Laboratory of Food Chemistry and Biochemistry, Department of Microbial and Molecular Systems (M²S), KU Leuven, 3001 Leuven, Belgium.
Laboratory of Livestock Physiology, Department of Biosystems, KU Leuven, 3001 Leuven, Belgium.
Poult Sci. 2019 Oct 1;98(10):4606-4621. doi: 10.3382/ps/pez159.
Endoxylanases are frequently used in cereal-based broiler feeds to improve the nutritional quality of the feed. It is hypothesized that the age of broilers and the age-related development of their intestinal microbiota influence the efficacy of these enzymes. Hence, the objective of this study was to identify possible age-related changes in arabinoxylan (AX) digestion in the different parts of the gastrointestinal (GI) tract of broilers. A feeding trial was performed with 240 1-day-old chicks (Ross 308) receiving a wheat-based feed containing no supplemented endoxylanase. Digesta samples from every section of the GI tract were collected at 5, 10, 15, 21, 28, and 35 d of age and analyzed for AX content, AX digestibility, intestinal viscosity, and microbial endoxylanase and arabinofuranosidase activities. In the first 2 wk, the microbiota were able to solubilize a part of the water-unextractable arabinoxylan (WU-AX), thereby increasing intestinal viscosity and water-extractable arabinoxylan (WE-AX) concentrations in the GI tract. In these young birds, WU-AX and WE-AX with low arabinose to xylose ratios were able to enter the caeca but were not yet extensively fermented by the caecal microbiota as indicated by the high caecal AX concentrations at 5 and 10 d (P < 0.01). Establishment of a more mature microbial community at 3 wk of age resulted in a further increase in both the solubilization of WU-AX and fermentation of WE-AX at the ileum and caecum (P < 0.10). Furthermore, the increase in AX degrading enzyme activities with age denotes the high AX degrading capacity of the caecal microbiota. Finally, a total tract AX digestion of 24% was achieved at slaughter age (day 35). Our results clearly indicate that the capacity of intestinal microbiota to degrade AX in the hindgut increases as the broiler ages. This suggests that the benefits of endoxylanase supplementation of broiler feeds depend on the interaction of the intestinal microbiota and AX present in the GI tract at specific broiler ages.
木聚糖酶常用于谷物型肉鸡饲料中，以改善饲料的营养价值。据推测，肉鸡的年龄及其肠道微生物群的年龄相关发育会影响这些酶的功效。因此，本研究的目的是确定肉鸡胃肠道（GI）不同部位中阿拉伯木聚糖（AX）消化的可能与年龄相关的变化。进行了一项饲养试验，用 240 只 1 日龄的 Ross 308 雏鸡（Ross 308）接受含有未补充内切木聚糖酶的小麦基础饲料。在 5、10、15、21、28 和 35 日龄时，从 GI 道的每个部位采集消化物样本，并分析 AX 含量、AX 消化率、肠道粘度以及微生物内切木聚糖酶和阿拉伯呋喃糖苷酶活性。在前 2 周，微生物能够溶解一部分水不溶性阿拉伯木聚糖（WU-AX），从而增加 GI 道中肠道粘度和水溶性阿拉伯木聚糖（WE-AX）的浓度。在这些幼鸟中，低阿拉伯糖/木糖比的 WU-AX 和 WE-AX 能够进入盲肠，但由于盲肠微生物群在 5 和 10 日龄时 AX 浓度较高（P < 0.01），它们尚未被广泛发酵。3 周龄时，微生物群落更加成熟，导致回肠和盲肠中 WU-AX 的溶解和 WE-AX 的发酵进一步增加（P < 0.10）。此外，随着年龄的增长，AX 降解酶活性的增加表明盲肠微生物群具有很高的 AX 降解能力。最后，在屠宰时（35 日龄）实现了 24%的全肠道 AX 消化率。我们的研究结果清楚地表明，随着肉鸡年龄的增长，后肠中肠道微生物群降解 AX 的能力增加。这表明，内切木聚糖酶对肉鸡饲料的补充效果取决于特定肉鸡年龄时肠道微生物群与 GI 道中存在的 AX 的相互作用。
