Age-related arabinoxylan hydrolysis and fermentation in the gastrointestinal tract of broilers fed wheat-based diets
Age-related arabinoxylan hydrolysis and fermentation in the gastrointestinal tract of broilers fed wheat-based diets
复制标题
DOI：
10.3382/ps/pez159
复制
发表时间：
2019-10-01
期刊：
影响因子：
4.4
通讯作者：
Courtin, C. M.
中科院分区：
文献类型：
--
作者：
Bautil, A.;Verspreet, J.;Courtin, C. M.
内切聚糖酶常用于谷类肉鸡饲料中，以提高饲料的营养品质。据推测，肉仔鸡的年龄及其肠道菌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仔鸡胃肠道不同部位阿拉伯木聚糖（AX）消化的可能与年龄相关的变化。本试验选用240只1日龄雏鸡（Ross 308）饲喂不添加内木聚糖酶的小麦基饲料。分别于5、10、15、21、28和35日龄采集消化道各部位食糜样本，分析AX含量、AX消化率、肠道黏度以及微生物内生聚糖酶和阿拉伯糖葡聚糖酶活性。在前2周，微生物群能够溶解一部分水不可提取的阿拉伯木聚糖（WU-AX），从而增加肠道粘度和水可提取的阿拉伯木聚糖（wee - ax）在胃肠道中的浓度。在这些雏鸟中，低阿拉伯糖/木糖比的WU-AX和WE-AX能够进入盲肠，但尚未被盲肠微生物群广泛发酵，这表明在第5天和第10天盲肠中高浓度的AX （P < 0.01）。3周龄时微生物群落更加成熟，回肠和盲肠WU-AX的增溶量和WE-AX的发酵量进一步增加（P < 0.10）。此外，随着年龄的增长，AX降解酶活性增加，表明盲肠微生物群具有较高的AX降解能力。最后，在屠宰日龄（第35天），全肠AX消化率达到24%。我们的研究结果清楚地表明，随着肉鸡年龄的增长，后肠肠道微生物群降解AX的能力增加。由此可见，肉仔鸡饲粮中添加内生木聚糖酶的效益取决于特定年龄时肠道菌群与胃肠道中存在的AX的相互作用。
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.