Vieira S L, Stefanello C, Sorbara J O B
Departamento de Zootecnia, Universidade Federal do Rio Grande do Sul, Avenida Bento Gonçalves, 7712, Porto Alegre, RS, Brazil 91540-000
Departamento de Zootecnia, Universidade Federal do Rio Grande do Sul, Avenida Bento Gonçalves, 7712, Porto Alegre, RS, Brazil 91540-000.
Poult Sci. 2014 Sep;93(9):2411-6. doi: 10.3382/ps.2013-03860. Epub 2014 Jul 10.
Since it started as an organized economic activity, poultry production has been undergoing an evolution toward the optimization of its feed formulation features. Notably, advances in the knowledge of birds' nutrient requirements have allowed recommendations that are increasingly closer to the needs of the birds. Over time, availability of nutrients and energy has been incorporated into those recommendations, especially to compensate for the variability in the digestibility of nutrients originating from variable feed ingredient sources. Instead of using the total energy and nutrient content, current tables of nutrient recommendations provide an estimate of the digestible fractions of the nutrients in ingredients. For instance, nonphytate P is preferred instead of total P to account for the unavailable phytate P, and digestible amino acids to account for the differences in digestibility of amino acids in different ingredients, whereas energy is usually expressed as a proportion that has been digested and metabolized (AME). With the increasing interest in the use of exogenous enzymes in poultry feeds, special attention is directed to the feed substrates such that an added enzyme can match it, forming an enzyme-substrate complex that will be followed by a chemical reaction within the gastrointestinal tract. As a consequence of a degradation reaction, nutrients released can be absorbed and metabolized. In general, nutritional data banks used in linear feed formulation software have limited data on the proportions of fractions of ingredients that are indigestible. Therefore, estimations of the presence of many substrates in the feeds, and therefore the benefits of adding exogenous enzymes, are frequently limited because of the scarcity of adequate information. The objective of this review paper is to provide insights into the use of expanded nutrient databanks to include all the molecules considered potentially indigestible for poultry such that the inclusion of exogenous enzymes allows the estimation of the values of the product originated by their hydrolysis.
自家禽生产作为一种有组织的经济活动开始以来，其饲料配方特性一直在朝着优化方向发展。值得注意的是，对家禽营养需求知识的进步使得推荐标准越来越接近家禽的实际需求。随着时间的推移，养分和能量的可利用性已被纳入这些推荐标准中，特别是为了弥补因饲料原料来源不同而导致的养分消化率差异。当前的营养推荐表不再使用养分和能量的总量，而是提供了饲料原料中养分可消化部分的估计值。例如，用非植酸磷代替总磷来计算不可利用的植酸磷，用可消化氨基酸来计算不同原料中氨基酸消化率的差异，而能量通常以已消化和代谢的比例（AME）来表示。随着在家禽饲料中使用外源酶的兴趣日益增加，人们特别关注饲料底物，以便添加的酶能够与之匹配，形成酶 - 底物复合物，随后在胃肠道内发生化学反应。作为降解反应的结果，释放出的养分能够被吸收和代谢。一般来说，线性饲料配方软件中使用的营养数据库关于饲料原料中不可消化部分比例的数据有限。因此，由于缺乏足够的信息，对饲料中许多底物存在情况的估计以及添加外源酶的益处往往受到限制。这篇综述文章的目的是深入探讨使用扩展营养数据库，将所有被认为家禽可能无法消化的分子纳入其中，以便在添加外源酶的情况下能够估计其水解产生的产物价值。
