Laboratory of Animal Pathology (LAP), Department of Preventive Veterinary Medicine, State University of Londrina, Londrina, Brazil; Livestock Gut Health Team (LiGHT), Department of Pathobiology, Pharmacology and Zoological Medicine, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium.
Livestock Gut Health Team (LiGHT), Department of Pathobiology, Pharmacology and Zoological Medicine, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium.
Poult Sci. 2023 Aug;102(8):102810. doi: 10.1016/j.psj.2023.102810. Epub 2023 Jun 1.
Galactomannans are abundant nonstarch polysaccharides in broiler feed ingredients. In broilers, diets with high levels of galactomannans have been associated with innate immune response stimulation, poor zootechnical performance, nutrient and lipid absorption, and excessive digesta viscosity. However, data about its effects on the gut microbiome are scarce. β-Mannanases are enzymes that can hydrolyze β-mannans, resulting in better nutrient utilization. In the current study, we have evaluated the effect of guar gum, a source of galactomannans, supplemented to broiler diets, either with or without β-mannanase supplementation, on the microbiota composition, in an attempt to describe the potential role of the intestinal microbiota in β-mannanase-induced gut health and performance improvements. One-day-old broiler chickens (n = 756) were randomly divided into 3 treatments: control diet, guar gum-supplemented diet (1.7%), or guar gum-supplemented diet + β-mannanase (Hemicell 330 g/ton). The zootechnical performance, gut morphometry, ileal and cecal microbiome, and short-chain fatty acid concentrations were evaluated at different time points. The guar gum supplementation decreased the zootechnical performance, and the β-mannanase supplementation restored performance to control levels. The mannan-rich diet-induced dysbiosis, with marked effects on the cecal microbiota composition. The guar gum-supplemented diet increased the cecal abundance of the genera Lactobacillus, Roseburia, Clostridium sensu stricto 1, and Escherichia-Shigella, and decreased Intestinimonas, Alistipes, Butyricicoccus, and Faecalibacterium. In general, dietary β-mannanase supplementation restored the main microbial shifts induced by guar gum to levels of the control group. In addition, the β-mannanase supplementation reduced cecal isobutyric, isovaleric, valeric acid, and branched-chain fatty acid concentrations as compared to the guar gum-supplemented diet group, suggesting improved protein digestion and reduced cecal protein fermentation. In conclusion, a galactomannan-rich diet impairs zootechnical performance in broilers and results in a diet-induced dysbiosis. β-Mannanase supplementation restored the gut microbiota composition and zootechnical performance to control levels.
半乳甘露聚糖是肉鸡饲料成分中丰富的非淀粉多糖。在肉鸡中，日粮中高水平的半乳甘露聚糖与先天免疫反应刺激、较差的生产性能、营养和脂质吸收以及食糜粘度增加有关。然而，关于其对肠道微生物组影响的数据却很少。β-甘露聚糖酶是一种可以水解β-甘露聚糖的酶，可提高营养物质的利用率。在本研究中，我们评估了瓜尔胶（半乳甘露聚糖的来源）添加到肉鸡日粮中，无论是单独添加还是与β-甘露聚糖酶一起添加，对微生物群落组成的影响，试图描述肠道微生物群在β-甘露聚糖酶诱导的肠道健康和性能改善中的潜在作用。将 1 日龄肉鸡（n=756）随机分为 3 个处理组：对照组日粮、添加瓜尔胶日粮（1.7%）或添加瓜尔胶日粮+β-甘露聚糖酶（Hemicell 330 g/吨）。在不同时间点评估生产性能、肠道形态学、回肠和盲肠微生物组以及短链脂肪酸浓度。瓜尔胶添加降低了生产性能，β-甘露聚糖酶添加使性能恢复到对照组水平。富含甘露聚糖的日粮导致了肠道微生物群的失调，对盲肠微生物群组成产生了显著影响。添加瓜尔胶日粮增加了盲肠中产乳酸乳杆菌、罗斯伯里氏菌、严格梭菌 1 属和大肠杆菌-志贺氏菌属的丰度，并降低了肠内菌属、拟杆菌属、丁酸球菌属和粪杆菌属的丰度。总的来说，日粮中添加β-甘露聚糖酶将瓜尔胶诱导的主要微生物变化恢复到对照组水平。此外，与添加瓜尔胶日粮组相比，β-甘露聚糖酶添加降低了盲肠中异丁酸、异戊酸、戊酸和支链脂肪酸的浓度，表明蛋白质消化得到改善，盲肠蛋白质发酵减少。总之，富含半乳甘露聚糖的日粮会损害肉鸡的生产性能，并导致饮食引起的肠道微生物失调。β-甘露聚糖酶的添加使肠道微生物群落组成和生产性能恢复到对照组水平。
