BACKGROUND Horses that undergo surgery for treatment of primary large colon disease have been reported to be at increased risk of developing recurrent colic episodes postoperatively. The reasons for this are currently unknown. The aim of the current study was to characterise the faecal microbiota of horses with colic signs associated with primary large colon lesions treated surgically and to compare the composition of their faecal microbiota to that of a control group of horses undergoing emergency orthopaedic treatment. Faecal samples were collected from horses in both groups on admission to hospital, during hospitalisation and following discharge from hospital for a total duration of 12 weeks. Additionally, colonic content samples were collected from surgical colic patients if pelvic flexure enterotomy was performed during laparotomy. A total of 12 samples were collected per horse. DNA was extracted from samples using a commercial kit. Amplicon mixtures were created by PCR amplification of the V1 - V2 regions of the bacterial 16S rRNA genes and submitted for sequencing using the Ion Torrent PGM next-generation sequencing system. Multivariate data analysis was used to characterise the faecal microbiota and to investigate differences between groups. RESULTS Reduced species richness was evident in the colonic samples of the colic group compared to concurrent sampling of the faeces. Alpha and beta diversity differed significantly between the faecal and colonic microbiota with 304 significantly differentially abundant OTUs identified. Only 46 OTUs varied significantly between the colic and control group. There were no significant differences in alpha and beta diversity of faecal microbiota between colic and control horses at admission. However, this lack of significant differences between groups should be interpreted with caution due to a small sample size. CONCLUSIONS The results of the current study suggest that faecal samples collected at hospital admission in colic cases may not accurately represent changes in upper gut microbiota in horses with colic due to large colon disease.

中文翻译：

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结肠微生物群的急性变化与外科绞痛的大肠形式有关。

背景技术据报道，接受外科手术治疗原发性大肠疾病的马在术后发生复发性绞痛发作的风险增加。目前尚不清楚其原因。本研究的目的是鉴定具有结肠征象的马的粪便微生物群，这些结肠征象与通过手术治疗的原发性大结肠病变有关，并将其粪便微生物群的组成与接受急诊矫形治疗的对照组马的粪便微生物群的组成进行比较。在入院时，住院期间和出院后从两组马中收集粪便样品，总共持续12周。此外，如果在剖腹手术期间进行了盆腔弯曲肠切开术，则从外科绞痛患者中收集结肠内容物样品。每匹马总共收集了12个样品。使用商业试剂盒从样品中提取DNA。通过PCR扩增细菌16S rRNA基因的V1-V2区创建扩增子混合物，并使用Ion Torrent PGM下一代测序系统进行测序。多变量数据分析用于表征粪便微生物群，并研究各组之间的差异。结果与同时采集粪便相比，绞痛组结肠样本中的物种丰富度明显降低。粪便和结肠菌群之间的α和β多样性存在显着差异，已鉴定出304种显着不同的丰富OTU。绞痛组和对照组之间只有46个OTU有显着差异。入院时绞痛和对照组马的粪便微生物群的α和β多样性没有显着差异。但是，由于样本量较小，因此应谨慎解释两组之间缺乏明显差异的情况。结论当前的研究结果表明，肠绞痛的病人在住院时收集的粪便样本可能无法准确地代表由于大肠疾病而患肠绞痛的马的上消化道微生物群的变化。