Salem Shebl E, Hough Rachael, Probert Chris, Maddox Thomas W, Antczak Philipp, Ketley Julian M, Williams Nicola J, Stoneham Sarah J, Archer Debra C
Department of Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Leahurst campus, Wirral, UK.
Department of Surgery, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Al Sharquiya, Egypt.
PeerJ. 2019 Apr 3;7:e6687. doi: 10.7717/peerj.6687. eCollection 2019.
Periparturient mares are at increased risk of colic including large colon volvulus, which has a high mortality rate. Alterations in colonic microbiota related to either physiological or management changes, or both, that occur at this time have been suggested as potential causes for increased colic risk in this population of horses. Although the effect of management changes on the horse faecal microbiota has been investigated, limited work has been conducted to investigate changes in faecal microbiota structure and function in the periparturient period. The objectives of the current study were to investigate temporal stability of the faecal microbiota and volatile organic compounds (VOCs) of the faecal metabolome in periparturient mares.
Faecal samples were collected weekly from five pregnant mares from 3 weeks pre-foaling to 7 weeks post-foaling. The microbiome data was generated by PCR amplification and sequencing of the V1-V2 regions of the bacterial 16S rRNA genes, while the VOC profile was characterised using headspace solid phase microextraction gas chromatography mass spectrometry.
The mare faecal microbiota was relatively stable over the periparturient period and most variation was associated with individual mares. A small number of operational taxonomic units were found to be significantly differentially abundant between samples collected before and after foaling. A total of 98 VOCs were identified. The total number of VOCs did not vary significantly between individual mares, weeks of sample collection and feeds available to the mares. Three VOCs (decane, 2-pentylfuran, and oct-2-ene) showed significant increase overtime on linear mixed effects modelling analysis. These results suggest that the mare faecal microbiota is structurally and functionally stable during the periparturient period. The findings also suggest that if changes in the gut microbiota are related to development of colic postpartum, altered risk may be due to inherent differences between individual mares. VOCs offer a cost-effective means of looking at the functional changes in the microbiome and warrant further investigation in mares at risk of colic.
围产期母马患绞痛的风险增加，包括大结肠扭转，其死亡率很高。与此时发生的生理或管理变化或两者相关的结肠微生物群改变被认为是该马群绞痛风险增加的潜在原因。尽管已经研究了管理变化对马粪便微生物群的影响，但关于围产期粪便微生物群结构和功能变化的研究有限。本研究的目的是调查围产期母马粪便微生物群和粪便代谢组中挥发性有机化合物（VOCs）的时间稳定性。
从5匹怀孕母马产前3周至产后7周每周采集粪便样本。通过对细菌16S rRNA基因的V1-V2区域进行PCR扩增和测序生成微生物组数据，同时使用顶空固相微萃取气相色谱质谱法对VOC谱进行表征。
母马粪便微生物群在围产期相对稳定，大多数变化与个体母马有关。在产后采集的样本之间发现少数操作分类单元的丰度存在显著差异。共鉴定出98种VOCs。个体母马、样本采集周数以及母马可获得的饲料之间的VOC总数没有显著差异。在线性混合效应模型分析中，三种VOCs（癸烷、2-戊基呋喃和2-辛烯）随时间显著增加。这些结果表明，母马粪便微生物群在围产期在结构和功能上是稳定的。研究结果还表明，如果肠道微生物群的变化与产后绞痛的发生有关，风险改变可能是由于个体母马之间的固有差异。VOCs提供了一种经济有效的方法来观察微生物组的功能变化，值得对有绞痛风险的母马进行进一步研究。
