Towards the determination of the level of dietary phosphorus in high-producing sows

本项目的主要目的是改善饲粮磷(P)代谢和干扰因素的知识，开发一个数学模型来描述饲粮中磷和钙在母猪中的去向，以优化它们的利用，更好地确定研究重点，并建立日粮磷和钙的建议。具体地说，目标是通过以下方式改善母猪的福利和寿命以及生产的可持续性：1)调整生长猪日粮中磷和钙的去向模型，以适应母猪。2)开发一种基于猪和母猪尿钙磷比的非侵入性评估工具，3)跟踪骨形成和骨吸收的血液标志物以及血和尿中的钙和磷与生产阶段(妊娠和哺乳期)的关系，4)模拟母猪骨储备的重建，5)利用所开发的模型建立最优的磷和钙的饲喂策略。与生长猪相比，对母猪矿物质需求的研究投入较少，这首先是因为可用的少数非侵入性方法，其次是母猪的研究成本是一个主要挑战。数学建模是一种强大的工具，它同时考虑到给定系统中涉及的所有机制，并通过整合已发表的关于研究对象的数据来预测描述其行为的关系。这种工具在营养方面非常强大，因为它允许采取多标准办法，并根据目标生产目标的目标调整建议。通过实验试验、荟萃分析和开发代表母猪日粮中磷和钙的去向的数学模型，开发一种将所获得的知识和新的基本结果相结合的多标准方法，将有助于优化它们的使用，更好地确定研究重点，并允许建立日粮磷和钙的建议。

The main purpose of this project is to improve the dietary phosphorus (P) metabolism and interfering factors' knowledge to develop a mathematical model representing the fate of dietary P and calcium(Ca) in the sow to optimize their use, better define research priorities and establish dietary P and Ca recommendations. Specifically the objectives are improving sow welfare and longevity and the sustainability of the production by: 1) Adapting the model of the fate of dietary phosphorus and calcium developed in growing pigs to sows. 2) Developing a non-invasive tool to assess bone mineral status based on Ca:P ratio in urine in pigs and sows, 3) Following-up blood markers of bone formation and resorption and Ca and P in blood and urine in relation to production stage (gestation and lactation), 4) Simulate bone reserves remodeling in sows, and 5) Establish optimal P and Ca feeding strategies using the developed model. In comparison to growing pigs low research effort has been given to the sow's mineral requirement because first of the few non-invasive methods available and second, the fact that research costs on sows a major challenge. Mathematical modelling is a powerful tool that simultaneously takes into account all the mechanisms involved in a given system and predicts the relationships that describe its behaviour by integrating the data already published on a subject of study. Such a tool is very powerful in nutrition because it allows a multicriteria approach and the adaptation of recommendations according to the objective of the targeted production objectives. The development of a multicriteria approach integrating the acquired knowledge and new fundamental results, through an experimental trial, a meta-analysis and the development of a mathematical model representing the fate of dietary P and Ca in the sow, will help optimize their use, better defined research priorities and allow the establishment of dietary P and Ca recommendations.