Laboratory Rabbits Research Articles

Status of diseases of laboratory animals in India: An Overview

Systemic disease investigation and studies on pathology of spontaneous diseases of laboratory animals is a neglected area in India. Most of Indian Veterinary Pathologists only publish incidental case reports of diseases of laboratory animals. A literature survey and analysis of 195 published research papers/case reports on spontaneous diseases of laboratory mice (29), rats (53), guinea pigs (20), rabbits (80) hamsters (5) and miscellaneous (8) in India were conducted. It revealed that:

Neoplasia and Tumor-Like Lesions in Pet Rabbits (Oryctolagus cuniculus): A Retrospective Analysis of Cases Between 1995 and 2019.

Prevalence and age distribution of tumors is largely unknown in pet rabbits. Currently available studies focused on specific organ systems or specific tumor types and never covered a comparative examination of all tumor types. Previous studies on laboratory rabbits suggested a low tumor prevalence but were mostly limited to young adult animals. In the present study, all tumor types and several tumor-like lesions of all organ systems were analyzed retrospectively in archived pet rabbit samples of all ages. Cases included necropsy cases (n = 2,014) or postmortem tissue samples (n = 102) as well as surgical biopsies (n = 854). All lesions suspicious of neoplasia were reevaluated by histopathology and, when indicated, by immunohistochemistry. Necropsy cases had a tumor prevalence of 14.4% in both sexes or 19.8% in female intact rabbits of all age groups, and up to 47.2% or 66.7%, respectively, in rabbits older than 6 years. Overall, the most common tumor types were uterine adenocarcinoma (prevalence in female intact animals: 13.1%), lymphoma (prevalence: 2.8%), and thymoma (prevalence: 2.1%). Lymphoma, the most common tumor of rabbits ≤24 months of age, were of B-cell immunophenotype in 96% of cases and most commonly located in the lymph nodes (57%), gastrointestinal tract (54%), kidneys (48%), spleen (42%), and liver (41%). Tumors accounted for 81.1% of surgical biopsies and mostly comprised cutaneous, mammary, and uterine tumors. In conclusion, tumor types and prevalence varied significantly with respect to age, revealing some differences from previous studies on laboratory rabbits.

Establishment and Validation of Theileria annulata Sporozoite Ak-93 Infection in Laboratory-Reared Hyalomma anatolicum Tick Using In Vivo and In Vitro Assays.

Background:Tropical Theileriosis caused by Theileria annulata is a tick-borne disease which transmitted by the ixodid tick members of the genus Hyalomma. Studies on different aspects of disease require to access infective sporozoite of parasite which produced by tick vector. This study was carried out to establish of T. annulata life cycle to achieve T. annulata infected ticks.Methods:Laboratory rabbit and calf were used for rearing of Hyalomma anatolicum different instars. Unfed nymphs were fed on T. annulata infected calf. Clinical signs, Giemsa stained smears and Polymerase Chain Reaction (PCR) methods were used for detection of infection in blood and tick specimens. Susceptible calf was used for confirmation of sporozoites maturation and infectivity in bioassay test.Results:Hyalomma anatolicum two and three-host strategies of life cycle was lasted 90 and 116 days respectively. The PCR confirmed T. annulata infection in blood and tick samples. Maturation of T. annulata sporozoites was confirmed in bioassy test. First clinical symptom of disease was seen earlier in the case of transmission of disease through feeding of live ticks in comparison with blood injection method.Conclusion:Complete life cycle of T. annulata was done and confirmed by clinical signs, microscopic examination, molecular methods and bioassay test. According to published reports to date, this is the first report of establishment of H. anatolicum tick infection with T. annulata using susceptible calf under controlled conditions in Iran.

Notoedric mange successfully treated with ivermectin in rabbits

Notoedric mange, caused by sarcoptiform Notoedres mites, an obligately parasite, causes potentially fatal dermatitis along with secondary systemic infections in small mammals, felids as well as humans. In the present case study, we describe clinical diagnosis and therapeutic management of notoedric mange with ivermectin in rabbits. Two New Zealand White rabbits (Oryctolagus cuniculus) naturally infested with notoedric mange reported with history of varied clinical signs like anorexia, patchy alopecia, intense pruritus, erythema and dry scabs. Several whitish crust-like lesions were observed on ears, nose, face, forelimbs and hindlimbs. Confirmatory diagnosis of Notoedres cati var cuniculi was done by skin scraping from supported by clinical signs and hematological alterations. Both the animals were successfully treated with Ivermectin, a broad spectrum anti-parasitic agent. Both rabbits showed recovery by the end of third week of treatment and it was subsequently confirmed by absence of mites in two consecutive skin scrapings examination at weekly interval. The mite, Notoedres cati is considered as a serious pest of rabbits with ivermectin as still effective drug in treating the clinical cases. Stringent diagnostic strategies need to be prepared for regular screening and control of notoedric infestations in laboratory and pet rabbits.

Fecal, oral, blood and skin virome of laboratory rabbits.

Here, we investigated the fecal, oral, blood, and skin virome of 10 laboratory rabbits using a viral metagenomic method. In the oral samples, we detected a novel polyomavirus (RabPyV), and phylogenetic analysis based on the large T antigen, VP1 and VP2 regions indicated that the novel strain might have undergone a recombination event. Recombination analysis based on related genomes confirmed that RabPyV is a multiple recombinant between rodent-like and avian-like polyomaviruses. In fecal samples, three partial or complete genome sequences of viruses belonging to the families Picobirnaviridae, Parvoviridae, Microviridae and Coronaviridae were characterized, and phylogenetic trees were constructed based on the predicted amino acid sequences of viral proteins. This study increases the amount of genetic information on viruses present in laboratory rabbits.Electronic supplementary materialThe online version of this article (10.1007/s00705-020-04808-y) contains supplementary material, which is available to authorized users.

Nervous System Sampling for General Toxicity and Neurotoxicity Studies in Rabbits.

Although manuscripts for multiple species recommending nervous system sampling for histopathology evaluation in safety assessment have been published in the past 15 years, none have addressed the laboratory rabbit. Here, we describe 2 trimming schemes for evaluating the rabbit brain in nonclinical toxicity studies. In both schemes, the intact brain is cut in the coronal plane to permit bilateral assessment. The first scheme is recommended for general toxicity studies (tier 1) in screening agents where there is no anticipated neurotoxic potential; this 6-section approach is consistent with the Society of Toxicologic Pathology (STP) "best practice" recommendations for brain sampling in nonrodents (Toxicol Pathol 41: 1028-1048, 20131). The second trimming scheme is intended for dedicated neurotoxicity studies (tier 2) to characterize known or suspected neurotoxicants where the nervous system is a key target organ. This tier 2 strategy relies on coronal trimming of the whole brain into 3-mm-thick slices and then evaluating 12 sections. Collection of spinal cord, ganglia, and nerve specimens for rabbits during nonclinical studies should follow published STP "best practice" recommendations for sampling the central nervous system1 and peripheral nervous system (Toxicol Pathol 46: 372-402, 20182).

Effects of General Anesthesia on Intraocular Pressure in Rabbits.

Measurement of intraocular pressure (IOP) is a standard procedure in ophthalmic research in animals, specifically in glaucoma research, and the control of IOP is essential during certain veterinary ophthalmic surgeries. We evaluated the effect of isoflurane on IOP in the clinically healthy laboratory rabbits and tested a way to minimize the alteration of IOP during isoflurane anesthesia. After measurement of the baseline IOP in each eye of 9 awake New Zealand white rabbits, animals were anesthetized by using either: (1) isoflurane without premedication, (2) a combination of ketamine and xylazine, or (3) isoflurane inhalation after an injection of ketamine-xylazine premedication. Isoflurane led to a sustained increase in IOP of approximately 12 mm Hg. In contrast, ketamine and xylazine decreased IOP by nearly 5 mm Hg (all values compared with baseline measurements in awake, unrestrained animals). The observed decrease in IOP after ketamine-xylazine anesthesia is consistent with anesthetic effects generally seen during anesthesia in other studies. The increased IOP after isoflurane anesthesia in rabbits in this study was an unexpected result that appears to be specific to this combination of anesthetic and animal species. Premedication with ketamine-xylazine diminished the effect of isoflurane inhalation on IOP. These results should be considered in the design of ophthalmic research studies using rabbits and in intraocular surgery where IOP stability is desired.

Median nerve conduction studies in rabbits

BackgroundWhen planning nerve conduction studies using animal models, the sciatic nerve is often used and the upper extremity nerves are not preferred due to the size of laboratory animals. This study aimed to present the method and mean values of median nerve conduction studies in laboratory rabbits. Fifty-five six-month-old male New Zealand white rabbits weighing 2 to 2.5 kg were included in nerve conduction studies performed under anesthesia. The compound muscle action potential amplitude and distal latency values were recorded for the median motor nerve with the electrodes placed on the flexor digitorum superficialis muscle and tendon.ResultsA total of 110 median nerves were evaluated. The mean amplitude of the median nerve was 30.6 ± 6.8, mV the median nerve distal latency was 1.3 ± 0.2 ms, and the mean intensity of stimulation inducing a response was 2.5 ± 1 mA.ConclusionsThe mean values obtained by the median motor nerve conduction method in this study can act as a guide for future nerve interventions undertaken in the upper extremities.

Technical note: Residues of gaseous air pollutants in rabbit (Oryctolagus cuniculus) tissues

The modern consumer is concerned not only for meat quality, but also about animal welfare and the environment. Studies were conducted to determine the concentration of gaseous residues in the tissues of rabbits. For this purpose, gaseous air pollutants were measured at the height of rabbit cages. Immediately after slaughter, samples were taken for analysis to determine the level of residual pollutants in the tissues (blood, perirenal fat and lung). Headspace gas chromatography was performed on the tissue samples to test for volatile toxic substances. Gas residues of 11 compounds were determined in the samples of blood, perirenal fat and lungs. The same chemicals were present in the air of the farm and the animal tissues, which may indicate their capacity for bioaccumulation. We recommend that the results should be used to develop guidelines regarding the welfare of meat rabbits and requirements for laboratory rabbits.

Physiological effect of trazodone hydrochloride use for anxiety and sedation in rabbits (Oryctolagus cuniculus)

Oral sedation options for rabbits (Oryctolagus cuniculus) have remained limited despite the need for medications with anxiolytic effects during transportation and high stress procedures. Trazodone HCl (TZN), a serotonin modulator, is a commonly prescribed medication in humans to treat depression and anxiety. The efficacy of TZN use in rabbits was initially investigated in 2016 and found TZN to be successful in producing mild sedation, however the safety of the medication still needed to be determined. To identify the systemic effects of repeated TZN administration in rabbits, New Zealand white laboratory rabbits (n = 12) were given orally 40 mg/kg TZN every 12 hours (± 1 hour) for 28 days. A control group (n = 4) was used to monitor standard hematological fluctuations. Heart and respiratory rate were collected daily, and a physical examination was performed by a veterinarian every 7 days. Blood was collected for cell counts and serum chemistry analysis prior to and every 14 days during the experiment. No significant changes in heart or respiratory rate were noted throughout treatment (p = 0.201 and p = 0.984 respectively). Some fluctuations were noticed in blood serum chemistry and hematology results in both the experimental and control group, particularly in the liver and kidney values following 28 days of treatment. Serum alanine aminotransferase (ALT) between the blood draws of both groups was significantly elevated (p = 0.002), however the elevations were noticed in both the control and TZN treated animals (p = 0.597). A simmilar trend was noticed with alkaline phosphatase (ALP; p = 0.001 between blood draws, p = 0.428 between groups), creatinine (p < 0.0001 between blood draws, p = 0.340 between groups), and blood urea nitrogen (BUN) levels (p = 0.025 between blood draws, p = 0.343 between groups) indicating the changes overtime were not due to TZN treatment. All physiologic parameters tested remained within normal rabbit physiologic reference ranges. These results indicate TZN could be a viable option to provide mild sedation as needed and act as an alternative option to conventional treatments of behavioral problems. Future studies could be performed on dose range and safety among rabbits of varying age, sex, and breed.

Visualisation of penile structures of laboratory rabbit: ultrasound, histology, and micro-CT

Current imaging methods in pre-clinical and animal model studies of penile disease are limited because of the small penis of a rat – standard laboratory animal used in this type of research. Routine visualization methods of surface and inner structures of the penis used in clinical medicine are not suitable in experimental animal researches. The only method available for these purposes is histopathological analysis, which does not provide complex view on penile structures due to two-dimensional imaging per slide. In the pre study we evaluated and compared capability of ultrasound, histopathological and micro-computed tomography imaging methods to visualize anatomical structures of laboratory rabbit penis. Ultrasound provides limited imaging in comparison with other methods. However, it could be useful in assessment rough structural alterations of tunica albuginea and corpora cavernosa as a secondary and supportive method. Micro computed tomography provides nearly the same image quality as histopathological analysis. Moreover, it gives a complex view on the whole penile sample due to three-dimensional reconstruction. This fact gives reason to use this method as a basic one in the pre-clinical trials and animal model studies.

Mapping the age of laboratory rabbit strains to human

Rabbit strains find immense application in biomedical research with every strain having their discrete advantage in specific research endeavor. Acceptability of rabbit strains as laboratory animals owes to their breeding ease, availability, cost-effectiveness, ethical conveniences, larger size, compared to rats and mice, and responsiveness. With respect to different life phases, the article displays that one human year is equivalent to: (1) in developmental phase, 56.77 days for New Zealand White (NZW) and New Zealand Red (NZR) rabbits, 71.01 days for Dutch belted and Polish rabbits, and 85.28 days for Californian rabbits; (2) in the prepubertal phase, 13.04 days for NZW and Dutch belted, 15.65 days for NZR and Californian, and 10.43 days for Polish rabbits; (3) in the adult phase, 18.25 days for NZW and Californian rabbits, 22.75 days for NZR, and 12 days for Dutch Belted and Polish rabbits; (4) during reproductive senescence, 42.94 days for NZW, NZR and Californian rabbits, 28.62 days for Dutch belted, and 25.05 days for Polish rabbits; (5) in the post-senescence phase, 50.34 days for NZW, 25.17 days for NZR, Dutch Belted and Californian and 31.46 days for Polish rabbits. The laboratory rabbit strains differ in various physiological, developmental and genetic make-ups, which also reflect upon the correlation of their age at different life stages with that of a human. The present article aids selection of laboratory rabbit strain of accurate age as per experimental need, by precisely relating the same with age of human considering different life stages.

Short term effects of continuous lighting on the cornea of cage-reared laboratory rabbits

This study was to assess the impact on the cornea and eye blink activity of adapting rabbits to continuous lighting (CL) compared to a 14:10 light:dark cycle. Female New Zealand White rabbits (2 to 2.5 kg) were maintained under a light: dark (L:D) cycle or switched to continuous fluorescent lighting (CL) for an average of 17 +/− 2 days. Animal behaviour in their cages was manually recorded using an event marker and in vivo slitlamp biomicroscopy at 40× undertaken in mid-afternoon. Animals were then euthanized and the corneas prepared for scanning electron microscopy (SEM). From images taken at 500× from the central region of the corneas, the number of exfoliating (desquamating) cells and the relative number of different cells with light, medium or dark reflexes were assessed for the corneal epithelial surface, while the number of cells/unit area were assessed for both corneal epithelium and endothelium. Exposure to continuous lighting was associated with higher number of eye blink events (15.7 vs 8.2/15 min) and mild corneal surface alterations evident by biomicroscopy with higher numbers of intra-epithelial ‘granules’ (32 +/− 14 vs. 4 +/− 3/sq. mm). SEM revealed low numbers of exfoliating cells on the corneal epithelial surface in all CL-adapted animals, but not in L:D controls. Trends were observed for there to be slightly higher numbers of epithelial cells/unit area, higher numbers of small light reflex cells and lower numbers of larger dark reflex cells in CL animals. The corneal endothelium showed no obvious adverse effects in CL-adapted animals but the percentage of ‘hexagonal’ cells was slightly higher compared to L:D controls. The results indicate that even a short period of exposure of laboratory-raised rabbits to constant lighting can be associated with mild adverse effects on the corneal epithelial surface.

Histomorphology of Seminal Vesicles Subsequent to Exogenous Neurokinin B Administration in New Zealand White Rabbits

Neurokinin B exists as a member of tachykinin family, which is encoded by Tac3 gene and binds to Tac3R. Several studies have shown that neurokinin B is involved in secretion of gonadotropin releasing hormone and maintenance of reproductive function. No data on the effect of neurokinin B on accessory sex glands is available till date. The current study is designed to determine the dose dependent effects of neurokinin B on seminal vesicles of New Zealand White Rabbits. For experimental procedure, 18 New Zealand white rabbits (Oryctolagus cuniculus) were purchased from National Institute Health, Islamabad Pakistan. Adult laboratory rabbits were administrated with neurokinin B at two different dose concentrations (1 ηg and 1 µg) twice daily for a period of continuous 12 days. The results demonstrated a significant increase in seminal vesicles weight and epithelial cell height at all tested doses (P < 0.05). Marked increase in epithelial folds was readily manifested, however the lumen was irregular. In this study histological and structural alterations in seminal vesicles manifest a progressive effect on seminal vesicles subsequent to subcutaneous twice-daily administration of Neurokinin B for 12 days.

EXPERIMENTAL STUDY OF THE USE OF BIODEGRADABLE COLLAGEN MEMBRANES IN THE CLOSURE OF POSTOPERATIVE DEFECTS OF THE RABBIT ORAL MUCOUS MEMBRANE

The aim is to increase the efficiency of surgical treatment of dental patients with the use of bioresorbable collagen membranes to close postoperative wound defects of the oral mucous membrane. Material and methods. The experimental model was created on 18 laboratory rabbits. The animals were divided into 3 groups: in the control group the healing of the mucous membrane defect on the hard palate was carried out by secondary tissue tension, in the research groups - under the xenopericardium membrane (1) and collagen membrane (2). The morphological study was based on biopsy of all animals' mucous membranes of the hard palate. Microvolume slices 4-5 microns thick were examined on a light microscope. Results. The results testify to the formation of granulation tissue an d epithelization of defects both in the research groups and in the control group. When using collagen materials, a noticeable activatio n of the wound process, shortening of epithelialization were found. A certain advantage of pericardium in activation of wound repair was noted. Conclusion. Application of collagen membranes can be recommended as a method of choice at closing of postoperative defects of the oral mucous membrane after clinical studies.

COMBINED SURGICAL TREATMENT LIVER ABCESSES IN EXPERIMENT

The results of surgical antibacterial rehabilitation and drainage of liver abscess largely depend on the effectiveness of local action of drugs. A promising direction in experimental liver abscess surgery is the local application of laser and nanotechnology. - The goal is to experimentally substantiate the effectiveness of the combined use of low-intensity laser radiation and copper nanoparticles in the surgical treatment of liver abscesses. Material and methods. In an experiment on 80 laboratory rabbits, a classic liver abscess was modeled. According to the variant of local two-week treatment, the animals were divided into 4 groups of 20 each. Animals of the first group were given daily standard sanitation of the cavity with an antiseptic solution; in the second group, low-intensity laser irradiation was locally administered; animals of the third group, the cavity of the abscess was washed with a suspension of copper nanoparticles; in the fourth group of animals, treatment with a suspension of copper nanoparticles in combination with low-intensity laser irradiation was applied. Clinical, planimetric, microbiological, morphological and instrumental research methods were used to evaluate the results of treatment. Results and discussion. The best clinical indicators of general condition by the 9th day were observed in the treatment of animals of the fourth group. Due to the active stimulation of reparative processes, by the 7th day of treatment of animals of this group, no aspirate cultures from the growth abscess cavity were given, which made it possible to speed up the closure of the purulent cavity, which by the 21st day according to ultrasound planimetry, the abscess cavity of the liver was completely obliterated. Conclusion. Used clinical and instrumental methods of research are effective ways to assess the results of treatment of simulated purulent cavity of the liver. The combined surgical treatment of simulated liver abscesses with topical application of uniformly scattered LLLT and copper nanoparticles provides accelerated cleansing of the abscess cavity causative agent and complete obliteration of the abscess cavity.

Predominance of Granular Cell Tumours among Testicular Tumours of Rabbits (Oryctolagus cuniculi f. dom.)

Testicular neoplasms are reported rarely in pet and laboratory rabbits (Oryctolagus cuniculi f. dom.), with interstitial cell tumours being the most commonly described testicular neoplasm. In this retrospective study, paraffin wax-embedded testicles with neoplastic changes from 52 rabbits were investigated. Five out of 52 animals exhibited more than one tumour type, resulting in a total of 57 tumours. Granular cell tumours were the most prevalent neoplasm with 36 examples (63%) out of the 57 testicular tumours. Interstitial cell tumours, Sertoli cell tumours and seminomas occurred less frequently. Granular cell tumours of the testis are rare in rabbits. Histological similarities between granular cell and interstitial cell (Leydig cell) tumours in haematoxylin and eosin-stained tissue sections may lead to misdiagnoses. The periodic acid-Schiff reaction or immunohistochemistry for periaxin and S100 protein, as well as ultrastructural analysis, are useful methods to confirm the diagnosis.

Study of Lercanidipine Drug Release from Medicine in Combination with Ramipril &lt;i&gt;in vitro&lt;/i&gt; and &lt;i&gt;in vivo

Introduction. Hypertension is the most common non-infectious disease in the world. New clinical recommendations for the diagnosis and management of patients with arterial hypertension are considering the issue of prescribing combination therapy and prefer fixed combinations of drugs in a single pill. The study of the pharmacokinetics of medicinal substances and the consideration of their pharmacokinetic parameters today is a necessary step in the complex of work, both in the creation of new original medicines and in the application of known generic drugs, and this is primarily due to obtaining objective characteristics of all processes occur in the body of the animal (human) with the drug. Pharmacokinetics is assessed in individual studies or as part of efficacy, safety, and tolerability studies.Aim. The study of the release of lercanidipine from bilayer tablets containing two API (ramipril and lercanidipine) in the dissolution medium used for quality control in vitro and release in vivo, after oral administration of the drug to rabbits.Materials and methods. Studies have been conducted on the release of lercanidipine from the combined drug in vitro and in vivo. As a test system were used laboratory rabbits Soviet chinchilla breed. Pharmacokinetic parameters were determined.Results and discussion. A graph of the release of lercanidipine from the combined drug was constructed and the dependence of the concentration of this substance in the blood plasma of rabbits on time was revealed. Calculated pharmacokinetic parameters. An in vivo release study shows that the pharmacokinetics of lercanidipine are consistent with literature data.Conclusion. The test drug has all the advantages of a rational fixed combination of antihypertensive drugs and simplifies therapy, meets the requirements of the latest clinical guidelines.

PECULIARITIES OF THE MORPHOLOGICAL STRUCTURE OF THE ORAL MUCOSA FLAPS DURING REST AND STRETCHING

In modern dental practice, there is a tendency towards correction of secondary adentia by using bone augmentation and dental implant placement. One of the main types of postoperative complications is the bone augmentation exposure and its infection as a result of ischemic processes in the mucous flap, which covers the augmentation, resulting from its overstretching. This study was aimed at improving the efficiency of flap operations and bone augmentation in patients with secondary adentia and reducing the risk of postoperative complications caused by ischemic changes in mucous flaps due to their overstretching, identifying features of the morphological structure of mucous flaps at rest and stretching. We conducted an investigation of mucosa flap microslides of 40 laboratory rabbits taken from the lower alveolar bone. The preparations were stained according to Van Gieson's technique with haematoxylin and eosin at low magnifications of the light microscope. The structural features of the mucous membrane of the upper and lower alveolar processes after stretching within 5% revealed minimal, slightly differed from the intact mucosa of the corresponding anatomical region. Thus, in the epithelium, the basal, intermediate, and superficial layers were located one above the other; their structural organization was mainly the same as in the intact animals. Our studies have shown that the morphological structure of the mucous membrane of the gums of laboratory rabbits is similar to the structure of human gums. The data obtained suggests that stretching of the gingival mucosa flaps when performing flap operations in the oral cavity within 5% of the initial length is morphologically substantiated and can cause no complications.

Creating a Stable Short-term Housing Environment for Rabbits in a Cargo Van.

A stable environment is a prerequisite for animal research. The absence of a suitable laboratory rabbit environment at the gyrotron facility, with the nearest housing being 6.3 miles away, made it challenging to investigate ocular damage induced in rabbit eyes due to exposure to high-frequency millimeter waves. Because rabbits are prone to transportation stress, it was vital to keep them on-site during research. Here we describe the creation of the stable environment necessary to perform reliable and reproducible animal experiments, by using a cargo van parked at the gyrotron facility. To control the interior environment, we placed a window air conditioner, humidifier, dehumidifier, and photocatalyst deodorizer inside the cargo area without altering the original configuration of the vehicle. Rabbits were housed in individual cages for a maximum of 6 d. Microbial contamination in the air was evaluated by using a passive sampling method. The average numbers of bacterial and fungal colony forming units per dish were 0.2 and 4.7, respectively, indicating that the van was as clean as a nonbarrier animal facility. The average temperature was 20.5 °C (range, 17.8 to 22.6 °C), and the average relative humidity was 49.4% (range, 36.2% to 63.2%). The concentration of ammonia was consistently below the detection limit of 0.5 ppm. Other environmental conditions were within appropriate levels. Rabbits lost 6.4% ± 2.2% (n =52) of their initial body weight during the 13- to 14-h transport but recovered the lost weight within 48 h after arrival.