Leigh Robert J, Corrigan Aoife, Murphy Richard A, Walsh Fiona
Antimicrobial Resistance and Microbiome Research Group, Department of Biology, Maynooth University, Co. Kildare, Ireland.
Alltech Inc. (Alltech European Bioscience Centre), Summerhill Road, Sarney, Dunboyne, Co. Meath, Ireland.
Anim Microbiome. 2022 Dec 19;4(1):66. doi: 10.1186/s42523-022-00208-6.
The broiler gastrointestinal microbiome is a potent flock performance modulator yet may also serve as a reservoir for pathogen entry into the food chain. The goal of this project was to characterise the effect of mannan rich fraction (MRF) supplementation on microbiome diversity and composition of the intestinum tenue and cecum of commercial broilers. This study also aimed to address some of the intrinsic biases that exist in microbiome studies which arise due to the extensive disparity in 16S rRNA gene copy numbers between bacterial species and due to large intersample variation.
We observed a divergent yet rich microbiome structure between different anatomical sites and observed the explicit effect MRF supplementation had on community structure, diversity, and pathogen modulation. Birds supplemented with MRF displayed significantly higher species richness in the cecum and significantly different bacterial community composition in each gastrointestinal (GI) tract section. Supplemented birds had lower levels of the zoonotic pathogens Escherichia coli and Clostridioides difficile across all three intestinum tenue sites highlighting the potential of MRF supplementation in maintaining food chain integrity. Higher levels of probiotic genera (eg. Lactobacillus and Blautia) were also noted in the MRF supplemented birds. Following MRF supplementation, the cecum displayed higher relative abundances of both short chain fatty acid (SFCA) synthesising bacteria and SCFA concentrations.
Mannan rich fraction addition has been observed to reduce the bioburden of pathogens in broilers and to promote greater intestinal tract microbial biodiversity. This study is the first, to our knowledge, to investigate the effect of mannan-rich fraction supplementation on the microbiome associated with different GI tract anatomical geographies. In addition to this novelty, this study also exploited machine learning and biostatistical techniques to correct the intrinsic biases associated with microbiome community studies to enable a more robust understanding of community structure.
肉鸡胃肠道微生物群是影响鸡群生产性能的重要因素，同时也可能成为病原体进入食物链的源头。本项目的目的是研究添加富含甘露聚糖的组分（MRF）对商品肉鸡小肠和盲肠微生物群多样性及组成的影响。本研究还旨在解决微生物群研究中存在的一些内在偏差，这些偏差是由于细菌物种之间16S rRNA基因拷贝数的巨大差异以及样本间的巨大差异而产生的。
我们观察到不同解剖部位之间微生物群结构存在差异但丰富，并观察到添加MRF对群落结构、多样性和病原体调控的显著影响。添加MRF的鸡在盲肠中显示出显著更高的物种丰富度，并且在每个胃肠道（GI）段中细菌群落组成显著不同。在所有三个小肠部位，添加MRF的鸡体内人畜共患病原体大肠杆菌和艰难梭菌的水平较低，这突出了添加MRF在维持食物链完整性方面的潜力。在添加MRF的鸡中还发现了更高水平的益生菌属（如乳酸杆菌属和布劳特氏菌属）。添加MRF后，盲肠中短链脂肪酸（SFCA）合成细菌的相对丰度和SCFA浓度均较高。
已观察到添加富含甘露聚糖的组分可降低肉鸡的病原体生物负荷，并促进更大的肠道微生物生物多样性。据我们所知，本研究是首次调查添加富含甘露聚糖的组分对与不同胃肠道解剖区域相关的微生物群的影响。除了这一新颖性之外，本研究还利用机器学习和生物统计技术来纠正与微生物群落研究相关的内在偏差，以便更深入地了解群落结构。
