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

Peromyscus species have been used in research for decades, yet there are no specific reports of mite infestations in the laboratory setting despite many reports of various mite species found in wild Peromyscus. This study documents P. californicus infestation with Radfordia lemnina in an academic research setting. During the colony quarantine period, deer mice tested positive on a general mite PCR but negative on all species-specific mite PCR assays. Tape tests were performed on a subset of cages, and 21% were positive for adult mites or viable eggs. Mites were sent for sequencing and identified as R. lemnina, for which the natural host is Microtus pennsylvanicus. The entire colony was treated with selamectin, applied topically to the nape of the neck, and repeated one month later. All deer mice were successfully treated using a novel method of restraint, and no gross adverse reactions to selamectin treatment were noted. Tape tests were performed weekly to biweekly on a subset of deer mice, and PCR was used to confirm negative tape test results. PCR was positive at 14 wk posttreatment, and tape tests were intermittently positive for egg casings for 27 wk, indicating continued presence of genetic material but not necessarily an active infection. Weaned offspring were tape test and/or PCR negative at 12 and 21 wk posttreatment, providing further support for successful treatment. At 31 wk, 2 rounds of tape tests and PCR were both negative. This report documents a safe and effective treatment method for mites in P. californicus.

Soft-pelleted, high-fat diets (HFD) are greasy and crumble easily leading to food wastage and hair coat grease accumulation when mice are fed using commercially available feeders. The ideal HFD feeder design should reduce food wastage, facilitate mouse weight gain, and minimize variables such as hair coat grease accumulation that have the potential to alter scratching behaviors. Our study compared the feeding efficiency of 2 commercially available feeders (feeders A and E) to 4 novel feeder designs (feeders B, C, D, and F). Novel feeders had alterations in feeding aperture size, feeding surface area, feeder configuration, and level of food presentation. Male C57BL/6NCrl mice (n = 120; 4/cage) were randomly assigned to cages containing one of the 6 feeder types and were fed HFD for 12 wk. Feeders and cage bottoms were weighed before use and then weekly at the time of cage change. Mice were weighed before starting the HFD and then biweekly. Scratching behavior was video recorded at 0, 4, 8, and 12 wk. Hair coat grease accumulation was visually scored biweekly. Feeder A use was associated with the highest feed cost due to HFD wastage ($36.98 ± 1.54/cage/wk). Mice fed using Feeder A had the highest average weight gain (23.75 ± 0.8 g, P < 0.005). However, mice also had significantly higher hair coat grease accumulation scores (P < 0.05) and significantly increased scratching frequency at 4 wk (P < 0.05) when compared with mice fed using other feeder types. Novel feeder designs utilized 10 to 21 times less HFD dispensed when compared to feeder A. Mice fed using novel feeders also displayed improved welfare, as evidenced by low hair coat grease accumulation scores, and no significant differences in scratching frequency when compared with baseline behavior.

Medetomidine/vatinoxan (Zenalpha^®) is a novel anesthetic combination used as a sedative and analgesic in dogs. Vatinoxan minimizes adverse cardiopulmonary effects associated with medetomidine administration while preserving sedation and analgesia. In this study, we evaluated the clinical safety and efficacy of 3 dosage combinations of Zenalpha with ketamine and buprenorphine extended release (ER) as compared with xylazine with ketamine and buprenorphine-ER for anesthesia of C57BL/6J mice. We hypothesized that anesthesia with 0.5 mg/kg of Zenalpha would more reliably provide a surgical anesthetic plane, lower mortality, and fewer adverse physiologic effects as compared with anesthesia with 8 mg/kg of xylazine. Ten-week-old male and female C57BL/6J mice were randomly administered 1 of 4 anesthetic cocktails subcutaneously: ketamine (80 mg/kg) and buprenorphine-ER (0.5 mg/kg) with 1) xylazine (8 mg/kg; XKB); 2) Zenalpha (0.25 mg/kg; ZKB/0.25); 3) Zenalpha (0.5 mg/kg; ZKB/0.5); or 4) Zenalpha (1.0 mg/kg; ZKB/1.0). Following drug administration, we assessed the anesthesia induction time by measuring the time to loss of righting reflex and loss of paw withdrawal reflex (PWR). Upon reaching a loss of righting reflex, physiologic parameters including heart rate, respiratory rate, oxygen saturation, indirect mean arterial blood pressure, body temperature, jaw tone, and skin color were monitored every 5 min. Thirty minutes after anesthetic drug administration (T_A), atipamezole (1 mg/kg SC) was administered. Recovery time was determined through time until return of PWR, righting reflex, and ambulation. Mice were monitored for 3 d postanesthesia. Results included: 1) ZKB anesthesia caused loss of PWR in a dose-dependent manner; 2) physiologic parameters were similar between XKB and ZKB mice by T_A in 100% O₂; 3) ZKB groups took longer to recover and had a 20% to 30% mortality rate in the mid-to-high dosage groups. We conclude that anesthesia with 0.5 mg/kg of Zenalpha more reliably produced a surgical anesthetic plane but also led to decreased mean arterial pressure and increased mortality as compared with anesthesia with 8 mg/kg of xylazine. We recommend using Zenalpha (0.25 to 1.0 mg/kg) with 80 mg/kg ketamine and 0.5 mg/kg buprenorphine-ER to provide general anesthesia in C57BL/6 mice, along with supplemental 100% oxygen and atipamezole.

Cardiac troponin I (cTnI) is a cardiac-specific biomarker, used for the detection of myocardial injury. While rabbits develop naturally occurring cardiovascular disease, they are also an animal model for human disease; thus, rapid detection of cTnI has implications for both veterinary and human medicine. The objective of this study was to validate and establish a reference interval for a point-of-care (POC) cTnI assay in New Zealand White rabbits. In the first portion of the study, rabbit cardiac and skeletal muscle tissues were used to create homogenates, serially diluted with saline or rabbit whole blood, and run by repeated analysis on the POC assay. In the second portion of the study, a reference interval of peripheral whole blood cTnI was determined by robust methods from 49 New Zealand White rabbits. The least diluted cardiac muscle homogenates produced detectable cTnI (mean 23.12 ± 3.557 ng/mL), while skeletal muscle homogenates produced low to undetectable cTnI. The CV ranged from 0.00% to 32.51% for cTnI of diluted cardiac muscle homogenates. Rabbit cardiac homogenate diluted in blood had a linear relationship to cTnI concentration (Y = 0.2254 × X + 0.5396, R² = 0.975). The reference interval for cTnI in this population was less than 0.04 ng/mL. This POC assay may be useful when rapid detection of cTnI is needed and differentiation between normal and elevated values is required. Given the high CV, this assay may not be appropriate for cases that require high sensitivity or detection of low concentrations of cTnI.

A variety of fish species have proven instrumental in the investigation of evolution, behavior, ecology, and physiology, among many other fields. Many model systems (e.g., zebrafish, guppies, and three-spined sticklebacks) have been maintained by institutions and have had protocols written with respect to their husbandry. Here we present the protocols we have developed to maintain and breed a variety of Corydoras catfish species, which are native to the tropical Americas. Corydoras species are excellent systems for investigating behavior, ecology, and other topics, and our husbandry protocols would be suitable for nearly every species in the genus. In addition, these protocols are appropriate for a variety of softwater Amazonian species, and we present options for a variety of housing and husbandry conditions. On the whole, we suggest that, in a scientific laboratory setting, the use of remineralized reverse osmosis water is most appropriate and that in context, a single measure, total dissolved solids, can be used to monitor the water chemistry for water introduced to fish enclosures.