Models of pig growth: problems and proposed solutions
Models of pig growth: problems and proposed solutions
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DOI：
10.1016/s0301-6226(97)00061-4
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发表时间：
1997-11-01
期刊：
影响因子：
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通讯作者：
Kyriazakis, I
中科院分区：
文献类型：
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作者：
Emmans, GC;Kyriazakis, I
从猪的基因型和饮食的知识来预测猪的生长和身体组成的系统是科学和实践兴趣和关注的问题之一。为了产生这样的预测系统，需要解决的三个主要问题在这里被考虑：（i）从猪及其状态的描述预测蛋白质保留的潜在速率;（ii）预测无脂质体的另外两个组分的保留速率，它们是灰分和水;（iii）根据对食物摄入率及其成分的了解，预测蛋白质和脂质的实际保留率。现有的建议这些问题的答案进行了描述和批评。然后，我们提出什么，在我们看来，是目前可用的最佳解决方案。第一个问题是通过使用Gompertz增长方程来解决的。第二个问题是处理异速生长，但有一个更好的理论基础。提出了第三个问题，即，当蛋白质的存留率由于有限的食物供应而低于潜在存留率时，预测蛋白质和脂质的实际存留率的问题可以通过使用简单的规则来解决。规则是，使用高于维持生长的理想蛋白质供应的边际材料效率与食物的能量：蛋白质比率成正比，直到最大值。因此，每单位额外食物能量所获得的额外蛋白质量仅取决于所提供的额外（理想）蛋白质量，而与活重和猪的基因型无关。这三个问题的解决方案构成了一个框架，可以应用于预测猪在某个时间和随着时间的推移对饮食的反应。鉴于需要评估的参数数量较少，该框架可以扩展以预测不同种类的猪对相同饮食的反应。假设参数值的分布是已知的，则该方法可以用于预测组成猪群体的个体对其饮食的反应。(C)1997年Elsevier Science B.V.
A system to predict the growth and body composition of a pig from a knowledge of its genotype and diet is one of both scientific and practical interest and concern. Three of the major problems that need to be solved in order to produce such a predictive system are considered here: (i) the prediction of the potential rate of protein retention from a description of the pig and its state; (ii) the prediction of the rates of retention of the two other components of the lipid-free body which are ash and water; (iii) the prediction of the actual rates of retention of protein and lipid from a knowledge of the rate of intake of food and its composition. The existing proposed answers to these problems are described and criticised. We then present what, in our view, are the best solutions currently available. The first problem is solved by the use of the Gompertz growth equation. The second problem is dealt with by allometry but with a better theoretical underpinning. It is proposed that the third problem, i.e., that of predicting the actual rates of retention of protein and lipid, when the rate of protein retention is below the potential rate because of the limiting food supply, can be solved by using a simple rule. The rule is that the marginal material efficiency of using the ideal protein supply above maintenance for growth, is directly proportional to the energy: protein ratio of the food up to a maximum value. Thus the amount of extra protein gained per unit of extra food energy depends only on the amount of extra (ideal) protein supplied with it and is independent of liveweight and of pig genotype. The solutions to the three problems constitute a framework which can be applied to predict the response of a pig to its diet at a time and over time. Given the small number of parameters that need to be evaluated, the framework can be extended to predict the responses of different kinds of pigs to the same diet. Providing that the distributions of the values of the parameters are known, the approach can be adopted to predict the responses of the individuals which comprise a population of pigs to their diet. (C) 1997 Elsevier Science B.V.