33 Award Talk: Precision calcium and phosphorus nutrition in pigs and poultry.

Abstract Monogastric livestock use little plant phosphorus (P), that is in the form of phytate (PP) because they do not have the phytase enzyme. In high-production, high-density countries, this leads to excessive fertilization that leaches into waterways and can lead to eutrophication of water bodies when animals excrete more P into the environment than plants need. In addition, to meet their P needs, mineral phosphate additions, a non-renewable resource that was recently estimated to peak around 2030 and replenish 100 years later and is also essential for crops, are required. Addressing this threat of a P resource shortage for the food system needs precise P nutrition which rely on research to understand modulating factors and precisely assess feed ingredients P value and pig and poultry requirements. Among the important factors to control, there is calcium that is essential to fixed P into bone but can reduced P absorption by the formation of insoluble complexes in the intestine. It is also interesting to note that birds may present a Ca apatite which is less true in swine. Also, limestone the main source of calcium is a important element to understand better as its solubility and particle size drive its interaction with P in the gut especially in poultry. Supplementation of diets with exogenous phytase is a common practice that allow increasing the use of PP. Continuous advances in protein engineering led to development of new generations of phytases and the 4th generation is arriving on the market offering the possibility to reduce or even eliminate the use of phosphates if its use is optimize. Optimizing the use of P also rely in multicriteria approach as P is crucial for bone, growth performance while it is useful for crop production, but when in excess can cause eutrophication. To reach the goal of optimizing P utilization, a combination is proposed. First experiments to measured growth performance, feces and urine excretion, plasma concentration and the most important parameters bone mineralization. It’s nowadays possible to follow the body composition including bone mineral content with dual X-ray absorptiometry, a powerful tool for research in micromineral. Then meta-analyses can be used to generate data for empirical (e.g., prediction equation, parameter estimation) and mechanistic model development and their validation. This allows us to develop robust multi-criteria models that adapt to context and can even perform real-time simulations.