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Topic:Microbiome
The equine microbiome refers to the diverse community of microorganisms, including bacteria, fungi, and viruses, residing in various parts of a horse's body, such as the gastrointestinal tract, skin, and respiratory system. These microorganisms are involved in numerous physiological processes, including digestion, metabolism, and immune function. The composition and diversity of the microbiome can be influenced by factors such as diet, environment, and health status. Research in this area explores the characterization of the equine microbiome, its impact on health and disease, and potential applications in managing equine health. This page compiles peer-reviewed research studies and scholarly articles that investigate the composition, function, and implications of the microbiome in horses.
Changes in the faecal microbiota of mares precede the development of post partum colic. Disruptions in the gastrointestinal microbiota may trigger development of post partum colic. Objective: To determine the effects of the periparturient period on the faecal microbiome and identify associations between the faecal microbiota and post partum colic. Methods: Longitudinal case-control study. Methods: Pre- and post partum faecal samples were collected from mares on 3 farms in central Kentucky. Next generation sequencing of the V4 region of the 16S rRNA gene was performed on samples from 13 mares that developed colic, 13 mares that did not display colic and 5 nonpregnant controls. Res...
Faecal microbiota of forage-fed horses in New Zealand and the population dynamics of microbial communities following dietary change. The effects of abrupt dietary transition on the faecal microbiota of forage-fed horses over a 3-week period were investigated. Yearling Thoroughbred fillies reared as a cohort were exclusively fed on either an ensiled conserved forage-grain diet ("Group A"; n = 6) or pasture ("Group B"; n = 6) for three weeks prior to the study. After the Day 0 faecal samples were collected, horses of Group A were abruptly transitioned to pasture. Both groups continued to graze similar pasture for three weeks, with faecal samples collected at 4-day intervals. DNA was isolated from the faeces and microbial 16S ...
Characterisation of the faecal metabolome and microbiome of Thoroughbred racehorses. The intestinal bacterial community of the horse is a key determinant of intestinal and whole body health. Understanding the bacterial community structure and function is an important foundation for studies of intestinal health and disease. Objective: To describe the faecal bacterial community and volatile organic compounds (VOCs) of the faecal metabolome of healthy Thoroughbred racehorses and to characterise responses to dietary supplementation with amylase-rich malt extract. Methods: Intervention study. Methods: Faecal samples were collected noninvasively before and 6 weeks after supplementat...
Probiotic use in horses – what is the evidence for their clinical efficacy? The gastrointestinal microbiota is extremely important for human and animal health. Investigations into the composition of the microbiota and its therapeutic modification have received increasing interest in human and veterinary medicine. Probiotics are a way of modifying the microbiota and have been tested to prevent and treat diseases. Probiotics are proposed to exert their beneficial effects through various pathways. Production of antimicrobial compounds targeting intestinal pathogens, general immune stimulation, and colonization resistance are among these mechanisms. Despite widespread ava...
Comparison of the bacterial community structure within the equine hindgut and faeces using Automated Ribosomal Intergenic Spacer Analysis (ARISA). The horse's hindgut bacterial ecosystem has often been studied using faecal samples. However few studies compared both bacterial ecosystems and the validity of using faecal samples may be questionable. Hence, the present study aimed to compare the structure of the equine bacterial community in the hindgut (caecum, right ventral colon) and faeces using a fingerprint technique known as Automated Ribosomal Intergenic Spacer Analysis (ARISA). Two DNA extraction methods were also assessed. Intestinal contents and faeces were sampled 3 h after the morning meal on four adult fistulated horses fed mea...
Anti-inflammatory and Intestinal Barrier-protective Activities of Commensal Lactobacilli and Bifidobacteria in Thoroughbreds: Role of Probiotics in Diarrhea Prevention in Neonatal Thoroughbreds. We previously isolated the commensal bacteria lactobacilli and bifidobacteria from the Thoroughbred intestine and prepared the horse probiotics LacFi(TM), consisting of Lactobacillus ruminis KK14, L. equi KK 15, L. reuteri KK18, L. johnsonii KK21, and Bifidobacterium boum HU. Here, we found that the five LacFi(TM) constituent strains remarkably suppressed pro-inflammatory interleukin-17 production in mouse splenocytes stimulated with interleukin-6 and transforming growth factor-β. The protective effects of the probiotic on impaired intestinal barrier function were evaluated in Caco-2 cells tr...
Fibre digestibility, abundance of faecal bacteria and plasma acetate concentrations in overweight adult mares. The purpose of the present study was to compare digestibility of grass hay, faecal and plasma volatile fatty acid (VFA) concentrations, and faecal bacterial abundance in overweight and moderate-condition mares. Five overweight adult mixed-breed mares and five adult mixed-breed mares in moderate condition were housed individually and limit-fed orchard grass (Dactylis glomerata) hay at 20 g/kg body weight (as fed) daily for 14 d. Forage DM and fibre digestibility were determined using AOAC methods; digestible energy was measured using bomb calorimetry; plasma and faecal VFA concentrations were ...
Effect of grass hay intake on fiber digestion and digesta retention time in the hindgut of horses. Eight Thoroughbred horses were used to examine the effects of grass hay intake on the fiber digestion and the retention time of digesta in the total gastrointestinal tract and the hindgut segments. The horses were randomly assigned to 2 groups and offered 2.0 (high intake [HI]) or 1.3 kg DM/(100 kg BW • d; low intake [LI]) of timothy hay in equal amounts every 3 h for 17 d. The digestibility and total tract mean retention time of digesta (tMRT) in the total gastrointestinal tract were measured from d 11 to d 15. To measure the mean retention time of digesta in each hindgut segment (sMRT), th...
Characterisation of the faecal bacterial community in adult and elderly horses fed a high fibre, high oil or high starch diet using 454 pyrosequencing. Faecal samples were collected from seventeen animals, each fed three different diets (high fibre, high fibre with a starch rich supplement and high fibre with an oil rich supplement). DNA was extracted and the V1-V2 regions of 16SrDNA were 454-pyrosequenced to investigate the faecal microbiome of the horse. The effect of age was also considered by comparing mature (8 horses aged 5-12) versus elderly horses (9 horses aged 19-28). A reduction in diversity was found in the elderly horse group. Significant differences between diets were found at an OTU level (52 OTUs at corrected Q<0.1). The ma...
Comparative analysis of the methanogen diversity in horse and pony by using mcrA gene and archaeal 16s rRNA gene clone libraries. Comparative analysis of methanogen compositions in the feces of horse and pony was carried out by constructing the α -subunit of methyl coenzyme-M reductase (mcrA) gene and 16S ribosomal RNA gene (16S rRNA) clone libraries. The mcrA clone library analysis indicated that Methanomicrobiales was predominant in both horse and pony. Furthermore, most of the clones of the 16S rRNA gene library showed that Methanomicrobiales was also predominant in horse and pony, but the LIBSHUFF analysis showed that the horse and pony libraries were significantly different (P < 0.05). Most of operational taxono...
The Genome of the Predominant Equine Lactobacillus Species, Lactobacillus equi, Is Reflective of Its Lifestyle Adaptations to an Herbivorous Host. We report the draft genome sequence of Lactobacillus equi strain DPC6820, isolated from equine feces. L. equi is a predominant Lactobacillus species in the horse hindgut microbiota. An examination of the genome identified genes and enzymes highlighting L. equi adaptations to the herbivorous gastrointestinal tract of the horse, including fructan hydrolases. This genome sequence may help us further understand the microbial ecology of the equine hindgut and the influence lactobacilli have on it.
Characterization of bovine ruminal and equine cecal microbial populations enriched for enhanced nitro-toxin metabolizing activity. The nitrotoxins 3-nitro-1-propionic acid (NPA) and 3-nitro-1-propanol (NPOH) are produced by a wide variety of leguminous plants, including over 150 different species and varieties of Astragalus potentially grazed by livestock. These toxins are known to be detoxified by at least one ruminal bacterium but detoxification by bacteria from other gut habitats is not known. In the present study, mixed populations of bovine ruminal and equine cecal microbes were enriched for NPA-metabolizing bacteria via consecutive 24-72 h culture in a basal minimal rumen fluid-based medium supplemented with 4.2 mM ...
Molecular monitoring of the bacterial community structure in foal feces pre- and post-weaning. This study assessed the time-scale variability of bacterial community structure in foal feces from birth to 365 days of age using Automated Ribosomal Intergenic Spacer Analysis (ARISA). Fecal samples were collected from five foals 2 h after birth (meconium) and in the morning at days 1, 2, 5, 10, 30, 60, 120, 179, 183, 194 and 365. The ARISA profiles were compared using an analysis of similarity (ANOSIM). Although both the age effect and the foal effect were highly significant (P < 0.010), the R-ANOSIM value for the foal effect was very low (R-ANOSIM = 0.089), while that of the age eff...
Illumina sequencing of the V4 hypervariable region 16S rRNA gene reveals extensive changes in bacterial communities in the cecum following carbohydrate oral infusion and development of early-stage acute laminitis in the horse. In the equine carbohydrate overload model of acute laminitis, disease progression is associated with changes in bacteria found in the cecum. To date, research has focused on changes in specific Gram-positive bacteria in this portion of the intestinal tract. Metagenomic methods are now available making it possible to interrogate microbial communities using animal protocols that sufficiently power a study. In this study, the microbiota in cecal fluid collected from control, non-laminitic horses (n=8) and from horses with early-stage acute laminitis induced with either oligofructan (n=6) or corns...
Identification of a core bacterial community within the large intestine of the horse. The horse has a rich and complex microbial community within its gastrointestinal tract that plays a central role in both health and disease. The horse receives much of its dietary energy through microbial hydrolysis and fermentation of fiber predominantly in the large intestine/hindgut. The presence of a possible core bacterial community in the equine large intestine was investigated in this study. Samples were taken from the terminal ileum and 7 regions of the large intestine from ten animals, DNA extracted and the V1-V2 regions of 16SrDNA 454-pyrosequenced. A specific group of OTUs clustered...
An in vitro model of the horse gut microbiome enables identification of lactate-utilizing bacteria that differentially respond to starch induction. Laminitis is a chronic, crippling disease triggered by the sudden influx of dietary starch. Starch reaches the hindgut resulting in enrichment of lactic acid bacteria, lactate accumulation, and acidification of the gut contents. Bacterial products enter the bloodstream and precipitate systemic inflammation. Hindgut lactate levels are normally low because specific bacterial groups convert lactate to short chain fatty acids. Why this mechanism fails when lactate levels rapidly rise, and why some hindgut communities can recover is unknown. Fecal samples from three adult horses eating identical di...
Isolation of Treponema and Tannerella spp. from equine odontoclastic tooth resorption and hypercementosis related periodontal disease. Red complex bacteria, i.e. Porphyromonas gingivalis, Treponema denticola and Tannerella forsythia, are involved in the onset and progression of periodontal disease in man, yet seldom inhabit the oral cavity of healthy individuals. Periodontal disease is also encountered in horses, with equine odontoclastic tooth resorption and hypercementosis (EOTRH) constituting a particular form of disease. However, only little is known about the oral microbiome of healthy and periodontitis-affected equids. Objective: We aimed to test the hypothesis that red complex bacteria are also associated with EOTRH-re...
Strong stability and host specific bacterial community in faeces of ponies. The horse, as a hindgut fermenter, is reliant on its intestinal bacterial population for efficient diet utilisation. However, sudden disturbance of this population can result in severe colic or laminitis, both of which may require euthanasia. This study therefore aimed to determine the temporal stability of the bacterial population of faecal samples from six ponies maintained on a formulated high fibre diet. Bacterial 16S rRNA terminal restriction fragment length polymorphism (TRFLP) analyses of 10 faecal samples collected from 6 ponies at regular intervals over 72 hour trial periods identifie...
The core faecal bacterial microbiome of Irish Thoroughbred racehorses. In this study, we characterized the gut microbiota in six healthy Irish thoroughbred racehorses and showed it to be dominated by the phyla Firmicutes, Bacteroidetes, Proteobacteria, Verrucomicrobia, Actinobacteria, Euryarchaeota, Fibrobacteres and Spirochaetes. Moreover, all the horses harboured Clostridium, Fibrobacter, Faecalibacterium, Ruminococcus, Eubacterium, Oscillospira, Blautia Anaerotruncus, Coprococcus, Treponema and Lactobacillus spp. Notwithstanding the sample size, it was noteworthy that the core microbiota species assignments identified Fibrobacter succinogenes, Eubacterium copr...
Effects of administration of live or inactivated virulent Rhodococccus equi and age on the fecal microbiome of neonatal foals. Rhodococcus equi is an important pathogen of foals. Enteral administration of live, virulent R. equi during early life has been documented to protect against subsequent intrabronchial challenge with R. equi, indicating that enteral mucosal immunization may be protective. Evidence exists that mucosal immune responses develop against both live and inactivated micro-organisms. The extent to which live or inactivated R. equi might alter the intestinal microbiome of foals is unknown. This is an important question because the intestinal microbiome of neonates of other species is known to change over...
Comparison of microbial populations in the small intestine, large intestine and feces of healthy horses using terminal restriction fragment length polymorphism. The composition of the microbiota of the equine intestinal tract is complex. Determining whether the microbial composition of fecal samples is representative of proximal compartments of the digestive tract could greatly simplify future studies. The objectives of this study were to compare the microbial populations of the duodenum, ileum, cecum, colon and rectum (feces) within and between healthy horses, and to determine whether rectal (fecal) samples are representative of proximal segments of the gastrointestinal tract. Intestinal samples were collected from ten euthanized horses. 16S rRNA gen...
Technical note: fatty acids and purine profile of cecum and colon bacteria as indicators of equine microbial metabolism. The potential use of odd- and branched-chain fatty acids (OBCFA) and purine bases (PB) as microbial markers in the equine hindgut was studied. For this purpose, feed particles adherent bacteria [solid associated bacteria (SAB)] and planktonic bacteria [liquid associated bacteria (PAB)] were isolated from total cecum and colon contents of 8 healthy, crossbred horses (9 ± 3 yr). Horses were fasted for 12 to 15 h before slaughter, and the cecum and colon were identified and clamped in their extremities to avoid mixing of digesta contents. The total cecum or colon contents was collected into ther...
Bacterial carbohydrate-degrading capacity in foal faeces: changes from birth to pre-weaning and the impact of maternal supplementation with fermented feed products. The present study aimed at (1) describing age-related changes in faecal bacterial functional groups involved in carbohydrate degradation and in their activities in foals (n 10) from birth (day (d) 0) to 6 months (d180) and (2) investigating the effect of maternal supplementation (five mares per treatment) from d - 45 to d60 with fermented feed products on response trends over time of the foal bacterial carbohydratedegrading capacity. Maternal supplementation with fermented feed products stimulated foal growth from d0 to d60 and had an impact on the establishment of some digestive bacterial gro...
Prevalence of yeasts in English full blood mares. The aim of the study was a quantitative and qualitative analysis of microflora, presentation of current data about prevalence of the microflora on the skin and mucous membranes, and determination of its possible effect on reproduction of English full blood horses bred in Poland. The material for analyses was sampled from the skin and mucous membranes (385 samples) of 55 English full blood mares. Taking into account reproduction traits, the mares were classified into three groups. Six yeast-like species, including five species from the genus Candida (C. albicans, C. guiliermondii, C. lusitaniae...
Pyrosequencing of 16S rRNA genes in fecal samples reveals high diversity of hindgut microflora in horses and potential links to chronic laminitis. The nutrition and health of horses is closely tied to their gastrointestinal microflora. Gut bacteria break down plant structural carbohydrates and produce volatile fatty acids, which are a major source of energy for horses. Bacterial communities are also essential for maintaining gut homeostasis and have been hypothesized to contribute to various diseases including laminitis. We performed pyrosequencing of 16S rRNA bacterial genes isolated from fecal material to characterize hindgut bacterial communities in healthy horses and those with chronic laminitis. Results: Fecal samples were collected...
Analysis of stomach bacterial communities in Australian feral horses. We investigated the community structure of bacteria that populate the stomach of the Brumby, a breed of feral horses from the Australian outback. Using a 16S rRNA gene clone library, we identified 155 clones that were assigned to 26 OTUs based on a 99.0 % sequence identity cutoff. Two OTUs represented 73.5 % of clones, while 18 OTUs were each assigned only a single clone. Four major bacterial types were identified in the Brumby stomach: Lactobacillaceae, Streptococcaceae, Veillonellaceae and Pasteurellaceae. The first three groups, which represented 98.1 % of the Brumby stomach library clones,...
Feed restriction enhances the depressive effects of erythromycin on equine hindgut microbial metabolism in vitro. Equine typholocolitis is a sporadic diarrheal disease causing high mortality rates. One of the risk factors responsible for this is the oral application of the macrolide antibiotic erythromycin. The aim of the present in vitro study was to investigate whether erythromycin in combination with feed restriction provokes changes in microbial hindgut metabolism and could therefore be involved in the pathogenesis of equine typhlocolitis. As application of erythromycin and feed restriction are risk factors for equine typhlocolitis, both factors were chosen to investigate their individual and combined...
Comparison of the fecal microbiota of healthy horses and horses with colitis by high throughput sequencing of the V3-V5 region of the 16S rRNA gene. The intestinal tract houses one of the richest and most complex microbial populations on the planet, and plays a critical role in health and a wide range of diseases. Limited studies using new sequencing technologies in horses are available. The objective of this study was to characterize the fecal microbiome of healthy horses and to compare the fecal microbiome of healthy horses to that of horses with undifferentiated colitis. A total of 195,748 sequences obtained from 6 healthy horses and 10 horses affected by undifferentiated colitis were analyzed. Firmicutes predominated (68%) among health...
