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.
Júnior AMCA, da Silva AH, Buroxid RP, Padovan JR, Nunes AT, Poleti MD, Fukumasu H, Gobesso AAO.Intense training in athletic foals may alter fecal microbiota, highlighting the need for nutritional strategies such as hydrolyzed collagen supplementation. Objective: This study aimed to evaluate the effects of dietary hydrolyzed collagen on the fecal microbiome of weanlings in training. Methods: Twenty Mangalarga Marchador foals (206 ± 18 kg; 7 ± 1 mo age) were assigned to two groups: a supplemented group (50 g/day of hydrolyzed collagen for 180 days) and a control group. A completely randomized design with repeated measures over time was used. Foals were exercised five consecutive days pe...
Kinoshita Y, Sato W, Ueno T.Microbial resilience is important to maintain a healthy gut environment in horses, especially after antibiotic administration, but the efficacies of post-antibiotic recovery strategies remain poorly characterized. We used microbial amplicon sequencing to compare spontaneous recovery, autologous fecal microbiota transplantation (FMT), and probiotic administration in 18 horses following antibiotic-induced dysbiosis. Clinically healthy horses received a combination of cephalothin and minocycline for 5 consecutive days before intervention. Fecal microbial recovery was longitudinally evaluated by u...
Ren J, Ma C, Yang K, Li X, Yang F, Guo X, Yao X, Wang C.Zn-CS chelate has shown beneficial effects on gut health and growth in piglets, but its impact on weaned foals remains largely unknown. This study evaluated the effects of dietary Zn-CS supplementation on growth performance, nutrient digestibility, physiological status, and fecal microbiota in weaned Ili foals. Thirty-two six-month-old foals were randomly assigned to four treatment groups receiving 0, 2, 4, or 6 mg Zn-CS/kg body weight per day for 90 days. Growth performance, nutrient digestibility, plasma biochemical parameters, liver function enzymes, serum hormones, antioxidant indices, fec...
van Heule M, Heil B, Norris JK, Gedye K, Lin X, De Spiegelaere W, Daels P, Dini P.Ascending placentitis is a leading cause of late-term pregnancy loss in mares. Although pathogens are presumed to ascend from the caudal reproductive tract, the association between the vaginal microbiome and placentitis has not been systematically examined. Objective: To characterise microbial and host gene expression in the equine vagina during gestation and to identify taxa or transcripts that were associated with the presence of an abnormal placenta at birth. Methods: Prospective, paired observational study. Methods: Vaginal wall swabs were collected from 49 multiparous Thoroughbred mares a...
Guo L, Holyoak GR, DeSilva U.The Earth's estimated 10 virions, primarily phages, significantly impact microbial ecosystems. Despite their abundance, viromes remain relatively understudied-particularly in domestic animals. While recent studies have described a dynamic commensal microbiome in mammalian uteri, no research has yet characterized the commensal virome in a mammalian uterus. In this study, we report for the first time the presence of a sparse, but diverse native virome in the equine uterus. The resulting virome database consists of 513 non-redundant viral genomes (> 2 kb). Taxonomic annotations revealed the...
Leduc L, Boucher L, Mach N, Leclère M, Costa M.Differences in gut microbiota composition related to diet have been reported in horses, but characterization of specific microbial taxa remains limited, particularly at the species level. The objective of this study was to use long-read sequencing of the 16S rRNA gene to provide additional taxonomic insight into the intestinal microbiota in horses. Fecal samples were collected from 12 horses on pasture and from 6 of them after switching to a hay diet. Sequencing yielded low read counts per sample, and the analysis failed to detect statistical differences in alpha- and beta-diversity among diet...
Pelenė U, Šiukščius A, Nainienė R, Merkelytė I, Šveistienė R.The equine reproductive microbiota has emerged as an important factor influencing reproductive health and fertility in both mares and stallions. Traditionally, the equine uterus was considered sterile, and microbial presence was interpreted primarily in the context of infection. However, sequencing-based studies have demonstrated that the reproductive tract, including the uterus and semen, contains detectable microbial communities or microbial DNA signatures, challenging this traditional paradigm. In mares, the vaginal microbiota is consistently dominated by , , , and , whereas the uterine env...
Liu P, Yang F, Li J, Li C, Guo X, Li X.This study aimed to investigate the impact of dietary L-citrulline supplementation on the health of mares during late gestation. Thirty-two healthy mares in late pregnancy were randomly assigned to four groups: a control group (CON, 0 g/d) and three treatment groups receiving 15, 30, and 45 g/d/head of L-citrulline, respectively. The trial spanned 72 days, including a 12-day adaptation phase and a 60-day formal feeding period. A fixed daily feeding amount of 11.2 kg/head was provided, ensuring complete consumption and consistent dry matter intake across all groups. Results demonstrated that su...
Khalil WA, Mostafa HE, Derbala MK, Hassan MAE, Abdelnour SA, El-Harairy MA.This experiment explores the comparative ability of vitamin E (VE) and its nano-emulsion (VEN) in enhancing cryo-resistance of stallion spermatozoa by examining semen quality, kinematic variables, acrosome integrity, apoptosis, antioxidant capacity, ultra-structural alterations and microbiota of cryopreserved stallion sperm. Semen from five stallions (8-10 years) was cryopreserved with 0.1 or 1 mM of VE or VEN; and a non-additive group served as the control. The VEN particles ranged in size from 72 to 172 nm, with a mean diameter of 287 nm. Supplementation with VE (1 mM) or VEN (0.1 ...
Ma R, Wang C.Gut microbiota is vital to host health, involving many aspects including immunity, metabolism and digestion. Exercise is recognized as a significant factor influencing the gut microbiota. However, the effects of exercise on the gut microbiota in horses remain unclear. Here, this study aims to investigate the effects of exercise on the gut bacterial and fungal communities in the horses using 16S rDNA and ITS genes amplicon sequencing. Results indicated that exercise significantly increased the ACE, Chao1 and Shannon indices of the gut bacterial community, accompanied by significant alterations ...
The animal microbiome plays a crucial role in determining the health, productivity, and welfare of livestock species, including sheep, horses, cattle, camel, and chicken. These animal species were selected due to the high consumption of their products in Kazakhstan. Enhancing their productivity, while maintaining the safety and quality of meat and milk derived from them, represents a pressing research priority. This review article includes current research on the composition, diversity, and purposes of the microbiota found within different organ systems of these species. This study focuses on ...
Bettio MK, Vidal T, Rose JJ, Jois M, Flavel M, Petrovski S.The gastrointestinal microbiota plays a critical role in horse health and performance. While sugarcane-derived polyphenols have shown microbiota-modulating properties in other species, their effects in horses remain unexplored. Objective: This study investigated whether supplementation with a sugarcane-derived polyphenol feed material modulates the hindgut microbiota of healthy adult horses. Methods: An observational longitudinal study was conducted on six horses over 12 weeks. Faecal samples were collected at three time points: baseline (P1), during supplementation (P2), and post-supplementat...
Ma Y, Zhang J, Li X, Zhao H, Lu W, Li H, Yang K.Anthelmintic treatment is widely used in equine health management to control parasitic infections; however, its potential effects on the gut microbiota and metabolic characteristics remain poorly understood. In this study, twelve Yili horses were randomly assigned to two groups: a control group (C), which received no anthelmintic treatment, and a Miechongshu-treated group (T), which was orally administered Miechongshu at a dose of 0.36 g/kg body weight on day 0. Fecal samples were collected from the rectums of Yili horses on day 14 after administration, and differences in gut microbial composi...
Hart KJ, Hegarty MJ, Hart EH.It is more evident that horse health is linked to the gastrointestinal tract and microbial community structure (MCS) as affected by diet. There are many marketed feeds available to enhance nutrition for horses, however the effects of these feeds on hindgut MCS are largely unknown. Objective: The aim was to test the effect of a complementary forage feed (FF) on the fermentation profile and MCS in contrasting basal diets. Methods: A 2×2 factorial design was used to assess the effect of basal diet, forage only (FOR) or forage/concentrate (MIX), and presence/absence of FF on fermentation paramete...
Dehghan H, Moghaddaszadeh-Ahrabi S, Hashemzadeh-Farhang H, Shahbazi P, Nobari B.The equine hindgut depends on microbial fermentation for efficient nutrient utilization but remains vulnerable to dysbiosis, hindgut acidosis, and suboptimal fiber digestion. Growing restrictions on antibiotic and synthetic feed additives have increased interest in natural phytogenic compounds. Medicinal plant extracts and condensed tannins are promising candidates to modulate microbial activity, improve fermentation efficiency, and enhance nutrient digestibility. This study aimed to investigate the individual and combined effects of hydroalcoholic extract of and condensed tannins extracted f...
Yu S, Yue X, Yang Q, Xu P, Yuan H, Tang W, Luan Y, Wang Q.Intestinal microbial homeostasis and metabolic balance play a crucial role in maintaining normal physiological function in horses. Exogenous stress involving abrupt turns and jumps during show jumping significantly impacts intestinal microbial homeostasis and metabolic balance in these animals. Results: By comparing rectal (faecal) samples from 10 Warmblood horses collected before and immediately after a show jumping competition on the same day, we observed substantial alterations in intestinal microbial homeostasis and metabolic balance post-exercise. Microbial evenness significantly increase...
Bustamante CC, Pereira PAM, Fernandes CC, Canola PA, Doria RGS, Costa MC, Valadão CAA.Starch overload induces dysbiosis primarily through a reduction in cecal pH. This study aimed to evaluate the cecal microbiota following excessive starch intake, with or without the administration of an intracecal buffering solution. We hypothesized that the buffering solution would mitigate changes in the intestinal microbiota and associated clinical signs. Ten horses were randomly assigned to two groups, each receiving distinct treatments (Group I: saline solution [WSa] and starch-buffer [SB]; Group II: buffer-water [WB] and starch-saline [SSa]). Following starch overload (17.6 g/kg body wei...
Li M, Xu Z, Sun L, Cheng Z, Yu Y, Chen Y, Li F, Zang C.This study aimed to investigate the effects of dietary NFC/NDF ratio on nutrient apparent digestibility, fecal fermentation parameters, microbial diversity, and plasma metabolomics in Yili horses. Twenty-four healthy Yili horses with similar body weights (406 ± 22.73 kg) were divided into four groups, each with six replicates: the Control Group (CG), Low-NFC Group (LG), Medium-NFC Group (MG), and High-NFC Group (HG). The experiment lasted 52 d, comprising a 7-day adaptation period and a 45-day experimental period. Total fecal collection was conducted from days 41 to 45 to calculate nutrient a...
Loublier C, Taminiau B, Seidel L, Moula N, Tano C, Cesarini C, Costa M, Lecoq L, Daube G, Amory H.Faecal microbiota transplantation (FMT) and probiotics are used in equine practice. Understanding veterinarians' perceptions and practices is crucial for effective implementation. Objective: (1) Evaluate the prevalence, usage patterns and perceived effectiveness of probiotics and FMT among equine veterinarians in France and Belgium. (2) Assess their knowledge, practices and influencing factors across demographics and settings. (3) Explore links between FMT protocols and treatment satisfaction. Methods: Cross-sectional survey. Methods: An online survey collected demographic data and responses o...
Cottone A, Seiter K, Thomas B, Schank N, Wulf M, Miller L, Anderson S, Munkhsaikhan U, Verma A, Abidi AH, Kassan M.Colic remains one of the most frequent and costly causes of equine morbidity and mortality, with significant welfare and economic implications. Disturbances in the gut microbiome are increasingly recognized as an important contributing factor. In recent years, prebiotics, non-digestible substrates that promote beneficial microbes, have emerged as promising microbiome-targeted strategies. () has gained attention for its unique ability to degrade mucin, maintain epithelial integrity, and exert potent anti-inflammatory effects. Although its benefits are well established in humans and rodent mode...
Santos R, Hunyadi L, Sundman E, Morales Luna L, Hyde SC, Cain M, Migl K, Ancira J, Tipton C, Rosa F.Severe equine asthma (SEA) is a chronic inflammation of airways affecting ~14-20% of adult horses in the Northern Hemisphere. SEA is characterized by a mixed phenotype of T helper cell responses with marked neutrophilia in the bronchoalveolar lavage fluid (BALF) of affected horses. Human studies have demonstrated the impact of gut microbiota in many diseases, including asthma susceptibility and severity. However, the potential role of the gut-lung axis in the development and persistence of SEA remains to be determined. This study aimed to identify key bacterial, archaeal, and fungal microbiota...
Donato GG, Necchi D, Gionechetti F, Ala U, Nebbia P, Robino P, Stella MC, Vandaele H, Pallavicini A, Nervo T.In the past, bacteria detected in the mare's uterus were generally interpreted as a sign of endometritis, since the uterus was considered a sterile environment. This assumption has been challenged by the introduction of culture-independent molecular techniques, particularly 16S rRNA amplicon sequencing, which have demonstrated that healthy mares harbor an endometrial microbiota. The aim of this study was to characterize the endometrial microbiota of healthy mares and to determine whether microbial composition differs between estrus and diestrus. Endometrial samples were collected from eleven h...
Li M, Lin J, Ma C, Wei G, Hu Q, Li X.L-selenomethionine (L-SeMet), a highly bioavailable organic form of selenium, plays a critical role in maintaining antioxidant homeostasis, regulating reproductive hormone secretion, and improving intestinal microbial ecology. Previous studies have demonstrated that appropriate supplementation with L-SeMet can significantly enhance the production performance and health status of ruminants. However, the nutritional regulatory mechanisms and physiological effects of L-SeMet in monogastric herbivores, particularly horses during mid- to late gestation, remain inadequately understood. Therefore, th...
Gentilini F, Ogundipe TG, Turba ME, Romagnoli N, Lambertini C, Pollera C, Cremonesi P, Stancampiano L.Gastrointestinal nematode infections significantly impact equine health and welfare, with rising anthelmintic resistance demanding alternative control strategies. Emerging evidence suggests that parasitic nematodes harbour distinct microbiomes, potentially influencing host-parasite dynamics and parasite survival. This study aimed to characterize and compare the microbiomes of equine gastrointestinal nematodes and their hosts, focusing on differences in composition, diversity, and core microbiota structure across different intestinal sites, nematode subfamilies, and sexes. Faecal and nematode s...
Fernandes MD, Ribeiro GSN, Joaquim JGF, Ferraz SM, Fonteque JH.In equine husbandry, oral cavity procedures are commonly performed and may be associated with complications, including extraoral diseases, potentially resulting from bacterial contamination and inadequate antisepsis. Bacterial resistance to antimicrobials is a major issue for healthcare professionals, including veterinarians that may misuse these pharmaceuticals. Therefore, developing novel methods for antisepsis is desirable. This study aims to test the effectiveness of a 100 µg/ml ozonized injectable water solution versus 0.12% chlorhexidine mouthwash. Fifty adult equines had swab samples...
Franzan BC, da Silva Coelho I, Ramos EM, de Souza ARP, de Almeida FQ, Silva VP.This study aimed to investigate the gradual adaptation of the fecal bacterial community and in vitro fermentative capacity of horses fed a complete extruded diet (CED). Twelve geldings weighing 370 kg were removed from a native pasture and fed coastcross hay (Cynodon spp) for 7 days. In the second week, horses were assigned to two groups: one group was fed exclusively with coastcross hay (HAY) for 28 days and the other group fed with weekly increases of CED (30%, 60%, and 100%) to replace HAY. Fecal samples were collected on Days 7, 14, 21, and 28 for microbiota and in vitro fermentati...
Liu J, Huang X, Wang Y, Wang Y, Luo R, Lu X, Cao K, Xing J, Tu Y, Zheng W.Antibiotic resistance genes (ARGs) are emerging contaminants threatening public health, yet their transmission risk via mare milk products remains understudied. Using metagenomics, we analyzed lactic acid bacteria (LAB)-inoculated fermented, naturally fermented, raw, and pasteurized mare milk to investigate the effect of LAB inoculation on the distribution and transmission pathways of ARGs in mare milk. The results showed that naturally fermented, raw, and pasteurized mare milk had the highest number of pathogens, relative abundance of ARGs, and relative abundance of mobile genetic elements (M...
He H, Han L, Ni W, Yu J, Liu K, Li W, Li C, Hu S, Li C, Li X.Herbivores represent crucial subjects for mining highly efficient carbohydrate-active enzymes (CAZymes) from gut microbiomes. Here, we analyzed 12,763 metagenome-assembled genomes (MAGs) from the horse gut, revealing that its microbial community as a rich reservoir of CAZymes diversity, with 5,204,848 glycoside hydrolases (GHs) and 4,596,191 glycosyl transferases (GTs) identified. Our findings demonstrate that Bacteroidota (5,479,287 CAZymes) and Bacillota_A (2,987,684 CAZymes) serve as the primary functional phyla for plant polysaccharide degradation. A total of 17,250 polysaccharide utilizat...
Zhang Y, Zhang M, Zhao Z, Peng Y, Deng F, Jiang H, Zhang M, Song B, Kim JK, Pan JH, Chai J, Li Y.Unique skin microbial communities have been shaped by the harsh climatic conditions in high-altitude areas, such as intense ultraviolet radiation and low oxygen concentration. However, it is unknown whether high altitude contributes to shaping common microbiota inhabiting the skin across different mammals. The skin microbial communities of humans and horses living in high-altitude (Tibetan) and low-altitude areas were analyzed using full-length 16S rRNA sequencing technology. Alpha diversity differed between high- and low-altitude groups ( < 0.01). Skin microbial community composition also dif...
Costa MC, Arroyo LG, Allen-Vercoe E, Stämpfli HR, Kim PT, Sturgeon A, Weese JS.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...
Costa MC, Silva G, Ramos RV, Staempfli HR, Arroyo LG, Kim P, Weese JS.The advance of new sequencing technologies has allowed more comprehensive characterization of complex microbial communities, including the ones inhabiting the intestinal tract. The presence of extreme environmental filters, such as low pH, digestive enzymes and anaerobic conditions along the tract, acts on the selection of unique bacteria in each compartment. The intestinal microbiota has an enormous impact on the maintenance of health. However, data about the bacteria present in the different intestinal compartments of horses are sparse. In this study, high throughput sequencing was used to c...
Steelman SM, Chowdhary BP, Dowd S, Suchodolski J, Janečka JE.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...
Dick LK, Bernhard AE, Brodeur TJ, Santo Domingo JW, Simpson JM, Walters SP, Field KG.The purpose of this study was to examine host distribution patterns among fecal bacteria in the order Bacteroidales, with the goal of using endemic sequences as markers for fecal source identification in aquatic environments. We analyzed Bacteroidales 16S rRNA gene sequences from the feces of eight hosts: human, bovine, pig, horse, dog, cat, gull, and elk. Recovered sequences did not match database sequences, indicating high levels of uncultivated diversity. The analysis revealed both endemic and cosmopolitan distributions among the eight hosts. Ruminant, pig, and horse sequences tended to for...
Dougal K, de la Fuente G, Harris PA, Girdwood SE, Pinloche E, Newbold CJ.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...
The intestinal tract is a rich and complex environment and its microbiota has been shown to have an important role in health and disease in the host. Several factors can cause disruption of the normal intestinal microbiota, including antimicrobial therapy, which is an important cause of diarrhea in horses. This study aimed to characterize changes in the fecal bacterial populations of healthy horses associated with the administration of frequently used antimicrobial drugs. Results: Twenty-four adult mares were assigned to receive procaine penicillin intramuscularly (IM), ceftiofur sodium IM, tr...
Weese JS, Holcombe SJ, Embertson RM, Kurtz KA, Roessner HA, Jalali M, Wismer SE.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...
Shepherd ML, Swecker WS, Jensen RV, Ponder MA.The diversity of the equine fecal bacterial community was evaluated using pyrosequencing of 16S rRNA gene amplicons. Fecal samples were obtained from horses fed cool-season grass hay. Fecal bacteria were characterized by amplifying the V4 region of bacterial 16S rRNA gene. Of 5898 mean unique sequences, a mean of 1510 operational taxonomic units were identified in the four fecal samples. Equine fecal bacterial richness was higher than that reported in humans, but lower than that reported in either cattle feces or soil. Bacterial classified sequences were assigned to 16 phyla, of which 10 were ...
Metcalf JL, Song SJ, Morton JT, Weiss S, Seguin-Orlando A, Joly F, Feh C, Taberlet P, Coissac E, Amir A, Willerslev E, Knight R, McKenzie V, Orlando L.The mammal gut microbiome, which includes host microbes and their respective genes, is now recognized as an essential second genome that provides critical functions to the host. In humans, studies have revealed that lifestyle strongly influences the composition and diversity of the gastrointestinal microbiome. We hypothesized that these trends in humans may be paralleled in mammals subjected to anthropogenic forces such as domestication and captivity, in which diets and natural life histories are often greatly modified. We investigated fecal microbiomes of Przewalski's horse (PH; Equus ferus p...
Garber A, Hastie P, Murray JA.Gastrointestinal microbiota play a crucial role in nutrient digestion, maintaining animal health and welfare. Various factors may affect microbial balance often leading to disturbances that may result in debilitating conditions such as colic and laminitis. The invention of next-generation sequencing technologies and bioinformatics has provided valuable information on the effects of factors influencing equine gut microbiota. Among those factors are nutrition and management (e.g., diet, supplements, exercise), medical substances (e.g., antimicrobials, anthelmintics, anesthetics), animal-related ...
Dougal K, de la Fuente G, Harris PA, Girdwood SE, Pinloche E, Geor RJ, Nielsen BD, Schott HC, Elzinga S, Newbold CJ.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...
Daly K, Proudman CJ, Duncan SH, Flint HJ, Dyer J, Shirazi-Beechey SP.We aimed to determine the effects of variations in dietary composition on equine gut microbiota and their fermentation products, and proposed that dietary modifications profoundly affect microbial ecosystems and their metabolites. Bacterial communities within the large intestine of three groups of horses were compared using oligonucleotide-RNA hybridisation methodology. Each group consisting of six horses was maintained on (1) a grass-only diet, (2) a concentrate diet (i.e. supplemented with hydrolysable carbohydrates) and (3) a concentrate diet but horses were affected by simple colonic obstr...
Dougal K, Harris PA, Edwards A, Pachebat JA, Blackmore TM, Worgan HJ, Newbold CJ.The microbiome and associated metabolome of faecal samples were compared to those from the caecum and right dorsal colon of horses and ponies euthanised for nonresearch purposes by investigating the microbial population community structure as well as their functional metabolic products. Through the use of 16S rRNA gene dendrograms, the caecum microbiome was shown to cluster separately from the other gut regions. 16S rRNA gene-based quantitative PCR (q-PCR) also demonstrated differences between the caecum and the other gut regions. Metabolites as identified by Fourier transform infrared cluster...
Kauter A, Epping L, Semmler T, Antao EM, Kannapin D, Stoeckle SD, Gehlen H, Lübke-Becker A, Günther S, Wieler LH, Walther B.Understanding the complex interactions of microbial communities including bacteria, archaea, parasites, viruses and fungi of the gastrointestinal tract (GIT) associated with states of either health or disease is still an expanding research field in both, human and veterinary medicine. GIT disorders and their consequences are among the most important diseases of domesticated Equidae, but current gaps of knowledge hinder adequate progress with respect to disease prevention and microbiome-based interventions. Current literature on enteral microbiomes mirrors a vast data and knowledge imbalance, w...
Ericsson AC, Johnson PJ, Lopes MA, Perry SC, Lanter HR.Horses are exquisitely sensitive to non-specific gastrointestinal disturbances as well as systemic and extraintestinal conditions related to gut health, yet minimal data are available regarding the composition of the microbiota present in the equine stomach, small intestine, and cecum and their relation to fecal microbiota. Moreover, there is minimal information regarding the concordance of the luminal and mucosal microbial communities throughout the equine gut. Illumina-based 16S rRNA gene amplicon sequencing of the luminal and mucosal microbiota present in seven regions of the gastrointestin...
Fernandes KA, Kittelmann S, Rogers CW, Gee EK, Bolwell CF, Bermingham EN, Thomas DG.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 ...
Mitchell CM, Davy BM, Hulver MW, Neilson AP, Bennett BJ, Davy KP.The objective of this systematic review of literature was to evaluate and summarize published research that has investigated the association between exercise and gut microbial composition in mammals. This review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The databases searched for this review included: PubMed; PubMed Central; Medline; Cumulative Index of Nursing and Allied Health Literature; Web of Science; Commonwealth Agricultural Bureaux Direct; Health Source: Nursing Academic Edition; Clinicaltrials.gov; International Prosp...
Salem SE, Maddox TW, Berg A, Antczak P, Ketley JM, Williams NJ, Archer DC.Colic (abdominal pain) is a common cause of mortality in horses. Change in management of horses is associated with increased colic risk and seasonal patterns of increased risk have been identified. Shifts in gut microbiota composition in response to management change have been proposed as one potential underlying mechanism for colic. However, the intestinal microbiota in normal horses and how this varies over different seasons has not previously been investigated. In this study the faecal microbiota composition was studied over 12 months in a population of horses managed at pasture with minima...
O' Donnell MM, Harris HM, Jeffery IB, Claesson MJ, Younge B, O' Toole PW, Ross RP.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...
Costa MC, Weese JS.The equine intestinal tract contains a complex microbial population (microbiota) that plays an important role in health and disease. Despite the undeniable importance of a 'normal' microbiota, understanding of the composition and function of this population is currently limited. As methods to characterize the microbiota and its genetic makeup (the microbiome) have evolved, the composition and complexity of this population are starting to be revealed. As is befitting a hindgut fermenter, members of the Firmicutes phylum appear to predominate, yet there are significant populations of numerous ot...
Willing B, Vörös A, Roos S, Jones C, Jansson A, Lindberg JE.Diets rich in readily fermentable carbohydrates, fed traditionally to meet the increased energy requirements of the performance horse, are associated with a number of gastrointestinal disorders that involve disturbances in the intestinal microbiota, however, these changes are poorly understood. Objective: With the long-term objective of improving intestinal health and to increase understanding of the relationship between diet and microbiota, the effect of feeding Standardbred horses a high-energy forage-only (F) diet was studied compared to a more traditional forage-concentrate (C) diet on fae...
Costa MC, Weese JS.This article provides readers with the basic concepts necessary to understand studies using recent molecular methods performed in intestinal microbiome assessment, with special emphasis on the high throughput sequencing. This review also summarizes the current knowledge on this topic and discusses future insights on the interaction between the intestinal microbiome and equine health.
Lindenberg F, Krych L, Fielden J, Kot W, Frøkiær H, van Galen G, Nielsen DS, Hansen AK.Billions of bacteria inhabit the gastrointestinal tract. Immune-microbial cross talk is responsible for immunological homeostasis, and symbiotic microbial species induce regulatory immunity, which helps to control the inflammation levels. In this study we aimed to identify species within the equine intestinal microbiota with the potential to induce regulatory immunity. These could be future targets for preventing or treating low-grade chronic inflammation occurring as a result of intestinal microbial changes and disruption of the homeostasis. 16S rRNA gene amplicon sequencing was performed on ...
Rodriguez C, Taminiau B, Brévers B, Avesani V, Van Broeck J, Leroux A, Gallot M, Bruwier A, Amory H, Delmée M, Daube G.The equine faecal microbiota is very complex and remains largely unknown, while interspecies interactions have an important contribution to animal health. Clostridium difficile has been identified as an important cause of diarrhoea in horses. This study provides further information on the nature of the bacterial communities present in horses developing an episode of diarrhoea. The prevalence of C. difficile in hospitalised horses at the time of admission is also reported. Results: Bacterial diversity of the gut microbiota in diarrhoea is lower than that in non-diarrhoeic horses in terms of spe...
Costa MC, Stämpfli HR, Allen-Vercoe E, Weese JS.The intestinal microbiota is a complex polymicrobial ecosystem that exerts extremely important roles in the development and maintenance of health. Recently, as new sequencing technologies have become more available, there has been a revolution in the understanding of the equine intestinal microbiota. However, studies characterising the pioneer intestinal bacteria colonising foals and its development over time are still limited. Objective: The objectives of this study were to characterise the intestinal bacterial colonisation of newborn foals and to follow individual animals over time until age...
Julliand V, Grimm P.In the early 1990s, the equine hindgut microbial ecosystem looked like a "black box." Its vital role in hydrolyzing and fermenting fiber, thus providing energy to the host, was recognized. Although there was a critical lack of information on the hindgut microbes, their role in preventing intestinal diseases was suggested. Traditionally, the microbes of the horse hindgut were studied using culture-dependent techniques. More recently, culture-independent methods have been used and provided further insight. This review presents the history and updated knowledge regarding the microbes that live in...
Al Jassim RA, Andrews FM.The gastrointestinal tract of the horse has unique characteristics that make it well suited for the ingestion and utilization of roughage. The horse is considered a simple-stomached herbivore and is classed as a hindgut fermenter. The upper segments of the gastrointestinal tract resemble those of a typical simple-stomached animal. The lower have undergone modification to become voluminous and host to a large number of microbial populations similar to those of the compartmental stomach of ruminant animals. The main advantage of this arrangement is the ability of the horse to extract valuable nu...
Morrison PK, Newbold CJ, Jones E, Worgan HJ, Grove-White DH, Dugdale AH, Barfoot C, Harris PA, Argo CM.Gastrointestinal microbial communities are increasingly being implicated in host susceptibilities to nutritional/metabolic diseases; such conditions are more prevalent in obese and/or older horses. This controlled study evaluated associations between host-phenotype and the fecal microbiome / metabolome. Thirty-five, Welsh Mountain pony mares were studied across 2 years (Controls, = 6/year, 5-15 years, Body Condition Score (BCS) 4.5-6/9; Obese, = 6/year, 5-15 years, BCS > 7/9; Aged, = 6 Year 1; = 5 Year 2, ≥19 years old). Animals were individually fed the same hay to maintenance (2% bo...
Antwis RE, Lea JMD, Unwin B, Shultz S.Microbiome composition is linked to host functional traits including metabolism and immune function. Drivers of microbiome composition are increasingly well-characterised; however, evidence of group-level microbiome convergence is limited and may represent a multi-level trait (i.e. across individuals and groups), whereby heritable phenotypes are influenced by social interactions. Here, we investigate the influence of spatial structuring and social interactions on the gut microbiome composition of Welsh mountain ponies. We show that semi-feral ponies exhibit variation in microbiome composition ...
Mach N, Foury A, Kittelmann S, Reigner F, Moroldo M, Ballester M, Esquerré D, Rivière J, Sallé G, Gérard P, Moisan MP, Lansade L.Weaning has been described as one of the most stressful events in the life of horses. Given the importance of the interaction between the gut-brain axis and gut microbiota under stress, we evaluated (i) the effect of two different weaning methods on the composition of gut microbiota across time and (ii) how the shifts of gut microbiota composition after weaning affect the host. A total of 34 foals were randomly subjected to a progressive (P) or an abrupt (A) weaning method. In the P method, mares were separated from foals at progressively increasing intervals every day, starting from five min ...
