research can be found in the report for the parent project 1265-12360-002-00D “Understanding Phosphorus Chemistry in Manure and Soil and their Interactions to Treat and Control Phosphorus Movement in the Environment” under National Program 206. Research information is critically needed on the contribution of manure organic phosphorus such as phytic acid from feeds to the sources and sinks of dissolved phosphorus in the soil-manure-water environments. Substantial amounts of organic phosphorus stored in feed grains are excreted in feces, contributing to water quality impairments rather than animal productivity. High-efficiency dietary phytases can enhance feed phosphorus assimilation and potentially lower the level of phosphorus discharged to the environment. The U.S. principal investigator hosted the Vietnamese counterpart in Beltsville to conduct studies of phytase enzymes in selected fungal strains. Growth and enzyme induction characteristics indicated a relationship between composition of the culture medium and expression and specific activity of the isolates. Enzyme stability and integrity of activity of purified isolates were observed in selected feed ingredients and environmental specimens such as manure and soils. Results were presented in a report entitled “Extracellular Phosphohydrolases: Sensing of Environmental Phosphorus” at the third International Conference on Enzymes in the Environment, Viterbo, Italy. Two theses of Master of Science candidates of HCMC Vietnam Polytechnic University based on the research objectives of the project have been submitted to further document project accomplishments. Methods of monitoring project progress have included regular electronic correspondence and mutual site visits in FY07 to conduct organic phosphorus mineralization studies, transfer of analytical protocols and methodologies, discuss experiment results, provide technical assistance, and validate adequacy and timeliness of fund transfer and control systems. Time adjustments of studies of dietary supplements have been discussed with the Vietnamese scientists in view of the occurrence of the avian influenza in Vietnam. While feeding trials are delayed, benchtop experiments were conducted to determine phosphorus bioavailability in selected feeds and study its predictability from an enzyme-labile bioactive phosphorus assay developed at the Environmental Management and By-Product Utilization Laboratory. Potentially, the research results can improve our understanding of the nutrition-environment linkage in poultry and other species of importance to livestock production in Vietnam and the U.S. and the development of sustainable production practices for enhancing their adoption by producers in both countries.