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Objective: The goal of this study was to describe clinical and hospital-related factors associated with time to feeding tube placement in hospitalized dogs and cats., Methods: This was a retrospective study from January 2014 through December 2023. Medical records at an academic veterinary teaching hospital were reviewed for small animal patients in the ICU with nasogastric or esophageal feeding tube placement for enteral nutrition due to inadequate food intake during hospitalization. Patients with feeding tubes placed prophylactically at hospital admission for surgery or physical inability to eat were excluded. Factors associated with placement including species, disease, inappetence, nutritional plans, and medical record recording of caloric intake were reviewed., Results: 295 patients (89 cats and 206 dogs) were included. Median duration of hospitalization prior to feeding tube placement was 2 days (0 to 17 days) and was shorter in cats. Weekend admission and initial placement of an esophageal tube were associated with increased time to placement. Adequate feeding instructions were provided for only 53 of 295 patients (18%) and associated with both higher likelihood of having caloric intake recorded (OR, 10.30) and earlier feeding tube placement., Conclusions: Provision of enteral nutrition occurred later than recommended by nutritional guidelines in many hospitalized patients. Clinician inclusion of specific diet instructions, weekday admission, and initial nasogastric tube placement reduced this duration., Clinical Relevance: Multiple factors may impact timely provision of nutrition in hospitalized dogs and cats. Close attention to energy requirements and exact food intake should be considered to optimize patient nutritional care.

Objectives: To determine the rate of accidental placement of nasoenteric tubes into the respiratory tract. To compare the methods of checking correct tube placement. To compare the complication rates between nasoesophageal and nasogastric tubes., Materials and Methods: Animals requiring nasoenteric feeding tubes were prospectively randomised to have either nasoesophageal or nasogastric tube placement. Various techniques for assessing tube position were compared with thoracic radiographic findings. Complications during placement and use were recorded., Results: Ninety-seven animals (82 dogs and 15 cats) were studied. The tube was misplaced into the respiratory tract in three (3.1%) cases. No technique for checking placement was completely concordant with radiography but the presence of negative pressure at the thoracic inlet during placement was consistent with the presence of the tube in the oesophagus in 86.2% cases, while capnography can be considered to confirm tracheal placement. The overall rate of complications during tube placement was 25.8%, with mostly minor clinical complications reported. There was no significant difference in the new-onset regurgitation/vomiting rate, or complications while the tube was in situ between the nasoesophageal and nasogastric groups., Clinical Significance: Misplacement of nasoenteric tubes is uncommon but a consistent alternative test to radiography for checking correct nasoenteric tube placement was not demonstrated. The choice of placement of either a nasoesophageal or nasogastric tube should be guided by clinician preference, and clients should be warned about possible complications during placement and while the nasoenteric tube is in situ., (© 2024 The Authors. Journal of Small Animal Practice published by John Wiley & Sons Ltd on behalf of British Small Animal Veterinary Association.)

Simulation in veterinary education is an important means of providing a safe, welfare-friendly way for students to hone their skills prior to performing procedures on live animals. Students may not get many chances to practice passing a nasogastric tube and checking for reflux in live horses during clinical rotations and extramural studies. A low-cost equine nasogastric intubation model was created at the University of Surrey, allowing students to practice passing a tube and checking for reflux. Thirty-two equine veterinarians evaluated the model for realism and its potential usefulness in teaching. Veterinarians found the model to be realistic, supported its use as a teaching aid, and provided helpful feedback for possible improvements. In addition, 83 year-4 veterinary students rated their level of confidence before and after using the model for nine specific aspects of nasogastric intubation. Students showed significantly increased confidence levels in all nine aspects after using the model, and reported that they appreciated being able to practice the skill in a safe environment prior to performing it on a live horse. The results of this study suggest that both clinicians and students considered that this model has educational value, which supports its use for training veterinary students prior to clinical placements. The model provides an affordable, robust educational aid that can be used in clinical skills teaching, increases student confidence, and allows students to practice the skill repeatedly.

Objective: To compare 4 point-of-care (POC) techniques to assess nasogastric (NG) tube placement versus radiographs as a reference standard. POC methods included air inflation with auscultation, fluid aspiration with pH measurement, ultrasonography, and capnography., Design: Prospective observational study in hospitalized dogs between 2020 and 2021., Setting: University teaching hospital., Animals: Fifty-one dogs requiring NG tube placement as part of their normal care., Interventions: After standard blind NG tube placement, each POC method was performed following standardized instructions. All POC methods were scored as to whether the investigator believed the tube to be in the gastrointestinal tract (as indicated by positive auscultation of borborygmus during insufflation, positive fluid aspiration with pH ≤5, presence of hyperechoic shadow in the esophagus, or absence of capnographic waveform). Subsequently, radiographs were taken to determine NG tube position as a gold standard. The sensitivity, specificity, and accuracy of each test as compared to 2-view thoracic radiographs were determined., Measurements and Main Results: Sensitivity, specificity, and accuracy for each POC technique were as follows: air auscultation (84.4%, 50.5%, and 80.4%, respectively), neck ultrasound (95.6%, 83.3%, and 94.1%, respectively), capnography (91.1%, 33.3%, and 84.3%, respectively), and fluid aspiration with pH measurement (22.2%, 100%, and 31.4%, respectively)., Conclusions: Among the 4 techniques evaluated, neck ultrasound had the best overall performance for assessing NG tube placement. Fluid aspiration with pH measurement might also have potential due to perfect specificity, but its clinical utility may be limited by low sensitivity and accuracy. Nonetheless, 2-view thoracic radiography should still be considered the standard method for confirmation of NG tube placement as none of the 4 POC techniques investigated showed both high sensitivity and perfect specificity., (© Veterinary Emergency and Critical Care Society 2023.)

Objective: Complications of feeding tube placement are uncommon, but life-threatening pneumothorax has been reported in human and veterinary patients during feeding tube placement. This article describes the development of pneumothorax and the outcome associated with misplacement of nasogastric (NG) tubes in the tracheobronchial tree in 13 dogs., Animals: 13 dogs being treated for various medical conditions that had NG tubes placed in 4 hospitals., Procedures: A review was carried out of the medical records of 13 dogs that developed pneumothorax after misplacement of NG tubes between 2017 and 2022., Results: 14 dogs out of 4,777 (0.3%) developed pneumothorax as an adverse effect of NG tube misplacement in the tracheobronchial tree. One dog was excluded due to incomplete medical records. The feeding tube size ranged from 5F to 10F, and the most common tubes utilized were polyurethane tubes with flushing stylets. Nine out of 13 dogs developed evidence of respiratory compromise after the NG tube was placed. Eleven dogs required thoracocentesis, and 5 dogs had thoracostomy tubes placed. Five dogs suffered cardiopulmonary arrest after developing pneumothorax, with 3 of 5 undergoing cardiopulmonary resuscitation. Two out of 3 dogs that underwent cardiopulmonary resuscitation were discharged from the hospital. Five of 13 dogs were successfully discharged from the hospital, while 5 dogs died or were euthanized because of the pneumothorax., Clinical Relevance: Pneumothorax is a rare but potentially life-threatening complication of NG tube placement in dogs and may lead to death if not immediately addressed. Practitioners should be aware of this complication and be ready to perform thoracocentesis quickly if appropriate.

Objectives: The aims of this study were to describe diseases, complications and outcomes associated with the use of feeding tubes in a population of sick cats with appetite disturbance managed at an internal medicine referral service., Methods: Clinicopathological data from cats receiving nasoenteral (NE) or oesophagostomy (O) tubes were studied. Cats were categorised according to their underlying disease and divided into subgroups (NE or O tube). The following factors associated with survival were analysed: disease category, type of tube and return to appetite., Results: Included in the study were 112 cats, representing 118 cases. Of the 118 cases, 98 (83%) and 20 (17%) received NE or O tubes, respectively. The most common underlying conditions were digestive (13.5%), hepatobiliary (11%) and upper urinary tract (11%) disorders. Hepatobiliary (50%) and upper respiratory tract (30%) conditions were predominant in the O tube group. Digestive (15%) and upper urinary tract (12%) diseases were more common in the NE tube group. Complications following tube placement occurred in 22/118 cases (18.6%). The global survival rate was 73% and did not differ between NE (71.4%) and O tube (80%) groups ( P  = 1.00) or disease categories ( P  = 0.61). Return of appetite before feeding tube removal occurred in 56 cases (47%), within a median of 3 days (range 1-30) and was not associated with mirtazapine administration ( P  = 1.00). Appetite returned earlier for cats with NE tubes (3 days, range 1-17) than for those with O tubes (33 days, range 5-60; P <0.05). Voluntary food intake was positively associated with survival (odds ratio 15.17). After discharge and feeding tube retrieval, return of appetite was observed in 67% of cases., Conclusions and Relevance: Feeding tubes were predominantly placed for the management of appetite disturbance in cats with digestive, hepatobiliary and upper urinary tract diseases. While complications were frequent, they were mostly mild, easily managed and did not preclude feeding tube use. Return to appetite occurred in a large proportion of cats during or after assisted enteral feeding and was associated with survival.

Provision of enteral nutrition via the use of nasoenteric feeding tubes is a commonly used method in both veterinary and human medicine. Although case reports in human medicine have identified fatalities due to misplacement of nasogastric (NG) tubes into the tracheobronchial tree and subsequent pneumothorax, there are no case reports, to our knowledge, of fatalities in veterinary patients. This case report describes two fatalities caused by misplaced NG tubes in intubated patients (one intraoperative, one postoperative). This report highlights risk factors for feeding tube complications and methods to prevent future fatalities such as two-view radiography, two-step insertion, capnography, laryngoscopic-assisted placement, and palpation of the NG tube in the stomach. The recent fatalities discussed within this case series demonstrate that deaths as a result of NG tubes misplaced into the tracheobronchial tree occur in veterinary patients, and measures should be taken to prevent this complication., (© 2021 by American Animal Hospital Association.)

Background: Tube feeding is a common procedure in neonatology. In humans, tube misplacement reportedly occurs in up to 59% of all cases and may lead to perforation in 1.1% of preterm intubated neonates. While numerous studies on optimal tube placement have been performed in human neonates, current recommendations on tube feeding in canine and feline neonatology are based, at best, on studies performed in adult animals. Herein, we aimed to test ultrasonography as a tool to verify tube placement in puppies and kittens and to compare different anatomical predictive markers used in human, canine and feline neonates., Results: The predictive tube length when held bent between the last rib and the mouth may induce trauma compared to when held straight. A strong positive linear correlation was observed between birthweight and gastric cardia localization. Ultrasonography findings were similar to coeliotomy findings. Stomach volume was less than 2 mL per 100 g in the less-than-one-day-old studied puppies (n = 25) and kittens (n = 28)., Conclusions: A weight-based equation was calculated to help predict appropriate tube placement. Ultrasonography can be used to control gastric tube placement, and neonates less than one-day-old have a smaller stomach capacity. Further studies are required to evaluate whether more-than-one-day-old puppies follow the same linear correlation with their weight. Further in vivo studies are warranted to determine the gold standard procedure for tube feeding in neonatal puppies and kittens.

Objectives: To evaluate the placement and the performance of a new post-pyloric feeding (PPF) system, and compare it to esophageal (E) feeding in dogs with severe acute kidney injury (AKI)., Design: Prospective study., Setting: University teaching hospital., Animals: Twenty client-owned dogs with severe AKI treated with hemodialysis., Interventions: Dogs were randomly assigned to 2 feeding techniques, PPF or E feeding; for PPF, an 8-Fr jejunal (J) tube was introduced through a standard 18-Fr E-tube and advanced endoscopically through the pylorus. A commercial liquid diet was administered at a continuous rate for at least 5 days. After the removal of the internal J-tube, feeding was continued through the E-tube. Control dogs were fed blended food 5 times daily through an E-tube. Placement technique, nutritional efficiency, and metabolic response to nutritional support were compared between the groups., Measurements and Main Results: Feeding tubes were placed a medium of 1 day (interquartile range, 0.8 d) after presentation. Median procedure-time in the group PPF was 26.5 min (11.5 min), including 8.5 min (2.7 min) for the E-tube and 17.5 min (5.0 min) for the J-tube. J-tubes were used for 5 days (1.5 d) with oral displacement observed in 3/10 dogs. The goal to administer 130% resting energy requirement within 3 days was reached in 13/20 dogs (8/10 PPF, 5/10 E). Despite nutritional support, dogs lost 1.2% body weight per day (1.1%), with no difference between the groups. The metabolic improvement was comparable between the groups, despite marked differences in the diet composition., Conclusions: This new feeding technique can be recommended as an efficient method for early nutritional support in dogs with severe AKI. The protein-energy wasting observed despite active nutritional support suggests, however, the necessity for increased feeding targets or qualitative changes in diet composition for dogs with AKI., (© Veterinary Emergency and Critical Care Society 2020.)

Placing a nasogastric tube can be a life-saving act for a horse but is considered an occupational hazard for veterinarians. An online questionnaire was performed to assess and specify potential risks. 123 equine veterinarians completed the survey, and the majority admitted using the mouth to handle the end of the nasogastric tube (sucking or blowing air) and having accidentally swallowed or aspirated stomach content or medications. This can potentially lead to aspiration pneumonia or pneumonitis. Mineral oil seems to be especially dangerous as aspiration may be asymptomatic at the beginning and lipoid pneumonitis may develop. Furthermore, 60% of responders would also handle the tube with their mouth if the horse was presented with fever and diarrhea or reflux formation, which might be affected by Salmonella sp. or Clostridium difficile producing toxins. The fact that nasogastric tubes are rarely being disinfected increases the risk of infection. 50% of veterinarians would use their mouth to suck or blow air into the tube during nasogastric intubation, even if the patient was presented with suspected poisoning. Rodenticide zinc phosphide is particularly dangerous as its breakdown product is a highly toxic gas. Inhalation leads to serious symptoms in humans, including pulmonary edema and neurological signs. Alternatives to mouth use (lavage, big syringe, or suction pump) when passing a tube should be considered, especially if a patient is presented with duodenitis-proximal jejunitis, diarrhea, or suspected poisoning. Awareness needs to be raised among veterinarians that nasogastric intubation is an extremely hazardous occupational practice., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Rectal fluid administration may offer a simple, safe and inexpensive alternative to intravenous or nasogastric fluid therapy in equine clinical cases., Objectives: To evaluate the tolerance and effects of rectally administered fluid and compare the measurements of haemodilution and intravascular volume with those during nasogastric and intravenous fluid administration., Study Design: Randomised controlled experimental trial., Methods: Six clinically normal Standardbred geldings were used in a 4-way crossover study: each received three different fluid treatments (intravenous, nasogastric and rectal) at 5 mL/kg/h for 6 h and underwent a control (no treatment) with water and feed withheld. Bodyweight was measured at baseline and 6 h. Packed cell volume (PCV), total solids (TS), albumin, electrolytes, lactate, urine specific gravity, vital parameters, gastrointestinal borborygmi and central venous pressure were measured every 2 h., Results: Rectal fluid administration with plain water was well tolerated and caused clinical chemistry changes consistent with haemodilution, indicating absorption. Mean (95% confidence interval) PCV decreased from 40% [40-42] at 0 h to 35% [34-36] at 6 h during rectal fluid treatment (P<0.001), similar to decreases in PCV occurring also with i.v. and nasogastric (NGT) treatment (P<0.001). The TS also decreased with i.v. and rectal fluid (P<0.001). There was a decrease in bodyweight in the control (P<0.001) but not with any of the fluid treatments., Main Limitations: A small sample size of healthy, euhydrated horses and a relatively short duration of fluid administration was used., Conclusions: Rectal fluid administration requires clinical evaluation, but may offer an inexpensive, safe alternative or adjunct to i.v. fluid administration, particularly when administration via NGT is not possible or contraindicated. The Summary is available in Portuguese - see Supporting Information., (© 2019 EVJ Ltd.)

Objective: To describe the postoperative use of gastrostomy tubes (GT) in dogs with septic peritonitis. A secondary objective was to identify factors associated with GT placement and use that may be related to outcome., Design: Retrospective study., Setting: University teaching hospital., Animals: Twenty-four dogs diagnosed with septic peritonitis with GT placement at the time of exploratory laparotomy., Interventions: None., Measurements and Main Results: Eighteen dogs (75%) survived to discharge. Eighteen dogs (75%) had a gastrointestinal source of septic peritonitis. Complications were reported in 12/24 (50%) patients. Four dogs (16.6%) had non-GT-related complications such as vomiting, regurgitation, or increased gastric residual volume. GT-related complications occurred in 8/24 (33.3%) dogs, the majority of which (6/8 [75%]) were minor and did not necessitate removal of the GT. Two dogs had major complications that required removal of the GT. Significant differences between survivors and nonsurvivors were found between the length of time after placement of the GT to when they began eating and outcome (discharge versus death versus euthanasia) (P = 0.03), and GT dwell time (length of time the GT was in place) and outcome (P = 0.006). Clinically relevant correlations were found between the time after placement of the GT until feeding and time after placement until voluntarily eating (P = 0.0349), time after placement of the GT until voluntarily eating and length of hospitalization (P = 0.0391), and time after placement of the GT until feeding and length of hospitalization (P = 0.036)., Conclusions: GTs can be placed during exploratory laparotomy in dogs with septic peritonitis. They facilitate early enteral nutrition and are associated with few clinically significant complications. Prospective studies are needed to determine the optimal postoperative feeding plan and the effects of early enteral nutrition on serum albumin concentration in this patient population., (© Veterinary Emergency and Critical Care Society 2019.)

Background: Early enteral nutrition in dogs with critical illnesses, including septic peritonitis, has been shown to have a positive influence on patient outcome. Surgical placement of a gastrostomy tube (GT) is one option for providing early enteral nutrition. Complications, including premature tube removal or separation of the stomach from the body wall, can result in leakage of gastric contents into the abdominal cavity and subsequent peritonitis. A safe and reliable technique for the placement of a GT is desirable to minimize such complications., Key Concepts: A modified method for surgical placement of a GT is described. A thoracic trocar catheter (TTC) with an attached Pezzer tube is inserted through a gastrotomy incision and exited through the left gastric body and body wall. A left-sided tube gastropexy is performed using an interlocking box (ILB) pattern., Significance: GT placement using a TTC is efficient, requiring minimal additional anesthesia time. The gastric defect created by the TTC conforms well with the Pezzer tube. As such, placement and utilization of the ILB suture pattern enables removal of the GT in the early postoperative period, if appropriate., (© Veterinary Emergency and Critical Care Society 2019.)

Objective: To investigate the pharmacokinetics and antihistaminic effects (pharmacodynamics) of olopatadine in a small population of healthy horses after administration via nasogastric tube., Animals: 4 healthy adult Thoroughbreds., Procedures: Olopatadine (0.1 mg/kg, once) was administered via nasogastric tube. Blood samples were collected at predetermined time points for pharmacokinetic analyses of the drug in plasma. Olopatadine effects were investigated by measurement of cutaneous wheals induced by ID histamine injection (0.1 mL [10 μg]/injection) at predetermined time points. Inhibition effect ratios were calculated on the basis of measured wheal size (area) after versus before olopatadine administration., Results: Mean ± SD maximum plasma olopatadine concentration was 48.8 ± 11.0 ng/mL approximately 1.5 hours after administration. Median terminal half-life was 6.11 hours. Mean ± SD maximal effect was 88.2 ± 4.9% inhibition approximately 3.5 hours after drug delivery, and the inhibition effect remained > 80% for 12.5 hours after treatment. No signs of adverse clinical effects were observed., Conclusions and Clinical Relevance: Results suggested olopatadine may have a strong, long-term inhibitory effect against histamine-induced wheals in the skin of horses. Clinical research with a larger number of horses is warranted.

Objective: To determine the impact of route of nutrition on length of hospitalization and survival to discharge in dogs with septic peritonitis., Design: Retrospective study from 2007 to 2016., Setting: University teaching hospital., Animals: Sixty-eight dogs with septic peritonitis that survived ≥48 hours., Interventions: None., Measurements and Main Results: Nutritional strategy was categorized into 1 of 4 groups: voluntary, feeding tube, parenteral (PN), and combined feeding tube and PN. Body weight, body condition score, time without caloric intake before and during hospitalization, length of hospitalization, and percentage of resting energy requirements provided during the first 3 days of nutritional support were recorded. Overall, 54/68 dogs survived (79%). Survival Prediction Index 2 scores were not significantly different between groups. Dogs receiving PN only were less likely to survive than those receiving any enteral nutrition (OR 9.7; 95CI 1.84-58.75). Compared to dogs not receiving PN, dogs receiving any PN were significantly less likely to survive (OR 9.66; 95% CI 1.7-105.8), and were in hospital significantly longer (P = 0.025). Metabolic complications associated with PN were frequent but not associated with increased length of hospitalization or survival to discharge., Conclusions: Dogs with septic peritonitis that received any PN were in hospital longer and less likely to survive but may have been sicker than those receiving other forms of nutritional support. Further studies are warranted to evaluate reasons for worse outcomes in dogs with septic peritonitis receiving PN., (© Veterinary Emergency and Critical Care Society 2019.)

Objective: To describe the clinical use of a novel, minimally invasive technique for fluoroscopic wire-guided esophagojejunal tube (FEJT) placement in dogs and cats., Design: Retrospective study (February 2010-September 2013)., Setting: University veterinary teaching hospital., Animals: Eighteen dogs and 2 cats with intolerance of, or contraindications to, gastric feeding that underwent attempted FEJT placement., Interventions: All patients underwent attempted FEJT placement using a novel fluoroscopic wire-guided technique., Measurements and Main Results: Patient data were collected including information about the FEJT placement and utilization of the tube postplacement. The primary diagnosis in dogs undergoing FEJT placement was pancreatitis in 61% of cases. The ability to achieve postpyloric access with the technique was 95% (19/20). Mean duration of the procedure in dogs where FEJT placement was successful was 63.8 minutes (SD, 28.6; min-max, 30-120 min). Mean fluoroscopy time was 19.4 minutes (SD, 11.5; min-max, 5.2-42.1-min). Esophagostomy site infection was a complication of FEJT placement in 2 dogs. The mean duration the FEJT remained in place in dogs was 3.8 days (SD, 2.2; min-max, 1-7 days), and mean duration of feeding was 3.6 days (SD, 2.2; min-max, 1-7 days). Vomiting was noted in 89% of patients prior to FEJT placement and was significantly reduced to only 24% of patients postplacement (P = 0.0001)., Conclusions: FEJT placement is a viable technique for providing postpyloric nutrition in dogs and cats intolerant of, or with contraindications to, gastric feeding., (© Veterinary Emergency and Critical Care Society 2019.)

Devil's claw is used for the treatment of inflammatory symptoms and degenerative disorders in horses since many years, but without the substantive pharmacokinetic data. The pharmacokinetic parameters of harpagoside, the main active constituent of Harpagophytum procumbens DC ex Meisn., were evaluated in equine plasma after administration of Harpagophytum extract FB 8858 in an open, single-dose, two-treatment, two-period, randomized cross-over design. Six horses received a single dose of Harpagophytum extract, corresponding to 5 mg/kg BM harpagoside, and after 7 days washout period, 10 mg/kg BM harpagoside via nasogastric tube. Plasma samples at certain time points (before and 0-24 hr after administration) were collected, cleaned up by solid-phase extraction, and harpagoside concentrations were determined by LC-MS/MS using apigenin-7-glucoside as internal standard. Plasma concentration-time data and relevant parameters were described by noncompartmental model through PKSolver software. Harpagoside could be detected up to 9 hr after administration. C max was found at 25.59 and 55.46 ng/ml, t 1/2 at 2.53 and 2.32 hr, respectively, and t max at 1 hr in both trials. AUC 0-inf was 70.46 and 117.85 ng hr ml -1 , respectively. A proportional relationship between dose, C max and AUC was observed. Distribution (V z /F) was 259.04 and 283.83 L/kg and clearance (CL/F) 70.96 and 84.86 L hr -1  kg -1 , respectively. Treatment of horses with Harpagophytum extract did not cause any clinically detectable side effects., (© 2018 The Authors. Journal of Veterinary Pharmacology and Therapeutics Published by John Wiley & Sons Ltd.)

We evaluated the influence of sampling technique (cannulation vs. stomach tube) and site (dorsal sac vs. ventral sac) on the rumen microbiome and fermentation parameters in Hanwoo steers. Rumen samples were collected from three cannulated Hanwoo steers via both a stomach tube and cannulation, and 16S rRNA gene amplicons were sequenced on the MiSeq platform to investigate the rumen microbiome composition among samples obtained via 1) the stomach tube, 2) dorsal sac via rumen cannulation, and 3) ventral sac via rumen cannulation. A total of 722,001 high-quality 16S rRNA gene sequences were obtained from the three groups and subjected to phylogenetic analysis. There was no significant difference in the composition of the major taxa or alpha diversity among the three groups ( p ＞ 0.05). Bacteroidetes and Firmicutes represented the first and second most dominant phyla, respectively, and their abundances did not differ among the three groups ( p ＞ 0.05). Beta diversity principal coordinate analysis also did not separate the rumen microbiome based on the three sample groups. Moreover, there was no effect of sampling site or method on fermentation parameters, including pH and volatile fatty acids ( p ＞ 0.05). Overall, this study demonstrates that the rumen microbiome and fermentation parameters are not affected by different sampling techniques and sampling sites. Therefore, a stomach tube can be a feasible alternative method to collect representative rumen samples rather than the standard and more invasive method of rumen cannulation in Hanwoo steers.

Most pathogens invade organisms through their mucosa. This is particularly true in fish as they are continuously exposed to a microbial-rich water environment. Developing effective methods for oral delivery of immunostimulants or vaccines, which activate the immune system against infectious diseases, is highly desirable. In devising prophylactic tools, good experimental models are needed to test their performance. Here, we show a method for oral intubation of adult zebrafish and a set of procedures to dissect and prepare the intestine for cytometry, confocal microscopy and quantitative polymerase chain reaction (qPCR) analysis. With this protocol, we can precisely administer volumes up to 50 µL to fish weighing approximately 1 g simply and quickly, without harming the animals. This method allows us to explore the direct in vivo uptake of fluorescently labelled compounds by the intestinal mucosa and the immunomodulatory capacity of such biologics at the local site after intubation. By combining downstream methods such as flow cytometry, histology, qPCR and confocal microscopy of the intestinal tissue, we can understand how immunostimulants or vaccines are able to cross the intestinal mucosal barriers, pass through the lamina propria, and reach the muscle, exerting an effect on the intestinal mucosal immune system. The model could be used to test candidate oral prophylactics and delivery systems or the local effect of any orally administered bioactive compound.

OBJECTIVE To evaluate the feasibility of manufacturing gastrojejunostomy tubes from jejunostomy and gastrostomy tubes that would allow for gastric and enteral feeding of and aspiration of gastric contents from small animal patients. DESIGN In vitro study. SAMPLE 9 gastrojejunostomy constructs. PROCEDURES Commercially available gastrostomy and jejunostomy tubes were combined to create 9 constructs. Three investigators tested each construct with 4 solutions (tap water, a commercial enteral diet, and 2 canned food-water mixtures) and 3 syringe sizes for ease of injection through the gastrostomy and jejunostomy tubes and aspiration through the gastrostomy tube. Flow rates were calculated and analyzed to evaluate effects of tube diameter and syringe size for each solution. RESULTS The 20F/8F, 24F/8F, 28F/8F, and 28F/10F (gastrostomy tube/jejunostomy tube) constructs allowed for injection and aspiration of all solutions. The 5F jejunostomy tubes allowed only water to be injected, whereas the 8F jejunostomy tubes did not allow injection of the canned food-water mixtures. The 20F/10F construct did not allow injection or aspiration through the gastrostomy tube, whereas the 18F/8F construct allowed injection but not aspiration through the gastrostomy tube. Faster flow rates through the gastrostomy tube were associated with larger gastrostomy tube diameter, smaller jejunostomy tube diameter, and smaller syringe size. Faster flow rates through the jejunostomy tube were associated with smaller jejunostomy tube diameter. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that homemade gastrojejunostomy constructs would allow for administration of a variety of enteral diets. Limitations to the administration and aspiration of various enteral diets as well as patient needs should be considered before a gastrojejunostomy tube combination is chosen.

Objective: To evaluate the incidence of hypochloremic metabolic alkalosis (HCMA) in dogs and cats in the ICU that had intermittent nasogastric tube (NGT) aspiration for up to 36 hours., Design: Prospective cohort study (December 2013 to October 2014)., Setting: Privately owned emergency and referral teaching hospital., Animals: Forty-nine client-owned dogs and 16 client-owned cats., Interventions: Patients wherein NGT placement was recommended and client consent was obtained were included in the interventional group. Those with an NGT placed (NGT group) had the NGT aspirated every 4 hours. Patients for whom placement of a NGT was declined by the owner served as a reference group (NoNGT). Venous blood gas and electrolyte values were obtained every 12 hours., Measurements and Main Results: Thirty-five dogs and cats had an NGT placed. Thirty dogs and cats did not have an NGT placed. The serum venous blood gas and electrolyte changes were compared over time within the NGT group and between the NGT and NoNGT groups. No cases developed HCMA. In the NGT group, blood pH increased over time. There was no significant difference between the NGT and the NoNGT group in the average value of pH, HCO 3 - , base excess, chloride, or corrected chloride. Serum venous blood gas, chloride, and corrected chloride changes were not associated with the volumes of gastric fluid aspirated over time., Conclusions: In this small population of dogs and cats, intermittent NGT aspiration was not associated with the development of HCMA over a period of up to 36 hours after NGT placement., (© Veterinary Emergency and Critical Care Society 2018.)

Nine horses received 20 mg/kg of intravenous (LEV IV ); 30 mg/kg of intragastric, crushed immediate release (LEV CIR ); and 30 mg/kg of intragastric, crushed extended release (LEV CER ) levetiracetam, in a three-way randomized crossover design. Crushed tablets were dissolved in water and administered by nasogastric tube. Serum samples were collected over 48 hr, and levetiracetam concentrations were determined by immunoassay. Mean ± SD peak concentrations for LEV CIR and LEV CER were 50.72 ± 10.60 and 53.58 ± 15.94 μg/ml, respectively. The y-intercept for IV administration was 64.54 ± 24.99 μg/ml. The terminal half-life was 6.38 ± 1.97, 7.07 ± 1.93 and 6.22 ± 1.35 hr for LEV CIR , LEV CER , and LEV IV , respectively. Volume of distribution at steady-state was 630 ± 73.4 ml/kg. Total body clearance after IV administration was 74.40 ± 19.20 ml kg -1  hr -1 . Bioavailability was 96 ± 10, and 98 ± 13% for LEV CIR and LEV CER , respectively. A single dose of Levetiracetam (LEV) was well tolerated. Based on this study, a recommended dosing regimen of intravenous or oral LEV of 32 mg/kg every 12 hr is likely to achieve and maintain plasma concentrations within the therapeutic range suggested for humans, with optimal kinetics throughout the dosing interval in healthy adult horses. Repeated dosing and pharmacodynamic studies are warranted., (© 2017 John Wiley & Sons Ltd.)

Background: Insulin dysregulation (ID) with basal or postprandial hyperinsulinemia is one of the key findings in horses and ponies suffering from the equine metabolic syndrome (EMS). Assessment of ID can easily be performed in clinical settings by the use of oral glucose challenge tests. Oral glucose test (OGT) performed with 1 g/kg bodyweight (BW) glucose administered via naso-gastric tube allows the exact administration of a defined glucose dosage in a short time. However, reliable cut-off values have not been available so far. Therefore, the aim of the study was to describe variations in insulin response to OGT via naso-gastric tubing and to provide a clinical useful cut-off value for ID when using the insulin quantification performed with an equine-optimized insulin enzyme-linked immunosorbent assay., Results: Data visualization revealed no clear separation in the serum insulin concentration of insulin sensitive and insulin dysregulated horses during OGT. Therefore, a model based clustering method was used to circumvent the use of an arbitrary limit for categorization. This method considered all data-points for the classification, taking into account the individual insulin trajectory during the OGT. With this method two clusters were differentiated, one with low and one with high insulin responses during OGT. The cluster of individuals with low insulin response was consistently detected, independently of the initialization parameters of the algorithm. In this cluster the 97.5% quantile of insulin is 110 µLU/mL at 120 min. We suggest using this insulin concentration of 110 µLU/mL as a cut-off value for samples obtained at 120 min in OGT., Conclusion: OGT performed with 1 g/kg BW glucose and administration via naso-gastric tubing can easily be performed under clinical settings. Application of the cut-off value of 110 µLU/mL at 120 min allows assessment of ID in horses.

Enteral nutrition improves survival rates and hospitalization times. Some diseases affecting the oral cavity can hinder spontaneous nutrition; in these cases the use of an esophagostomic tube can resolve nutritional problems. The innovative method described in this study is easier and more rapid than those currently known because the end of the tube does not need to be extracted from the oral cavity and then be reinserted with a number of maneuvers into the esophagus. The procedure does not require specific instruments, endotracheal intubation, and nor does it require the head to be moved or lifted. In addition, it can be carried out without the support of an assistant even with big or giant dogs. The new method involves the introduction of hemostatic forceps into the oral cavity, which pass through the esophagus wall and skin, then the distal extremity of the tube is firmly held between the extremity of the forceps and oriented caudally. The forceps, holding the tube, need to be retracted in the esophagus and then pushed ventrally and aborally in order to pass the esophagus stoma, without needing to extract the tube from the oral cavity and thus the risk of tube kinking., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Ingestion of geosediment (further referred as sand) may cause weight loss, diarrhea and acute or recurrent colic in horses. Our aim was to compare the efficacy of three treatment protocols in clearing colonic sand accumulations in clinical patients. This retrospective clinical study consisted of 1097 horses and ponies, which were radiographed for the presence of colonic sand. Horses included to the study (n = 246) were displaying areas of sand in the radiographs of ≥75 cm 2 and were treated medically monitoring the response with radiographs. The horses were assigned into three groups based on the given treatment: Group 1 was fed psyllium [1 g/kg body weight (BW)] daily at home for a minimum of 10 days (n = 57); Group 2 was treated once with psyllium or magnesium sulfate by nasogastric tubing followed by daily feeding of psyllium (1 g/kg BW) at home for a minimum of 10 days (n = 19), and Group 3 was treated by daily nasogastric tubing for 3-7 days with psyllium and/or magnesium sulfate (1 g of each/kg BW) (n = 170)., Results: The initial area of sand did not differ significantly between the treatments. Group 3 had significantly less residual sand than Groups 1 and 2, and the proportion of resolved horses was higher in Group 3 than in Groups 1 and 2., Conclusions: Daily nasogastric tubing with psyllium and/or magnesium sulfate for 3-7 days removes large accumulations of sand from the colon in horses more effectively than feeding psyllium for at least 10 days.

Objective: To develop and describe a technique for percutaneous radiologic gastrojejunostomy tube placement in the dog., Design: Prospective technique development study., Setting: University teaching hospital., Animals: Six healthy adult male Beagles., Interventions: Following anesthetic induction, fluoroscopic and ultrasound guidance were used to identify an appropriate gastropexy site on the left lateral abdomen. Gastropexy was performed using gastrointestinal suture anchors. An over-the-wire catheter technique using fluoroscopic guidance was used to achieve jejunal access. An 18F/8F, 58 cm, dual-lumen gastrojejunal feeding tube was placed via serial over-the-wire dilation of the body wall using an 18F peel-away introducer kit. Tube location was determined radiographically immediately following placement and on days 2, 4, after emesis on day 4, and at time of gastrojejunal feeding tube removal (day 16-18)., Measurements and Main Results: Percutaneous radiologic gastrojejunostomy (PRGJ) tube placement was successful in all dogs. Median time to pyloric passage with the guide wire was 23.5 minutes (range, 9-93 minutes). Median total procedure time was 53 minutes (range, 49-113 minutes). Significant tube migration was not observed at any point during the study. One dog developed linear foreign body obstruction secondary to the tube on day 5 that was relieved by release of the jejunal component. Other complications were minor and included mild-to-moderate peristomal inflammation in all dogs and removal of the feeding tube on day 3 by 1 dog. Feedings were well tolerated in all dogs., Conclusions: PRGJ tube placement in the dog is a safe and minimally invasive technique that allows for jejunal feeding without surgery or endoscopy. The high success rates, acceptable procedural times, and minimal complications are appealing for use in critically ill patients. Although additional evaluations are needed, PRGJ tube placement may be considered for dogs that require postpyloric feeding with or without gastric decompression., (© Veterinary Emergency and Critical Care Society 2016.)

Objective: To describe the use of postoperative intrajejunal feeding and to evaluate the association of preoperative plasma albumin concentrations with intrajejunal feeding-related complications and clinical outcome., Design: Prospective, observational study., Setting: University veterinary teaching hospital., Animals: Sixty-four dogs., Interventions: Jejunostomy tube placement during abdominal surgery., Measurements and Main Results: Most dogs (81%) survived. The median intrajejunal feeding period was 2.1 days (range: 1-16 days; n = 64). Only 3 (5%) dogs received their estimated resting energy requirement by intrajejunal feeding. Of dogs that were fed intrajejunally (58 out of 64), most (55 out of 58) received intrajejunal feeding within 24 hours after surgery. Energy provision via the jejunal feeding tube did not differ between dogs with and without complications (P = 0.592), or between nonsurvivors and survivors (P = 0.298). Thirty-five dogs ate voluntarily concurrently with intrajejunal feeding. Of dogs that ate voluntarily concurrently with intrajejunal feeding for ≤50% of the postoperative period, most (74%) survived to discharge. Complications were seen in 22% of dogs, and none were life-threatening; gastrointestinal signs were most common. There was no difference in preoperative plasma albumin concentration between dogs with and without complications (P = 0.432) and between nonsurvivors and survivors (P = 0.727). Fecal score was not significantly different between the 2 liquid diets studied (FormulaV Enteral Care HLP and CliniCare Canine/Feline; P = 0.927)., Conclusions: A jejunostomy tube placed during abdominal surgery was likely to be used at the study institution. Few complications were seen and none were life-threatening. Intrajejunal feeding was initiated early after surgery and did not interfere with the initiation of voluntary oral intake. Fecal scores were high and were useful for an objective assessment of fecal consistency in dogs with intrajejunal feeding., (© Veterinary Emergency and Critical Care Society 2016.)

Background: Early enteral nutrition in dogs and cats can have significant benefit in the therapeutic management of critical illness. Blind placement of nasogastric or nasoesophageal feeding tubes to accomplish this goal has become standard practice. However, complications from tube misdirection into the tracheobronchial tree can lead to significant patient morbidity and mortality. Safe and consistent alternatives are desirable to minimize these risks., Key Concepts: A modified method for placement of nasoenteric tubes is described. The main variation from standard procedure involves a second tube measurement, with the distal tip of the tube positioned at the thoracic inlet and measured to the nostril. The tube is advanced to this level and tested for negative pressure using a 12 mL syringe attached to the end of the feeding tube. This improves confidence in esophageal positioning before complete advancement of the tube to its distal endpoint., Significance: This procedural adaptation to feeding tube placement has the potential to reduce bronchopulmonary trauma from intratracheal misdirection by providing an early safety check to identify malpositioning. Prospective validation studies are needed to support its advantages over standard tube placement techniques., (© Veterinary Emergency and Critical Care Society 2016.)

Objective: To determine optimal techniques for CT enterography in clinically normal dogs and to evaluate luminal distention after oral administration of lactulose solution as a contrast agent., Animals: 15 healthy dogs., Procedures: CT was performed in a control group (2 dogs that underwent CT to evaluate metastasis and 5 other dogs). In a bolus administration group (5 dogs from the control group), lactulose solution (1.34 g/mL) was administered (60 mL/kg) rapidly via gastric tube to anesthetized dogs, and CT was performed every 10 minutes for 1 hour. In a continuous administration group of 8 other dogs, lactulose solution (60 mL/kg) was administered slowly via nasoesophageal tube over a period of 45 minutes. Then, 15 minutes after anesthetic induction, CT was performed every 10 minutes for 1 hour. Luminal distention of the small intestines was evaluated qualitatively by use of a 3-point scale., Results: All small intestinal segments had poor luminal distention in the control group. The terminal ileum had poor luminal distention for the bolus administration group. Nearly all segments had good luminal distention for the continuous administration group with mild adverse effects. Luminal distention scores from 0 to 20 minutes after lactulose administration were significantly higher than scores from 30 to 60 minutes. Interobserver reproducibility was high for all intestinal segments., Conclusions and Clinical Relevance: CT performed between 0 and 20 minutes after continuous administration of lactulose solution (60 mL/kg) may reveal adequate luminal distention for examination of small intestinal segments in dogs.

Flupirtine (FLU) is a non-opioid analgesic drug, with no antipyretic or anti-inflammatory effects, used in the treatment of a wide range of pain states in human beings. It does not induce the side effects associated with the classical drugs used as pain relievers. The aim of this study was to evaluate the pharmacokinetic profiles of FLU after IV and PO administration in healthy horses. Six mixed breed adult mares were randomly assigned to two treatment groups using an open, single-dose, two-treatment, two-phase, paired, cross-over design (2 × 2 Latin-square). Group 1 (n = 3) received a single dose of 1 mg/kg of FLU injected IV into the jugular vein. Group 2 (n = 3) received FLU (5 mg/kg) via nasogastric tube. The animals then swapped groups after a 1-week wash-out period and the doses were repeated. Blood samples (5 mL) were collected at 0.25, 0.5, 0.75, 1, 1.5, 2, 4, 6, 8, 10, 24, 36 and 48 h and plasma was then analysed by a validated HPLC method. Some mild and transient adverse effects (that spontaneously resolved within 5 min) were observed in 2/6 animals after IV administration. No adverse effects were noticed in the PO administration group. After IV and PO administrations, FLU was detectable in plasma for up to 36 h. The mean elimination half-life was longer after PO (10.27 h) than after IV (3.02 h) administration. The oral bioavailability was 71.4 ± 33.1%. After compartmental simulation/modelling, an oral dose of 2.6 mg/kg was calculated to give Cmax and AUC values in horses similar to those reported in humans after a clinical dose administration with a theoretical FLU effective plasma concentration of 187 ng/mL. These findings may form the basis for further studies concerning this active ingredient in equine medicine., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Neonatal foals have unique pharmacokinetics, which may lead to accumulation of certain drugs when adult horse dosage regimens are used. Given its lipophilic nature and requirement for hepatic metabolism, metronidazole may be one of these drugs. The purpose of this study was to determine the pharmacokinetic profiles of metronidazole in twelve healthy foals at 1-2.5 days of age when administered as a single intravenous (IV) and intragastric (IG) dose of 15 mg/kg. Foals in the intravenous group were studied a second time at 10-12 days of age to evaluate the influence of age on pharmacokinetics within the neonatal period. Blood samples were collected at serial time points after metronidazole administration. Metronidazole concentration in plasma was measured using LC-MS. Pharmacokinetic parameters were determined using noncompartmental analysis and compared between age groups. At 1-2.5 days of age, the mean peak plasma concentration after IV infusion was 18.79 ± 1.46 μg/mL, elimination half-life was 11.8 ± 1.77 h, clearance was 0.84 ± 0.13 mL/min/kg and the volume of distribution (steady-state) was 0.87 ± 0.07 L/kg. At 10-12 days of age, the mean peak plasma concentration after IV infusion was 18.17 ± 1.42 μg/mL, elimination half-life was 9.07 ± 2.84 h, clearance was 1.14 ± 0.21 mL/min/kg and the volume of distribution (steady-state) was 0.88 ± 0.06 L/kg. Oral approximated bioavailability was 100%. Cmax and Tmax after oral dosing were 14.85 ± 0.54 μg/mL and 1.75 (1-4) h, respectively. The elimination half-life was longer and clearance was reduced in neonatal foals at 1-2.5 days as compared to 10-12 days of age (P = 0.006, P = 0.001, respectively). This study warrants consideration for altered dosing recommendations in foals, especially a longer interval (12 h)., (© 2014 John Wiley & Sons Ltd.)

The objective of the study was to compare the performance of five types of stomach tubes for rumen fluid sampling. Rumen fluid was sampled in rumen fistulated cows assigned to a 5×5 Latin square study design. The pH values of samples taken by stomach tubes and via fistulas were measured; the results were compared with indwelling sensor measurements. The practicability of the stomach tubes for regular use was tested in the field. Rumen fluid samples were obtained rapidly. Volumes for transfaunation could be obtained. The pH-values of samples taken with the four out of the five tubes (Dirksen, Geishauser, tube 4 and a simple water hose used with a gag) did not show significant differences to samples taken via rumen fistulas. Mean differences ranged between -0.02 and +0.09. Samples taken with tube 4 and the water hose showed also no significant differences to pH-sensor measurements. This study demonstrates that stomach tubes are suitable for rumen fluid sampling. Tube 4 seems to be the best probe for work in the field. It was well tolerated by the animals, saliva contamination is negligible. We, therefore, conclude that the evaluation of rumen acid base status in the field is possible., (British Veterinary Association.)

Sinusitis has not been reported as a complication of long-term nasogastric intubation in horses. We describe 3 horses that developed nosocomial sinusitis following abdominal surgery with associated perioperative nasogastric intubation. Sinusitis was suspected by the presence of malodorous discharge and confirmed by percussion, upper airway endoscopy, radiographs (n = 3), and bacterial culture (n = 1).

This case report presents two cases of inadvertent intrapleural nasogastric tube (NGT) misplacement with consequent creation of a bronchopleural fistula and the development of an iatrogenic pneumothorax in dogs. Due to the simplicity and relative ease of NGT placement and the lack of reported life-threatening complications in the veterinary literature, the serious risks associated with this procedure are often overlooked. Although pulmonary complications with NGT misplacement have been previously reported in the human literature, serious and potentially fatal complications have not been currently described in veterinary patients. Both of the cases described herein were medically managed with successful outcomes; however, one case was associated with significant morbidity.

Objective: To determine the oral bioavailability, single and multidose pharmacokinetics, and safety of silibinin, a milk thistle derivative, in healthy horses., Animals: 9 healthy horses., Procedures: Horses were initially administered silibinin IV and silibinin phospholipid orally in feed and via nasogastric tube. Five horses then consumed increasing orally administered doses of silibinin phospholipid during 4 nonconsecutive weeks (0 mg/kg, 6.5 mg/kg, 13 mg/kg, and 26 mg/kg of body weight, twice daily for 7 days each week)., Results: Bioavailability of orally administered silibinin phospholipid was 0.6% PO in feed and 2.9% via nasogastric tube. During the multidose phase, silibinin had nonlinear pharmacokinetics. Despite this, silibinin did not accumulate when given twice daily for 7 days at the evaluated doses. Dose-limiting toxicosis was not observed., Conclusions and Clinical Relevance: Silibinin phospholipid was safe, although poorly bio-available, in horses. Further study is indicated in horses with hepatic disease.

The zebrafish has become an important in vivo model in biomedical research. Effective methods must be developed and utilized to deliver compounds or agents in solutions for scientific research. Current methods for administering compounds orally to adult zebrafish are inaccurate due to variability in voluntary consumption by the fish. A gavage procedure was developed to deliver precise quantities of infectious agents to zebrafish for study in biomedical research. Adult zebrafish over 6 months of age were anesthetized with 150 mg/L of buffered MS-222 and gavaged with 5 μl of solution using flexible catheter implantation tubing attached to a cut 22-G needle tip. The flexible tubing was lowered into the oral cavity of the zebrafish until the tip of the tubing extended past the gills (approximately 1 cm). The solution was then injected slowly into the intestinal tract. This method was effective 88% of the time, with fish recovering uneventfully. This procedure is also efficient as one person can gavage 20-30 fish in one hour. This method can be used to precisely administer agents for infectious diseases studies, or studies of other compounds in adult zebrafish.

Objective: To compare complication rates between nasoesophageal (NE) and nasogastric (NG) feeding tubes in dogs., Design: Retrospective study., Setting: University referral veterinary hospital., Animals: A total of 46 dogs that were fed through a NE (n = 28) or NG (n = 18) tube between January 2007 and December 2011 and that also had either thoracic radiography or computed tomography performed so that location of the distal tip of the tube in either the esophagus or stomach could be confirmed., Interventions: None., Measurements and Main Results: The medical record of each eligible case was reviewed and data recorded included signalment, underlying disease, body weight, body condition score, medications, duration of feeding, diet used, and complications observed (ie, vomiting, regurgitation, diarrhea, early tube removal, clogged tube, epistaxis, pulmonary aspiration, hyperglycemia, and refeeding syndrome). Dogs with NE tubes were significantly younger than dogs with NG tubes (P = 0.03) but there were no other significant differences in signalment, underlying disease, medications, duration of anorexia, percent of resting energy requirement achieved, or change in weight during tube feeding. There also was no significant difference between the NE and NG groups for any of the recorded complications. Significantly fewer dogs in the NE group died or were euthanized (3/28) compared to the NG group (7/18; P = 0.02) but outcome was not associated with age, underlying disease, or any of the recorded tube complications., Conclusions: This study did not identify a difference in complication rate between NE and NG feeding tubes in dogs. Additional studies are required to determine the optimal terminal location of feeding tubes in dogs., (© Veterinary Emergency and Critical Care Society 2013.)

The zebrafish has emerged as a powerful model organism for studying intestinal development(1-5), physiology(6-11), disease(12-16), and host-microbe interactions(17-25). Experimental approaches for studying intestinal biology often require the in vivo introduction of selected materials into the lumen of the intestine. In the larval zebrafish model, this is typically accomplished by immersing fish in a solution of the selected material, or by injection through the abdominal wall. Using the immersion method, it is difficult to accurately monitor or control the route or timing of material delivery to the intestine. For this reason, immersion exposure can cause unintended toxicity and other effects on extraintestinal tissues, limiting the potential range of material amounts that can be delivered into the intestine. Also, the amount of material ingested during immersion exposure can vary significantly between individual larvae(26). Although these problems are not encountered during direct injection through the abdominal wall, proper injection is difficult and causes tissue damage which could influence experimental results. We introduce a method for microgavage of zebrafish larvae. The goal of this method is to provide a safe, effective, and consistent way to deliver material directly to the lumen of the anterior intestine in larval zebrafish with controlled timing. Microgavage utilizes standard embryo microinjection and stereomicroscopy equipment common to most laboratories that perform zebrafish research. Once fish are properly positioned in methylcellulose, gavage can be performed quickly at a rate of approximately 7-10 fish/ min, and post-gavage survival approaches 100% depending on the gavaged material. We also show that microgavage can permit loading of the intestinal lumen with high concentrations of materials that are lethal to fish when exposed by immersion. To demonstrate the utility of this method, we present a fluorescent dextran microgavage assay that can be used to quantify transit from the intestinal lumen to extraintestinal spaces. This test can be used to verify proper execution of the microgavage procedure, and also provides a novel zebrafish assay to examine intestinal epithelial barrier integrity under different experimental conditions (e.g. genetic manipulation, drug treatment, or exposure to environmental factors). Furthermore, we show how gavage can be used to evaluate intestinal motility by gavaging fluorescent microspheres and monitoring their subsequent transit. Microgavage can be applied to deliver diverse materials such as live microorganisms, secreted microbial factors/toxins, pharmacological agents, and physiological probes. With these capabilities, the larval zebrafish microgavage method has the potential to enhance a broad range of research fields using the zebrafish model system.

Objective: To assess gastric trocarization and orogastric tubing as a means of gastric decompression for the initial management of gastric dilatation-volvulus., Methods: Retrospective review of 116 gastric dilatation-volvulus cases from June 2001 to October 2009., Results: Decompression was performed via orogastric tubing in 31 dogs, gastric trocarization in 39 dogs and a combination of both in 46 dogs. Tubing was successful in 59 (75·5%) dogs and unsuccessful in 18 (23·4%) dogs. Trocarization was successful in 73 (86%) dogs and unsuccessful in 12 (14%) dogs. No evidence of gastric perforation was noted at surgery in dogs undergoing either technique. One dog that underwent trocarization had a splenic laceration identified at surgery that did not require treatment. Oesophageal rupture or aspiration pneumonia was not identified in any dog during hospitalization. No statistical difference was found between the method of gastric decompression and gastric compromise requiring surgical intervention or survival to discharge., Clinical Significance: Orogastric tubing and gastric trocarization are associated with low complication and high success rates. Either technique is an acceptable method for gastric decompression in dogs with gastric dilatation-volvulus., (© 2013 British Small Animal Veterinary Association.)

Six rumen-fistulated dairy cows were used in 2 trials to validate the technique for the collection of ruminal fluid by an oral stomach tube (OST). Trial 1 was conducted to compare the differences of ruminal fermentation parameters among rumen sites (cranial dorsal, cranial ventral, central, ventral, caudal dorsal, and caudal ventral). The ruminal fluid was collected once per day for 3 consecutive days through rumen cannula (RC). The samples were analyzed for pH, volatile fatty acids (VFA), ammonia N, sodium, potassium, calcium, chloride, and phosphorus concentrations. The ruminal fermentation parameters varied significantly among rumen sites. Compared with the central or ventral rumen, the cranial dorsal rumen had significantly higher pH, ammonia, and sodium concentrations and lower acetate, propionate, and butyrate concentrations, indicating that the sampling site may be one of the main factors contributing to the difference in ruminal fermentation parameters between the samples collected via the OST and RC. In trial 2, the fermentation parameters of ruminal fluid collected via OST at 2 insertion depths (180 or 200 cm) were compared with those of ruminal fluid collected via RC (ventral sac). Ruminal fluid was collected once per week at 5 to 6h after morning feeding. When the OST was inserted to a depth of 180 cm, the OST head was located in the cranial dorsal (atrium) of the rumen. The ruminal fluid collected via the OST had higher pH and sodium concentrations but lower VFA, potassium, calcium, and phosphorus concentrations than that collected via RC. However, when the OST was inserted to a depth of 200 cm, the OST head could pass through the front rumen pillar and reach the central rumen for sampling. No differences were found in pH, VFA, ammonia N, and ion concentrations between the samples collected via the 2 sampling methods. These results indicated that the OST should be inserted to reach the central rumen to obtain representative rumen fluid samples., (Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Objective: To compare the apparent efficiency of absorption of IgG and failure of passive transfer of immunity rates between calves fed colostrum by nipple bottle (NB) and oroesophageal tubing (OET)., Design: Randomized controlled study., Animals: 26 Holstein bull calves (age, 4 to 8 hours)., Procedures: Calves were randomly assigned to receive colostrum by either NB or OET. Pooled colostrum was used for feeding each group of calves. Calves received either a maximum of 4 L of colostrum fed through an NB over a period of 20 minutes or an equivalent volume of colostrum fed by OET. Subsequently, a pair of similarly aged calves received similar volumes of colostrum with similar immunoglobulin concentrations. Colostrum was fed only once. Thereafter, calves were fed 2 L of milk replacer every 12 hours. All calves survived to at least 48 hours of age. Serum samples were collected prior to feeding colostrum and at 48 hours of age for determination of serum immunoglobulin concentrations., Results: There were no differences in failure of passive transfer of immunity rates and apparent efficiency of absorption of IgG between calves fed by NB or OET. Volume of colostrum fed was the only significant variable in determining failure of passive transfer of immunity in calves at 48 hours., Conclusions and Clinical Relevance: Reported advantages and disadvantages of either feeding method are likely to be of minimal practical relevance in achieving adequate passive transfer of immunity in calves when calves are fed a similar volume of colostrum with comparable immunoglobulin concentrations.

Toltrazuril sulfone (ponazuril) is a triazine-based antiprotozoal agent with clinical application in the treatment of equine protozoal myeloencephalomyelitis (EPM). In this study, we synthesized and determined the bioavailability of a sodium salt formulation of toltrazuril sulfone that can be used for the treatment and prophylaxis of EPM in horses. Toltrazuril sulfone sodium salt was rapidly absorbed, with a mean peak plasma concentration of 2400 ± 169 (SEM) ng/mL occurring at 8 h after oral-mucosal dosing and was about 56% bioavailable compared with the i.v. administration of toltrazuril sulfone in dimethylsulfoxide (DMSO). The relative bioavailability of toltrazuril sulfone suspended in water compared with toltrazuril sulfone sodium salt was 46%, indicating approximately 54% less oral bioavailability of this compound suspended in water. In this study, we also investigated whether this salt formulation of toltrazuril sulfone can be used as a feed additive formulation without significant reduction in oral bioavailability. Our results indicated that toltrazuril sulfone sodium salt is relatively well absorbed when administered with feed with a mean oral bioavailability of 52%. Based on these data, repeated oral administration of toltrazuril sulfone sodium salt with or without feed will yield effective plasma and cerebrospinal fluid (CSF) concentrations of toltrazuril sulfone for the treatment and prophylaxis of EPM and other protozoal diseases of horses and other species. As such, toltrazuril sulfone sodium salt has the potential to be used as feed additive formulations for both the treatment and prophylaxis of EPM and various other apicomplexan diseases., (© 2011 Blackwell Publishing Ltd.)

An 82-cm fragment of nasogastric tube was removed from the stomach of an adult horse under standing sedation by use of an endoscope and electrocautery snare. This is the first report of successful non-surgical removal of a nasogastric tube fragment from the stomach of a horse.

Objective: To evaluate the isoflurane-sparing effects of lidocaine administered by constant rate infusion (CRI) during umbilical surgery in calves., Study Design: Randomized 'blinded' prospective clinical study., Animals: Thirty calves (mean 4.7 ± SD 2.5 weeks old) undergoing umbilical surgery., Methods: After premedication with xylazine (0.1 mg kg(-1) , IM), anaesthesia was induced with ketamine (4 mg kg(-1) , IV) and maintained with isoflurane in O(2) administered through a circle breathing system. The calves were assigned randomly to receive a bolus of 2 mg kg(-1) lidocaine IV after induction of anaesthesia, followed by CRI of 50 μg kg(-1) minute(-1) (group L, n=15) or a bolus and CRI of 0.9% sodium chloride (NaCl, group S, n=15). End-tidal isoflurane was adjusted to achieve adequate depth of anaesthesia. Heart rate, direct arterial blood pressure and body temperature were measured intraoperatively. Groups were compared by t- tests, anova or Mann-Whitney rank sum test as appropriate., Results: The end-tidal concentration of isoflurane (median, IQR) was significantly lower in group L [1.0% (0.94-1.1)] compared to group S [1.2% (1.1-1.5)], indicating a 16.7% reduction in anaesthetic requirement during lidocaine CRI. Cardiopulmonary parameters and recovery times did not differ significantly between groups., Conclusion and Clinical Relevance: Lidocaine CRI may be used as a supplement to inhalation anaesthesia during umbilical surgery in calves in countries where such a protocol would be within the legal requirements for veterinary use in food animals. This study did not show any measurable benefit to the calves other than a reduction in isoflurane requirement., (© 2011 The Authors. Veterinary Anaesthesia and Analgesia. © 2011 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesiologists.)

Interest in noninvasive feeding tube placement in companion animals led to the adaption of a human technique utilizing endoscopy to place nasojejunal feeding tubes. Data from medical records in which nasojejunal feeding tubes were attempted were reviewed. Feeding tubes were attempted and successfully placed in five dogs within a median of 35 min. Feeding tubes remained in place for approximately 7 days. Complications included facial irritation (5/5), sneezing (5/5), fractured facial sutures (4/5), vomiting (3/5), diarrhea (3/5), crimping of feeding tube (3/5), regurgitation (1/5), epistaxis (1/5), clogging of the feeding tube (2/5), and oral migration with premature removal of the feeding tube (1/5). The deployment technique used in this study was found to be cumbersome. Despite minor complications, endoscopy can be used to rapidly and accurately place nasoenteric feeding devices.

Objective: To describe the clinical use of a novel, minimally invasive fluoroscopic technique for the wire-guided placement of nasojejunal tubes (NJT) in dogs., Design: Retrospective study (September 22, 2006-October 2, 2010)., Setting: University veterinary teaching hospital., Animals: Twenty-six consecutive dogs with intolerance of, or contraindications to gastric feeding that underwent attempted fluoroscopic NJT placement. No dogs were excluded from analysis., Interventions: All dogs underwent attempted fluoroscopic NJT placement using a novel fluoroscopic wire-guided technique., Measurements and Main Results: Patient data were collected in concert with information about the NJT placement procedure as well as the maintenance and utilization of the tube. The primary diagnosis in dogs undergoing NJT placement was pancreatitis in 60%. The ability to achieve transpyloric passage of the tube was 92.3% (24/26) and the ability to achieve jejunal access was 78.2%. In the second half of the study period, the ability to achieve jejunal access was significantly higher than in the first half of the study period suggesting that technical proficiency improves over time. Mean duration of the procedure was 35.3±20 minutes. Significant oral migration was a complication of NJT placement in some dogs. The median duration of feeding was 3.3 days (range 0.3-10.5)., Conclusions: Fluoroscopic wire-guided NJT placement is a viable method for sustained postpyloric feeding in dogs. Success in acquiring jejunal access improves with experience. The NJT may be utilized as a strategy to provide enteral nutritional support to the population of dogs with contraindications to, or intolerance of gastric feeding., (© Veterinary Emergency and Critical Care Society 2011.)

Objective: To develop an indirect method for measurement of intraabdominal pressures in the standing horse using measurement of gastric pressures as a less invasive technique, and to compare this method with direct intraabdominal pressures obtained from the peritoneal cavity., Design: Prospective, experimental study., Setting: University-based equine research facility., Animals: Ten healthy adult horses, 7 geldings and 3 mares., Interventions: Gastric pressures were measured using a nasogastric tube with a U-tube manometry technique, while intraperitoneal pressures were measured with a peritoneal cannula. Measurements of intraabdominal pressure were obtained by both methods, simultaneously, and were evaluated using 5 increasing volumes of fluid infused into the stomach (0, 400, 1,000, 2,000, and 3,000 mL). Bias and agreement between the 2 methods were determined using Bland-Altman analysis and Lin's concordance correlation coefficients., Measurements and Main Results: Mean gastric pressure was 14.44 ± 4.69 cm H(2)O and ranged from 0 to 25.8 cm H(2)O. Intraperitoneal pressure measurements were generally subatmospheric, and ranged from -6.6 to 3.1 cm H(2) O (mean ± SD, -1.59 ± 2.09 cm H(2)O). Measurements of intraperitoneal pressures were repeatable; however, intra- and interindividual variance was significantly larger for measurements of gastric pressures. The mean and relative bias for comparison between the 2 techniques was 15.9 ± 5.3 cm H(2)O and 244.3 ± 199.2%, respectively. The Lin's concordance correlation coefficient between gastric and intraperitoneal pressures was -0.003 but this was not statistically significant (P=0.75)., Conclusions: There was no statistical concordance between measurements of intraabdominal pressure using gastric and intraperitoneal pressure measurement, indicating that gastric pressures cannot be substituted for intraperitoneal pressure measurement. Direct measurement of intraperitoneal pressures may be a more consistent method for comparison of intraabdominal pressures between horses, due to less variability within and between individuals., (© Veterinary Emergency and Critical Care Society 2011.)

Objective: To compare continuous to intermittent feeding at delivering prescribed nutrition in hospitalized canine and feline patients., Design: Retrospective clinical study., Setting: University teaching hospital., Animals: Fifty-four cats and 37 dogs., Measurements and Main Results: Twenty-four-hour periods of prescribed and delivered nutrition (kcal) were recorded, and the percentage of prescribed nutrition delivered (PPND) was calculated. If the patient received nasoenteric feeding for >1 day, then the average PPND per day was calculated. Frequency of gastrointestinal complications (vomiting, diarrhea, and regurgitation) was calculated per patient for each group. The PPND was not significantly different between patients fed continuously (99.0%) and patients fed intermittently (92.9%). Vomiting affected 29% of patients (26/91), diarrhea affected 26% of patients (24/91), and regurgitation affected 5% of patients (5/91). There was no significant difference in incidence of gastrointestinal complications between the patients fed continuously and the patients fed intermittently. There was a significantly higher incidence of diarrhea and regurgitation in dogs than in cats., Conclusions: PPND was not significantly different for continuous versus intermittent feeding via nasoenteric tubes. Frequencies of gastrointestinal complications were not significantly different between patients fed continuously and patients fed intermittently. Enterally fed dogs had a significantly higher frequency of regurgitation and diarrhea than enterally fed cats. Prospective studies are warranted to investigate causes for these potential inter-species differences.