2007 Annual Report 1a.Objectives (from AD-416) 1. Establish a long-term international collaborative research and exchange to address concerns in animal systems and environmental stewardship between ARS-Beltsville and Vietnam, 2. Optimize dietary phytases enzymes production and utilization in animal nutrition, 3. Improve feed efficiency and animal performance in assimilating feed phosphorus, and system productivity, and 4. Characterize feed and excreta phosphorus and controlling mechanisms of P solubilization across enzymes sources and feeding regimes to develop sustainable waste management strategies. 1b.Approach (from AD-416) Series of experiments will be establishe to screen for high-phytase producing strains of Aspergillus spp, and high specific activity; establish animal studies to complement the phytase selection/screening work with the feeding of the finished product(s) to poultry at various levels of supplementation of enzymes. Measurements of feed efficiency, animal growth parameters etc... and P recovery, assimilation, and excretion in the manure will be determined. 3.Progress Report This report documents research conducted under a reimbursable agreement between ARS and the USDA-Foreign Agricultural Service to establish long-term research collaboration with 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 Byproduct 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.