Adapting to changing conditions has always been necessary for AALAS journals, and current times are no different. Since the publication of Proceedings of the Animal Care Panel in 1951, AALAS journals have undergone significant name and scope changes, and the publication offerings by AALAS have evolved many times to meet the scientific, clinical care, and technical needs of the AALAS community (Figure 1; adapted from Mulder3). These collective changes have culminated in the current catalog of Laboratory Animal Science Professional (LAS Pro), Journal of the American Association for Laboratory Animal Science
The Association of Primate Veterinarians (APV) recognizes that cerebrospinal fluid (CSF) collection may be required for both clinical and research purposes in nonhuman primates (NHP). Because there are inherent risks associated with the technique, the laboratory animal veterinarian should determine the need and utility of CSF collection for clinical evaluation. CSF collections for research purposes must be scientifically justified and approved by the institutional animal care and use committee (IACUC) or equivalent regulatory body hereafter referred to as IACUC. The following recommendations provide basic information for IACUCs, researchers using NHP models, and veterinary personnel to consider when developing policiesPurpose
Organizations that receive public money to conduct research using animals should be able to explain the importance of and need for that work. More generally, anyone who believes that properly conducted and regulated animal research either does or does not make the world a better place wants the public to understand why they hold their belief. In a world with divided support for animal research, honest communication about these issues is essential to develop sound public policy. Specifically, communication about animal research (or any type of research) needs to address the scientific, ethical, and regulatory considerations that underlie public policy decisions. This opinion article describes a 7-step communication strategy designed to address these issues. The 7 elements of this approach are 1) motivation, 2) the right mix of information, 3) a team approach, 4) respect for your audience, 5) determination and courage, 6) humility and honesty, and 7) persistence.Abstract
Genotyping is a common and necessary procedure performed on genetically modified animals to distinguish carriers from noncarriers of the variants of interest. Established methods involve collection of tissues such as tips of tails or notches of ears. Noninvasive methods have been described but not widely adopted for reasons including inertia to change, needs to adjust PCR protocols, and the lack of validation; noninvasive genotyping methods are a refinement on animal welfare, but questions remain regarding how they compare with invasive methods in terms of genotyping accuracy rate and reproducibility. To gain answers to these questions, we compared the detection accuracy of the transgene and determination of zygosity in B6;C3-Tg(Prnp-SNCA*A53T)83Vle and B6;C3-Tg(Prnp-SNCA*A53T)83Vle Sncatm1Mjff neonatal mice between tail biopsies and buccal swabs. Moreover, we weighed and observed mice following genotyping to see if any clinical differences can be discerned. Weight data did not support statistically significant differences in mice undergoing different genotyping procedures and control. No statistically significant difference was found between using buccal swabs or tail biopsies for genotyping with PCR or quantitative PCR. None of the pups swabbed was rejected by the dam. Our findings indicate that buccal swabbing is a more humane and feasible alternative to tail biopsies for high-throughput genotyping.Abstract
Validated glass bead sterilization protocols to effectively sterilize rodent surgical instruments after bacterial exposure (for example, cecal contamination) are lacking. To refine current approaches, we added either a multienzyme detergent, neutral pH detergent, or chlorhexidine scrub step before glass bead sterilization of forceps or needle drivers exposed to cecal contents. We exposed sets of forceps and needle drivers to cecal contents, which were then air dried for 3 min. Immediately after, the instruments were wiped several times with a clean, dry paper towel. The contaminated tips were soaked in either a multienzyme or neutral pH detergent (t = 5 min), chlorhexidine scrub (t = 2 min), or no pretreatment solution. To further increase debris removal, instruments (from all groups) were brushed using a clean toothbrush. The nonpretreatment instruments were briefly soaked in saline before brushing. After being rinsed with sterile water, all instruments were exposed to a glass bead sterilizer for 60 s at 500 °F (260 °C). Sets were then swabbed for bacterial culturing. Swabs were plated onto either sheep blood agar (n = 23) or chocolate agar (n = 20) for aerobic culturing or Brucella agar (n = 20) for anaerobic culturing. A subset of instruments was sampled to determine organic material presence after treatment using an ATP luminometer (n = 21). Multiple agar types and bioluminescence were used to more deeply evaluate tool sterility and to differentiate the relative effectiveness of each protocol. From the saline group, only one pair of forceps yielded growth on Brucella agar, and 2 pairs yielded growth on chocolate agar. No other bacterial growth was observed. The use of a pretreatment agent also lowered overall organic contamination levels in needle drivers compared with using only saline. These results indicate that brushing instruments to mechanically remove debris from instruments is paramount to ensure sterility. However, a best practice would be to also use one of the pretreatment options used in this study.Abstract
Sterilization of rodent feed is recommended to eliminate potential murine pathogens and minimize microbial variability between batches. Most research institutions sterilize feed using steam/pressure (autoclave) or irradiation. Both methods have advantages and disadvantages that contribute to their suitability, including cost, maintenance, availability, and alterations to the exposed product. Dry heat sterilization, which has been in use for over 75 y, uses higher temperatures and longer sterilization times than steam autoclave and is most often used for delicate instruments or products that would be damaged by water such as powders or oil-based liquids. Dry heat sterilization in vivaria has been limited to date but is gaining popularity due to lower initial purchase and ongoing operational costs as compared with steam autoclaves. Little published information exists on the effects of dry heat sterilization on animal feed. We evaluated the sterility and chemical alterations of a natural ingredient, pelleted, rodent diet (NIH-31) after exposure to dry heat. Feed sterility was achieved using a dry heat exposure temperature of 160 °C (320 °F) for 4 h. This exposure resulted in a significant loss of heat-labile vitamins and significantly more acrylamide production as compared with the nonsterile, irradiated, and autoclaved feed.Abstract
Type of feed is an important consideration in herbivore colony management, yet limited studies report on the effects of diet on common conditions such as urolithiasis in guinea pigs. Urolithiasis is a well-documented cause of lower urinary tract disease in guinea pigs, with calcium carbonate uroliths reported as the predominant calculi formed in the guinea pig urinary tract. A calcium-rich diet has been suggested as a risk factor for of urolithiasis, with numerous commercially available guinea pig diets formulated for adults avoiding ingredients that are higher in calcium. Due to the high incidence of urolithiasis in our strain 13/N guinea pig colony, we conducted a prospective control study following the implementation of dietary changes aimed at improving overall urinary tract health and reducing risk factors for urolithiasis, thus improving colony welfare. A control group was kept on the original ad libitum alfalfa hay–based pellet diet with restricted loose timothy hay (control diet, 14 juveniles and 24 adults). An experimental group was placed on a portioned, 1 oz daily, timothy hay–based pellet diet with ad libitum loose timothy hay (experimental diet, 21 juveniles and 23 adults). Juveniles and adults were followed for a total of 14 and 26 wk, respectively. Longitudinal blood and urine samples were collected to evaluate blood chemistry and urinary parameters, along with weight and body condition scores to assess general health. Overall, dietary changes did not improve parameters associated with improved urinary tract health or reduced risk of urolithiasis; feeding strategy was not found to meaningfully affect calcium crystalluria, urine protein, urine specific gravity, or renal values. These data support alfalfa hay–based pellet or timothy hay–based pellet, when fed with loose timothy hay, as viable options and suggest that practices aimed at reducing dietary calcium by reducing pelleted diet portions are insufficient to mitigate risk factors for urolithiasis in guinea pigs.Abstract
The collection and examination method of vaginal smears is the standard for the determination of ovulation or phases of the estrous cycle of rodents used in research. However, this method is time consuming and may not be amenable to continual monitoring of a large number of animals. Infrared thermography has recently emerged as a noninvasive technique that requires relatively little handling of animals. The body temperature of rodents has been shown to correlate with the ocular surface temperature. This study aimed to evaluate the use of thermographic monitoring of the ocular surface for the identification of estrus in rats. Vaginal smears were collected from female Wistar rats (n = 22) for 14 consecutive days. Core body temperature was estimated by measuring ocular surface temperature using a thermal camera; vaginal temperature was measured using a digital thermometer. Average temperatures were calculated for each rat for each phase of the estrous cycle. The highest core body and vaginal temperature were measured during the estrus phase (37.2 ± 0.6 °C and 37.7 ± 0.6 °C, respectively). The temperatures then fell as the rat entered the diestrus phase (36.8 ± 0.5 °C and 37 ± 0.5 °C). The core body temperature was positively correlated with vaginal temperature (r = 0.697, P < 0.001). In conclusion, thermography is a less invasive method of determining estrus in rats as compared with vaginal smear collection. However, thermography is less accurate and requires at least a 12-d period of measurement.Abstract
Facial expressions have increasingly been used to assess emotional states in mammals. The recognition of pain in research animals is essential for their well-being and leads to more reliable research outcomes. Automating this process could contribute to early pain diagnosis and treatment. Artificial neural networks have become a popular option for image classification tasks in recent years due to the development of deep learning. In this study, we investigated the ability of a deep learning model to detect pain in Japanese macaques based on their facial expression. Thirty to 60 min of video footage from Japanese macaques undergoing laparotomy was used in the study. Macaques were recorded undisturbed in their cages before surgery (No Pain) and one day after the surgery before scheduled analgesia (Pain). Videos were processed for facial detection and image extraction with the algorithms RetinaFace (adding a bounding box around the face for image extraction) or Mask R-CNN (contouring the face for extraction). ResNet50 used 75% of the images to train systems; the other 25% were used for testing. Test accuracy varied from 48 to 54% after box extraction. The low accuracy of classification after box extraction was likely due to the incorporation of features that were not relevant for pain (for example, background, illumination, skin color, or objects in the enclosure). However, using contour extraction, preprocessing the images, and fine-tuning, the network resulted in 64% appropriate generalization. These results suggest that Mask R-CNN can be used for facial feature extractions and that the performance of the classifying model is relatively accurate for nonannotated single-frame images.Abstract
Helicobacter spp. infections in mice can have broad-ranging effects on gastrointestinal, reproductive, and immune systems. This can introduce significant confounding variables for research and may reduce scientific rigor. Screening mouse colonies for Helicobacter species can be accomplished via noninvasive PCR testing on filter paper placed in animal-free dirty bedding sentinel cages. In our facility, one tablespoon of dirty bedding from each cage on a rack is added to a designated sentinel cage every 3 wk at cage change, and PCR testing is performed on in-cage filter paper quarterly. We hypothesized that cages that received Helicobacter spp.-positive bedding at later time points would have a lower detection rate of Helicobacter spp. with PCR testing compared with cages that received positive bedding at earlier time points due to the filter paper becoming saturated. To determine if screening would be able to detect one positive row of cages on a rack, 9 tablespoons of Helicobacter-positive bedding and 71 tablespoons of negative bedding were added at the 3-, 6-, or 9-wk time points to 14 empty sentinel cages per time point. Negative bedding was added every 3 wk to cages not scheduled to receive positive bedding. Negative controls received 80 tablespoons of negative bedding and positive controls received 80 tablespoons of positive bedding at each time point. Filter paper was tested via PCR for Helicobacter spp. at 12 wk. All positive controls tested positive, and all negative controls tested negative. Two 3-wk cages, two 6-wk cages, and three 9-wk cages were positive, indicating no difference between time points. This resulted in a 16.7% Helicobacter spp. detection rate. These results indicate that PCR on in-cage filter paper may not be reliable in detecting low levels of Helicobacter spp. nucleic acid in dirty bedding.Abstract
This study aimed to compare the minimum anesthetic concentration (MAC) of sevoflurane in green iguanas using electrical stimulation and tail clamping as noxious stimuli. Seven adult green iguanas (Iguana iguana) weighing 580 to 1,300 g were enrolled. Each iguana was anesthetized twice after a 1-week washout period, with MAC being determined using a tail clamp (MACt) or electrical stimulation (MACe) techniques. After sevoflurane mask induction and endotracheal intubation, the fraction of expired sevoflurane (Fe’Sevo) was maintained at 3.1% for 15 min before noxious stimulation. In a bracketing design, the subsequent Fe’Sevo values were increased or decreased by 10% after positive or negative responses, respectively. Each targeted Fe’Sevo was kept constant for 15 min before stimulation. In MACt, the noxious stimulus involved closing a Kelly hemostatic curved forceps to the first ratchet at the base of the tail. At the same site, in MACe, 2 30 × 0.8–mm hypodermic needles inserted 1 cm apart were connected to an electrical stimulator set to deliver 30 mA at 50 Hz at a 6.5-ms interval. The hemostat and the needles were repositioned 2 cm distally and on alternate tail sides at each stimulation round. Individual MAC was obtained when 2 consecutive crossover events occurred (a positive response preceding a negative response or vice versa), with the MAC of each group represented by the average of the individual MAC values. Median (interquartile range) values for the sevoflurane MAC did not differ significantly between groups (2.2 [2.2 to 2.8%] in MACe and 2.2 [1.8 to 3.5%] in MACt; P = 0.812). Time to anesthesia induction, time to MAC measurement, heart rate (HR), end-tidal carbon dioxide (ET’CO2), and cloacal temperature were not different between groups. Both the tail-clamping and the electrical stimulation techniques yielded resembling sevoflurane MAC values in green iguanas, which makes the tail clamp a reliable alternative to electrical stimulation-based MAC research in this species.Abstract
Extended-release (ER) local anesthetics are often incorporated in multi-modal analgesia or as an alternative when the effect of systemic analgesics may confound research. In this study, we compared the analgesic efficacy of 2 ER bupivacaine anesthetics with different ER mechanisms, a slow-release bupivacaine-meloxicam polymer (BMP) and a sucrose acetate isobutyrate bupivacaine (SABER-B) system. We used a full-thickness unilateral skin incision porcine model to evaluate the efficacy of these 2 ER bupivacaine analgesics. Eighteen male swine were randomized into 3 groups: control (saline; n = 6), bupivacaine:meloxicam (10 mg/kg, 0.3 mg/kg; n = 6), and SABER-B (10 mg/kg; n = 6). After surgery, pigs were assessed for changes in body weight, salivary cortisol level, and response to von Frey testing at 1, 3, 6, 24, 48, 72, 96, 120, and 168 h. Body weight and salivary cortisol levels were not significantly different between groups. Based on the von Frey testing, the pigs that received analgesics showed a significantly higher withdrawal threshold of nociceptive stimulus than those that received saline at 1, 3, 6, and 24 h after the surgery. At 48 h after surgery, the SABER-B group had a significantly higher withdrawal threshold than the saline group. The withdrawal threshold was not significantly different from the baseline measurement on intact skin at 3 and 6 h after surgery in the BMP group or 1 and 3 h for the SABERB group. The analgesic effects of BMP were greatest at 3 and 6 h after surgery and that of SABER-B as 1 and 3 h SABER-B provided an earlier onset of analgesia and longer analgesia duration than did BMP. This study demonstrates that ER bupivacaine can provide pigs with 24 to 48 h of analgesia for incisional pain.Abstract
Despite the major use of mice in biomedical research, little information is available with regard to identifying their postmortem changes and using that information to determine the postmortem interval (PMI), defined as the time after death. Both PMI and environmental conditions influence decomposition (autolysis and putrefaction) and other postmortem changes. Severe decomposition compromises lesion interpretation and disease detection and wastes limited pathology resources. The goal of this study was to assess postmortem changes in mice in room temperature cage conditions and under refrigeration at 4 °C to develop gross criteria for the potential value of further gross and histologic evaluation. We used 108 experimentally naïve C57BL/6 mice that were humanely euthanized and then allocated them into 2 experimental groups for evaluation of postmortem change: room temperature (20 to 22 °C) or refrigeration (4 °C). PMI assessments, including gross changes and histologic scoring, were performed at hours 0, 4, 8, and 12 and on days 1 to 14. Factors such as temperature, humidity, ammonia in the cage, and weight change were also documented. Our data indicates that carcasses held at room temperature decomposed faster than refrigerated carcasses. For most tissues, decomposition was evident by 12 h at room temperature as compared with 5 d under refrigeration. At room temperature, gross changes were present by day 2 as compared with day 7 under refrigeration. Mice at room temperature lost 0.78% of their baseline body weight per day as compared with 0.06% for refrigerated mice (95% CI for difference 0.67% to 0.76%, P < 0.0005). This study supports the consideration of temperature and PMI as important factors affecting the suitability of postmortem tissues for gross and histologic evaluation and indicates that storage of carcasses under refrigeration will significantly slow autolysis.Abstract
This corrects the article DOI: In the list of authors for the article entitled, “Extrinsic Environmental Variables: The Umwelt of Research Animals and the Implications for the 3Rs and Study Reproducibility,” published in Vol 63, Issue 2 (March 2024), page 106, one author was identified as Fiona C. Hankenson, DVM, MS, DACLAM. Instead, this author should be identified as F. Claire Hankenson, DVM, MS, DACLAM.
The American Association for Laboratory Animal Science (AALAS) currently publishes two journals containing data-driven, peer-reviewed articles. The mission of Comparative Medicine (CM) is to disseminate high-quality, peer-reviewed information that expands biomedical knowledge and promotes human and animal health through the study of laboratory animal disease, animal models of disease, and basic biologic mechanisms related to disease in people and animals.General