Vertebral heart scoring (VHS) is a semiquantitative method to assess the presence and severity of cardiomegaly by using thoracic radiographs. VHS in rhesus macaques (Macaca mulatta) has not been validated or used routinely in the clinical or research setting. We hypothesized that rhesus macaques with cardiac disease diagnosed by using echocardiography would have higher VHS than animals without cardiac disease. A total of 150 rhesus macaques were enrolled in this study. All animals underwent echocardiography and thoracic radiography (right lateral [RL], dorsoventral [DV], and ventrodorsal [VD] views). According to echocardiography, 121 rhesus macaques had no cardiac disease and were used to establish reference intervals for VHS. The remaining 29 macaques had hypertrophic cardiomyopathy (n = 20) or other cardiac disease (n = 9). Results showed that VHS of RL and VD views were significantly higher in macaques with any of the identified cardiac diseases and in the cardiac disease group that excluded hypertrophic cardiomyopathy. VHS of animals with HCM was not significantly different than that of control animals. In the RL view, VHS was moderately accurate for predicting the presence of cardiac disease, with an AUC of 0.71 and an optimal cut-off value of 10.25 (sensitivity: 62%, specificity: 77%). In the VD view, VHS was a mildly accurate test for cardiac disease, with an AUC of 0.654 and an optimal cut-off value of 10.65 (sensitivity, 66%; specificity, 63%). Study results indicated that VHS could be a useful screening tool for clinically identifying rhesus macaques with cardiac disease. However, VHS is unlikely to replace echocardiographic examination for determining the presence, type, and severity of cardiac disease in this species.

One of the goals of environmental enrichment is to encourage species-typical behaviors, while discouraging abnormal behaviors or stereotypies. Assessing the effectiveness of various enrichment modalities can be challenging, particularly for prey species such as rabbits that exhibit freezing responses in the presence of people. In this study, we housed rabbits in 3 different sized cages and observed their behaviors. The 3 cage sizes were our standard rabbit housing cage, a medium sized cage, and a large run. Based on analysis of the recordings, ethograms were constructed and behaviors were quantified. The rabbits in large runs spent more time performing active, exploratory behaviors (431 ± 74 s) than rabbits in the standard cages (184 ± 55 s). However, space constraints inside research facilities often make it impractical to house rabbits in large runs. Therefore, we decided to explore if enrichment devices could promote the expression of active behaviors, similar to those displayed by rabbits housed in the large runs. We selected 3 devices: a hanging toy, a destructible device, and a dig bin. All 3 enrichment devices promoted more time spent performing active, exploratory behaviors (389 ± 48, 463 ± 50, and 420 ± 44 s, respectively), compared with control rabbits housed without an enrichment device (226 ± 53 s). We also analyzed the fecal glucocorticoids of rabbits after shipping or surgery to determine if enrichment devices could mitigate the physiologic impact of these stressors. We found no significant differences in fecal glucocorticoid levels between rabbits that experienced the stressor and rabbits that did not, or between rabbits with or without enrichment devices. Overall, the provision of larger caging and/or addition of enrichment devices encouraged a broad spectrum of active, species-typical rabbit behaviors, suggestive of improved animal welfare.

This study evaluated the efficacy of ionized hydrogen peroxide (iHP) fog and mist for environmental and surface decontamination of Syphacia obvelata ova in rodent rooms. Ova were collected by perianal tape impression from S. obvelata infected mice. In experiment 1, ova were exposed to iHP using a whole-room fogging decontamination system with a 15 min initial fog application cycle in unoccupied rodent rooms. Ova were removed from the fogged environment after a 15 min, 30 min, 90 min, or 240 min iHP exposure time. In experiment 2, a second cohort of ova were exposed to iHP using the whole-room fogging decontamination system. Ova were removed after 3, 4 or 6 continuous fog application cycles with 45 min dwelling time between each cycle and 15 h dwelling time for the last time point. In experiment 3, a third set of ova was exposed to an iHP surface misting unit with 1, 2, or 3 iHP mist applications. A 7 min contact time followed each application. After exposure, ova were incubated in a hatching medium for 6 h. Control ova were maintained at room temperature without iHP exposure before incubation in the hatching medium. After incubation, the number of ova hatched was assessed by microscopic examination. For experiment 1, results ranged from 46% to 57% of exposed ova hatched. For experiment 2, results ranged from 43% to 49% of ova hatched. For experiment 3, 37% to 46% of exposed ova hatched. Conversely, for the control groups above 80% of ova hatched for all 3 experiments. These data suggest that exposure to iHP fog and mist has variable effectiveness in reducing viability of S. obvelata ova at the time points tracked. Further studies are needed to identify iHP exposures that will further reduce or eliminate the hatching of rodent pinworm ova.

Collection of blood samples for research or clinical evaluation is one of the most common procedures performed in non-human primates. Several possible methods can be used to obtain samples. In the early days of primate research, manual or physical restraint was used, which was stressful for the animal and risky for the human. As the field developed, chemical immobilization with ketamine or other anesthetics has become the most commonly used method. More recently, training using positive reinforcement has allowed collection of blood samples from unsedated primates that are unrestrained or minimally restrained. Elimination of anesthesia reduces risks to the animal. We wanted to determine whether the risks to humans were different between the sedated or unsedated blood collection. We evaluated injury and near-miss reports in conjunction with blood collection data from 2009 to 2019 at the Washington National Primate Research Center, which houses macaques (M. nemestrina, M. mulatta, and M. fasicularis) and squirrel monkeys (S. sciureus), and has housed baboons (Papio sp.) in the past. Injuries associated with sedated blood collection included those occurring during the sedation procedure and recovery as well as those directly associated with blood collection. Injuries associated with unsedated blood collection included those which occurred both during animal training and during blood collection. Overall, 22 human injury exposures and 5 near misses were associated with 73,626 blood collection procedures. Based on these numbers, 0.026% of sedated blood collections and 0.116% of unsedated blood collections were associated with exposure incidents. In conclusion, our data indicate a very low risk of exposure associated with blood collection. In this data set, the risk was statistically higher for unsedated animals, but the low number of incidents and the variability in the methods of blood collection make the general applicability of this finding questionable.

General anesthesia is a common procedure in laboratory rats; however, it impairs thermoregulation, rapidly leading to hypothermia as warm core blood is distributed to the cooler periphery. The protective strategy of prewarming before the onset of anesthesia delays hypothermia, but only for a short period. This prospective, randomized, cross-over, experimental study in adult male and female SD rats (n = 8) was designed to compare passive (fleece blanket) and active (temperature controlled heating pad) warming. Initial treatment order was randomized, with a cross-over after a minimum 5 d washout period. Both groups underwent a period of prewarming in a warming box to increase core temperature by 1% (median 0.4 °C). At completion of prewarming, general anesthesia was induced and maintained for 30 min with isoflurane carried in oxygen. Core temperature was monitored for a further 30 min after anesthesia. Active warming resulted in higher core temperatures during anesthesia. During passive warming, hypothermia occurred after approximately 30 min of anesthesia and continued into recovery. In contrast, active warming prevented hypothermia. Prewarming followed by passive warming delayed hypothermia for approximately 30 min, but active warming was more effective at maintaining normothermia both during and after general anesthesia.

Injectable anesthesia protocols for five striped palm squirrels (Funambulus pennantii) are poorly described in the literature. In this study, male intact squirrels received intramuscular injections of either alfaxalone (6 mg/kg) and ketamine (40 mg/ kg; AK group, n = 8); alfaxalone (6 mg/kg), ketamine (20 mg/kg), and dexmedetomidine (0.1 mg/kg; AKD group, n = 8); or alfaxalone (8 mg/kg), butorphanol (1 mg/kg), and midazolam (1 mg/kg; ABM group, n = 8). Atipamezole (0.15 mg/kg IM) and flumazenil (0.1 mg/kg IM) were administered 40 min after anesthesia induction (defined as loss of the righting reflex) with AKD and ABM, respectively. Heart rate, respiratory rate, rectal temperature, and reflexes were recorded every 5 min during anesthesia. Anesthetic induction was rapid in all groups (AK: median, 49 s; range, 33 to 60 s; AKD, 60 s; 54 to 70 s; and ABM, 15 s; 5 to 58 s). The anesthetic duration (from induction to full recovery) for the AK group was 62 ± 3 min (mean ± 1 SD). There was no statistically significant difference between the ABM and AKD groups regarding recovery time after partial antagonist administration and was 51 ± 5 and 48 ± 5 min, respectively. All AK animals showed twitching and abnormal vocalization during recovery. The righting reflex was absent in all squirrels for 20 min in the AK treatment group and throughout the 40 min anesthetic period in the AKD and ABM groups. The frontlimb withdrawal response was absent in all squirrels for the 40 min anesthetic period in the AKD and ABM groups, with variable responses for the AK treatment. All tested protocols in this study provided safe and effective immobilization in five striped palm squirrels, but oxygen and thermal support were indicated. Anesthetic depth must be determined before surgical procedures are performed in palm squirrels anesthetized by using these regimens.

Tricaine methanesulfonate (MS222) is widely used for the anesthesia and euthanasia of laboratory zebrafish. Fresh solutions have been recommended for each use; however, researchers often mix and store concentrated stock solutions for convenience and to reduce occupational exposure and environmental waste. While this is common practice, published guidelines are often inconsistent. Thus, the objective of this study was to evaluate the stability and anesthetic efficacy of MS222 after long-term storage and to develop specific storage parameters. Stock solutions (100 mg/mL MS222) were mixed and stored in amber jars at 4 °C and -20 °C for 2- and 6-mo. Stability of the solutions was analyzed using liquid chromatography-ion trap mass spectrometry and compared with fresh MS222. Fifty adult (30 male, 20 female) wildtype AB zebrafish (Danio rerio) were randomly anesthetized with 150 mg/L of one of the following MS222 solutions to evaluate anesthetic efficacy: 1) freshly prepared (0m); 2) 2 mo at 4 °C (2m4); 3) 2 mo at -20 °C (2m-20); 4) 6 mo at 4 °C (6m4); 5) 6 mo at -20 °C (6m-20). Time to cessation of swimming, loss of equilibrium, lack of response to von Frey (VF) stimulation, return of equilibrium, and resumption of swimming were compared between groups. Two fish from each group were euthanized at 24-h and 2-wk after anesthesia, and histopathology was performed. All solutions were determined to be stable under all storage conditions. No clinically significant differences were observed between the fresh and stored stock groups during anesthetic testing. No evidence of anesthetic-related histologic changes were noted in the gills, skin, kidneys, muscle, and central nervous system. Hepatic megalocytosis and a reduction in hepatic vacuolation were seen to varying degrees across all groups, but did not follow a treatment-related trend. Therefore, 100 mg/mL solutions of MS222 can be stored in amber jars at 4 °C or -20 °C for 6 mo and still used to effectively anesthetize zebrafish.

The reproducibility of results obtained with rodent models depends on the genetic purity of the strain and the stability of the environment. However, another potential factor is changes in the gut microbiota due to the transmission of mother's bacteria during embryo transfer. In this study, we demonstrate the transmission of the microbiota and immune cell blood phenotype to the offspring of 2 strains, C57BL/6JNskrc and BALB/cJNskrc, from surrogate dams of different genotypes. Interstrain embryo transfer resulted in a change in the number of Enterococcus spp. organisms, as shown by quantitative PCR analysis. The number of blood leukocytes was also affected, as estimated by flow cytometry. The number of blood leukocytes, including B cells and helper T cells, and the number of Enterococcus spp. organisms in male C57BL/6JNskrc offspring born to BALB/cJNskrc surrogate dams became similar to those of male BALB/cJNskrc mice born to BALB/cJNskrc dams. Likewise, the same parameters of male BALB/cJNskrc mice born to C57BL/6JNskrc dams became similar to those of male C57BL/6JNskrc offspring. Researchers should be aware of the possible transmission of the dam's microbiota and immune cell phenotypes to the experimental strains when planning embryo transfer experiments, because these factors could affect the experimental outcomes or the reproducibility of experimental results.

The present study assessed the effect of nearby construction activity on the responses of rat middle cerebral arteries (MCA) to the endothelium-dependent vasodilator acetylcholine and the NO donor sodium nitroprusside (SNP) and the activity of MaxiK potassium channels in MCA smooth muscle cells from male Sprague–Dawley rats. Two monitoring systems were used to assess vibrations in the animal rooms during and immediately after construction activities near the research building where the animal facility is located. One was a commercially available system; the other was a Raspberry-Pi (RPi)–based vibration monitoring system designed in our laboratory that included a small computing unit attached to a rolling sensor (low sensitivity) and a piezoelectric film sensor (high sensitivity). Both systems recorded increased levels of vibration during construction activity outside the building. During the construction period, vasodilator responses to acetylcholine and SNP were abolished, and MaxiK single-channel current opening frequency and open-state probability in cell-attached patches of isolated MCA myocytes were dramatically decreased. Recovery of acetylcholine- and SNP-induced dilation was minimal in MCA from rats studied after completion of construction but housed in the animal facility during construction, whereas responses to acetylcholine and SNP were intact in rats purchased, housed, and studied after construction. Baseline levels of vibration returned after the completion of construction, concomitant with the recovery of normal endothelium-dependent vasodilation to acetylcholine and of NO sensitivity assessed by using SNP in MCA from animals obtained after construction. The results of this study indicate that the vibration associated with nearby construction can have highly disruptive effects on crucial physiologic phenotypes.

The gut microbiota (GM) is the sum of hundreds of distinct microbial species that can equal or outnumber their host's somatic cells. The GM influences a multitude of physiologic and immunologic processes in the host, and changes in the GM have been shown to alter the phenotypes of animal models. Previous studies using rodents have also shown that the composition of the GM is affected by many factors, including diet, husbandry, housing, and the genetic background of the animals. However, limited information exists about factors that may modulate GM in other laboratory species, such as dogs. We sought to eliminate sporadic Giardia colonization of dogs using fenbendazole (FBZ), an antiprotozoal widely used in biomedical research dog colonies. Concerns that FBZ could have inadvertent effects on the canine GM led us to assess GM over the course of treatment. FBZ (50 mg/kg) was given orally to all dogs in 3 different facilities (n = 19 to 25) for 10 consecutive days. Fecal samples were obtained 2 d before the initiation of treatment, on the last day of treatment, and 2 wk after the completion of treatment. Targeted 16S rRNA gene sequencing was used to analyze fecal microbiota. All dogs were clinically normal throughout the sample collection period. Statistical analyses of data showed significant differences between dogs housed in the 3 different facilities, further emphasizing the effect of housing and husbandry factors on the GM. However, negligible differences were seen between time points, indicating that FBZ did not significantly alter the canine GM. Comparison of the GM of Giardia lamblia positive and negative dogs revealed no significant difference between the 2 groups. These findings suggest that FBZ can be used therapeutically in dogs with minimal impact on the GM. Furthermore, the presence of G. lamblia in clinically normal animals may not be sufficient to influence the normal canine microbiota.

Models of type-I diabetes are well-characterized and commonly used in the preclinical evaluation of drugs and medical devices. The diabetic minipig is an excellent example of a translational model. However, chronic glucose monitoring in this species can be challenging; frequent blood sampling can be technically difficult and poorly tolerated in conscious swine. Skin-patch continuous blood glucose monitors are FDA-approved for human use and offer a potential refinement to cageside blood collection. However, this modality has not been evaluated in pigs. In this study, young adult male STZ-induced diabetic Yucatan minipigs (n = 4) and healthy York pigs (n = 4) were implanted with a 14-d skin-patch continuous glucose monitor. Readings from continuous glucose monitors were time-matched to whole blood samples, with glucose measurements performed using point-of-care blood glucose monitors, serum chemistry or both. The aims of the study were to assess if a continuous glucose monitoring system could accurately detect glucose levels in swine, and to compare the readings to both point-of-care glucometers and serum chemistry results. We hypothesized that a continuous glucose monitoring system would accurately detect glucose levels in swine in comparison with a validated analyzer and could serve as an animal welfare refinement for studies of diabetes. We found that the continuous glucose monitor used in this study provided an adequate adjunct for clinical management in the stable diabetic pig and a minimally invasive and inexpensive option for colony maintenance of chronically diabetic swine.

To select animals of appropriate size for preclinical studies of cardiovascular devices, reference knowledge of the cardio- vascular anatomy relative to body weight is crucial. We measured the luminal diameters of the arteries (carotid, femoral, and iliac arteries) that are the common access vessels for endovascular and vascular procedures in Yorkshire × Landrace swine. Measurements were performed by using both ultrasound and angiographic methods and were correlated with body weight. Results showed no statistically significant difference between the left and right vessels in the diameters of the carotid, femoral, and iliac arteries. The diameters of the measured arteries showed high correlation with animal weight in pigs that weighed less than 70 kg.