Gastrointestinal disease in guinea pigs and rabbits

Rabbit Gastroenterology

Gastrointestinal (GI) disorders are a common cause of emergency presentation in rabbits. Gastrointestinal stasis is a syndrome that is frequently caused by various primary conditions (including but not limited to affections of the GI tract itself). Over the last years, clinical features, diagnosis, management, and prognosis of GI disorders-such as GI obstructions, appendicitis, rabbit hemorrhagic virus disease, or liver lobe torsion-have been studied. Recent data about diseases of the stomach, intestine, liver, and pancreas in rabbits are reviewed in this article.

Gastroenterology in Rodents

Gastrointestinal (GI) diseases are frequently diagnosed in rodents. Clinical signs are usually nonspecific and include anorexia, weight loss, chronic wasting, abdominal discomfort, gas accumulation in the intestine and stomach, and diarrhea. Malabsorption associated with GI dysfunction or gastroenteritis quickly leads to negative energy balance and metabolic acidosis. Therefore, all disorders of the GI tract should be treated as soon as possible. The article describes selected disorders of the GI tract in guinea pigs (Cavia porcellus), chinchillas (Chinchilla lanigera), degus (Octodon degus), and rats (Rattus norvegicus).

Three-Dimensional Morphometrical Study on Small Intestine in Rabbit Using Unbiased Design-Based Stereology

Three-dimensional structural parameters correlate better with the intestinal function compared to two-dimensional structural parameters. The objective of the present study was to investigate the three-dimensional morphometrical features of the small intestine in rabbits using a design-based stereology. Five adult male New Zealand rabbits were used in this research. The total volume, volume fraction of different layers, internal surface area, villus and circular folds amplification factors were estimated in the whole and various segments of the small intestine. The small intestine volume was estimated to be 59.57 ± 8.57 cm3. The jejunum and ileum showed the most and the least total volumes, respectively (p < 0.05). The volume fractions of the tunica mucosa, tela submucosa and tunica muscularis were 62.57% ± 2.78%, 21.11% ± 2.01% and 16.25% ± 0.94%, respectively. The minimum volume of the tela submucosa was observed in the ileum (p < 0.05) and the fractional volume of the tunica muscularis in the ileum was significantly more than those of other segments (p < 0.05). The surface area of the entire small intestine was estimated to be 8302.31 ± 1872.39 cm2. The jejunum and ileum segments showed the most and the least surface areas, respectively. The increase in the intestinal surface area attributable to the presence of villi was estimated to be 6.82 ± 0.84, and that for circular folds was accounted for 1.36 ± 0.09. The largest amplification factors of villi and circular folds were observed in the duodenum and ileum, respectively. Our data presented the three-dimensional morphometry of the small intestine of the rabbit as a translational model and provided basic findings for the diagnosis and treatment of intestinal diseases in this species.

CHRONIC GASTRIC INSTABILITY IN REHABILITATED VIRGINIA OPOSSUMS (DIDELPHIS VIRGINIANA)

Chronic gastric instability (CGI), potentially part of the gastric dilatation and volvulus (GDV) syndrome, was identified in four free-ranging Virginia opossums (Didelphis virginiana) treated at the Wildlife Rehabilitation Center of Minnesota in Roseville, Minnesota. These individuals displayed lack of expected weight gain, inappetence, gastric gas distension, and delayed gastric emptying time. One was diagnosed with GDV via diagnostic radiology, whereas the other three were diagnosed with suspected CGI using radiographs, ultrasound, and confirmed with exploratory surgery. Clinical signs fully resolved after surgical intervention and supportive management in all four cases. This case series illustrates the clinical signs, diagnostics, and treatment of CGI in Virginia opossums.

Use of subcutaneous maropitant at two dosages for pain management in domestic rabbits (Oryctolagus cuniculus) undergoing elective ovariohysterectomy or orchiectomy

OBJECTIVE

To describe the effect of two doses of maropitant on pain scores, food intake, and fecal output in domestic rabbits (Oryctolagus cuniculus) undergoing elective ovariohysterectomy or orchiectomy.

ANIMALS

26 (11 female, 15 male) rabbits from three institutions.

PROCEDURES

Rabbits were randomly assigned to one of three treatment groups: low-dose maropitant (LDM; 2 mg/kg SC once; n=8), moderate-dose maropitant (MDM; 4 mg/kg SC once; n=10), and control (saline equivalent to 4 mg/kg maropitant SC once; n=8), administered prior to surgery. Following surgery, all rabbits were provided buprenorphine (0.06 mg/kg q 8 hours) and meloxicam (1 mg/kg q 24 hours) intramuscularly. Rabbits were monitored using video surveillance postoperatively until 24 hours after surgery or discharge from the hospital, whichever came first. Pain scores were assessed by three blinded observers, and results were grouped into early (0-4 hours), mid (5-8 hours), and late (12-24 hours) time frames. Food intake and fecal output were compared between groups. Statistical analysis was performed using Chi square, Fisher's exact tests, and a mixed model approach.

RESULTS

There were no adverse effects with maropitant administration. Rabbits that received MDM had significantly lower pain scores in the mid-time frame and behavior scores in the late-time frame compared to controls. Male rabbits consumed more food than females and rabbits hospitalized longer than 12 hours consumed more food than those that were discharged prior. No significant differences were detected in facial grimace scale scores, food intake, or fecal production among treatment groups.

CONCLUSIONS AND CLINICAL RELEVANCE

Moderate dose maropitant decreased pain related behaviors in the mid-time frame and behavior scores in the late-time frame after surgery. Further studies are necessary to better characterize the potential use of maropitant in postoperative analgesia.

Effect of Agroindustrial Waste Substrate Fermented with Lactic Acid Bacteria and Yeast on Changes in the Gut Microbiota of Guinea Pigs

The aim of the study was to evaluate the impact of probiotics obtained from an agroindustrial waste substrate fermented with lactic acid bacteria and/or yeasts on the health and changes in the microbiota of the digestive tract of guinea pigs. Eighty male guinea pigs, Kuri breed, 30 days old and 250 g live weight, were randomly selected and divided into four groups of 20 animals each: T0, control; T1, Lactobacillus acidophilus and L. bulgaricus; T2, Saccharomyces cerevisiae and Kluyveromyces fragilis; and T3. L. acidophilus, L. bulgariccus, S. cerevisiae and K. fragilis. T1, T2 and T3 contained molasses-vinasse substrate in their base, the dose administered was 1.00 mL/animal orally every 3 days. The indicators evaluated were weight gain, occurrence of diarrhea and mortality, macroscopic lesions in the digestive tract organs and changes in the microbiota of the stomach, caecum, small and large intestine. Treatments T1, T2 and T3 improved weight gain (p < 0.05) and reduced the presence of guinea pigs with diarrhea (p < 0.05) and there was no mortality; animals in the control group presented a greater amount (p < 0.05) of macroscopic lesions in the digestive tract organs; in the T1, T2 and T3 groups there was an improvement in the natural microbiota. It is concluded that the inclusion of a microbial additive in young guinea pigs improves intestinal health and consequently improves weight gain, reduces diarrhea and deaths and normalizes the natural microbiota of the gastrointestinal tract.

The acute vapour inhalation toxicity of 2-butoxyethanol. Points considered when designing and conducting a study in Guinea pigs and evaluating existing inhalation toxicity data on low volatility solvents

This publication reports the outcome of an acute inhalation toxicity study with guinea pigs by nose-only exposure to the substance 2-butoxyethanol at exposures close to the maximum attainable saturation vapour concentration. We describe the methods used to ensure exposure only to saturation vapour at a level as high as could be practically achieved whilst avoiding aerosol formation. We consider the practical difficulties and implications of testing substances at or close to their saturation vapour concentration and the criteria that should be used to critically assess such studies, especially with reference to the GHS (Globally Harmonised System) for classification and labelling, where a clear differentiation between gases, vapours and dust and mists applies. Guinea pigs showed no adverse effects when exposed for 4 h to the maximum attainable concentration of pure 2-butoxyethanol vapour. If guinea pigs are regarded as the most appropriate species to assess short term toxicity to humans from exposure to 2-butoxyethanol, because they are like humans not sensitive to haemolysis of red blood cells caused by exposure to the substance, then the data from this study shows that 2-butoxyethanol presents a low acute inhalation toxicity hazard.

Comparison of two point of care lactate instruments in guinea pigs (Cavia porcellus)

Background

Lactate measurements have been utilized as diagnostic and prognostic tools for a variety of veterinary species. Reference intervals for lactate have not been published or validated in guinea pigs.

Methods

Whole blood from 48 anesthetized laboratory guinea pigs (46 Dunkin Hartley [38 males, eight females]; two Strain 13 [two males]) was analyzed using two point of care instruments (iSTAT and Lactate Plus). There were two consecutive timepoints on the iSTAT (iSTAT time 1 and time 2) and three consecutive timepoints on the Lactate Plus (Lactate Plus time 1, time 2, and time 3).

Results

There was agreement with no constant or proportional bias between the two instruments compared at equivalent timepoints (iSTAT time 1 and Lactate Plus time 3) as determined by Bland-Altman (bias: -0.19; 95% LoA: -0.55 to 0.16) and Deming linear regression analyses (slope: 1.092, 95% confidence intervals (CI): -0.9 to 1.29; y-intercept: 0.09, 95% CI: -0.12 to 0.30). Reference intervals for iSTAT time 1 were 0.49 to 1.83 mmol/L and Lactate Plus time 1 were 0.60 to. 2.2 mmol/L. There was a significant increase in lactate values from iSTAT time 1 to iSTAT time 2 and from Lactate Plus time 1 to Lactate Plus time 3.

Conclusions and Clinical Relevance

This study found strong agreement between the point of care instruments. Reference intervals for lactate for both the iSTAT and Lactate Plus instruments were similar to canine and feline intervals. Analysis should occur within 5 minutes of sample collection. Future work should assess lactate as a prognostic indicator in guinea pigs.

Clinicopathological and radiographic indicators for orogastric decompression in rabbits presenting with intestinal obstruction at a referral hospital (2015-2018)

BACKGROUND

Orogastric decompression is regularly recommended as a part of both medical and pre-surgical treatment for small intestinal obstruction in rabbits. However, guidelines as to when orogastric decompression is indicated are sparse.

METHODS

The medical records of 35 rabbits diagnosed with gastrointestinal obstruction over a 3-year period were examined. Differences in presentation, clinicopathological and radiographic examination findings, treatments and outcome were evaluated.

RESULTS

Approximately 49% of the cases evaluated were considered to have non-life-threatening disease, while 51% were considered to have life-threatening disease. The severity of gastric obstruction was correlated with the severity of hyperglycaemia (average 25.7 mmol/L; 463 mg/dl) and corresponding hyponatraemia (Na < 138 mmol/L; 138 mEq/L). These patients were treated with orogastric decompression and medical management only.

LIMITATIONS

This is a retrospective study and there are inherent limitations involving the quality of the data and data collection. Additional studies should be completed that strive for larger sample sizes to compare the differences in outcome between surgical and medical management, as well as investigate the outcomes of rabbits with hyperglycaemia and hyponatraemia that did not have an orogastric decompression performed.

CONCLUSIONS

Blood glucose and sodium concentrations, in combination with radiographic findings, may aid clinicians in determining if orogastric decompression is indicated to stabilise rabbits with small intestinal obstructive disorders.

Case report: Diagnosis and treatment of a chinchilla’s old radius and ulna fracture

The cortex of the limb bones of chinchillas is very thin and brittle, so it is prone to fractures of the limb bones, among which fractures of the tibia, radius and ulna are the most frequent types. When a chinchilla has a closed fracture, it can be immobilized with a splint, cast, or bandage. If the broken end of the fracture pierces the skin, it is best to choose internal fixation or external fixation brackets for treatment. In this report, a 0.661 kg, 2-year-old male uncastrated chinchilla was presented to the Veterinary Teaching Hospital of Huazhong Agricultural University due to an old fracture of the right forearm. With the consent of the owner, we decided to use a 25-gauge needle as an IM pin to fix the fracture. Ten days after surgery, the wound had healed well, and the limb could support body weight, but the palm did not show a grasping position. Twenty four days after the operation, the affected limb had not regained the ability to grasp. The X-ray showed a slight rotation of the IM pin and good callus growth in the ulna, but not in the radius. One month after the operation, it was found that the function of the affected limb of the chinchilla was normal and the grasping ability was restored through follow-up consultation and the return visit.

Effects of Buprenorphine and Carprofen on Appetite in New Zealand White Rabbits (Oryctolagus cuniculus)

Rabbits are especially susceptible to adverse effects related to surgery, which can lead to inappetence and gastrointestinal (GI) stasis. However, these adverse effects may be related to discomfort from the procedure, anesthesia, the analgesics used, and the stress of restraint for analgesic administration. Opioid and NSAID analgesics which are frequently used in rabbits, can contribute to these adverse effects. This study compared the clinical GI side effects of buprenorphine and carprofen to saline controls in New Zealand White rabbits after a nonsurgical anesthetic event. Nine rabbits (3 females and 6 males, aged 8 to 20 mo) were randomly rotated through 5 treatment groups with a 7-d washout period between treatments: anesthesia control (no treatment), buprenorphine (0.05 mg/kg SC every 12 h for 72 h), carprofen (5 mg/kg SC every 24 h for 72 h), twice daily saline control (equivalent volume to buprenorphine SC every 12 h for 72 h), and once daily saline control (equivalent volume to carprofen SC every 24 h for 72 h). All rabbits were anesthetized 5 times and received initial treatments on the day of anesthesia. Generalized linear mixed models were used to assess food intake, water intake, and fecal output score for 7 days after anesthesia. Analysis showed that buprenorphine-treated rabbits had a significant 4-d decrease in food intake and a 3-d decrease in fecal output score compared with baseline. None of the other treatment groups showed any changes in food intake or fecal output score compared with baseline. These findings demonstrate that in the absence of pain, buprenorphine significantly depresses food intake in rabbits and that restraint and injections have minimal effect on food intake despite the possibility of increased stress.

Cross-sectional survey of husbandry for pet guinea pigs (Cavia porcellus) in New Zealand

AIMS

To describe basic husbandry (veterinary care, substrate and bedding, toys, frequency of cleaning) provided to guinea pigs (Cavia porcellus) by a sample of owners in New Zealand.

METHODS

Respondents were invited to complete a survey disseminated through the social media channels of animal interest and advocacy groups (3 September 2020 to 3 November 2020). Respondents who agreed to participate were asked a range of questions regarding provision of husbandry to their oldest pet guinea pig. Descriptive statistics are reported here relating to husbandry, length of ownership, provision of substrate, bedding and toys, frequency of cleaning and veterinary care.

RESULTS

A total of 503 responses were received, of which 329 complete responses were analysed. Of these respondents, 208/329 (63.2%) had owned guinea pigs for more than 2 years. Most owners provided a cage with a wooden base as substrate (144/321, 44.9%), bedding (308/329; 93.6%) and toys (169/329; 51.1%). Half (176/329; 53.5%) of respondents reported taking their guinea pig to a veterinarian. Just over half of owners surveyed cleaned water (165/329; 50.1%) and food (181/329; 55.0%) bowls daily, and a third picked up droppings (109/329; 33.1%) daily.

CONCLUSIONS AND CLINICAL RELEVANCE

While owners provided an array of toys, and a range of bedding and substrate types to their guinea pigs, cages were cleaned out less frequently than recommended, and it was common for guinea pig cages to be cleaned out less frequently than recommended. Future research is required to provide robust and evidence-based links between husbandry and the welfare of pet guinea pigs.

Retrospective analysis of liver lobe torsion in pet rabbits: 40 cases (2016-2021)

BACKGROUND

Liver lobe torsion (LLT) in rabbits can be under-recognised and potentially fatal. The clinical features of cases presented to an exotic animal veterinary service in Australia were retrospectively reviewed.

METHOD

Medical records of confirmed rabbit LLT cases between 2016 and 2021 were reviewed for signalment, clinical signs and findings, diagnostic imaging results, management strategies and outcomes. Variables of interest were analysed for statistical association with outcome.

RESULTS

A total of 40 rabbits were included. The mean presenting age was 56.2 months (SD 30.5). Neutered males (23/40, 57.5%) were over-represented. Common clinical signs and findings included reduced appetite (40/40, 100%), lethargy (32/40, 80.0%), reduced faecal production (16/40, 40.0%), a doughy distended stomach (20/40, 50.0%), pale mucous membranes (19/40, 47.5%) and hypothermia (17/40, 42.5%). Anaemia and elevated plasma alanine aminotransferase and blood urea nitrogen were common clinicopathologic findings. Computed tomography (CT) was performed in 34 of 40 rabbits, confirming the presence and position of LLT (34/34, 100%), stenosis of the caudal vena cava or portal system (28/34, 82.4%) and increased free peritoneal fluid (29/34, 85.3%). Fifteen (15/40, 37.5%) rabbits were medically managed, and surgical intervention was performed in 23 of 40 (57.5%) rabbits. Overall, 30 of 40 (75.0%) rabbits survived. Surgical intervention did not confer a significant difference in outcome compared to medical management (odds ratio 0.77, 95% confidence interval 0.15-4.10, p = 0.761).

CONCLUSION

CT can be an invaluable diagnostic modality for rabbit LLT. Favourable outcomes can be achieved in selected cases with medical management alone.

Paracostal versus ventral midline approach for caudate liver lobectomy in the rabbit

Objective

To describe the paracostal approach to caudate liver lobectomy in rabbits and compare the outcome of paracostal versus ventral midline approach for caudate liver lobectomy in rabbits with caudate liver lobe torsion (LLT).

Study design

Cadaveric and retrospective study.

Animals

Normal rabbit cadavers (n = 5) and rabbits with caudate LLT (n = 22).

Methods

Cadavers – a right paracostal or ventral midline approach was made. Accessibility of the caudate liver lobe and relationship to the gastrointestinal (GI) tract were assessed. Clinical LLT cases – 9 cases were treated via the paracostal approach and 13 were treated via the ventral midline approach. Medical records (January, 2018 to October, 2021) were reviewed. Anesthesia and surgical times, mortality rate, and relevant clinical data were compared between groups.

Results

In cadavers, caudate liver lobectomy was feasible through a paracostal approach without retraction of the GI tract. In clinical cases, there was no difference in anesthesia time (P = 0.1397) or surgical time (P = 0.9462) between groups. All rabbits that underwent paracostal approach survived to discharge. Mortality was lower (P = .053) and postoperative time until eating was shorter (P = .0238) for patients undergoing paracostal approach.

Conclusion

Rabbits experienced lower mortality and shorter time until eating when treated through a right paracostal approach compared to the ventral midline approach. The paracostal approach resulted in minimal to no manipulation of the GI tract.

Clinical significance

A right paracostal approach for caudate liver lobectomy in rabbits provides good exposure while avoiding GI tract manipulation. This approach may result in improved survival and earlier eating in rabbits with caudate LLT.

Retrospective analysis of risk factors, clinical features, and prognostic indicators for urolithiasis in guinea pigs: 158 cases (2009-2019)

OBJECTIVE

To investigate risk factors, clinical features, and prognostic indicators in guinea pigs with urolithiasis.

ANIMALS

158 guinea pigs with urolithiasis.

PROCEDURES

Medical records of an exotics animal specialty service were searched, identifying guinea pigs with urolithiasis. Signalment, clinical data, and outcomes were recorded. Variables of interest were analyzed for statistical associations with outcome.

RESULTS

Overall, 54.4% (86/158) of animals survived to discharge. Median survival time was 177 days. Females (53.2%; 84/158) were more common than males (46.8%; 74/158). Males were presented younger (mean age, 3.64 years) than females (4.41 years). In 81 of 154 (52.5%) cases, animals were presented with primary urinary concerns, while 73 (47.5%) presented for nonurinary primary concerns. Females more commonly presented with distal urinary tract urolithiasis (63/84; 75%) but fared better overall with a longer median survival time (1,149 days) than males (59 days). Surgical intervention was not a risk factor for nonsurvival; however, increased age (> 4.1 years), male sex, anorexia, weight loss, and lower rectal temperature (< 37.2 °C) on presentation were associated with nonsurvival. Reoccurrence was noted in 13.9% (22/158) of cases, at an average of 284 days.

CLINICAL RELEVANCE

Urolithiasis should always be considered a differential diagnosis for any unwell guinea pig. In particular, distal urinary tract urolithiasis should be considered in females. A poorer prognosis was associated with older, male guinea pigs, and those displaying anorexia, weight loss, and hypothermia. The need for surgical intervention should not confer a poorer outcome. Further studies are needed to determine specific risk factors and identify possible preventative measures.

Research-Relevant Conditions and Pathology of Laboratory Mice, Rats, Gerbils, Guinea Pigs, Hamsters, Naked Mole Rats, and Rabbits

Animals are valuable resources in biomedical research in investigations of biological processes, disease pathogenesis, therapeutic interventions, safety, toxicity, and carcinogenicity. Interpretation of data from animals requires knowledge not only of the processes or diseases (pathophysiology) under study but also recognition of spontaneous conditions and background lesions (pathology) that can influence or confound the study results. Species, strain/stock, sex, age, anatomy, physiology, spontaneous diseases (noninfectious and infectious), and neoplasia impact experimental results and interpretation as well as animal welfare. This review and the references selected aim to provide a pathology resource for researchers, pathologists, and veterinary personnel who strive to achieve research rigor and validity and must understand the spectrum of "normal" and expected conditions to accurately identify research-relevant experimental phenotypes as well as unusual illness, pathology, or other conditions that can compromise studies involving laboratory mice, rats, gerbils, guinea pigs, hamsters, naked mole rats, and rabbits.

Ethnopharmacological survey and antibacterial activity of medicinal plant extracts used against bacterial enteritis in rabbits

Bacterial enteritis is one of the diseases negatively affecting the rabbit farming industry. Communities across the globe are using medicinal plants as an alternative treatment against many diseases in rabbits. This study aimed at identifying medicinal plants used by local farmers in Cameroon and evaluate their antibacterial activity alone and in combination with oxytetracycline against some bacterial causative agents of diarrhoea in rabbits. The ethnopharmacological survey was performed in Cameroon’s Western and Central regions, where breeders were interviewed about their knowledge on the medicinal plants and plant parts often used to cure rabbit diseases, the methods of preparation and the route of administration. Plants were collected, and extracts were prepared by decoction, infusion and maceration using distilled water. The antibacterial activity of extracts and combinations was evaluated against enteropathogenic Escherichia coli, Salmonella enterica and Clostridium perfringens (WAL-14572 HM-310) using the microdilution and checkerboard methods. From the survey, fifteen medicinal plants belonging to nine families, with Asteraceae being the most represented, were identified as currently used to treat diarrhoea in rabbits. Bidens pilosa and Psidium guajava were the most mentioned medicinal plant species with 24 and 17 citations, respectively. Leaves were the most commonly used plant parts, and maceration in water was the primary preparation method of remedies administered orally. Out of the forty-five extracts prepared, only six from Tithonia diversifolia (TdlM, TdlI, TdlD) and Psidium guajava (PglM, PglI, PglD) exhibited potency with MIC values ranging from 1.25 to 5 mg/mL. The combination of infusion extract from leaves of Tithonia diversifolia (TdlI) and decoction extract from Psidium guajava (PglD) exhibited synergistic interaction (FICI = 0.312; 0.281; 0.265), while oxytetracycline in combination with decoction extract from leaves of Psidium guajava (PglD) exhibited a synergistic interaction (FICI = 0.5). The phytochemical screening of the six extracts revealed polyphenols, glycosides, saponins, terpenoids, anthraquinones, tannins and flavonoids. The antibacterial activity of extracts from medicinal plants P. guajava and T. diversifolia demonstrated in the present study supports the use of these plants by farmers of the targeted localities to treat diarrhoea in rabbits.

Computed tomography with Hounsfield unit assessment is useful in the diagnosis of liver lobe torsion in pet rabbits (Oryctolagus cuniculus)

Clinical signs of liver lobe torsion in rabbits are often nonspecific and mimic those that are also generally detected with gastrointestinal stasis. Nonspecific clinical signs may result in pursuit of full-body imaging such as computed tomography (CT). The aim of this multicenter, retrospective, case series study was to describe CT findings of liver lobe torsion in a group of rabbits. Computed tomography studies of six rabbits with confirmed liver lobe torsion by surgery or necropsy were evaluated. The caudate liver lobe was affected in six out of six rabbits and was enlarged, rounded, hypoattenuating, heterogeneous, and minimally to noncontrast enhancing, with scant regional peritoneal effusion. Precontrast, mean Hounsfield units (HU) of the torsed liver lobe (39.3 HU [range, 24.4-48.1 HU]) were lower than mean HU of normal liver (55.1 HU [range, 49.6-60.8 HU]), with a mean torsed:normal HU ratio of 0.71 (range, 0.49-0.91). Postcontrast, mean HU of the torsed liver lobe (38.4 HU [range, 19.7-48.9 HU]) were also lower than mean HU of normal liver (108.4 HU [range, 84.5-142.0 HU]), with a lower postcontrast mean torsed:normal HU ratio of 0.35 (range, 0.14-0.48) compared to precontrast. Mean HU of torsed liver lobes had little difference pre- and postcontrast (postcontrast HU 1.0 times the average precontrast HU [range, 0.81-1.1]), and contrast enhancement of the torsed liver lobes was on average 50% lower than in normal liver. Liver lobe torsion should be considered in rabbits with an enlarged, hypoattenuating, heterogeneous, minimally to noncontrast enhancing liver lobe, particularly the caudate lobe, and scant regional peritoneal effusion.

Teixobactin Provides Protection against Inhalation Anthrax in the Rabbit Model

The use of antibiotics is a vital means of treating infections caused by the bacteria Bacillus (B.) anthracis. Importantly, with the potential future use of multidrug-resistant strains of B. anthracis as bioweapons, new antibiotics are needed as alternative therapeutics. In this blinded study, we assessed the protective efficacy of teixobactin, a recently discovered antibiotic, against inhalation anthrax infection in the adult rabbit model. New Zealand White rabbits were infected with a lethal dose of B. anthracis Ames spores via the inhalation route, and blood samples were collected at various times to assess antigenemia, bacteremia, tissue bacterial load, and antibody production. Treatments were administered upon detection of B. anthracis protective antigen in the animals’ sera. For comparison, a fully protective dose of levofloxacin was used as a positive control. Rabbits treated with teixobactin showed 100% survival following infection, and the bacteremia was completely resolved by 24–48 h post-treatment. In addition, the bacterial/spore loads in tissues of the animals treated with teixobactin were either zero or dramatically less relative to that of the negative control animals. Moreover, microscopic evaluation of the tissues revealed decreased pathology following treatment with teixobactin. Overall, these results show that teixobactin was protective against inhalation anthrax infection in the rabbit model, and they indicate the potential of teixobactin as a therapeutic for the disease.

Clinical characteristics and short-term outcomes for rabbits with signs of gastrointestinal tract dysfunction: 117 cases (2014-2016)

OBJECTIVE

To describe the clinical findings and short-term outcomes for rabbits with signs of gastrointestinal tract dysfunction or rabbit gastrointestinal syndrome (RGIS).

ANIMALS

117 client-owned rabbits.

PROCEDURES

The electronic medical records database of a veterinary teaching hospital was searched to identify rabbits that were examined because of altered or absent food intake and decreased or absent fecal output between June 1, 2014, and June 30, 2016. For each rabbit, information extracted from the record included history of prior episodes of gastrointestinal tract dysfunction, signalment, physical examination and diagnostic test results, and outcome.

RESULTS

117 of the 484 (24%) rabbits examined at the hospital during the study period met the inclusion criteria and were enrolled in the study. Fifty-nine and 58 rabbits were managed on an inpatient and outpatient basis, respectively. Gastrointestinal stasis without overt obstruction was diagnosed for 43 rabbits on the basis of abdominal radiographic, ultrasonographic, or necropsy results. Many rabbits had concurrent disease and biochemical abnormalities. Fifteen, 18, and 84 rabbits died, were euthanized, and survived to hospital discharge, respectively. Rabbits that were hypothermic (rectal temperature, ≤ 36.6°C [97.9°F]) during the initial examination were 5 times as likely to die or be euthanized as were euthermic rabbits, after controlling for potential confounders.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that the prognosis was generally good for rabbits with signs of RGIS unless they were hypothermic during initial examination. Prospective studies are warranted to further elucidate and characterize RGIS and assess the efficacy of various treatments and outcomes for affected rabbits.

Injection techniques for auricular nerve blocks in the rabbit cadaver

OBJECTIVE

To describe the landmarks for localization and to determine the methodology and volume of methylene blue dye to adequately stain the auricular nerves in rabbit cadavers.

STUDY DESIGN

Prospective, randomized, cadaveric study.

ANIMALS

A total of 26 rabbit cadavers (Dutch-Belted and New Zealand White breeds).

METHODS

Part I: anatomical dissections were performed to identify the sensory auricular nerves and to establish the ideal injection approach and volume of dye required for nerve staining. Part II: a single injection technique using 0.1 mL kg^-1 dye was evaluated for staining the greater auricular nerve and two techniques (perpendicular and angled needle approaches) using 0.075 mL kg^-1 dye were evaluated for the auriculotemporal nerve. Dye spread was evaluated through cadaveric dissections and nerve staining graded using a 0-2 point scale. Injections were considered successful if the nerve was stained circumferentially. Cadavers were assessed for staining of the mandibular nerve owing to the close proximity to the auriculotemporal nerve. Fisher's exact test and mixed effects logistic regression model were used for statistical analysis.

RESULTS

The greater auricular nerve was stained in 24/27 (88.9%) injections. The auriculotemporal nerve was stained in 7/12 injections (58.3%) with the perpendicular needle approach; staining success increased to 80% (12/15 injections) with the angled needle approach; however, this difference was not statistically significant (p = 0.228). Mandibular nerve staining occurred on seven auriculotemporal injections with no statistically significant difference in the incidence of nerve staining between techniques.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that the auricular nerves in rabbit cadavers can be successfully located and stained using anatomic landmarks and the described injection techniques.

Morbidity and mortality of domestic rabbits (Oryctolagus cuniculus) under primary veterinary care in England

Background

The domestic rabbit is a common pet species, but limited research exists on the health of pet rabbits. This study aimed to characterise common disorders of pet rabbits and reasons for mortality as recorded by veterinary practices in England.

Methods

This cross-sectional study covered anonymised clinical records of 6349 rabbits attending 107 primary veterinary care clinics.

Results

The median age was 3.2 years (interquartile range (IQR) 1.6–5.1), and the median adult bodyweight was 2.1 kg (IQR 1.7–2.6). The most common breed types were domestic (n=2022, 31.9 per cent), lop (1675, 26.4 per cent) and Netherland dwarf (672, 10.6 per cent). For those rabbits that died during the study period, the median age at death was 4.3 years (IQR 2.1–7.0). The most common causes of death were recorded as myiasis (prevalence 10.9 per cent, 95 per cent confidence interval (CI): 7.4 to 15.2), anorexia (4.9 per cent, 95 per cent CI: 4.0 to 10.4), recumbency/collapse (4.9 per cent, 95 per cent CI: 4.0 to 10.4) and ileus (4.3 per cent, 95 per cent CI: 3.5 to 9.5). The most prevalent specific disorders recorded were overgrown claw/nails (16.0 per cent, 95 per cent CI: 14.5 to 17.5), overgrown molar(s) (7.6 per cent, 95 per cent CI: 6.6 to 8.7), perineal soiling (4.5 per cent, 95 per cent CI: 3.7 to 5.4), overgrown incisor(s) (4.3 per cent, 95 per cent CI: 3.5 to 5.2) and ileus (4.2 per cent, 95 per cent CI: 3.4 to 5.0).

Conclusions

This study augments the limited evidence base on rabbit health and can assist veterinarians to better advise owners on optimal animal husbandry priorities.

Frequency of Owner-Reported Bacterial Infections in Pet Guinea Pigs

Domestic guinea pigs suffer morbidity and mortality due to a range of bacterial infections amongst other causes. Microorganisms such as Bordetella bronchiseptica and Streptococcus pneumoniae are commonly implicated in respiratory disease; however, there is a lack of research surrounding the prevalence of these bacterial infections. The aim of this study was to investigate the frequency with which owners reported bacterial infections in pet guinea pigs and to assess owner knowledge of correct husbandry practices to inform prevention of the development of bacterial infections. An online questionnaire, consisting of 30 questions was promoted to guinea pig owners. Of all respondents (n = 524), 39.39% reported that their guinea pig(s) had been clinically diagnosed with a bacterial infection, with upper respiratory tract infections the most commonly reported (46.95%), followed by urinary tract (15.49%) and then gastrointestinal infections (11.73%). Owners demonstrated knowledge of correct husbandry practices and there was no significant effect (p = 0.475) of owner knowledge on having owned a guinea pig with a bacterial infection. Bacterial infections may be more common in guinea pigs than was previously thought. Further research is required to understand why bacterial infections are common in pet guinea pigs and to help owners to prevent and recognize these infections.

Salix babylonica L. as a Natural Anticoccidial Alternative in Growing Rabbits

Coccidiosis in rabbit production is responsible for high morbidity, mortality, and economic losses. The use of natural antimicrobial substances in rabbits represents a promising way to improve their health and production. The aim of the present study was to assess the activity of Salix babylonica hydroalcoholic extract (SBHE) on the elimination of Eimeria spp. in rabbits. The phytochemical compounds and chemical composition of SBHE were determined. The cytotoxicity of SBHE was determined by a microwell assay using Artemia salina. Twenty-five New Zealand rabbits, 28 days old and 872 ± 171 g body weight (BW), were used in a completely randomized design. The rabbits were assigned to five groups of five rabbits, control group (A) received only basal diet (BD), B group received BD + 25 mg/kg BW of SBHE, C group received BD + 50 mg/kg BW of SBHE, D group received BD + 100 mg/kg BW of SBHE, and E group received BD + coccidiostat Baycox® (75 mg/kg body weight) for 28 days. Feces samples were collected at days 0, 7, 14, 21, and 28; morphological and morphometric identifications of Eimeria were carried out by the flotation technique and counting of oocysts by the McMaster technique. The rabbits were found naturally infected with Eimeria spp. The SBHE present phytochemicals with anticoccidial activity, and the cytotoxicity test indicate that this extract is nontoxic. This study demonstrates that oral administration of SBHE at 25 and 50 mg/kg BW reduced the release of oocysts per gram of feces. This effect was observed at day 14 and had the most significant effect at day 28 for both concentrations. The results indicate that SBHE could be a natural alternative for the control of coccidiosis in rabbit production.

Evaluation of gastrointestinal activity in healthy rabbits by means of duplex Doppler ultrasonography

OBJECTIVE

To use duplex Doppler ultrasonography to compare gastrointestinal activity in healthy sedated versus nonsedated rabbits and to evaluate agreement between B-mode and pulsed-wave Doppler (PWD) ultrasonographic measurements.

ANIMALS

10 healthy client-owned rabbits brought for routine physical examination and 11 brought for routine ovariohysterectomy or castration.

PROCEDURES

Duplex Doppler ultrasonography of the gastrointestinal tract was performed once for the 10 rabbits that underwent physical examination and twice (before and after presurgical sedation) for the 11 rabbits that underwent routine ovariohysterectomy or castration. Mean number of peristaltic contractions during a 30-second period was determined for the stomach, duodenum, jejunum, cecum, and colon from B-mode and PWD ultrasonographic images that had been video recorded. Findings for the duodenum and jejunum were compared between B-mode and PWD ultrasonography and between sedated and nonsedated rabbits.

RESULTS

Duodenal and jejunal segments had measurable peristaltic waves; however, the stomach, cecum, and colon had no consistent measurable activity. B-mode and PWD ultrasonographic measurements for the duodenum and jejunum had high agreement. No significant difference was identified between nonsedated and sedated rabbits in mean number of peristaltic contractions of the duodenum or jejunum.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that both B-mode and PWD ultrasonography of the duodenum and jejunum may be suitable for noninvasive evaluation of small intestinal motility in rabbits and that the sedation protocol used in this study had no impact on measured peristaltic values.

Investigation of significant microRNA-mRNA pairs associated with nonspecific digestive disorder in rabbits

Nonspecific digestive disorders (NSDD) are one of the major intestinal problems in rabbit, with considerable economic losses in industrial rabbit farms. MicroRNAs (miRNAs), as small non-coding RNAs, have significant biological involvement in intestinal disorders. In this study, we investigated the expression levels of 25 genes and 25 miRNAs in ileum, rabbit sacculus rotundus (RSR) and colon tissues from 9 rabbits with different severity of NSDD. These molecules have been found to be related to NSDD or inflammatory bowel disease, which will help recognise the miRNA-mRNA pairs. Finally, 108 possible pairs of miRNA-mRNA pairs with an anti-correlation were identified by Pearson’s correlation analysis between differentially expressed 25 miRNAs and 23 mRNAs. Ninety-five of these miRNA-mRNA pairs were hitherto unexplored, and their roles in NSDD biology require further elucidation. Our results give a clue to the potential miRNA-mRNA pairs for the NSDD that can further improve the understanding of the pathogenesis of NSDD in rabbit.

Technical note: Influence of feed on image quality of abdominal ultrasonography in New Zealand white kits

<p class="Body">The aim of this study was to evaluate the influence of feed change on image quality of ultrasound scanning of the gallbladder, kidney and jejunum in New Zealand White kits. Thirty-nine 35-day-old rabbits were used, distributed into 4 diet groups: C, only commercial feed; CH, commercial feed and hay; C24H, only commercial feed, replaced by hay 24 h before examination; and CH24H, commercial feed and hay, with the commercial feed withdrawn 24 h before the exam. The rabbits received the diet for 42 d (from 35 to 77 d of age) and the ultrasound evaluations were performed on days 56 and 77. Ultrasonographic assessment for image quality focused on the possibility of visualisation and an image quality rating (3 scores: unacceptable, acceptable or excellent) for the gallbladder, kidneys and jejunum. The kidneys were visualised in 100% of animals of all diets and ages. There was no difference in visualisation (P&gt;0.05) of the gallbladder among the animals fed different diets on days 56 and 77. The C24H diet had a higher visualisation possibility (P&lt;0.05) of the jejunum compared to the C and CH diets on day 77. For the image quality score, there was no difference in the studied organs on day 56. However, on day 77, there was a difference for the jejunum (P&lt;0.05), and only the C24H and CH24H diets presented images classified as excellent. In conclusion, the image quality of the kidneys and gallbladder was unaffected by feed, and the jejunum had an improved image quality with the inclusion of hay and without the commercial feed 24 h before the test in New Zealand White rabbits at 77 d of age.</p>

Jejuno-jejunal intussusception in a guinea pig (Cavia porcellus)

An approximately four-year-old male castrated guinea pig (Cavia porcellus) was presented for painful defecation with a 24-hour history of hyporexia and intermittent episodes of rolling behavior. Upon presentation the patient was quiet, alert, and responsive, and mildly hypothermic. Abdominal palpation revealed an approximately 2-cm long oblong mass within the caudal abdomen. Abdominal radiographs revealed gastric dilation without volvulus and a peritoneal mass effect. The patient was euthanized following gastric reflux of brown malodorous fluid from his nares and oral cavity. A necropsy was performed and revealed a jejuno-jejunal intussusception causing mechanical gastrointestinal ileus, and gastric dilatation without volvulus. While non-obstructive gastrointestinal stasis is common and obstructive ileus is uncommon in guinea pigs, this report shows that intestinal intussusception is a differential in guinea pigs with ileus and gastric dilatation.

Influence of simethicone and fasting on the quality of abdominal ultrasonography in New Zealand White rabbits

Presence of significant quantities of gas in the intestines may hinder a proper conduction of abdominal ultrasonography. In humans, preparatory techniques are used to solve this, but measures to avoid ultrasonographic complications due to intestinal gas in rabbits have not been reported. The objective of this study was to evaluate the influence of fasting and simethicone administered orally on the quality of ultrasonographic images of the gallbladder, kidneys, and jejunum in adult New Zealand White (NZW) rabbits. A total of 28 adult NZW rabbits were included in a crossover design study, involving four groups: F: fasting for 4–6 h before the examination; FS: fasting and application of simethicone (20 mg/kg, orally) 20 to 30 min before the examination; S: application of simethicone 20–30 min before the examination without fasting; and C: controls without fasting and no application of simethicone. Evaluation of the ultrasonographic images was done in terms of percentage of visualization of each organ and image quality using a 3-point scoring system (unacceptable, acceptable, or excellent). The kidneys and the gallbladder were visualized at an equal frequency in all groups, while the jejunum was visualized more frequently in the FS group. The image quality scores for gallbladder, right kidney, and left kidney was similar for all groups, but for the jejunum, a higher number of images with acceptable scores was found within the FS group.

ExNOTic: Should We Be Keeping Exotic Pets?

There has been a recent trend towards keeping non-traditional companion animals, also known as exotic pets. These pets include parrots, reptiles, amphibians and rabbits, as well as small species of rodent such as degus and guinea pigs. Many of these exotic pet species are not domesticated, and often have special requirements in captivity, which many owners do not have the facilities or knowledge to provide. Keeping animals in settings to which they are poorly adapted is a threat to their welfare. Additionally, owner satisfaction with the animal may be poor due to a misalignment of expectations, which further impacts on welfare, as it may lead to repeated rehoming or neglect. We investigate a range of commonly kept exotic species in terms of their suitability as companion animals from the point of view of animal welfare and owner satisfaction, and make recommendations on the suitability of various species as pets.

Common Emergencies in Rabbits, Guinea Pigs, and Chinchillas

Rabbits, guinea pigs, and chinchillas are some of the more common exotic pets seen in emergency clinics. They frequently present with acute illnesses that are the result of several chronic conditions, most related to inadequate diet and husbandry. This article reviews the diagnosis and treatment of some of the more common acute illnesses. It also discusses the predisposing factors that culminate in acute presentations, so that emergency providers can recognize and be mindful of underlying causes of disease before treatment of acute illnesses.

Rabbit Soft Tissue Surgery

This article summarizes the available information on different soft tissue surgical procedures in rabbits, based on the literature and the authors' experiences, emphasizing the differences between rabbits and the more familiar dogs and cats. The major surgical principles in rabbits are discussed, and common surgical procedures, such as abdominal exploration, gastrotomy, enterotomy, liver lobectomy, nephrectomy, cystotomy, cystectomy, ovariohysterectomy, ovariectomy, orchidectomy, are described.

Manipulating the Gut Microbiota: Methods and Challenges

Eukaryotic organisms are colonized by rich and dynamic communities of microbes, both internally (e.g., in the gastrointestinal and respiratory tracts) and externally (e.g., on skin and external mucosal surfaces). The vast majority of bacterial microbes reside in the lower gastrointestinal (GI) tract, and it is estimated that the gut of a healthy human is home to some 100 trillion bacteria, roughly an order of magnitude greater than the number of host somatic cells. The development of culture-independent methods to characterize the gut microbiota (GM) has spurred a renewed interest in its role in host health and disease. Indeed, associations have been identified between various changes in the composition of the GM and an extensive list of diseases, both enteric and systemic. Animal models provide a means whereby causal relationships between characteristic differences in the GM and diseases or conditions can be formally tested using genetically identical animals in highly controlled environments. Clearly, the GM and its interactions with the host and myriad environmental factors are exceedingly complex, and it is rare that a single microbial taxon associates with, much less causes, a phenotype with perfect sensitivity and specificity. Moreover, while the exact numbers are the subject of debate, it is well recognized that only a minority of gut bacteria can be successfully cultured ex vivo. Thus, to perform studies investigating causal roles of the GM in animal model phenotypes, researchers need clever techniques to experimentally manipulate the GM of animals, and several ingenious methods of doing so have been developed, each providing its own type of information and with its own set of advantages and drawbacks. The current review will focus on the various means of experimentally manipulating the GM of research animals, drawing attention to the factors that would aid a researcher in selecting an experimental approach, and with an emphasis on mice and rats, the primary model species used to evaluate the contribution of the GM to a disease phenotype.

Diagnosis and clinical management of gastrointestinal conditions in exotic companion mammals (rabbits, guinea pigs, and chinchillas)

Gastrointestinal disorders are common in exotic mammals such as rabbits, guinea pigs and chinchillas. Presenting clinical signs of gastrointestinal disease can vary widely. Small herbivores require specific dietary support and therapeutic treatments. Ileus is a common clinical condition and can be a primary or secondary disease. Common forms of treatment for ileus include fluid therapy, pain relief, nutritional support, and prokinetic therapy. The prognosis of the exotic mammal patient with gastrointestinal disease depends on the timing of the diagnosis and initiation of treatment. Surgical conditions such as gastrointestinal obstruction can have a good outcome if diagnosed early.