Effects of processing barley on its digestion by horses

Four horses were randomly fed a diet containing rolled, micronised or extruded barley; the barley intake was adjusted to supply 2 g starch/kg bodyweight per day. During a 10-day acclimatisation period the horses were also fed 1 kg grass hay/100 kg bodyweight per day. Samples of blood and breath were collected at the end of each period after the test meal of barley had been fed after a 12-hour overnight fast. The glycaemic and insulinaemic responses of the horses were measured as an indication of the pre-caecal digestibility of starch, and postprandial breath hydrogen and methane were measured to detect microbial fermentation of starch. The highest peak serum glucose and serum insulin concentrations were observed after feeding the extruded barley, lower concentrations were observed after feeding the micronised barley and the lowest concentrations were observed after feeding the rolled barley. Breath hydrogen increased within four hours of feeding all the barley diets, and the mean (sd) peak hydrogen concentrations were 98.3 (55.2) ppm for rolled barley, 59.3 (31.5) ppm for micronised barley and 96.1 (51.9) ppm for extruded barley. There were wide variations within individual horses but these concentrations were not significantly different. Breath methane concentrations were very variable and, although there were no significant differences, there was a trend for higher methane concentrations after the feeding of rolled barley.     

Reducing the dilution of breath samples for breath hydrogen testing

Breath hydrogen testing has a diagnostic potential as a gastrointestinal function test that could be performed in general practice. The purpose of this study was to improve techniques for collection of breath samples and transfer of samples to transport vessels. Breath samples from 10 dogs were collected using both a snug-fitting and a loose-fitting standard anesthetic mask attached to a reservoir bag, and a modified snug-fitting system. CO₂ was used as internal standard and mean CO₂ concentrations were 1.19 ± 0.76, 2.17 ± 0.66 and 2.68 ± 0.92, respectively. Additional samples were saved in transport tubes for 19 days, during which the hydrogen and carbon dioxide concentrations remained stable. A reliable method for transferring the breath samples from the reservoir bag to vacuum transport tubes was also identified. Our results demonstrate less contamination of breath samples with air than previously reported, and a reproducible method to transfer breath samples to transport vessels.     

Evaluation of carbohydrate malassimilation and intestinal transit time in cats by measurement of breath hydrogen excretion

Techniques for the measurement of breath hydrogen excretion have been evaluated in dogs and the breath hydrogen test has been shown to be useful for clinical diagnosis and as a research tool. A simple method was developed for collection of expired air and measurement of breath hydrogen concentrations in cats, which enabled demonstration of carbohydrate malassimilation. Breath hydrogen concentrations were measured in healthy cats after food was withheld and after xylose and lactulose administration. Breath samples were collected by use of an open flow system with the cat confined in an acrylic plastic chamber. Breath hydrogen excretion did not exceed 0.53 ml of hydrogen/h in cats not fed. Breath hydrogen concentrations after the ingestion of xylose, a pentose sugar given orally at 0.75 g/kg of body weight, were not significantly higher from those of cats not fed. After ingestion of 3.35 g of lactulose, a nonabsorbable disaccharide, breath hydrogen excretion increased and breath hydrogen concentrations were significantly higher by 45 minutes (P less than 0.05) and 60 minutes (P less than 0.01) from breath hydrogen concentrations measured in cats not fed and after xylose administration. Administration of lactulose at an increased dosage resulted in further significant (P less than 0.01) increases in breath hydrogen excretion. In this study, mouth-to-cecum transit times were variable. A mean +/- SEM mouth-to-cecum transit time of 86 +/- 6 minutes was calculated from measurement of breath hydrogen excretion after oral administration of 3.35 g of lactulose.(ABSTRACT TRUNCATED AT 250 WORDS)     

Current and future uses of breath analysis as a diagnostic tool

The analysis of exhaled breath is a potentially useful method for application in veterinary diagnostics. Breath samples can be easily collected from animals by means of a face mask or collection chamber with minimal disturbance to the animal. After the administration of a 13C-labelled compound the recovery of 13C in breath can be used to investigate gastrointestinal and digestive functions. Exhaled hydrogen can be used to assess orocaecal transit time and malabsorption, and exhaled nitric oxide, carbon monoxide and pentane can be used to assess oxidative stress and inflammation. The analysis of compounds dissolved in the aqueous phase of breath (the exhaled breath condensate) can be used to assess airway inflammation. This review summarises the current status of breath analysis in veterinary medicine, and analyses its potential for assessing animal health and disease.     

Breath hydrogen concentration and small intestinal malabsorption in calves

Breath hydrogen concentrations were measured to assess intestinal carbohydrate malabsorption in preruminating calves. Oral administration of 1.25 g of lactulose (a nonabsorbable carbohydrate)/kg to calves produced breath hydrogen concentrations significantly (P less than 0.001) higher than values determined after calves were fed milk and before the treatment was given. This indicates that, in the calf, fermentation of nonabsorbed carbohydrates results in increased breath hydrogen values. To induce small intestinal malabsorption, chloramphenicol was administered orally at 50 mg/kg, 2 times a day, to 5 calves for 3 days. Before therapy was started, each calf was fitted with a duodenal cannula to facilitate collection of intestinal mucosal biopsy samples during treatment. Chloramphenicol therapy significantly (P less than 0.001) increased breath hydrogen concentrations from those values measured after calves were fed milk alone. Concurrently, chloramphenicol administration significantly decreased intestinal villous length (P less than 0.001) and D-xylose absorption (P less than 0.05), compared with those values before treatment was given. These results demonstrate that decreased intestinal absorptive capacity is associated with an increase in breath hydrogen concentrations and that breath hydrogen may be useful in evaluating malabsorption in calves with naturally occurring enteric disease.     

Determination of lactose and xylose malabsorption in preruminant diarrheic calves.

In preliminary studies feeding the poorly absorbed carbohydrate sorbitol at 2.3 g/kg body weight as an indication of maximal fermentative capacity failed to produce the expected large increase in breath hydrogen excretion but did produce a transient diarrhea in five out of six control calves. Twelve healthy control and eighteen diarrheic calves were fed lactose or D-xylose on consecutive days at 1.15 g/kg body weight and a concentration of 46 g/L. Breath and blood samples were collected at 1 h intervals from 0 to 7 h. After administration of lactose, there was a significant increase in breath hydrogen excretion in diarrheic versus control calves. The increase in plasma glucose concentrations was delayed in diarrheic calves but the area under the absorption curve was similar in control and diarrheic calves. After administration of D-xylose, breath hydrogen excretion did not increase significantly but plasma D-xylose concentrations were significantly reduced in diarrheic calves. The pathogens commonly isolated from the feces were Cryptosporidium species, rotavirus and coronavirus. The number of pathogens and the severity of the calves' acid-base deficit were not related to the severity of carbohydrate malabsorption. Decreased absorption of lactose and D-xylose may be the result of intestinal villous atrophy caused by viral or parasite infection. It was concluded that carbohydrate malabsorption rather than a specific lactose maldigestion is a significant problem in diarrheic calves. Diarrheic calves appear to digest and absorb lactose when fed in small amounts.     

Evaluation of intestinal carbohydrate malabsorption in the dog by pulmonary hydrogen gas excretion

Breath H2 was measured for the assessment of intestinal carbohydrate absorption in healthy, fasted dogs before and after the ingestion of carbohydrate test meals. The dogs were fed lactulose, xylose, glucose, a hypoallergenic diet, or the hypoallergenic diet supplemented with rice, corn, or wheat flour. Breath samples for H2 analysis were collected by an interval-sampling technique during tidal breathing and were analyzed by thermal conductivity gas chromatography. Pulmonary H2 excretion in fasted dogs never exceeded 1 part per million (molecules of H2 per 10(6) molecules of air). Breath H2 excretion after the ingestion of 12.5 g of glucose, a completely absorbed monosaccharide, was not significantly different (P greater than 0.05) from that during fasting; however, ingestion of 12.5 g of xylose, an incompletely absorbed pentose, significantly increased (P less than 0.001) breath H2 excretion. After ingestion of 12.5, 25, or 50 g of lactulose, a nonabsorbable disaccharide, pulmonary H2 excretion increased significantly (P less than 0.001) over fasting amounts and the increases were different (P less than 0.001) from one another. Increases in breath H2 excretion correlated (r = 0.97) with increases in lactulose dose. Breath H2 excretion after the ingestion of the hypoallergenic diet did not significantly (P greater than 0.05) differ from that after fasting. The addition of rice flour to this diet did not significantly (P greater than 0.05) increase H2 production. However, the addition of wheat or corn flour to this diet significantly (P less than 0.001) increased breath H2 excretion.(ABSTRACT TRUNCATED AT 250 WORDS)     

The(13)C-octanoic acid breath test for detection of effects of meal composition on the rate of solid-phase gastric emptying in ponies

The aim of this study was to apply the(13)C-octanoic acid breath test for detection of alterations in the rate of solid-phase gastric emptying, induced by changes in test meal composition, in ponies. After a 14 hour fast the ponies (n = 4) ingested a test meal with 0, 35 or 70 ml soya oil, and labelled with 250 mg(13)C-octanoic acid. Each pony was given each of the three test meals on three separate occasions, in a randomised order. Exhaled breath samples were collected for 12 hours after ingestion of the test meal. Breath samples were analysed by continuous flow isotope ratio mass spectrometry. Three indices of breath(13)C-enrichment were computed, half-dose recovery time (t 1/2), gastric emptying coefficient (GEC) and time to peak breath(13)C-excretion t(max). The(13)C-octanoic acid breath test was a reliable means of assessing the significantly decreased rate of gastric emptying in the pony, associated with addition of soya oil to the test meal.     

The effect of mixing and changing the order of feeding oats and chopped alfalfa to horses on: glycaemic and insulinaemic responses, and breath hydrogen and methane production

The aim of this study was to investigate the effects of feeding oats alone before or after feeding chopped alfalfa or, in admixture with the alfalfa on the glycaemic and insulinaemic responses of horses as well as post-prandial breath hydrogen and methane excretion. Horses were fed in a randomized order, chopped alfalfa as a source of dietary fibre and unprocessed oats as a source of starch. Chopped alfalfa intake was adjusted to a crude fibre intake of 0.5 g/kg bodyweight (BW) per meal and the oats intake was adjusted to a starch intake of 2 g/kg BW per meal. The feeds were offered in three different ways: (i) alfalfa followed by oats (A/O), (ii) oats followed by alfalfa (O/A) or (iii) a mixture of alfalfa and oats (A + O). Oats alone were used as a control. Blood and breath were collected after the test meal was fed at the end of a 11.5-h overnight fast following a 10-day acclimatization period. The highest glycaemic and insulinaemic responses were measured when the A/O and O/A diets orders were fed, whereas most hydrogen was produced after feeding oats alone. It was concluded that adding alfalfa chaff to a meal of oats prolonged the pre-caecal digestion of starch, but there was no evidence for any effect on pre-caecal starch digestibility.     

Validation of the 13C-urea breath test for use in cheetahs (Acinonyx jubatus) with Helicobacter.

Historically, therapeutic monitoring for prescribed eradication treatment of Helicobacter in cheetahs (Acinonyx jubatus) with associated gastritis has been accomplished only through endoscopic biopsies. The 13C-urea breath test (UBT) can offer an alternative to repeated biopsies for therapeutic monitoring. Five male and five female cheetahs and one male Sumatran tiger (Panthera tigris) were studied. All were clinically healthy before and after this investigation. Breath samples of end-tidal expiration were taken before and after administration of a 13C-enriched urea solution through a gastroesophageal tube. Twenty-milliliter breath samples were taken at 10, 20, 30, and 40 min after administration of the urea solution. The results of the breath analysis were compared with the results of rapid urease testing, histopathologic examination, and impression smears of gastric biopsies taken at the time of the breath test. The sensitivity and specificity for the 13C-UBT in this investigation were 100%. and the positive predictive value and negative predictive value were both 100%. Although the 13C-UBT is a good noninvasive diagnostic tool for monitoring the presence of Helicobacter sp. in the gastric mucosa, endoscopy should still be used for initial diagnosis and grading of gastritis and for monitoring the progression of disease in cheetahs. The 13C-UBT is a valuable, simple, accurate, and sensitive tool for monitoring eradication of Helicobacter during therapy for clinical gastritis.     

Investigation of the molecular detection of vaccine-derived equine herpesvirus type 1 in blood and nasal secretions from horses following intramuscular vaccination.

The objective of this study was to investigate whether intramuscular vaccination of healthy adult horses with a killed or a modified live equine herpesvirus type 1 (EHV-1) vaccine could induce transient positive PCR results in either blood or secretions collected on a nasopharyngeal swab. Four horses in each group received either a single killed or a modified-live vaccine intramuscularly. Two local commingled and 2 distant nonvaccinated controls were included for each group. All horses were observed daily for evidence of clinical abnormalities throughout the study periods. Blood and nasopharyngeal swabs were collected twice before vaccination and once weekly for 4 weeks after vaccination and submitted for PCR testing for EHV-1 by 2 independent laboratories using different real-time PCR methodologies. Serum samples collected from all horses on the vaccination day and 21 days later were tested for antibodies against EHV-1 using a serum neutralization test. Whereas the 2 vaccine strains tested positive in both EHV-1 PCR assays, nasopharyngeal swabs and whole blood collected from vaccinated and control horses had negative PCR test results for EHV-1 during the entire study period. Serum neutralization testing revealed a 2- to 4-fold increase in titers for all vaccinated horses, whereas titers in control horses were largely unchanged. The use of seropositive horses before immunization and the sampling frequency of 7 days may have prevented the occasional molecular detection of the vaccine virus in whole blood and nasopharyngeal secretions. However, the study results demonstrate that detection of EHV-1 DNA by PCR in vaccinated and unvaccinated healthy horses is not a common event.     

High Seroprevalence Against Lawsonia intracellularis Among Adult Horses in Belgium

Lawsonia intracellularis (LI) is an obligate intracellular gram-negative rod causing equine proliferative enteropathy (EPE). Occasional cases of EPE have been reported in foals living in Belgium, but the seroprevalence of equine LI in this country is unknown. The target population included clinically healthy adult horses, whose blood samples were collected and analyzed for specific IgG antibodies against LI using a blocking enzyme-linked immunosorbent assay test. The results were expressed as percentage of inhibition (PI). Samples that had a PI <20% were judged as negative, those between 20 and 30% as inconclusive, and those >30% were considered positive. A total of 356 blood samples were analyzed with 352 horses (98.8%) testing positive, 2 horses (0.6%) testing negative, and 2 horses (0.6%) showing inconclusive results. The large percentage of seropositive samples obtained in this study confirms a widespread exposure of Belgian horses to LI.     

Values of urine specific gravity for thoroughbred horses treated with furosemide prior to racing compared with untreated horses.

The distribution of specific gravity values for 2,599 urine samples collected from racing Thoroughbred horses that were known to have received furosemide prior to racing was compared with that for 1,669 urine samples from racing Thoroughbred horses that reportedly had not received furosemide. Values of specific gravity for furosemide-treated horses were significantly lower (P < 0.001) than those for horses that had not received furosemide, and the proportion of horses with urine specific gravity either <1.010 or <1.012 was significantly greater (P < 0.001) among the furosemide-treated horses. These data indicate that evaluation of urine specific gravity would be a useful component of drug testing programs for regulation of furosemide use.     

Use of breath hydrogen measurement to evaluate orocecal transit time in cats before and after treatment for hyperthyroidism.

Orocecal transit time was evaluated in 13 cats diagnosed with hyperthyroidism. Transit was determined by measuring the change in breath hydrogen and methane concentrations following oral administration of a nonabsorbable carbohydrate (lactulose). Transit times before and three to four weeks after treatment of the hyperthyroidism with radioactive iodine were compared. There was a significant prolongation of transit time, as determined by a change in hydrogen concentration, following correction of the hyperthyroidism (p = 0.034). Average transit times and standard errors were 27.7 +/- 3.7 minutes before treatment and 56.5 +/- 12.1 minutes after treatment. Methane was not detected in any of the samples. Hyperthyroidism appears to be associated with an accelerated small intestinal transit time in cats.     

Occurrence of Trypanosoma evansi in Horses in the State of Minas Gerais,Brazil

Ttrypanosomosis caused by Trypanosoma evansi is a condition that causes significant losses to farmers in endemic areas. This study aimed to report one case of trypanosomiasis in the municipality of Itabira, state of Minas Gerais, Brazil. In November 2010, on a farm with 16 horses, three horses had clinical signs of anemia, limb edema, weight loss, lameness, muscle atrophy, and incoordination of the hind limbs. Trypanosomosis was suspected, and the animals with clinical signs were treated with two doses of diminazene aceturate (7 mg/kg, intramuscular) every 7 days; the treated animals recovered from the clinical symptoms. Blood samples were collected from six horses on the farm, including the three treated animals, to perform polymerase chain reaction specific for T evansi. Four samples were polymerase chain reaction negative, including those collected from three treated horses. However, two other asymptomatic horses were positive for the parasite based on the molecular testing. Based on the results, we concluded that the initial clinical suspect of trypanosomosis was correct, and the treatment used was effective. Probably the disease was introduced to Minas Gerais State through a stallion, which acquired the infection in an endemic area in southern Brazil.     

The Prevalence of Aeromonas Species in Feces of Horses with Diarrhea

Feces collected from 40 horses with diarrhea and 34 horses without diarrhea were examined to determine if an association existed between isolation of Aeromonas spp. and diarrhea. Samples were also examined for Salmonella spp., and identification of viruses and parasite ova. Neither Salmonella spp. nor Aeromonas spp. were isolated from the feces of 34 control horses. Aeromonas spp. were isolated from feces of 22 of 40 (55%) horses with diarrhea. Salmonella spp. were isolated from feces of 8 (20%) horses, and of these, 5 (12.5%) were also positive for Aeromonas spp. Twenty-nine isolates of Aeromonas spp. were recovered from the feces of 22 diarrheic horses. Of these isolates, more than 80% were susceptible on in vitro testing to amikacin, ceftiofur, chloramphenicol, and gentamicin. All isolates were susceptible to enrofloxacin. Diarrheic horses positive for Aeromonas were significantly (P = .04) older than diarrheic horses negative for Aeromonas spp. A significantly greater number of fecal samples were positive for Aeromonas spp. during March through August than samples examined in other months (P = .014). Results of this study indicate that Aeromonas spp. should be considered as a cause of diarrhea in horses.     

Assessment of the rate of solid-phase gastric emptying in ponies by means of the 13C-octanoic acid breath test: a preliminary study

The aim of this study was to assess the feasibility of applying the 13C-octanoic acid breath test for assessment of gastric emptying in ponies by investigating the pattern of 13C enrichment in breath following the administration of a test meal +/- 13C-octanoic acid. After a 14 h fast, the ponies received either no meal (Test I) or a standardised test meal labelled with 0 mg (Test II), 125 mg (Test III), 250 mg (Test IV) or 500 mg (Test V) 13C-octanoic acid. For each test (I-V), exhaled breath samples were collected in duplicate at 1 h and immediately before ingestion of the test meal and at frequent intervals thereafter for 12 h. Breath samples were analysed by continuous flow isotope ratio mass spectrometry. Three indices of breath 13C-enrichment were computed; half dose recovery time (t1/2), gastric emptying coefficient (GEC) and time to peak breath 13C-enrichment t(max). For Tests I and II, the ratio of 13CO2:12CO2 remained stable for the duration of the sampling period. For Tests III, IV and V, an increase in the ratio of 13CO2:12CO2 was detected. The test was reproducible within individuals, and intersubject variation was low. Further validation studies of this noninvasive technique are justified.     

Identification of sources of Salmonella organisms in a veterinary teaching hospital and evaluation of the effects of disinfectants on detection of Salmonella organisms on surface materials

OBJECTIVE: To determine sources of Salmonella organisms in a veterinary teaching hospital, compare bacterial culture with polymerase chain reaction (PCR) testing for detection of Salmonella organisms in environmental samples, and evaluate the effects of various disinfectants on detection of Salmonella organisms on surface materials. DESIGN: Prospective study. SAMPLE POPULATION: Fecal samples from 638 hospitalized horses and 783 environmental samples. PROCEDURE: Standard bacterial culture techniques were used; the PCR test amplified a segment of the Salmonella DNA. Five disinfectants were mixed with Salmonella suspensions, and bacterial culture was performed. Swab samples were collected from 7 surface materials after inoculation of the surfaces with Salmonella Typhimurium, with or without addition of a disinfectant, and submitted for bacterial culture and PCR testing. RESULTS: Salmonella organisms were detected in fecal samples from 35 (5.5%) horses. For environmental samples, the proportion of positive bacterial culture results (1/783) was significantly less than the proportion of positive PCR test results (110/783), probably because of detection of nonviable DNA by the PCR test. Detection of Salmonella organisms varied with the surface material tested, the method of detection (bacterial culture vs PCR testing), and the presence and type of disinfectant. CONCLUSIONS AND CLINICAL RELEVANCE: Results of the present study suggested that Salmonella organisms can be isolated from feces of hospitalized horses and a variety of environmental surfaces in a large animal hospital. Although recovery of Salmonella organisms was affected by surface material and disinfectant, bleach was the most effective disinfectant on the largest number of surfaces tested.     

Antimicrobial resistance in commensal faecal Escherichia coli of hospitalised horses

The objective of this study was to examine the impact of hospitalisation and antimicrobial drug administration on the prevalence of resistance in commensal faecal E. coli of horses. Faecal samples were collected from ten hospitalised horses treated with antimicrobials, ten hospitalised horses not treated with antimicrobials and nine non-hospitalised horses over a consecutive five day period and susceptibility testing was performed on isolated E. coli. Results revealed that hospitalisation alone was associated with increased prevalence of antimicrobial resistance and multidrug resistance in commensal E. coli of horses. Due to the risk of transfer of resistance between commensal and pathogenic bacteria, veterinarians need to be aware of possible resistance in commensal bacteria when treating hospitalised horses.