Topic:Hindgut
The hindgut of horses is a critical component of their digestive system, responsible for the fermentation of fibrous plant materials. It consists primarily of the cecum and colon, where a complex community of microorganisms breaks down cellulose and other fibers into volatile fatty acids, which are then absorbed as a significant energy source for the horse. The hindgut also plays a role in water absorption and the synthesis of certain vitamins. Disruptions in hindgut function can lead to digestive disorders such as colic or laminitis. This page gathers peer-reviewed research studies and scholarly articles that explore the anatomy, function, and health implications of the equine hindgut, as well as management practices to maintain its optimal function.
Comparison of the fecal microbiota with high- and low performance race horses. Exercise plays an important role in regulating energy homeostasis, which affects the diversity of the intestinal microbial community in humans and animals. To the best of the authors' knowledge, few studies have reported the associations between horse gut microbiota along with their predicted metabolic activities and the athletic ability of Jeju horses and Thoroughbreds living in Korea. This study was conducted to investigate the association between the gut microbiota and athletic performance in horses. This study sequenced the V3 and V4 hypervariable regions of the partial 16S rRNA genes obta...
Effects of concentrate levels on intestinal fermentation and the microbial profile in Japanese draft horses. In racehorses, feeding a high-concentrate diet could cause abnormal fermentation in the hindgut. This feeding management regime is not suitable for the nutritional physiology of horses. However, studies on the hindgut environment have yet to be reported in Japanese draft horses, so feeding management needs to be investigated in these horses. Therefore, the objective of this study was to investigate the effects of a high-concentrate diet on hindgut fermentation in Japanese draft horses. Feces were collected from 20 male Japanese draft horses managed by two stables with different feeding designs...
Effect of micronization and meal size of corn grain on glycemic response and in vitro hindgut acidosis potential in horses. This study aimed to 1) evaluate the interaction of corn grain micronization and starch levels per meal on equine plasma glucose, and 2) determine if micronization affects the risk of hindgut acidosis. Six mature (aged 6 to 10 years), healthy, non-pregnant mares (initial body weight [BW]: 301 to 463 kg) were used in a 2×3 factorial cross-over design. The treatments included two forms of corn grain (ground and micronized flaked) at three levels of starch (1, 1.5, and 2 g/kg BW per meal). The blood was sampled before and 30, 60, 90, 120, 180, 240, and 300 min after morning feeding and the glucos...
Diversity and functional prediction of fungal communities in different segments of mongolian horse gastrointestinal tracts. Anaerobic fungi are effective fibre-degrading microorganisms in the digestive tract of horses. However, our understanding of their diversity and community structure is limited, especially in different parts of the gastrointestinal tract. For the first time, high-throughput sequencing technology was used to analyse and predict fungal microbial diversity in different parts of the gastrointestinal tract of Mongolian horses. The results revealed that the richness and diversity of fungi in the hindgut of Mongolian horses were much higher than those in the foregut. The foregut was dominated by Basid...
Effects of Differences in Fibre Composition and Maturity of Forage-Based Diets on the Fluid Balance, Water-Holding Capacity and Viscosity in Equine Caecum and Colon Digesta. Horses are herbivores, and their hindgut functions as a fluid reservoir as forage fibre properties have great impact on the water content of digesta and the milieu in the ecosystem. Our objective was to compare the effect of grass fibre maturity and legume forage on the water-holding capacity (WHC) and viscosity of the equine hindgut and the body weight (BW) and fluid balance of horses. Three diets: concentrate and late harvested grass haylage (35:65 energy ratio) (C); early and late harvested grass haylage (80:20) (G); lucerne and late harvested grass haylage (80:20) (L) were fed to six caecu...
An Investigation into the Effects of Changing Dorso-Plantar Hoof Balance on Equine Hind Limb Posture. Links between poor hind hoof balance, pathologies in the hind limb and associated altered posture have been suggested but not quantified. The hoof is proposed as a neuro-sensory organ responsible for informing equine stance with implications for musculoskeletal health in the hind limb and trunk of the horse. This study aims to quantify equine limb posture and its relationship with hoof balance. Twelve horses presenting with negative plantar angles were photographed and limb posture documented before and after the creation of positive plantar angles and improved three-dimensional proportions ar...
No size-dependent net particle retention in the hindgut of horses. Sieve analyses of hindgut contents of horses as well as observations in horses where plastic markers had been applied to a caecal cannula suggested that there may be a discrimination by particle size in the passage or retention of digesta. Here, we performed a similar experiment with five caecum-cannulated horses (562 ± 31 kg) fed a constant amount (6.81 kg dry matter/day) of grass hay. Passage markers representing the liquid (Co-EDTA) as well as the particulate digesta phase (Yb-undefined; Cr mordanted fibre 1-2 mm; Ce-mordanted fibre 8 mm) were given as a pulse-dose into the can...
Chemical composition and physical characteristics of faeces in horses with and without free faecal liquid – two case-control studies. Free faecal liquid (FFL) is a condition in horses characterised by two-phase (one solid and one liquid) separation of faeces. Causes of the condition are unknown, but disturbed hindgut fermentation has been suggested as it may alter biochemical composition and appearance of faeces in equines. However, information on faecal composition in horses with FFL is scarce. Faecal chemical composition (dry matter, osmolality, ash, macro minerals, short-chain fatty acids (SCFA) and pH) and physical characteristics (free liquid, sand, water holding capacity and particle size distribution) were compared in...
Effect of Donor Diet on In Vitro Digestibility of Forages by Fecal Inoculate. Previous research indicates equine fecal inoculates produce comparable results to cecal fluid when used for in vitro procedures to analyze dry matter digestibility (DMD). Equine hindgut microbial communities represented in fecal samples have been shown to be affected by diet. The study's objective was to determine the effect of the donor diet on in vitro DMD when fecal donors were fed high starch, or high fiber diets. Six Quarter Horses were used in a crossover design to compare the effects of a grain versus forage diet on in vitro digestion of forages ranging from: CP 7.7 to 16.4 %DM, NDF 53 ...
Effects of Pasture Grass, Silage, and Hay Diet on Equine Fecal Microbiota. Diet is an important factor affecting intestinal microbiota in horses. Fecal microbiota is commonly used as a substitute for studying hindgut microbiota when investigating the relationship between intestinal microbial changes and host health. So far, no study has compared the difference between the fecal microbiota found in horses that are fed pasture grass, silage, and hay. The present study aims to characterize the fecal microbiota in horses that were exclusively on one of the three forage diets, and to analyze the potential impact of these forages, especially silage, on horse intestinal hea...
Sequential Modulation of the Equine Fecal Microbiota and Fibrolytic Capacity Following Two Consecutive Abrupt Dietary Changes and Bacterial Supplementation. In horses, abrupt changes from high-fiber (HF) to high-starch (HS) diets can affect the cecal and colonic microbiota. This study investigated modifications and recovery of fecal microbiota after two consecutive abrupt dietary changes. Twelve horses fed HF for 2 weeks were changed to HS for 5 days then returned to HF for 7 weeks. Six received lactic acid bacteria supplementation. Bacterial population diversity, structure, and activity, especially fibrolysis, were assessed to obtain an overview of alteration in hindgut microbiota. Two days after the abrupt change from HF to HS, the findings in f...
The equine hindgut as a reservoir of mobile genetic elements and antimicrobial resistance genes. Antibiotic resistance in bacterial pathogens is a growing problem for both human and veterinary medicine. Mobile genetic elements (MGEs) such as plasmids, transposons, and integrons enable the spread of antibiotic resistance genes (ARGs) among bacteria, and the overuse of antibiotics drives this process by providing the selection pressure for resistance genes to establish and persist in bacterial populations. Because bacteria, MGEs, and resistance genes can readily spread between different ecological compartments (e.g. soil, plants, animals, humans, wastewater), a "One Health" approach is need...
The pelvic flexure separates distinct microbial communities in the equine hindgut. As hindgut fermenters, horses are especially dependent on the microbiota residing in their cecum and large intestines. Interactions between these microbial populations and the horse are critical for maintaining gut homeostasis, which supports proper digestion. The current project was motivated to determine if any features of the fecal microbiota are informative of the microbial communities from the cecum, ventral colon, or dorsal colon. Digesta from the cecum, ventral colon, dorsal colon and feces were collected from 6 yearling miniature horses. Microbial DNA was isolated and the microbiota fr...
Changes of microbial and metabolome of the equine hindgut during oligofructose-induced laminitis. Laminitis is a common and serve disease which caused by inflammation and pathological changes of the laminar junction. However, the pathologic mechanism remains unclear. In this study we aimed to investigate changes of the gut microbiota and metabolomics in oligofructose-induced laminitis of horses. Results: Animals submitted to treatment with oligofructose had lower fecal pH but higher lactic acid, histamine, and Lipopolysaccharide (LPS) in serum. Meanwhile, oligofructose altered composition of the hindgut bacterial community, demonstrated by increasing relative abundance of Lactobacillus and...
Methodical considerations when estimating nutrient digestibility in horses using the mobile bag technique. Total collection of faeces is considered the golden standard for estimating apparent total tract digestibility (ATTD) in horses. However, the evaluation of individual feedstuffs is limited and determination of nutrient digestibility in different segments of the gastrointestinal tract (GIT) is excluded. The rationale for performing this study was that the mobile bag technique (MBT) can provide information on individual feedstuffs' degradation, and the use of fistulated animals does provide additionally information regarding degradation in individual segments of the GIT. Recommendations for usin...
In Vitro Gas Production from Batch Cultures of Stomach and Hindgut Digesta of Horses Adapted to a Prebiotic Dose of Fructooligosaccharides and Inulin. Fructooligosaccharides (FOS) and inulin may modulate hindgut fermentation. It was tested if digesta batch cultures taken from horses adapted to FOS and inulin show different fermentation compared with such taken from nonsupplemented horses. Six horses received 0.15 g FOS and inulin/kg body weight/d via Jerusalem artichoke meal (JAM) upon a hay-based diet; six horses received corncob meal without grains (CMG) as placebo. The horses were euthanized after 20 days. Digesta samples were taken from stomach, cecum, ventral colon ascendens (VCA), and colon transversum (CT). Digesta batch cultures we...
Transporting and Exercising Unconditioned Horses: Effects on Microflora Populations. The objective of this study was to determine if transportation and exercise stress in horses affect the microflora populations in the equine hindgut. Four horses were subjected to three transport periods (0, 3, and 6 hours) with a 7-d rest period between each transport. Horses were fed 0.91 kg/day of Purina Impact All Stages 12% and had ad libitum access to Cynodon dactylon (Coastal Bermudagrass) hay. Fecal samples were collected before (0 hours) and after (48 hours) transport. In addition, three horses underwent a different standardized exercise test with a 7-d rest period between each ex...
Evaluation of equine rectal inoculum as representative of the microbial activities within the horse hindgut using a fully automated in vitro gas production technique system. The in vitro gas production technique (IVGPT) has been a valuable tool in ruminant nutrition research for decades and has more recently been used in horse nutrition studies to investigate fermentation activities of the equine hindgut though primarily using feces as inoculum. This study was conducted to evaluate the use of equine rectal content in the IVGPT system as a viable inoculum that can be considered representative of the activities throughout the equine hindgut. Additionally, the study was conducted to measure the effects on fermentation kinetics and end-product production using inoculu...
Dietary composition and yeast/microalgae combination supplementation modulate the microbial ecosystem in the caecum, colon and faeces of horses. Starchy diets can induce hindgut dysbiosis in horses. The present study evaluated the impact of a yeast (Saccharomyces cerevisiae) and microalgae (Aurantiochytrium limacinum) supplementation on caecal, colonic and faecal microbial ecosystem and on blood inflammatory parameters of horses fed high-fibre or high-starch diets. Six fistulated geldings in a 2 × 2 Latin-square design were alternatively supplemented and received during each period 100 % hay (4 weeks) followed by a 56/44 hay/barley diet (3 weeks). Caecal, colonic and faecal samples were collected 4 h after the morning meal three times...
Hindgut Ciliate Composition of Thoroughbred Mares in Kentucky, USA, and Binary Fission in Polymorphella ampulla. Species composition and distribution of hindgut ciliates were investigated in the feces of 20 thoroughbred mares in Kentucky, USA. Thirty-three species and six morphotypes belonging to 21 genera were identified. The average density of hindgut ciliates in mares was 13.5 ± 13.7 × 104 cells ml-1, whereas mean number of ciliate species per host was 14.4 ± 5.3. Bundleia nana, B. elongata, B. piriformis, Blepharoconus hemiciliatus, Holophryoides ovalis, H. macrotricha, Blepharoprosthium polytrichum, Prorodonopsis coli, Paraisotrichopsis composita, Blepharocorys microcorys, and Ochoterenaia append...
Effects of sodium caseinate on hindgut fermentation and fiber digestion in horses. Eight cecally cannulated Quarter Horses were used in a replicated 4 × 4 Latin square experiment conducted in four 14-d periods to determine effects of sodium caseinate (casein) on hindgut fermentation and fiber digestion. During each period, horses were assigned to one of four treatments consisting of control (water; CON), 0.125 g casein/kg BW (LOW), 0.25 g casein/kg BW (MED), or 0.5 g casein/kg BW (HI). Casein was solubilized in 800 mL water and dosed directly into the cecum at 0700 and 1900 hours using a metal dosing syringe. Smooth Bromegrass hay (CP 8.50%), water, and salt were provided a...
Equine Contribution in Methane Emission and Its Mitigation Strategies. Greenhouses gas emission mitigation is a very important aspect of earth sustainability with greenhouse gasses reduction, a focus of agricultural and petrochemical industries. Methane is produced in nonruminant herbivores such as horses because they undergo hindgut fermentation. Although equine produce less methane than ruminant, increasing population of horses might increase their contribution to the present 1.2 to 1.7 Tg, estimate. Diet, feeding frequency, season, genome, and protozoa population influence methane production equine. In population, Methanomicrobiales, Methanosarcinales, Methan...
Effect of Starch Source in Pelleted Concentrates on Fecal Bacteria in Prepartum and Postpartum Mares. Dietary starch source has been shown to affect fecal bacterial communities of horses fed minimally processed cereal grains. However, processing may increase foregut starch digestibility, reducing effects of starch source on fecal bacterial communities. This study aimed to determine the effect of starch source in pelleted concentrates on fecal Lactobacillus spp., amylolytic bacteria, and cellulolytic bacteria in broodmares mares, during the prepartum and postpartum period. Thoroughbred mares (n = 18) were paired by last breeding date then randomly assigned to either an oat-based or a corn and ...
Effects of two equine digestive aid supplements on hindgut health. Gastrointestinal disease is the number one killer of horses. Little is known about the maintenance of microbes in the equine hindgut and how to distinguish a healthy gut in a live horse. Utilization of internal and external digestibility markers and starch fermentation has been extensively studied in ruminants and is the basis for research conducted on horses. The aims of this study were to investigate the effects of two equine feed digestive aid supplements on hindgut health () as reflected in fecal pH and digestibility and to compare and validate DM digestibility measurements through the use...
A comparison of methanogens of different regions of the equine hindgut. The diversity of the methanogenic archaea associated with the six segments of the horse and donkey hindgut (caecum, right ventral colon, left ventral colon, left dorsal colon, right dorsal colon, and rectum) was analyzed using 16S rDNA gene clone library. A total of 641 positive clones, 321 from the horse and 320 from the donkey hindgut, were examined by the RFLP, revealing 9 different ribotypes, 8 in the horse and 5 in the donkey hindgut. In both the animals Methanobacteriales (Methanobrevibacter-like sequences) and Methanomicrobiales (Methanocorpusculum-like sequences) were detected as the d...
Interaction between the sequence of feeding of hay and concentrate, and boiling of barley on feed intake, the activity of hydrolytic enzymes and fermentation in the hindgut of Arabian mares. The interaction between the sequence of feeding of hay and concentrate and the hydrothermal processing of barley in alleviating concentrate effects on intake, and hindgut fermentation in horses was tested. Six Arabian mares (4-10 years of age, 410 ± 35 kg body weight) were used to evaluate the effects of feeding sequence (FS) and type of barley (TB) on intake, and faecal volatile fatty acids (VFA), activities of α-amylase (AA: EC 3.2.1.1), carboxymethyl cellulase (CMCase: EC 3.2.1.4), microcrystalline cellulase (MCCase: EC 3.2.1.91) and general filter paper degrading activity (FPD). Mare...
Revealing the influence of glucocorticoid treatment on the excretion of anabolic-androgenic steroids in horses through in vitro digestive simulations and an in vivo case study. Anabolic-androgenic steroids (AAS) are strictly forbidden in equine sports because of their stimulating effect on muscle growth and performance. Nevertheless, low levels of AAS have been found in some horses, untreated with AAS. Glucocorticoids (GC), used as an anti-inflammatory therapy and structurally related to AAS, might play a role in this phenomenon. In order to unravel this possible correlation the influence of glucocorticoid treatment on the excretion of AAS was studied both in vivo and in vitro. In vivo effects were investigated by analysing urine samples collected from a gelding trea...
Thoracolumbar movement in sound horses trotting in straight lines in hand and on the lunge and the relationship with hind limb symmetry or asymmetry. Equine movement symmetry is changed when turning, which may induce alterations in thoracolumbosacral kinematics; however, this has not previously been investigated. Our objectives were to document thoracolumbar movement in subjectively sound horses comparing straight lines with circles on both reins and to relate these observations to the objectively determined symmetry/asymmetry of hindlimb gait. Fourteen non-lame horses were assessed prospectively in a non-random, cross-sectional survey. The horses were trotted in straight lines and lunged on both reins and inertial sensor data collected at ...
Effect of concentrate feeding sequence on equine hindgut fermentation parameters. Feeding a diet with a small amount of hay and a high proportion of concentrate given in large meals entails a risk of colic to horses as this can impact the hindgut microbial ecosystem. To counteract this potential negative effect, one feeding strategy is to modify the distribution sequence of concentrate and hay. The purpose of the present study was to assess the impact of feeding the concentrate meal before or with the hay meal on fermentative parameters postprandial variations in caecum and right ventral colon contents and faeces. We focused on the comparison of pH value and volatile fatty ...
Mouldy feed: A possible explanation for the excretion of anabolic-androgenic steroids in horses. To ensure fair competition and to protect the horse's welfare, horses have to compete on their own merits, without any unfair advantage that might follow the use of drugs. Therefore, regulatory authorities list all substances that are not allowed in competition, including most anabolic-androgenic steroids. As zero-tolerance is retained, the question arose whether the consumption of mouldy feed could lead to the excretion of steroids, due to the biotransformation of plant phytosterols to steroids. A rapid ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analyt...