Journal of the American Association for Laboratory Animal Science : JAALAS最新文献

The addition of supplemental diets to laboratory animals, specifically rodents, is a common practice for the provision of additional nutritional support. We set out to investigate whether the use of commercially available supplemental diets during breeding affected fertility rate, litter size, pup health, and pup survival. Genetically modified female breeding mice with a C57BL/6 background were divided into 3 groups (n = 16 per group) that received standard rodent chow alone or standard rodent chow with one of 2 commercially available supplemental diets: Love Mash (Bio-Serv) extruded pellet or Nutra-Gel (Bio-Serv) diet gel. Male and female mice began receiving the supplemental diet 1 wk before being paired with a partner of the same supplemental group. The mice were allowed to breed for 1 wk before separation from the male. The dams were continued on the diet until all pups were weaned. Overall, breeding dams supplemented with the Love Mash diet experienced significantly greater reproductive success rates and pup survivability compared with the standard diet control group. Dams supplemented with either of the 2 supplemental diets supported significantly larger litters compared with the standard diet control group. Furthermore, Love Mash supplemented diet groups produced significantly larger pups compared with the Nutra-Gel supplemented groups. This study demonstrates that supplemental diets given 1 wk before breeding and continued throughout gestation, parturition, and weaning significantly improved reproductive success, increased litter sizes, and supported pup health and survival.

Improved diagnostic capabilities and a desire to reduce or refine the use of animals as soiled bedding sentinels (SBS) have driven interest in developing the use of PCR-based testing methods, such as exhaust dust testing (EDT), for routine rodent health surveillance. We compared the absolute and quantitative PCR results from EDT filters with SBS mice by routine screening via a panel of 19 infectious agents including agents known to be excluded or present in the colony. In this study, EDT and SBS were compared at days 0, 90, and 180 in 3 facilities (n = 12 rooms) with animals housed on IVC racks (n = 19 double-sided and 23 single-sided racks). All racks were negative for excluded agents (n = 15 agents) during the study. The bacterial agent Helicobacter spp. was consistently detected on EDT filters while less consistently detected via SBS. EDT filters detected Corynebacterium bovis better than SBS in areas where the agent was present. EDT filters and SBS mice tested for murine norovirus (MNV) demonstrated agreement for positive tests by both PCR and serology. For rodent chaphamaparvovirus-1 (RCHPV-1) we compared EDT to urine and feces from SBS. Six cages of SBS were positive for RCHPV-1 by fecal PCR with 5 out of 6 testing positive on urine, while only 3 out of 6 EDT filters tested positive. Since real-time fluorogenic PCR was used for testing, relative PCR copy numbers for each positive finding were evaluated to estimate organism load at the rack level. Copy numbers allowed for further characterization of agent presence within a colony. Furthermore, we compared copy numbers with cage census for MNV and Helicobacter spp., which was positively correlated for EDT testing but not for SBS. Overall, our results demonstrate that EDT's ability to detect many commonly excluded agents is comparable to or better than SBS.

The search for alternatives to live animal sentinels in rodent health monitoring programs is fundamental to the 3Rs (Reduction, Replacement, and Refinement) of animal research. We evaluated the efficacy of a novel battery-operated tumbler device that rotates soiled bedding in direct contact with sample media against the use of exhaust sample media and soiled bedding sentinel (SBS) mice. Four rodent racks were used, each with 3 test cages: a cage with a tumbler device that rotated for 10min twice a week (TUM10), a cage with a tumbler device that rotated for 60min twice a week (TUM60), and a cage housing 2 female Crl:CD1(ICR) mice. Every 2 wk, each test cage received soiled bedding collected from all cages on each respective rack. In addition to soiled bedding, the tumbler device contained various sample collection media: a contact Reemay filter (3mo-cRF) that remained in the tumbler for the duration of the study, a contact Reemay filter (1mo-cRF) that was replaced monthly, adhesive swabs (AS) that were added at every biweekly cage change, and an exhaust Reemay filter located at the exhaust outlet of the cage. All analyses were performed by direct PCR for both sample media in the animal-free methods, and fecal pellet, body swab, and oral swabs were collected from sentinel mice. Out of 16 total pathogens detected, assessment of 1mo-Crf from both TUM10 and TUM60 cages detected 84% and 79% of pathogens, respectively, while SBS samples detected only 47% of pathogens. AS in TUM60 and TUM10 cages detected the fewest pathogens (24% and 13%, respectively). These results indicate that the novel tumbler device is an effective and reliable tool for rodent health monitoring programs and a suitable replacement for live animal sentinels. In this study, 1mo-cRF in TUM10 cages detected the highest number of pathogens.

Due to a lack of evidence-based standards for cage-change intervals for antelope ground squirrels (AGS, Ammospermophilus leucurus), we evaluated cage ammonia accumulation in our colony of adult, wild-caught AGS and identified factors that influenced ammonia levels. Intracage ammonia was measured daily in singly housed AGS in static caging that contained a running wheel and 1/2, 3/4, 1, or 2 quart (qt) of corncob bedding. Cages were changed when ammonia levels reached greater than 50ppm, our upper acceptable limit for ammonia based on mouse studies of ammonia aversion and toxicity. We also measured average daily water consumption over 2 wk to examine any correlation between water use and ammonia accumulation. We hypothesized that the desert-dwelling AGS would not reach intracage ammonia levels of greater than 50ppm in a 2-wk interval at any bedding volume. Our data showed that intracage ammonia was highly variable among individuals and was significantly associated with water consumption and bedding volumes. Seventeen percent of AGS on 1/2qt of bedding and 18% on 3/4qt of bedding reached greater than 50ppm ammonia before 7 d. All AGS on 1 and 2qt of bedding remained below 50ppm ammonia for 1 wk. Even when maintained on 2qt of bedding, not all AGS remained below 50ppm ammonia for 2 wk. Therefore, we concluded that the most appropriate option was weekly cage change for singly housed AGS on 1qt of bedding in static caging.

Intrafacility transport of mice is an essential function for both laboratory and husbandry personnel. However, transport may induce a stress response that can alter research findings and negatively impact animal welfare. To determine minimally adverse intrafacility transport methods, in-cage noise and vibration exposure during transport on a variety of transport vehicles (hand carrying, stainless steel rack, flatbed cart, metal teacart, plastic teacart, and a cart with pneumatic wheels) were measured. Under-cage and in-cage padding was tested for its ability to decrease noise and vibration on each vehicle. Behavioral (open field test and elevated plus maze) and corticosterone responses of mice were then measured following transport on the most adverse (metal teacart) and least adverse (pneumatic cart) methods of multicage transport. Behavioral measures showed no difference between transported mice and untransported mice in both single- and group-housed settings. Plasma corticosterone was significantly elevated in mice transported on the metal teacart immediately following transport and continued to have elevated trends in circadian peaks during the 48h of sampling. The cart with pneumatic wheels was most effective at reducing noise and vibration, reflected in posttransport corticosterone readings that remained equivalent to those in untransported mice. This study demonstrates that mitigation of noise and vibration during cart transport may decrease the impact of transport on certain stress parameters in mice.

The ability to apply findings from animal studies efficiently and effectively is predicated on an understanding of biology and pathobiology, how that biology relates to the human systems being modeled, and how the studies are conducted and reported. This overview discusses various factors in research within the animal environment (referred to as extrinsic factors) that the NIH now expects to be documented to foster replicability in science and expand interpretations of study outcomes. Specifically, an important extrinsic factor in research with animals is that of individual personnel who perform handling practices, participate in research interactions, and share an overall presence in the housing facility with animals, all of which can confound reproducibility efforts in biomedical science. An improved understanding of the influences and behaviors of animal research personnel on animal responses is critical with regard to research results and the interpretation of data collected from animal models of biomedical disease.

Nonhuman primates used in biomedical research may experience clinically significant weight loss for a variety of reasons. Episodes of anorexia (complete loss of appetite) or hyporexia (decreased appetite) can result in significant weight loss, potentially altering animal welfare and scientific studies. The FDA has approved several appetite stimulants for use in domestic species, but currently none are approved for use in NHP. Treatment of inappetence and weight loss in NHP often relies on the extralabel use of these compounds. Capromorelin is a ghrelin receptor agonist. As a growth hormone secretagogue, capromorelin increases appetite, leading to weight gain. Studies in several species have shown a positive correlation between capromorelin administration and weight gain; in 2017, an oral solution of capromorelin received FDA approval for use in dogs. We tested this solution in healthy adult rhesus macaques (n = 3 males and 3 females) for its effects on body weight and insulin like growth factor-1 (IGF-1). A control group (n = 2 males and 2 females) was used for comparison. Treated macaques received a 3mg/kg oral dose daily for 7 d. Clinical signs were observed daily. Weights were collected before, during and at the end of treatment. Blood was drawn before, during and after treatment for measurement of IGF-1 levels and standard hematology and biochemistry parameters. Baseline-adjusted mean body weights and IGF-1 levels were significantly higher in treated as compared with control monkeys after 7 d of beginning treatment (body weight of 10.5±0.1kg (mean ± SEM) and 10.1±0.1kg, respectively; IGF-1 of 758±43ng/mL and 639±22ng/mL, respectively). Capromorelin administration was not associated with appreciable changes in hematologic and biochemical values in treated macaques. These findings suggest that capromorelin may be useful for treating inappetence and weight loss in NHP, and based on blood analysis, a 7-d course of treatment does not appear to cause acute toxicity.

Despite the long-term contributions of the spiny mouse (Acomys cahirinus) to research, basic knowledge of appropriate nutrition is lacking for this species. In the wild, spiny mice eat a high-fiber, high-protein food source. In the research setting, spiny mice are prone to obesity that can lead to diabetes mellitus. Common dietary modifications for weight control in humans with diabetes mellitus consist of increased fiber and protein. We hypothesized that increasing the dietary protein or fiber of spiny mice would reduce weight gain and improve their glycemic control, whereas the combination of protein and fiber in the diet would achieve optimal weight management and glycemic control without diet-related pathologic changes. We randomly assigned cages of young adult spiny mice (n = 34) to one of 4 diets: high protein (HP), high fiber (HF), a combination of both high protein and high fiber (HPF), or the base (control) diet (BD). Over the 8-wk study, spiny mice given HF diets maintained baseline weights despite the elevated dietary protein. None of the diets altered blood glucose levels; all diet groups maintained mean blood glucose levels within normal ranges. Spiny mice seem particularly sensitive to changes within their environment, as seen by increased food waste and transient elevated blood glucose levels when the spiny mice were transitioned to novel diets. The short-term elevations in protein and fiber that we tested were well tolerated by spiny mice. Although HF was effective in controlling weight, the ideal percentage of fiber still needs to be determined. The combination diet (HPF) maintained weight and body condition scores and showed a nonsignificant elevation of blood glucose that warrants a longer diet trial before our recommending this specific combination.

The New Zealand white rabbit (Oryctolagus cuniculus) is a frequently used surgical model. Pain management after surgery is a critical aspect of animal welfare. Recently, a long-acting buprenorphine formulation (Ethiqa XR; EXR) was approved for use in rats and mice but has not yet been investigated in rabbits. The current study aimed to determine whether a single subcutaneous dose of 0.15mg/kg of EXR could achieve and maintain therapeutic buprenorphine plasma concentrations (0.1ng/mL) for 72h in male and female rabbits. We also evaluated the safety profiles of EXR and the fentanyl patch (FP) by assessing fecal output after surgery, because opioids are known to decrease intestinal motility. Behavior and pain scores were compared for rabbits that received either EXR or the FP after undergoing an annulus puncture procedure to induce osteoarthritis. EXR at 0.15mg/kg SC provided a shorter time to onset and sustained analgesia for 72h in male and female rabbits, whereas the FP provided suboptimal analgesia after 48h. Both EXR and FP reduced fecal output after surgery. Output returned to baseline levels within 72h for the EXR group and remained slightly below baseline at 96h after surgery for the fentanyl group. Grimace pain scores revealed no significant difference between treatment groups. These results suggest that EXR is a safe and effective option for postoperative pain management in rabbits.

Many experiments require the collection of serial blood samples from mice. However, the size of mice limits the volume of blood that can be safely collected as a survival procedure. In IACUC protocols, investigators may report the amount of blood they collect from mice as a number of drops. Many institutions, including ours, use an anecdotal conversion factor (1drop of mouse blood = 25μL) to ensure that blood-collection volumes are compliant with institutional guidelines. To our knowledge, previous work has not experimentally determined the volume of a drop of mouse blood. In this 10-wk crossover experiment, 2 phlebotomists bled 30 C57BL/6J mice from 3 sites (facial, saphenous, and tail) using one or 2 different needle gauge sizes per site. Male and female mice were weighed weekly and divided among 5 groups (n = 6): left and right tail vein, left and right saphenous vein, and facial vein. A single blood drop from each site was weighed, and the volume of each drop was calculated using the average blood density determined from 8 mice terminally bled at the end of the study. Venipuncture site and side significantly influenced blood-drop weight and thus calculated volume. Facial vein puncture produced the largest drop volume (mean: 21.7μL), followed by the saphenous vein (mean: 9.97μL) and tail vein (mean: 4.96μL). Collection from the facial vein was associated with more hemorrhage and morbidity. Left-sided venipuncture was associated with slightly larger-volume blood drops, though the effect size of side was small. The results of this study may be useful in more accurately estimating blood loss via conversion of drops to volume. Our data indicate that blood collection from saphenous and tail veins minimizes blood loss relative to facial vein puncture and may optimize both serial collection of small-volume blood samples and animal welfare.