Changes in the faecal bacterial microbiota during hospitalisation of horses with colic and the effect of different causes of colic

Abstract

Background: Previous studies have identified alterations in the faecal microbiota of horses with colic; however, further work is needed to interpret these findings.Objectives: To compare the faecal microbiota of horses presenting for colic at hospital admission, day 1 and day 3/discharge and with different colic duration and lesion locations. Study design: Prospective observational clinical study.Methods: Faecal samples were collected from 17 colic cases at hospital admission, on day 1 and on day 3 post-admission or at the time of hospital discharge if prior to 72 hours. Faecal samples were extracted for genomic DNA, PCR-amplified, sequenced and analysed using QIIME. Species richness and Shannon diversity (alpha diversity) were estimated. The extent of the relationship between bacterial communities (beta diversity) was quantified using pairwise UniFrac distances, visualised using principal coordinate analysis (PCoA) and statistically analysed using permutational multivariate analysis of variance (PERMANOVA). The relative abundance of bacterial populations at the different time points and in different types of colic was compared using ANCOM.Results: There was a decrease in species richness from admission to day 3/hospital discharge (P < .05), and a lower species richness (P = .005) and Shannon diversity (P = .02) in horses with colic ≥60 h compared to <60 h. Based on PCoA and PERMANOVA, there was a significant difference in bacterial community composition for horses with different colic duration (P = .001) and lesion location (P = .006).Several differences in bacterial phyla and genera were observed at different time points and with different types of colic. Main limitations:Relatively low numbers and a diverse population of horses. Conclusions:The microbiota change from hospital admission to day 3/discharge in horses with colic and horses with colic ≥60 h and large colon lesions have a distinct bacterial population compared to horses with colic <60 h and small intestinal lesions.

Comparison of the Fecal Microbiota of Horses with Intestinal Disease and Their Healthy Counterparts

“…In addition, the average F/B ratios were 1.94, 2.37, and 1.74 for horses with large intestinal disease, small intestinal disease, and healthy controls, respectively. In contrast to previous reports, increased Bacteroidetes in horses admitted for colic was not observed in the current research [ 19 , 42 ]. This suggests that the F/B ratio alone is not enough to evaluate the intestinal disease status of horses.…”

“…As demonstrated in other studies [ 19 , 21 , 29 ], this study confirms that the bacterial community compositions of horses with intestinal diseases are considerably different from that of their clinically healthy counterparts. In particular, horses with large intestinal colic had lower species evenness and richness than the healthy horses, with some bacterial species no longer detectable and the generation of greater evenness.…”

“…Studies performed on different animal species have shown that the gut microbial dynamics can be influenced by various factors, including the environment, diet, gestational age, hospitalization, antibiotics, delivery mode, stress, and feeding method [ 7 , 8 , 9 , 12 , 17 , 18 ]. Similarly, differences in the fecal bacterial communities between horses with gastrointestinal diseases and their healthy counterparts have been reported [ 6 , 19 , 20 , 21 , 22 ]. Furthermore, an acute change in the colonic microbiota was observed in horses that underwent an exploratory laparotomy to treat equine colic [ 23 ].…”

“…Alteration of the equine hindgut microbiota in clinical conditions has been reported in many studies [ 2 , 6 , 11 , 19 , 20 , 21 ]. Similarly, discrepancies in the hindgut microbiota in horses with intestinal disease and healthy horses have been reported [ 2 , 6 , 20 , 21 , 22 ].…”

Species-Level Gut Microbiota Analysis after Antibiotic-Induced Dysbiosis in Horses

“…In horses and other herbivorous species, the gut microbiota is involved in producing short-chain fatty acids, which in turn provide them with energy [4]. A marked imbalance of the healthy gut microbiota is more commonly referred to as dysbiosis and has been reported mainly in horses with colitis [5,6], colic [7], and after antibiotic administration [8,9].…”