Gastrointestinal Tract Of Horses Research Articles

The use of lidocaine during anesthesiological support, in the surgical treatment of inversion of the large colon in horses

Volvulus of the large colon is one of the most severe diseases of the gastrointestinal tract in horses. Without surgical treatment of this pathology, the mortality of horses reaches 100%. The success of surgical treatment depends on the complexity of the pathology, the time since the onset of the disease, the patient's condition before surgery. Operations in this pathology are impossible without general multimodal anesthesia. However, the anesthetic support of such patients is often accompanied by a large number of complications due to hemodynamic and metabolic disorders in the body, as a result of strangulation and stretching of the intestinal wall, abdominal compartment syndrome, as well as the impossibility of full stabilization of the patient's condition due to the need to perform the operation as soon as possible. This article discusses our experience of anesthetic management in the surgical treatment of horses diagnosed with volvulus of the large colon with and without lidocaine, the effect of lidocaine on the patient's condition during general anesthesia, recovery from anesthesia, and the occurrence of postoperative complications. The material for the article was data from twelve patients who underwent surgery for the elimination of volvulus of the large colon at the Forside Veterinary Clinic in the period 2021-2023. During the analysis of the data obtained, it was revealed that with the inclusion of infusion at a constant rate of lidocaine at a dosage of 2 mg/kg per hour in the protocol of multimodal anesthesia, the concentration of isoflurane decreased by an average of 1%, and the use of tiletamine-zolazepam became irrelevant. This made it possible to reduce the time of recovery from anesthesia and recovery of patients in the soft box, as well as the number of postoperative complications associated with general anesthesia, such as paralytic ileus and myopathy, even in patients with severe hemodynamic disturbances in the preoperative period. A lethal outcome was recorded in two out of six operated horses, in the anesthetic protocol of which lidocaine was not used. In patients with the use of lidocaine in the anesthesia protocol, a lethal outcome was recorded in one case out of six. Thus, after the inclusion of constant-rate infusion of lidocaine into the anesthesia protocol, the mortality rate was halved, from 30 to 15%.

A review of horses as a source of spreading livestock-associated methicillin-resistant Staphylococcus aureus to human health.

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) was first discovered in horses in 1989. Since then, LA-MRSA has begun to be considered an important strain of pathogenic bacteria in horses, which can cause LA-MRSA infection and colonization in humans with public health impacts. The anterior nares are the primary site of LA-MRSA colonization in horses, although LA-MRSA colonization may also occur in the gastrointestinal tract in horses. LA-MRSA-infected horses typically exhibit clinical infection or may not exhibit clinical infection. There are two potential risks associated with LA-MRSA colonization in horses: The possibility of disease development in horses infected with LA-MRSA and the possibility of LA-MRSA transfer to humans and other horses. The diagnosis of LA-MRSA in horses can be made by conducting in vitro sensitivity testing for oxacillin and cefoxitin, and then followed by a molecular test using polymerase chain reaction. LA-MRSA transmission in animal hospitals and on farms is most likely due to contact with horses infected or colonized by LA-MRSA. The history of prior antibiotic administration, history of prior LA-MRSA colonization, and length of equine hospitalization were described as risk factors in cases of infection and colonization of LA-MRSA in horses. Nebulized antibiotics may be a viable alternative to use in horses, but nebulized antibiotics are only used in horses that are persistently colonized with LA-MRSA. Controlling the spread of LA-MRSA in horses can be done by regularly washing horses, eradicating vectors in horse stalls such as rats, and maintaining the cleanliness of the stable and animal hospital environment. Meanwhile, cleaning hands, using gloves, and donning protective clothes are ways that humans can prevent the transmission of LA-MRSA when handling horses. This review will explain the definition of LA-MRSA in general, LA-MRSA in horses, the epi­demiology of LA-MRSA in horses, the diagnosis of LA-MRSA in horses, the transmission of LA-MRSA in horses, risk factors for spreading LA-MRSA in horses, public health impact, treatment of LA-MRSA infection in horses, and control of the spread of LA-MRSA in horses.

Associative parasitoses of the gastrointestinal tract of horses and assessment of anti-parasitic drugs efficiency

Invasive diseases of horses are an urgent problem in the horse breeding industry of the Republic of Belarus, as well as in the near and far abroad countries. The main role among the parasitic pathology is occupied by helminths of the small and large intestine, as well as larvae of gasterophilus. In associative course, they are the cause of significant economic losses associated with the growth and development of sick young animals, reduced performance, endurance of animals, increased susceptibility to other diseases, and even the death of animals. Planned therapeutic and preventive measures using broad-spectrum anthelmintics is a priority measure to reduce economic damage in development of the horse breeding industry. The paper provides data on spread of parasitoses of gastrointestinal tract in horses in the Republic of Belarus during period of 2004-2020. The paper presents the species composition of horse parasites localized in the stomach, small and large intestines. Data on extensiveness and intensity of invasions of horses by parasitocenosis of digestive tract in terms of age are presented. Therapeutic efficiency of antiparasitic drugs of various pharmacological groups in mono- and polyinfestations of gastrointestinal tract of horses are studied. High extensibility of Avermectin series preparations (Avermectin paste 1 %, Rivertin 1 %) has been determined for nematodes of gastrointestinal tract of horses and gastrointestinal disease. High efficiency has been obtained from a new complex antiparasitic preparation for horses “Prazimax” in mono- and polyinfestations caused by parasites of gastrointestinal tract, including nematodes of the small and large intestines, larvae of gasterophilus and Anoplocephala perfoliata cestodes. Data on spread of associative course of parasitocenoses of the digestive tract of horses, age and seasonal dynamics will allow veterinary specialists to make timely diagnosis, conduct differential diagnostics, determine the optimal timing of diagnostic, therapeutic and preventive treatments, taking into account the specifics of parasitocenosis.

Comparison of gastrointestinal transit times in stabled Thoroughbred horses fed freshly cut pasture and three conserved forage-based diets

Context The type of forage offered to horses varies in physical form, moisture content and nutrient quality, and these variables could affect the intake, passage rate and digestibility of the forage consumed. Aims To investigate the changes in passage rate of digesta through the gastrointestinal tract in horses fed four different forage-based diets (diet effect). Methods Thoroughbred mares (n = 6) were stabled in loose boxes for 6 weeks. During Weeks 1, 3 and 5 (washout periods), all horses were fed freshly cut pasture, either in restricted quantities (Week 1) or ad libitum (Weeks 3 and 5). Using a 3 × 3 Latin square design during Weeks 2, 4 and 6, each pair of horses was abruptly transitioned to one of three conserved forage-based diets (chopped ensiled forage fed exclusively or with oats, or perennial ryegrass hay with oats) fed ad libitum. At the beginning of each week, indigestible polyethylene markers (n = 200) were administered to the horses via a nasogastric tube, followed immediately by transition to the new diet. Key results There was a significant diet effect on the daily dry-matter intake of feed (P < 0.0001), percentage of time spent eating (P < 0.001), frequency of voiding faeces (P < 0.05) and quantity of faeces voided (P < 0.0001). There was a significant horse effect on the daily dry-matter intake of feed (P < 0.0001) and quantity of faeces voided (P < 0.0001), but no differences in the percentage of time spent eating or the frequency of voiding faeces. There were significant diet and horse effects on the time to recovery of the first marker in the faeces (P < 0.01 and P < 0.01 respectively) and the mean retention time of markers in the gastrointestinal tract (P < 0.05 and P < 0.001 respectively). Mean retention time was negatively correlated with feed intake and quantity of faeces voided (r2 = –0.51 and r2 = –0.64 respectively). Conclusions Longer mean retention time was associated with a greater fibre content in the diet and a restricted feed supply, thus supporting the hypothesis that horses alter mean retention time on the basis of a nutrient absorption optimisation model. Implications Feed composition, but also the quantities offered, may alter measurement of apparent feed digestibility in horses.

Ex vivo comparison of ultrasonographic intestinal wall layering with histology in horses: A feasibilty study.

Ultrasonography is increasingly being used as a clinical and research method for evaluating the gastrointestinal tract in horses, however published studies comparing ultrasonographic and histologic characteristics of equine intestinal wall layers are currently lacking. Objectives of this prospective, observational, methods comparison, case series study were to compare the layering pattern and thickness of the intestinal wall layers determined using ex vivo and in vivo ultrasonography with those determined using histology. For the ex vivo study, twelve horses were euthanized for reasons unrelated to gastrointestinal disease, and samples of the duodenum, jejunum, ileum, cecum, right dorsal colon, and small colon were collected and imaged sonographically ex vivo in an isotonic bath within 1hour of euthanasia. For the in vivo study, ultrasonography was performed in four clinical cases, and findings were compared with histopathology. A 5-layer pattern of alternating echogenicity was observed in 70 of 72 ex vivo samples. Agreement between histologic and sonographic measurements was deemed good for all segments except the ileum. Formalin fixation did not alter the sonographic appearance or wall measurements. Findings from the four clinical cases illustrated the feasibility of also obtaining ultrasonographic images with sufficient sonographic detail in vivo to recognize wall layering and obtain comparable results to pathologic lesions. Findings from the current study can serve as background for future studies comparing ultrasonographic characteristics of the intestinal wall in horses with different gastrointestinal diseases.

Estimation of Nitrite-Nitric Oxide Derivative-In Horses with Intestinal Colic by ESR Spectroscopy.

Diseases of the gastrointestinal tract of horses are caused by many factors and have a complex pathogenesis. Developing effective methods of differential diagnostics is of high fundamental and applied importance. The pathogenesis of diseases of the digestive tract of horses accompanied by the development of inflammation and oxidative stress, can be associated with a lack of the nitrogen monoxide which controls many signaling pathways in the body. The level of the nitric oxide (NO) is involved in the regulation of the immune and nervous systems, the tone of all the blood vessels, and the courses of many pathological processes. The nitric oxide activates guanylate cyclase (sGC) and leads to vascular relaxation. The aim of this investigation was to study the metabolites of nitric oxide in horses suffered from intestinal diseases. The levels of nitric oxide in the blood serum of horses depending on their age and health state was studied. The concentration of nitrites in the blood serum of horses aged 6–25 years was 3.4 ± 4.2 μM, and in the young horses (1–5 years) the level of this indicator was 8.2 ± 5.4 μM. A sharp decrease in nitrite was observed in all the horses with intestinal diseases of 2 ± 0.9 μM, especially with tympanitic caecun of 0.6 ± 0.4 μM and with spasmodic colic of 1.8 ± 0.5 μM. The level of nitrosylhemoglobin HbNO in the blood of the diseased animals was higher than that in clinically healthy horses, regardless of age.

Reduced Nitric Oxide Bioavailability in Horses with Colic: Evaluation by ESR Spectroscopy

The pathogenesis of diseases of the gastrointestinal tract in horses is accompanied by inflammation and oxidative stress and may be caused by a lack of nitric oxide, which controls various signaling pathways in the body. The level of nitrites, which are metabolites of nitric oxide in horses with various intestinal diseases, has been evaluated in blood serum at 3.60 ± 3.02 μM and 8.3 ± 6.0 μM in horses at ages of 7–26 years and 1–5 years, respectively. A sharp reduction in the nitrite concentrations was observed in all horses with intestinal diseases (3.39 ± 2.85 μM), especially in horses with tympanitic caecum (0.6 ± 0.4 μM) and obstruction of the colon (0.81 ± 0.5 μM).

SOME ASPECTS OF EPIZOOTOLOGY OF EQUID STRONGYLATOSIS IN THE NOVOSIBIRSK REGION

The aim of the research was to study the invasiveness of horses with strongylates of the gastrointestinal tract in the Novosibirsk Region. Diagnostic methods generally accepted in helminthology were used in the work, such as the helminthovoscopic flotation method by Fulleborn and the helmintholarvoscopic method by BermanOrlov. Material for our study, namely, feaces samples, were collected at the farms of certain districts of the Novosibirsk Region and private sports stables in Novosibirsk which differ in the technology of keeping horses. The wide distribution of equid helminthiases has been established. The variety of helminths in the gastrointestinal tract of horses is represented by helminths of the Nematoda class, which includes 2 suborders – Strongylata (families Trichonematidae and Strongylidae) and Ascaridata (Parascaris equorum). Parasitoses in horses of the stable and stablepasture management occur in the form of mixtinvasions with strongylates prevailing; Parascaris equorum act as subdominants. The average number of animals infected with strongylates at the farms of the Novosibirsk Region where the stable and pasture maintenance of horses is practiced amounted to 74.9%, respectively, with an average number of eggs 739.9 per gram of feces. In urban conditions, the invasiveness of horses by strongylates is 2 times lower and recorded at 33.3%. Trichonematids are the basis of the strongylate community, however, the infection rate of one-hoofed animals in Novosibirsk is also 2 times lower than at the farms of the Novosibirsk Region and amounts to 25.8%.

Традиционные способы киргизского народа по диагностике и лечению колик у лошадей

Abstract. The purpose of research is the collection and analysis of traditional methods of the Kyrgyz people for the diagnosis and treatment of horse colic from the point of view of scientific veterinary medicine. In the study, methods of observation, interrogation of veterinary specialists and horse breeders were used. A total of 55 carriers of traditional veterinary knowledge were interviewed. The studies were conducted in the pastoral areas of the Kyrgyz Republic, where horse breeding in conditions of year-round grazing, with the preferential using of productive herd technology is mainly used. According to the data of the National Statistical Committee of the Kyrgyz Republic as of 01.01.2020, the total number of horses is 522.6 thousand heads. Results. It has been established that: in the traditional veterinary medicine of the Kyrgyz people, horses were diagnosed with urinary colic – tuttukma (in Kyrgyz), overfeeding – zhem zhatalak (in Kyrgyz), blockage – zhin zhatalak (in Kyrgyz), colic from cold water – suu zhatalak (in Kyrgyz), mechanical intestinal obstruction – sezgenich zhatalak (in Kyrgyz), intestinal flatulence – tүynөk zhatalak (in Kyrgyz); in the diagnosis of horse colic, anamnesis collection methods, observation, rectal examination and auscultation of the abdominal cavity were used. When treating horse colic, Kyrgyz folk veterinary medicine used mechanotherapy methods and medicinal plants, as well as diet and exercise. Our results and their comparison with the data of scientific veterinary medicine confirm that Kyrgyz folk methods for diagnosing and treating colic in horses are in tune with modern algorithms and tactics for diagnosing and treating diseases of the gastrointestinal tract in horses, accompanied by a symptom complex of colic. Scientific novelty. In the conditions of year-round grazing of horses in the Kyrgyz Republic, types of colic were determined, methods for diagnosing and treating diseases of the gastrointestinal tract in horses, accompanied by a symptom complex of colic, were clarified.

Epidemiological and pathological aspects of noninfectious diseases of the gastrointestinal tract in 114 horses in Southern Brazil

ABSTRACT: Equine colic is one of the most common cause of death in horses, but few studies have investigated specifically the conditions at the necropsy. This study aimed to describe the epidemiological and pathological features of noninfectious diseases of the gastrointestinal tract in horses. A retrospective study was conducted in search of cases of these diseases affecting horses from 2005 to 2017. During this period, 114 horses died of noninfectious diseases of the gastrointestinal tract, and the main causes were: primary gastric dilation (27/114), volvulus (27/114), enterolithiasis (20/114), rectal (colonic) perforation (15/114), gastric or cecocolonic impaction (10/114), incarcerations (6/114), intussusception (4/114), and others (5/114). Mixed breeds horses (56/114) and males (69/114) were mostly affected. The horses had a median and mean age of 10 and 10.9-years old, respectively. Primary gastric dilation was characterized by distension of the stomach by moderate to large amounts of content, which in 21 cases caused tearing of the stomach wall at the greater curvature (peritonitis), and the main predisposing factor was alimentary overload (17/27). Intestinal volvulus occurred within the small intestine (14 cases) and within the large intestines (13 cases). Grossly, there was intestinal ischemia with reddened to deep-black serosa and diffusely red mucosae. Enterolithiasis caused partial or complete obstruction of the right dorsal colon (9/20), transverse colon (4/20), small colon and right dorsal colon (3/20), rectum and right dorsal colon (2/20), and small colon (2/20). Viscera perforation and peritonitis occurred in 11 cases. Rectal (colonic) perforation involved the rectum (10/15), rectum/small colon (4/15), and the small colon (1/15). It was characterized by a focally extensive transmural tearing, associated with reddened borders, and retroperitoneal to diffuse peritonitis. Palpation related iatrogenic injuries (11/15) were the main cause. Impactions affected the large colon (7/10), the cecum (2/10), and the stomach (1/10). Incarcerations consisted of inguinoscrotal hernias (2/6), small intestine entrapment by a mesenteric failure (2/6), diaphragmatic hernia, and umbilical eventration. Grossly, the organs were constricted by a hernial ring, with intestinal ischemia and reddened to dark-red serosa. Predisposing factors included previous surgeries (2/6) and patent inguinal ring (1/6). Intussusception involved the small intestine (3/4) and ileocecum (1/4). Foals with lack of colostrum intake and concomitant pneumonia was a characteristic presentation (3/4). Grossly, the intussusceptum slipped into intussuscipiens, with diffuse deep black-red discoloration. Other causes included large colon displacement (2/5), extrinsic and intrinsic obstruction of the small intestine (2/5), and an intestinal adenocarcinoma. Noninfectious gastrointestinal diseases are major causes of death in horses. Epidemiological and gross features of the conditions should be accounted to obtain a final diagnosis of the cause of the colic.

Guanylin, Uroguanylin and Guanylate Cyclase-C Are Expressed in the Gastrointestinal Tract of Horses.

Guanylate cyclase-C (GC-C) is a multifunctional receptor encoded by the GUCY2C gene, representing an attractive target for therapy in several gastrointestinal diseases in humans. Little is known about this system in horses. We investigated for the first time the gene expression of guanylin, uroguanylin and GC-C receptors in different horse’s gastrointestinal tracts. Tissue samples from stomach, duodenum, jejunum, ileum, head and body of cecum, left and right dorsal colon, left and right ventral colon, pelvic flexure, transverse colon, descending colon and rectum were collected from adult horses within 1 h post mortem. For each sample, total RNA was extracted from 100 mg of ground tissue, and qRT-PCR performed on GUCA2a, GUCA2b and GUCY2 transcripts on a CFX96 Touch instrument. Data analysis was carried out with Bio-Rad CFX Manager software, and genes of interest normalized relative to the abundance of the two reference genes (SDHA, HPRT). Additionally, the protein expression levels of GC-C receptor were analyzed through western blotting. A common pattern of expression throughout the gastrointestinal lumen for all three investigated transcripts was found. The expression of GUCA2a, GUCA2b and GUCY2 genes was higher in jejunum, ileum, descending colon and rectum. The levels of expression of GC-C protein confirmed these data. The findings of this study might open new scenarios for the therapeutic approach to enteric diseases of horse using selective agonists of GC-C.

Isolation and identification of cellulolytic bacteria from gastrointestinal tract of Arabian horse and investigation of their effect on the nutritional value of wheat straw.

This study was conducted to isolate and identify the cellulolytic bacteria from gastrointestinal tract of Arabian horse and investigate their effect on the nutritional value of wheat straw (WS). Fresh faeces were collected from four Arabian horses. The cellulose-hydrolytic bacteria were isolated by using a medium amended with carboxymethyl cellulose (CMC). The activity of CMC was determined by measuring the release of reducing sugars from CMC. Among the isolates, four isolates (L11, L12, L2 and Z2) showed maximum hydrolysis capacity. 16S rRNA sequence analysis showed that these isolates possessed 99, 99, 99 and 98% similarity with Paenibacillus polymyxa, Paenibacillus polymyxa, Enterobacter cloacae and Escherichia coli respectively. Wheat straw was incubated with the isolated bacteria in liquid medium. Disappeared dry matter (DM) and crude protein (CP), neutral detergent fibre (NDF), indigestible NDF (iNDF) and acid detergent fibre (ADF) contents of WS were affected by microbial treatments (P<0·05). The highest disappearance of DM and CP contents and the lowest NDF, iNDF and ADF contents of WS were observed by treating with P. polymyxa L11. The values of NDF, iNDF and ADF were the highest and CP was the lowest in control. Gas production parameters and digestibility of processed samples were determined. Bacterial treatments enhanced (P<0·05) DM, OM, CP, NDF and ADF digestibility of WS. The highest and lowest (P<0·05) DM, OM, CP, NDF and ADF digestibilities were observed for WS treated with isolates L12 and control respectively. Potential of gas production (b), truly degraded organic matter (TDOM) and microbial biomass of bacteria treatments were significantly higher (P<0·05) compared to control. Generally, the results of this study showed that the isolated bacteria from horse faeces are capable of changing the chemical composition, increasing digestibility as well as enhancing nutrition value of WS. Wheat straw is a major agro-residue fed to ruminants. However, high fibre contents reduce digestibility and limit animal productivity. It seems that enhancement of ruminal degradation of these by-products is necessary. The results of this study revealed that cellulolytic bacteria isolated from gastrointestinal tract of horse can be used for biological treatment of WS.

Gastrointestinal effects of general anaesthesia in horses undergoing non abdominal surgery: focus on the clinical parameters and ultrasonographic images

The ultrasonographic images of the gastrointestinal tract in horses can be influenced by fasting and sedation but the proper effect of general anaesthesia (GA) on them has not been determined yet. This study aimed to evaluate the effects of GA on ultrasonographic images of the gastrointestinal tract in horses and to compare these effects with a clinical evaluation. Twenty horses undergoing non-abdominal surgeries were evaluated by ultrasonography before and 4 times within 24 h after GA. Each ultrasonographic exam focused on the stomach, the duodenum and on 5 locations on the jejunum. The four-quadrant auscultation and the postoperative faecal output were also recorded. Pre and post anaesthetic values were compared using linear mixed effects models. None of the horses presented colic signs or reduced faecal output. During the first 2 post anaesthetic evaluations, the gut sounds were significantly decreased and, when taking all jejunal locations together, the jejunal diameter and visualisation frequency significantly increased. No intestinal loop appeared thickened and most of their diameters remained within the normal range. Our results suggest that the effects of GA on the ultrasonographic images of the small intestine are mild and of short duration and can therefore be differentiated from a pathological process.

Adhesion of Lactobacillus reuteri strain Lr1 to equine epithelial cells and competitive exclusion of Clostridium difficile from the gastro-intestinal tract of horses

Lactobacillus reuteri Lr1, isolated from healthy horses, remained viable after 2 h at pH 2.0 and in the presence of 1.5 % (w/v) bile. Strain Lr1 survived passage through the equine gastro-intestinal tract (GIT). However, no viable cells of L. reuteri Lr1 were detected on the third day after administration, suggesting that the strain did not colonise the GIT for longer than two days. Strain Lr1 adhered to non-viable, but not to viable, buccal epithelial cells in vitro. Adherence of strain Lr1 to buccal epithelial cells increased 25 % after treatment of the bacterial cells with pepsin. Treatment with pronase prevented the adhesion to epithelial cells. This suggested that specific proteins on the cell surface of L. reuteri Lr1 are involved in adhesion to epithelial cells. Strain Lr1 aggregated with Clostridium difficile C6, isolated from the GIT of a horse that died from severe colic. Adherence of C. difficile C6 to epithelial cells declined from 60 % to 3 % when challenged with L. reuteri Lr1 and the number of viable clostridia decreased tenfold during dosage. Red blood cell, haemoglobin and haemocrit levels were significantly (P ≤ 0.05) lower after dosage with L. reuteri Lr1. Cholesterol and glucose levels were mildly elevated for one day during dosage, but decreased significantly thereafter to levels similar than before dosage. Genes encoding adhesion to collagen, production of aggregation substances, cytolysin and β hemolysin III, resistance to vancomycin A, B and C, and gelatinase activity were not detected, suggesting that L. reuteri Lr1 is a potential probiotic that may be used to control C. difficile cell numbers in the GIT.

Coadministration of sodium alginate pellets containing the fungi Duddingtonia flagrans and Monacrosporium thaumasium on cyathostomin infective larvae after passing through the gastrointestinal tract of horses

The predatory nematophagous fungi have been used as an alternative control of gastrointestinal nematodes of domestic animals in natural and laboratory conditions. However, it is unclear if the association of some of these species could bring some kind of advantage, from a biological standpoint. In this context, this study consisted of two tests in vitro: in assay A, the assessment of the viability of the association of pellets in sodium alginate matrix containing the fungus Duddingtonia flagrans (AC001) and Monacrosporium thaumasium (NF34) and its predatory activity on infective larvae (L3) of cyathostomin after passing through the gastrointestinal tract of horses and assay B, assessment of the cyathostomin L3 reduction percentage in coprocultures. Twelve crossbred horses, females, with a mean weight of 356kg and previously dewormed were divided in three groups with four animals each: group 1, each animal received 50g of pellets containing mycelial mass of the fungus D. flagrans and 50g of pellets of the fungus M. thaumasium, associated and in a single oral dose; group 2, 100g of pellets containing D. flagrans and 100g of pellets containing M. thaumasium, associated and in a single oral dose; group 3, control. Faecal samples were collected from animals in the treated and control groups at time intervals of 12, 24, 36, 48, 60 and 72h after the administration of treatments and placed in Petri dishes containing 2% water-agar (assay A) and cups for coprocultures (assay B). Subsequently, 1000 cyathostomin L3 were added to each Petri dish (assay A) and 1000 cyathostomin eggs were added to each coproculture (assay B) of fungi-treated and control groups. At the end of 15days, there was observed that the two associations of pellets containing the fungi tested showed predatory activity after passing through the gastrointestinal tract of horses (assay A). In assay B, all the intervals studied showed reduction rate in the number of L3 recovered from coprocultures exceeding 80%. However, no difference (p>0.01) was seen in recovery of not predated L3 between the fungi-treated groups in the time intervals studied. The results obtained showed that the associations of pellets (50 or 100g of each fungal isolate) were viable after passage through the gastrointestinal tract in horses and could be used in natural conditions.

Saccharomyces boulardii viability and efficacy in horses with antimicrobial-induced diarrhoea

Saccharomyces boulardii has been successfully used in the prevention and treatment of antimicrobial-associated diarrhoea in humans. We hypothesised that a viable, dried lyophilised preparation of S boulardii would survive in...

Expression of pleiotrophin, an important regulator of cell migration, is inhibited in intestinal epithelial cells by treatment with non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most widely used drugs for the suppression of inflammation and pain. However, the analgesic properties of NSAIDs are also associated with significant negative side effects, most notably in the gastrointestinal (GI) tract. Increasingly, evidence indicates that the ulcerogenic properties of some NSAIDs are not exclusively the result of inhibition of cyclooxygenase isoforms in the GI tract, and other mechanisms, including inhibition of cell migration and epithelial restitution, are being explored. Recently, microarray analysis was used to identify potential novel targets of NSAID activity in intestinal epithelial cells. Treated cells exhibited significant reductions in the gene expression of pleiotrophin (PTN), a cytokine and growth factor known to participate in angiogenesis and bone growth. This report aimed to confirm the microarray results reported previously, and to measure protein expression of PTN in intestinal epithelial cells. Furthermore, we also examined the effects of exogenous PTN on cell migration in the presence and absence of either NSAIDs with variable ulcerogenic potential or PTN-specific siRNA. Our results demonstrated that indomethacin and NS-398, two NSAIDs with ulcerogenic potential significantly decrease both gene and protein expressions of PTN in IEC-6 cells and protein expression in IEC-6-Cdx2 cells. Additionally, cell migration experiments with PTN siRNA showed that PTN is an important mediator of IEC-6 cell migration, and addition of exogenous PTN partially restores the deficits in cell migration caused by treatment with indomethacin and NS-398. Finally, measurement of PTN protein expression in the GI tract of horses treated with phenylbutazone showed that PTN expression is reduced by NSAIDs in vivo. Our results show that PTN is an important mediator of cell migration in IEC-6 cells, and PTN is a potential target through which NSAIDs may inhibit cell migration, epithelial restitution, and wound healing in the GI tract.

Viability of the nematophagous fungus Pochonia chlamydosporia after passage through the gastrointestinal tract of horses

The predatory capacity of the nematophagous fungus Pochonia chlamydosporia (isolate VC4) embedded in sodium alginate pellets after passage through the gastrointestinal tract of horses was assessed in vitro against Oxyuris equi eggs. Twelve previously dewormed crossbred mares, average weight of 362.5 kg (±21) were used in the experiment. Each animal of the treated group received an oral dose (100 g) of sodium alginate pellets containing P. chlamydosporia mycelial mass. The control group received pellets without fungus. Faecal samples from fungus-treated and control groups were collected at intervals of 8, 12, 24, 36, 48 and 72 h after pellet administration and placed in Petri dishes containing 2% water-agar. One thousand eggs of O. equi were plated in Petri dishes of both treated and control groups, with six replicates, and incubated in oven, 25 °C, in the dark, for 30 days. At the end of the experiment, one hundred eggs were removed from each Petri dish and classified according to the following parameters: type 1, physiological and biochemical effect without morphological damage to eggshell, with hyphae adhered to the shell; type 2, lytic effect with morphological change in the eggshell and embryo without hyphal penetration, and type 3, lytic effect with morphological change in the eggshell and embryo, with hyphal penetration and internal egg colonization. Chlamydospore production was observed in Petri dishes of the treated group. The isolate VC4 remained viable after passing through the gastrointestinal tract of horses and maintained the ovicidal activity against O. equi eggs when compared with the control group ( p < 0.01) after each collection interval: 29.1% (8 h), 28.2% (12 h), 31.1% (24 h), 27.4% (36 h), 30.9% (48 h) and 28.4% (72 h). The results suggest that P. chlamydosporia could be used as an effective biological control agent of O. equi eggs in natural conditions.

Mucosal distribution of eosinophilic granulocytes within the gastrointestinal tract of horses

To establish reference values for the range of the number of eosinophils found in equine gastrointestinal mucosa and to describe the distribution of this cell within the equine gastrointestinal mucosa. Gastrointestinal mucosal specimens from 14 adult horses euthanatized for reasons other than gastrointestinal disease. Gastrointestinal mucosal specimens were collected and grouped according to their anatomic regions. For histologic examination slides were stained with Luna's eosinophil stain to determine eosinophil accumulation and distribution. The mucosa was divided into 5 sections for each anatomic location, and the percentage of eosinophils in each of the 5 sections relative to the total eosinophil count in all sections was determined. Additionally, the number of eosinophils per square millimeter of mucosa was calculated as a measure of the degree of eosinophil accumulation. Lowest numbers of eosinophils were found in the stomach, and numbers increased from there to the cecum, then decreased from the ascending colon (right ventral colon, left ventral colon, pelvic flexure, left dorsal colon, and right dorsal colon) to small colon. In all gastrointestinal sections, most eosinophils were located near the muscularis mucosae and were rarely found near or on the luminal surface of the mucosa. The distribution of eosinophils in the gastrointestinal tract of horses followed a pattern within the mucosa and between different sections of the gastrointestinal tract. The derived reference values and distribution data could be used to detect changes in eosinophil response in the equine gastrointestinal mucosa caused by diseases states.

Preliminary study of mucosal IgA in the equine small intestine: specific IgA in cases of acute grass sickness and controls

There is much evidence to suggest that group III Clostridium botulinum (types C and D) are involved in the aetiology of equine grass sickness (EGS). Antibodies have been detected previously in the blood and high levels associated with resistance to disease. Specific mucosal antibodies in the gastrointestinal (GI) tract are likely to be important in protection, and this study was performed to ascertain if such antibodies could be detected and if their levels were related to disease state. To develop a method for quantifying IgA antibodies to C. botulinum types C and D in the GI tract of horses and to relate antibody levels to disease status. Samples of tissue (n = 25: 6 duodenum, 7 jejunum and 12 ileum) were taken from acute grass sickness (AGS) cases and from control horses (n = 12; 4 samples from each site) at post mortem. They were extracted with the detergent saponin in the presence of protease inhibitors and assayed for total IgA, for specific IgA against botulinum neurotoxins types C and D (BoNT/C or BoNT/D), and against surface antigens of a BoNT/C negative strain of C. botulinum type C (SA) and of Clostridium tetani (TetSA), as a control. Specific IgA was expressed as percentage total IgA. Compared to controls, significantly higher levels of specific IgA against BoNT/C were detected in the jejunum (P = 0.04) and ileum (P = 0.02) of AGS cases. Similarly, higher specific levels against BoNT/D were demonstrated in duodenum (P = 0.01) and jejunum (P = 0.02). Significantly higher levels of IgA against SA were demonstrated only in duodenal samples (P = 0.01). Levels of IgA antibody to BoNTs in control horses were at near undetectable levels, suggesting no recent exposure to toxins. In AGS cases, significantly higher levels of specific IgA were detected predominantly in jejunum and ileum. If specific IgA is protective then any successful vaccine for EGS should induce a mucosal response.