Corn is a common energy source in pig diets globally; when financially warranted, industrial corn coproducts, such as corn distiller’s dried grains with solubles (DDGS), are also employed. The energy provided by corn stems largely from starch, with some contribution from protein, fat, and non-starch polysaccharides (NSP). When corn DDGS are used in the diet, it will reduce starch within the diet; increase dietary protein, fat, and NSP levels; and alter the source profile of dietary energy. Arabinoxylans (AXs) comprise the majority of NSP in corn and its coproducts. One strategy to mitigate the antinutritive effects of NSP and improve its contribution to energy is by including carbohydrases within the diet. Xylanase is a carbohydrase that targets the β-1,4-glycosidic bonds of AX, releasing a mixture of smaller polysaccharides, oligosaccharides, and pentoses that could potentially be used by the pig. Xylanase is consistently effective in poultry production and moderately consistent in wheat-based swine diets, but its efficacy in corn-based swine diets is quite variable. Xylanase has been shown to improve the digestibility of various components of swine-based diets, but this seldom translates into an improvement in growth performance. Indeed, a review of xylanase literature conducted herein suggests that xylanase improves the digestibility of dietary fiber at least 50% of the time in pigs fed corn-based diets, but only 33% and 26% of the time was there an increase in average daily gain or feed efficiency, respectively. Intriguingly, there has been an abundance of reports proposing xylanase alters intestinal barrier integrity, inflammatory responses, oxidative status, and other health markers in the pig. Notably, xylanase has shown to reduce mortality in both high and low health commercial herds. These inconsistencies in performance metrics, and unexpected health benefits, warrant a greater understanding of the in vivo mechanism(s) of action (MOA) of xylanase. While the MOA of xylanase has been postulated considerably in the literature and widely studied in in vitro settings, in wheat-based diets, and in poultry, there is a dearth of understanding of the in vivo MOA in pigs fed corn-based diets. The purpose of this review is to explore the role of xylanase in corn-based swine diets, discuss responses observed when supplemented in diets containing corn-based fiber, suggest potential MOA of xylanase, and identify critical research gaps.

中文翻译：

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基于玉米的猪日粮中的木聚糖酶补充：综述着重于潜在的作用机制。

玉米是全球猪饲料中的常见能源。在经济上有保证的情况下，也可以使用工业玉米副产品，例如带有可溶物的玉米蒸馏器干粮（DDGS）。玉米提供的能量主要来自淀粉，蛋白质，脂肪和非淀粉多糖（NSP）的贡献很大。日粮中使用玉米DDGS时，会减少日粮中的淀粉。增加饮食中的蛋白质，脂肪和NSP水平；并改变膳食能量的来源。阿拉伯木聚糖（AXs）占玉米及其副产品中NSP的大部分。减轻NSP的抗营养作用并改善其对能量的贡献的一种策略是在饮食中添加糖化酶。木聚糖酶是一种针对AX的β-1,4-糖苷键的糖化酶，释放出较小的多糖，低聚糖和戊糖的混合物，可能被猪使用。木聚糖酶在家禽生产中一直有效，在小麦为主的猪日粮中保持一定程度的一致性，但是其在玉米为主的猪日粮中的功效变化很大。木聚糖酶已被证明可以改善猪日粮中各种成分的消化率，但这很少转化为生长性能的改善。确实，在此进行的木聚糖酶文献综述表明，在饲喂玉米日粮的猪中，木聚糖酶至少可在50％的时间内改善膳食纤维的消化率，但只有33％和26％的时间可使日增重或日增重增加。饲料效率。有趣的是，已有大量报道提议木聚糖酶改变猪的肠屏障完整性，炎症反应，氧化状态和其他健康指标。值得注意的是，木聚糖酶已显示出可以降低健康状况良好的商业畜群和低健康状况的商业畜群的死亡率。这些性能指标上的不一致以及意外的健康益处，需要对体内作用机制有更深入的了解（但是分别只有33％和26％的时间平均日增重或饲料效率有所提高。有趣的是，已有大量报道提议木聚糖酶改变猪的肠屏障完整性，炎症反应，氧化状态和其他健康指标。值得注意的是，木聚糖酶已显示出可以降低健康状况良好的商业畜群和低健康状况的商业畜群的死亡率。这些性能指标上的不一致以及意外的健康益处，需要对体内作用机制有更深入的了解（但是分别只有33％和26％的时间平均日增重或饲料效率有所提高。有趣的是，已有大量报道提议木聚糖酶改变猪的肠屏障完整性，炎症反应，氧化状态和其他健康指标。值得注意的是，木聚糖酶已显示出可以降低健康状况良好的商业畜群和低健康状况的商业畜群的死亡率。这些性能指标上的不一致以及意外的健康益处，需要对体内作用机制有更深入的了解（MOA），木聚糖酶。尽管木聚糖酶的MOA已经在文献中被假定为相当可观的，并且在体外，以小麦为基础的日粮和家禽中得到了广泛的研究，但对以玉米为基础的日粮饲喂的猪体内MOA缺乏了解。这篇综述的目的是探讨木聚糖酶在以玉米为基础的猪日粮中的作用，讨论在含玉米纤维的日粮中添加木聚糖酶时观察到的反应，建议木聚糖酶的潜在MOA，并找出关键的研究空白。