Laboratory Animals最新文献

To carry out research with genetically modified animals, their genotype has to be assessed. A standard protocol to obtain required tissue samples from zebrafish is finclipping. However, some studies reported considerable stress induced by this protocol. We therefore assessed ventilation as a read-out for stress in zebrafish that underwent finclipping during routine genotyping in our fish facility. Our analysis could not confirm a strong increase of ventilation as had been previously reported. Instead, handled zebrafish showed ventilation rates in the range of controls that remained in their holding tanks. Additionally, we detected a slight reduction of ventilation rates up to an hour after anaesthesia in zebrafish treated with tricaine only, suggesting a prolonged protecting effect by this anaesthetic.

Outbred stocks of mice are widely used in pre-clinical research as these animals possess a diversified genetic background when compared with inbred strains of mice. It is crucial to assess particular alterations in the physiological and functional profiles of laboratory animals using haematological and biochemical indicators. These values can also differ between laboratories because they are influenced by many different factors. We aimed to provide normal values and reference intervals for selected haematology and biochemistry analytes of 570 ICR mice at three different ages: 6-8 weeks, 10-14 weeks and 6-9 months. Reference values were calculated by non-parametric methods. For comparisons between sexes, the independent-sample t-test and Mann-Whitney test were employed, and analysis of variance was used for age differences. The findings of the study revealed age-related declines in haemoglobin concentration, haematocrit, mean corpuscular volume and mean corpuscular haemoglobin concentrations. Mice aged 6-9 months had statistically higher platelet counts in their blood than mice of other ages. The white blood cell count had a significant age effect and progressively decreased with age. As mice get older, the percentage of neutrophils, monocytes and basophils increases, but the percentage of lymphocytes decreases. For the biochemical values, age-related significant differences in glucose, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and albumin concentrations were found. It was also found that creatinine concentrations were comparable across all age ranges. The values presented in the present work can be used as a reference to interpret clinical pathology data for other studies and to evaluate health status.

One of the favored options for generating complex transgenic laboratory mice is through in-house breeding and management strategies. One consideration in the management of these colonies is how the animals' environment may affect reproductive success. Several aspects of the microenvironment can be controlled or manipulated, including cage type, bedding, enrichment, diet, and temperature and humidity. This study sought to evaluate reproductive outcomes for C57BL/6J mice that were randomly assigned to one of two different bedding types: paper based or corncob bedding. Our hypothesis was there would be no significant difference in reproductive outcomes between the two bedding types. A total of 10 males and 10 females were paired at 45 days of age. Animals were allowed to breed for 15 consecutive weeks. Cages were checked daily for the presence of pups and a pup count was performed at 7 days of age. Weaning occurred at 20 or 21 days of age, at which time a final pup count, pup weight, and sex were recorded. All litters born and pups weaned in the 15-week timeframe were used for data analysis. Statistical analysis compared cannibalization between the two groups and the results showed no statistical difference between groups (p > 0.05). Other parameters analyzed included average litter size, average weaning weight, and number of litters per group. All pups counted at Day 7 survived to weaning age in both groups. We concluded that both bedding types produced similar success regarding breeding fecundity in C57BL/6J mice.

As a step towards implementing non-aversive handling techniques at a big mouse breeding facility in Germany, tunnel handling was introduced in a breeding unit comprising three inbred mouse strains. To assess whether tunnel handling would be feasible for the animal technicians in their everyday work and beneficial for the mice when being handled during weekly cage change only, the behaviour of tunnel- and tail-handled animals of both sexes was examined before, during and after the handling events over a period of nine weeks. Moreover, the time expenditure was compared between both handling techniques. It was possible to use the tunnel in all three mouse strains. However, the impact of the handling techniques on the behavioural parameters investigated in the present study were strain-specific. All behavioural parameters suggested that NZW mice benefited the most from tunnel handling. The results obtained from Hello Kitty and WNK mice were ambiguous, which may suggest that a brief handling session during the cage clean may have not been sufficient to habituate them to the process of handling. It took the animal technicians approximately 3 seconds longer per mouse when using a tunnel. The strain-specific results should encourage researchers to share their experiences with non-aversive handling techniques in different mouse strains, for example, along with their research articles.

Although pulmonary adenomas have been reported in ICR mice, spontaneous adenomas have not been reported in mice aged ≤10 weeks. Here, we report a well-circumscribed nodule (1 mm × 1 mm) in the peripheral lesion of the left lateral lobe of a 10-week-old male ICR mouse. Histopathologic evaluation revealed a well-demarcated nodule compressing the surrounding tissue. The neoplastic cells were polygonal with indistinct cellular borders, round/oval nuclei and abundant cytoplasm. These characteristics led to the diagnosis of type II cell-derived bronchioloalveolar adenoma. Given that they are generally observed in aged laboratory animals, this case represents a rare manifestation of a spontaneous tumor in young laboratory mice before puberty.

Urine collection can be challenging in studies involving small rodents like mice, as the actual methods of collection are anxiogenic and constrain animal welfare while having high variability in the volume of urine collected. To improve the current methods and eventually reduce the impact on the well-being of mice, we developed an innovative 3D-printed urine collection device (UCD). This two-compartment UCD is shaped to fit in classical husbandry cages and allows urine collection by spontaneous urination from two mice housed in their own cage without cross-contamination while enabling potential social interactions. We used our UCD to study the evolution of urinary parameters related to renal functions in a model of antibody-mediated chronic kidney disease. Overall, we report here a time-saving and affordable method for urine collection providing a large amount of uncontaminated urine and which we believe may improve animal welfare in comparison with other methods.

An alternative in an attempt to minimize the effects triggered by intravenous (IV) bolus administration of α-2 adrenergic receptor agonists are continuous rate infusions (CRI). The requirement for sedation protocols in sheep for procedures to be performed without physical restraint and with reduced adverse effects, commonly observed with bolus use, justifies the study of CRI. The aim of study was to compare the cardiopulmonary and sedative effects of IV bolus injection and CRI of dexmedetomidine (DEX) in sheep. Six adult male sheep (38.3 ± 7.6 kg) received DEX as a bolus (5 µg kg^-1, DEX_bolus treatment) or CRI (5 µg kg^-1 h^-1 for 1 h, DEX_CRI treatment). We recorded heartrate (HR), respiratory rate, systemic arterial blood pressure, pulse oximetry, hemodynamic parameters, blood gases and sedation scores over 120 min. HR was significantly lower in DEX_bolus at 5 and 15 min than in DEX_CRI, with HR reduction observed for 30 min in DEX_bolus. Hypoxemia was noted in DEX_bolus at 10 and 30 min. Pulmonary vascular resistance index increased at 5 min, and cardiac index (CI) decreased at all timepoints compared with baseline in DEX_bolus. In DEX_CRI, CI decreased only at 45 min. Sedation scores were higher in DEX_bolus at 15 and 30 min. DEX CRI administration resulted in fewer cardiorespiratory and hemodynamic changes compared with bolus injection and lower sedation scores (<4/10), which would not allow animal handling without a reaction. The load dose used in CRI was a limitation to constant infusion.

When biomedical research investigates the human surgical situation in the need of a chronic course, it is more often possible to do so using large animal models. The use of farm animals always poses special challenges for the institution conducting the research in terms of infection prevention and occupational safety. Especially for the zoonotic disease coxiellosis it is important to be aware of the constant risk of pathogen introduction by small ruminants and to take appropriate precautions. In this way, personal injury should be avoided or at least be kept to a minimum in the event of infection since then sustainable zoonosis control can be immediately initiated. Using the example of a Q fever outbreak at a research facility, we want to share with this extended case report the importance of central emergency structures, provisions and the inclusion of relevant experts and disciplines in a crisis team. Its primary purpose is to support the affected facility and coordinate the implementation of necessary cleaning, disinfection and decontamination measures in close contact with the responsible local authorities. The aim is to inactivate the pathogen in a systematic and controlled manner in few steps of action only and to keep the interruption of the facility's operations as short as possible.

A retrospective comparison of welfare indicators in male rats undergoing thoracotomy for intrapleural dosing is presented. The initial cohort (n = 7) breathed room air after recovery from anaesthesia, while later cohorts (n = 12) had oxygen supplementation for up to 48 h post-surgery. Rats breathing room air sustained a statistically significant average body-weight loss of -1.62% (±1.7%) 2 days after surgery, compared with rats given oxygen supplementation, which maintained a mean weight gain of 0.87% (±1.75%) (p = 0.009). Oxygen-supplemented rats also had lower pain scores on the evening after surgery (median 0.075 [range 0-1.75] vs. median 1.5 [range 0.5-2]). This difference was not statistically significant (p = 0.063) but may be of clinical significance. All rats displayed transient sedation after post-operative opioid administration on the day of surgery, and hypoxaemia (SpO₂ <90%) was observed in rats maintained on room air. Use of an oxygen concentrator to provide post-operative extended oxygen supplementation was easy to implement and may improve animal welfare post-thoracotomy.

Animal care and use personnel in research laboratory facilities are inherently exposed to a variety of workplace hazards. The health and safety of the workforce working directly with or around research animals is of paramount importance, and as such, an occupational health and safety program for at-risk staff is essential. In order to maximize participation in and the effectiveness of health and safety training and occupational health program enrollment for animal care and use personnel at an academic health sciences university, an innovative annual "health fair" was developed and implemented at The University of Texas Health Science Center at Houston. This event allows personnel working in positions that present exposure risk to research animals to be able to obtain hazard-specific health and safety training, re-enroll in the occupational health oversight program and update their medical history, and participate in the institution's other safety programs as required by job title or assigned job tasks. By providing a comprehensive health fair that offers convenient access to the necessary safety training and occupational health services in one location during a designated period of time, management and staff are incentivized to participate and have reported satisfaction with and appreciation of the convenient access. Summarized here is how we plan, organize, and effectively execute the annual health fair so that other institutions who might wish to use this strategy can learn from our approach.