Using refined methods to pick up mice: A survey benchmarking prevalence & beliefs about tunnel and cup handling.

Refined handling improves laboratory mouse welfare and research outcomes when compared to traditional tail handling, yet implementation does not seem to be widespread. Refined handling includes picking up a mouse using a tunnel or cupped hands. The aim of this study was to determine the current prevalence of and beliefs towards refined handling using the theory of planned behavior. It was predicted that refined handling prevalence is low compared to traditional handling methods, and its implementation is determined by individual and institutional beliefs. Research personnel were recruited via online convenience sampling through email listservs and social media. A total of 261 participants in diverse roles (e.g. veterinarians, managers, caretakers, researchers, etc.) responded primarily from the USA (79%) and academic institutions (61%) Participants were surveyed about their current use, knowledge, and beliefs about refined handling. Quantitative data were analyzed via descriptive statistics and generalised regression. Qualitative data were analyzed by theme. Research personnel reported low levels of refined handling implementation, with only 10% of participants using it exclusively and a median estimate of only 10% of institutional mice being handled with refined methods. Individually, participants had positive attitudes, neutral norms, and positive control beliefs about refined handling. Participants' intention to provide refined handling in the future was strongly associated with their attitudes, norms, and control beliefs (p<0.01). Participants believed barriers included jumpy mice, perceived incompatibility with restraint, lack of time, and other personnel. However, participants also believed refined handling was advantageous to mouse welfare, handling ease, personnel, and research. Although results from this survey indicate that current refined handling prevalence is low in this sample, personnel believe it has important benefits, and future use is associated with their beliefs about the practice. People who believed refined handling was good, felt pressure to use it, and were confident in their use reported higher implementation. Increased refined handling could be encouraged through education on misconceptions, highlighting advantages, and addressing important barriers.

Compassion Fatigue in Laboratory Animal Personnel during the COVID-19 Pandemic.

Compassion Fatigue (CF) is commonly observed in professions associated with human and animal care. The COVID-19 pandemic compelled laboratory animal research institutions to implement new work practices in order to maintain essential animal care operations. These modifications ranged from shift changes to last-resort measures, such as culling animal colonies, to accommodate reduced staffing. Such changes could cause personnel to experience increased stress, isolation, and helplessness-all of which can increase CF risk. In the current study, 200 persons involved with animal research completed an online survey to gauge whether CF among laboratory animal personnel had increased during the pandemic. The survey examined professional quality of life, self-assessed levels of CF, institutional changes, perceived changes in animal welfare, and institutional measures intended to alleviate CF. A total of 86% of participants had experienced CF at some point in their career, with 41% experiencing a CF event (new or worsening symptoms of CF) during the pandemic. In addition, 90% of participants who reported a CF event also reported subsequent effects on their personal or professional lives. Health, employment, and animal-related stress that arose due to the pandemic were all found to influence CF scores significantly. Although 96% of respondents were considered essential workers, 67% did not feel as valued for their work as other essential personnel. Furthermore, 88% of personnel responsible for the euthanasia of healthy animals who experienced a CF event reported that CF also affected their personal life, professional life, or both, and 78% responded that interventions from internal CF programs or leadership did not help to alleviate symptoms of CF. The COVID-19 pandemic and resultant institutional changes will likely have lasting effects on persons and organizations. By determining and subsequently mitigating sources of CF, we can better assist the laboratory animal community during future crises.

Effects of Analgesics on Tumor Growth in Mouse Models of Prostate Cancer Bone Metastasis.

Murine models of tumor development often require invasive procedures for tumor implantation, potentially causing pain or distress. However, analgesics are often withheld during implantation because of concerns that they may adversely affect tumor development. Previous studies examining the effects of analgesics on the development and metastasis of various tumor lines show that the effect of analgesics depends on the tumor line and analgesic used. A blanket statement that analgesics affect the general growth of tumors is not adequate scientific justification for withholding pain relief, and pilot studies or references are recommended for each specific tumor cell line and treatment combination. In this study, we evaluated the effects of 2 commonly used analgesics on tumor growth in 2 models of prostate cancer (PCa) bone metastasis. We hypothesized that a one-time injection of analgesics at the time of intratibial injection of tumor cells would not significantly impact tumor growth. Either C57BL/6 or SCID mice were injected subcutaneously with an analgesic (carprofen [5 mg/kg], or buprenorphine [0.1 mg/kg]) or vehicle (0.1 mL of saline) at the time of intratibial injection with a PCa cell line (RM1 or PC3, n = 10 to 11 per group). Tumor growth (measured by determination of tumor burden and the extent of bone involvement) and welfare (measured by nociception, locomotion, and weight) were monitored for 2 to 4 wk. Neither carprofen or buprenorphine administration consistently affected tumor growth or indices of animal welfare as compared with the saline control for either cell line. This study adds to the growing body of literature demonstrating that analgesia can be compatible with scientific objectives, and that a decision to withhold analgesics must be scientifically justified and evaluated on a model-specific basis.

Effects of Trio and Pair Breeding of Mice on Environmental Parameters and Nasal Pathology and Their Implications for Cage Change Frequency.

According to the Guide, cage change frequencies must be considered when cage density requirements are exceeded. We monitored ammonia, carbon dioxide, cage wetness, health status, and breeding parameters of trio and pair breeding cages containing CD1 mice in ventilated and static microisolation caging (4 cages per condition) daily for approximately 6 wk. Minimum cage change frequencies for each condition were determined on the basis of performance data. At 3 d after cage change, static trio and pair cages had average ammonia levels of 74 and 38 ppm. Ventilated cages remained below the 25ppm threshold reported to be potentially deleterious for mice until at least day 7 after cage change. By 7 d after cage change, ammonia levels had risen to an average of 100 ppm and 64 ppm in static trio and pair cages and to 34 ppm and 20 ppm in ventilated trio and pair cages, respectively. Ammonia levels in ventilated cages continued to rise slowly through day 14 after cage change. CO2 levels exceeded 5000 ppm in all groups at 2 d after cage change. Pair breeders in ventilated cages took the longest-10 to 14 d-to reach cage wetness threshold scores. On day 7, pups in trio static cages were noted to have decreased and squinted eyes, whereas in ventilated cages containing trios and pairs, these clinical signs were rare to absent. Histologically, there was an increasing incidence and severity of nasal lesions in weanlings with increasing housing density and decreasing ventilation, consistent with nasal epithelial toxicity. Given these parameters, we concluded that under the current husbandry conditions, it may be necessary to change breeders in static cages more frequently than every 7 d. Additional studies are necessary to evaluate the effects of more frequent cage changes on reproductive parameters, given that cage changing is stressful for mice and affects breeding results.

Enrichment Preferences of Singly Housed Zebrafish (Danio rerio).

Despite the increasing popularity of zebrafish (Danio rerio) as an animal model, the environmental enrichment preferences of this species have been largely unexplored. We sought to determine the preferences of mature female zebrafish that were singly housed with or without access to one of 10 inanimate forms of enrichment. As a marker of preference, in-tank fish location was observed by video recording. All subjects showed a preference for the front of the tank when caretakers entered the room, demonstrating an effect of human presence on tank location. Among the 10 enrichment items tested, subjects showed the strongest preference for mirrored paper on the side of the tank when compared with the barren half of the tank. Fish also were observed interacting with PVC pipe, marbles, and tulle. Given the preference for enrichment imitating social interaction, we conducted a second study to assess the value of visual exposure of conspecifics in adjacent tanks. The experimental zebrafish were then provided one of 3 conditions-a singly housed neighbor fish, group-housed neighbor fish, or no neighbor fish. All zebrafish housed next to neighboring fish showed a preference to be on the side of the tank nearer to the other fish. Overall, our data indicate that singly housed zebrafish prefer enrichment items that resemble or promote social behaviors. Therefore items such as mirrored paper or housing next to conspecifics should be strongly considered as enrichment strategies for singly housed zebrafish.

Assessment of Mouse Handling Techniques During Cage Changing.

Mouse handling during cage changing and health evaluation has traditionally been performed by using forceps. This method was adopted as a biosecurity measure but can adversely affect employee ergonomics and rodent behavior. In this study, we evaluated alternative methods of rodent handling and their potential implications for efficiency, biosecurity, and animal welfare. Study groups included plastic cups, gloved hands, 2 methods of tunnel handling, and forceps. Evaluations included speed of cage change, ATP-based assessment of sanitization, and retrospective analysis of colony health and breeding data. The time to change 14 cages was significantly faster at each time point for the gloved hands and forceps groups as compared with the other methods. Overall speed did not increase significantly with each subsequent study week for any group. ATP levels after sanitization with hydrogen peroxide-peracetic acid mixture differed significantly between gloves and forceps. When ATP level was evaluated on a per-cm² basis, no significant difference between gloves and forceps was detected. Although tunnel and cup handling both increased the time for cage-changing, the tunnel served as both an indirect handling method and a shelter when left within the cage. Retrospective analysis revealed that breeding performance and colony health were similar among groups. Although efficiency is a concern for large-scale implementation of novel handling methods, the tunnel method may prove beneficial for sensitive strains or studies requiring indirect handling. In addition, using gloved hands to directly handle mice during cage changing is efficient and avoids the ergonomic strain associated with forceps. Precautions should be taken when handling mice with gloves, given that the increased contact area carries an increased load of organic debris. Changing gloves between rack sides or before proceeding to the animals belonging to a different investigator minimizes the potential for cross-contamination.

Using Cageside Measures to Evaluate Analgesic Efficacy in Mice (Mus musculus) after Surgery.

Recent studies have revealed some of the most frequently used analgesics in mice are not effectively treating postoperative pain. Our laboratory sought to compare and assess the validity and reliability of 2 cageside pain assessments that we recently developed for use in mice-nesting consolidation and grooming transfer tests. We then applied these tests to compare the efficacy of commonly used analgesics-buprenorphine (0.1 mg/kg SC every 12 h for 48 h) and carprofen (30 mg/kg in drinking water for 72 h)-alone and in multimodal combination as a refinement for treating postoperative pain in mice. Briefly, C57BL/6 and CD1 male and female mice underwent assessment under conditions of baseline, anesthesia-analgesia, and laparotomy. Results showed that multimodal analgesia displayed the greatest analgesic coverage over the postoperative period, whereas buprenorphine showed slightly less coverage, and carprofen and saline groups displayed signs of pain at most postoperative time points. After anesthesia-analgesia, buprenorphine and multimodal mice lost significant body weight in the absence of a painful stimulus and displayed other significant drug-related changes. Animals treated with carprofen showed few drug-related changes after anesthesia-analgesia but also demonstrated minimal benefit from postsurgical analgesia. Overall, multimodal analgesia was more effective for treating postsurgical pain in mice than the single-analgesic protocols we tested; however, effects on weight loss need to be considered during analgesic selection. Nesting consolidation and grooming transfer tests were valid and highly reliable over time, in inbred and outbred mice, in male and female mice, under different housing conditions. In addition, the nesting consolidation test had excellent reliability between observers. These findings can be used in refining the detection and treatment of postoperative pain in mice.