Toward precision feeding in pig production: optimal phosphorus and calcium dietary levels

动物生产的成功和可持续性面临着许多挑战，例如饲养成本的不断增加，公众对农业影响的日益增长，以及有效的营养循环以最大限度地减少对环境的破坏。考虑到磷(P)既是肥料又是污染物，了解如何最大限度地利用磷在动物饲料中的使用，以优化健康并将损失降至最低，从而对环境造成影响，这一点很重要。因此，提高猪对磷的利用效率至关重要。在规定的时间内向畜群中的所有动物提供单一饲料，并提供旨在使牲畜生产性能最大化的水平的饲料磷的做法，一直是许多研究的主题。提高猪对磷的整体利用率的最好方法是每天提供每种动物的确切需要量。这可以通过监测个体饲料摄入量和生长模式的精准喂养来实现。生产成本可降低4%，磷排泄量可降低30%以上，这将极大地提高生猪生产的可持续性。然而，对于猪来说，精准饲养代表着范式的转变和相当大的挑战，因为在猪的情况下，钙(Ca)和磷等矿物质与生理状态有很强的相互作用。很难根据多种反应标准(如生长性能、骨骼矿化、磷排泄)和生产目标(如盈利能力、动物福利、环境)确定精准饲喂饲料中的最佳矿物质水平。*这项研究计划的总体目标是根据我迄今对磷和钙代谢的研究结果，通过使用为精准日粮配制的饲料，结合对猪个体钙和磷需求的实时估计，进行基础研究，以优化猪的磷利用。我打算通过两个步骤来实现这一点：1-通过动物实验增加对猪磷和钙代谢的基本了解，2-将新知识整合到迄今开发的模型中，使用该模型设计饲养策略、测试策略并相应地调整模型。

Animal productions are facing many challenges for their successfulness and sustainability such as the constant increases in feeding cost, the growing public opinion about the impact of agriculture, and effective nutrient recycling to minimize environmental damages. Given that the phosphorus (P) both a fertilizer and a pollutant if present in excess, it is important to understand how to maximise its use in animal feed to optimize health and minimise losses and so, the environmental impact. Improving the efficiency of P use by pigs is therefore essential. The practices of providing a single feed to all animals in the herd over prescribed periods of time and providing dietary P at levels intended to maximize livestock performance have been the subject of numerous studies. The best way to improve overall P utilization by pigs would be to provide the exact requirement of each animal on a daily basis. This can be achieved by precision feeding which monitoring individual patterns of feed intake and growth. Production costs can be reduced by up to 4 % and P excretion by more than 30 %, which would increase considerably the sustainability of hog production. However, precision feeding represents a paradigm shift and a considerable challenge in the case of swine, in which minerals such as calcium (Ca) and P interact strongly with physiological status. Optimal mineral levels in diets formulated for precision feeding are difficult to establish for multiple response criteria (e.g. growth performance, bone mineralization, P excretion) and production objectives (e.g. profitability, animal welfare, environment). ***The general goal of this research program is to pursue basic research to optimize P utilization by pigs through the use of feeds formulated for precision diets in conjunction with real-time estimation of Ca and P requirements of individual pigs, based on the findings of my P and Ca metabolism research so far. I intend to achieve this in two steps: 1- increase fundamental understanding of porcine metabolism of P and Ca through animal experiments, and 2- integrate the new knowledge into the model developed so far, use the model to design feeding strategies, test the strategies and adjust the model accordingly.