Effects of transport, fasting and anaesthesia on the faecal microbiota of healthy adult horses

Reasons for performing studyThe intestinal microbiota is important for health and disease. Factors that disturb the equine intestinal microbiota need further investigation. ObjectivesTo determine the effects of transport, fasting and anaesthesia on the faecal microbiota of healthy adult horses using next-generation sequencing. Study designExperimental trial. MethodsFaecal samples were taken from 8 horses at baseline, after transport, 12h of fasting and 24, 48 and 72h after a 6h anaesthesia. Next generation sequencing of the V4 region of the 16S rRNA gene was used to assess the microbial composition of faeces. Alpha diversity, phylogenetic structures and beta diversity were assessed. ResultsThere were significant changes in the relative abundances of phyla, classes, orders and families after transport, fasting and anaesthesia. Most notably horses had a significantly lower abundance of Clostridiales after transport compared with baseline (P=0.03) and a decreased abundance of Rickettsiales after fasting (P=0.024). Alpha diversity was not significantly different between time points (all P>0.21). When parsimony analysis was applied, anaesthesia had a significant effect on community membership and structure (Jaccard index and Yue and Clayton index both P=0.02). ConclusionsThere was some effect of transport, fasting and anaesthesia on the composition and structure of the microbiota of healthy horses. This indicates these are potentially stress factors for the equine intestinal microbiota. Further investigation is required to look at the potential impact of changes in the microbiota on the development of disease in the post anaesthetic period.