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Accounting for the effects of interactions between Phosphorous, Calcium and exogenous phytase on pig dietary requirements and performance

考虑磷、钙和外源植酸酶之间的相互作用对猪日粮需求和生产性能的影响

基本信息

批准号：
1788946
负责人：
金额：
--
依托单位：
Newcastle University
依托单位国家：
英国
项目类别：
Studentship
财政年份：
2016
资助国家：
英国
起止时间：
2016 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=studentship-1788946
关键词：
Accounting effects interactions between Phosphorous

项目摘要

The project addresses BBSRC Strategic Priority: Agriculture and Food Security relating to the Animal Sector, and in particular the priority of Biotechnologies as applied to animal feed. It aims to investigate the interactions in the digestive tract of the pig between exogenous phytase and Phosphorous (P) and Calcium (Ca) contents in pig feed in order to lead to a better feed utilisation. This will be done in the context of an existing simulation model that supports a Decision Support Tool (DST) to reduce P excretion and improve growth in growing and finishing pigs in the UK. Both Ca and P are well-known to have important skeletal and physiological functions. At the same time, P is the third most expensive component in pig diets due to the low digestibility of plant dietary P and the consequent need to supplement with expensive inorganic P supplements. From an environmental point of view, P supplies are limited and non-renewable and low feed conversion efficiency leading to the high excretion of water-soluble P in manure causes water pollution in the form of eutrophication. The Industry, e.g. AHDB Pork, recognises the importance of reducing P excretion whilst ensuring that pig performance and health are maintained, and has been involved in research to achieve these objectives. The majority of plant based P and hence most P in pig feed is bound to the phytate molecule. This form of P is poorly digested by non-ruminant animals as they do not generate sufficient levels of endogenous phytase required for phytate dephosphorylation. One, increasingly popular way of improving bioavailability of plant based P is through supplementation of exogenous phytase. Exogenous phytase hydrolyses the phytate molecule to release inorganic P, which can then be absorbed by an animal. It has been estimated that exogenous phytase supplementation can lead to 30-60% reduction of P excretion, which would permit lower levels of supplement of P in pig diets. However, in order to fully understand the problem at hand, digestion, absorption and excretion of P must be studied simultaneously with Ca, as these two major macrominerals are interdependent and interact in their utilisation by the pig in its digestive tract. Historically, Ca has not generated as much academic interest as P and Ca is considered to be the most underestimated factor contributing to phytate-P bioavailability. This is mostly due to the fact that inorganic Ca supplementation is cheap as well as widely accessible, and excessive Ca excretion does not explicitly cause any environmental concerns. There have been very few studies that have attempted to separate the effects of the Ca: P ratio on the basis of digestibility, which takes into account endogenous losses of nutrients, rather than total concentrations in feed ingredients. Over the past 10 years, the Industry has formulated diets on the basis of total Ca: digestible P ratio (2:1). Formulating diets based on digestible Ca: digestible P ratio is essential to minimise P for a more effective minimisation of P excretion.Mathematical modelling can be seen as a useful tool to study P retention and excretion, incorporate factors such as Ca levels and phytase supplementation affecting these processes and in general, undertake many in-silico experiments which would not be possible in-vivo. Development of a new mathematical model accounting for the interactions between Ca and P should inform practices for overall reduction of the environmental impact caused by P and help to maximise nutrient utilisation benefiting swine production industry. The new model and DST will aim to accurately predict digestibility of Ca and its impact on animal excretion and growth. Simulation of the fate of digestible Ca in the model will lead to a more accurate prediction of reduction in P excretion and utilisation of P for growth. This objective has not been achieved so far by any prior model.

该项目涉及BBSRC战略优先事项：与动物部门有关的农业和粮食安全，特别是应用于动物饲料的生物技术的优先事项。本试验旨在研究外源植酸酶与猪饲料中磷、钙含量在猪消化道中的相互作用，以提高饲料利用率。这将在现有的模拟模型的背景下，支持决策支持工具（DST），以减少磷排泄和提高生长和肥育猪在英国的增长。钙和磷都具有重要的骨骼和生理功能。与此同时，由于植物饲料磷的消化率低，因此需要补充昂贵的无机磷补充剂，磷是猪饲料中第三大最昂贵的组分。从环境的角度来看，磷的供应有限且不可再生，饲料转化效率低，导致粪便中水溶性磷的大量排泄，从而以富营养化的形式造成水污染。该行业，如AHDB猪肉，认识到减少磷排泄的重要性，同时确保猪的性能和健康得到保持，并已参与研究，以实现这些目标。大部分植物来源的磷和猪饲料中的大部分磷都与植酸分子结合。这种形式的P被非反刍动物消化不良，因为它们不能产生足够水平的植酸脱磷酸化所需的内源性植酸酶。一种日益流行的提高植物基P的生物利用度的方法是通过补充外源植酸酶。外源植酸酶水解植酸分子释放无机磷，然后可以被动物吸收。据估计，外源植酸酶的补充可导致30-60%的磷排泄减少，这将允许在猪日粮中较低水平的磷补充。然而，为了充分理解手头的问题，必须同时研究P的消化、吸收和排泄以及Ca，因为这两种主要的宏量矿物质是相互依赖的，并且在猪的消化道中相互作用。从历史上看，钙并没有像磷那样产生那么多的学术兴趣，钙被认为是最被低估的因素，有助于植酸磷的生物利用度。这主要是由于无机钙补充剂便宜且广泛可用，并且过量的钙排泄不会明确引起任何环境问题。很少有研究试图在消化率的基础上分离钙磷比的影响，消化率考虑了营养素的内源性损失，而不是饲料成分中的总浓度。在过去的10年里，该行业根据总钙与可消化磷的比例（2：1）制定了饮食。根据可消化的钙：可消化的磷比例制定日粮对于最大限度地减少磷排泄是必不可少的。数学模型可以被视为研究磷的保留和排泄的有用工具，将影响这些过程的因素如钙水平和植酸酶补充纳入其中，并且在一般情况下，进行许多在体内不可能进行的计算机实验。一个新的数学模型的发展占钙和磷之间的相互作用，应告知实践的整体减少对环境的影响所造成的磷，并有助于最大限度地提高养分利用，有利于养猪业。新模型和DST旨在准确预测钙的消化率及其对动物排泄和生长的影响。在模型中模拟可消化钙的命运将导致更准确的预测减少磷排泄和利用磷的增长。迄今为止，任何先前的模型都没有实现这一目标。