Here we present the results of a demographic analysis of 25 y (1985 to 2010) of common marmoset (Callithrix jacchus) and cotton-top tamarin (Saguinus oedipus) records from the New England Primate Research Center. Summaries of longevity and survivorship are analyzed by birth-type category (including singletons, twins, triplets, and quadruplets) and sex. In addition, a brief evolutionary review is presented. Surrogates of hematopoietic chimerism, twinning, and reproductive output are explored in a large number of animals to help decipher the potential effects of chimerism on life history in marmosets and tamarins. In addition to exploring chimerism through demographic data, multiple-birth frequency and survivorship are compared between species. New World primates can make ideal translational models for disease and behavioral research across multiple disciplines. A better understanding of their reproductive success and survivorship in captivity helps develop these nonhuman primate models, their role in aging research, and understanding of their behavioral ecology. This mission is likely to only increase in its importance to biomedical research due to both the sequencing of the marmoset genome and the growing demand for alternatives to Old World primate models.

Tibetan macaques (Macaca thibetana), also known as Chinese stump-tailed macaques, are a threatened primate species. Although Tibetan macaques are Old World monkeys in the genus of Macaca, limited age- and sex-related physiologic data are available for this particular species. We used 69 apparently healthy Tibetan male and female macaques to explore the effect of age and sex on physiologic parameters. Somatometric measurements, biochemistry, and hematologic parameters were analyzed. Significant age-related differences were found for weight, BMI, RBC count, Hgb, Hct, neutrophils, eosinophil count, ALT, AST, ALP, GGT, creatine kinase (muscle and brain subtypes), LDH, α-amylase, creatinine, apolipoprotein A1, total protein, albumin, cholesterol, HDL, and potassium. Significant differences by sex were noted for weight, BMI, ALT, total bilirubin, and indirect bilirubin. An interaction between age and sex accounted for statistically significant differences in the values for weight, BMI, and lymphocyte and eosinophil counts. These physiologic data will provide veterinarians and researchers with important age- and sex-specific reference ranges for evaluating experimental results from Tibetan macaques.

We undertook the present study to investigate the echographic characteristics of the uterus and cervix of female bonnet monkeys ( Macaca radiata ) during the proliferative and secretory phases of the menstrual cycle. The cervix was tortuous in shape and measured 2.74 ± 0.30 cm (mean ± SD) in width by 3.10 ± 0.32 cm in length. The cervical lumen contained 2 or 3 colliculi, which projected from the cervical canal. The echogenicity of cervix varied during proliferative and secretory phases. The uterus was pyriform in shape (2.46 ± 0.28 cm × 1.45 ± 0.19 cm) and consisted of serosa, myometrium, and endometrium. The endometrium generated a triple-line pattern; the outer and central lines were hyperechogenic, whereas the inner line was hypoechogenic. The endometrium was significantly thicker during the secretory phase (0.69 ± 0.12 cm) than during the proliferative phase (0.43 ± 0.15 cm). Knowledge of the echogenic changes in the female reproductive organs of bonnet monkeys during a regular menstrual cycle may facilitate understanding of other physiologic and pathophysiologic changes.

Minimizing and alleviating pain and distress in laboratory mice without compromising the methodologic integrity of research is a crucial goal. However, current methods for welfare assessment in mice are not well suited to cageside checks. In the present study, we developed a simple assessment tool—the time-to-integrate-to-nest test (TINT)—and evaluated its ability to identify mice with compromised welfare. To conduct the TINT, a nominal amount of nesting material is added to a mouse cage, and the nesting behaviors that occur immediately thereafter are observed. The TINT yields a positive result when a mouse integrates the new nesting material into the main nest site within 10 min; failure to interact with the nesting material is defined as a negative TINT. Our first experiment examined whether genetic background and sex are associated with differences in the likelihood of a positive TINT in unmanipulated mice. A significant effect related to mouse strain was found: C3H/HeNCrl had the lowest positive TINT rate among the 10 strains evaluated. A second experiment assessed whether results of the TINT would be altered after a painful surgical procedure, such as carotid artery injury. Despite all mice having received buprenorphine as analgesia at the time of surgery, significantly more mice had a negative TINT for 2 d after surgery than before surgery. Based on the results of the current study, additional work is needed to specifically validate the TINT in injured and noninjured subjects.

Although human subjects are widely used to study sleep and sleep disorders, animals have been invaluable in developing our understanding of the physiology of sleep and underlying mechanisms of sleep disorders. Environmental stimuli are likely to modify sleep in both animals and people, suggesting that environmental stability must be controlled carefully by both husbandry and research staff to allow collection of valid results with minimal numbers of animals. However, few studies have measured the effects of cage condition on sleep parameters in mice. Current guidelines recommend social housing and environmental enrichment for standard rodent housing. Environmental factors such as these create potential confounds in studies for which facets of sleep are outcome measures. We therefore sought to determine whether cage changes, group housing, or single housing with a shelter altered measures of sleep in C57BL/6J mice. The resulting data indicate that 1) cage changing disrupts sleep for approximately 3 h; 2) group housing is associated with shorter bouts of rapid-eye-movement sleep (REMS) and less slow-wave sleep (SWS) during the light phase and with more REMS during the dark phase; and 3) mice housed with a shelter spend less time awake and more time in SWS, with longer bouts of SWS during the dark phase. In additional, both group housing and housing with a shelter were associated with less locomotor activity than occurred in individually housed mice without a shelter. These findings provide evidence for long-held beliefs that housing conditions must be controlled carefully in studies that require assessment of sleep.

Educational institutions maintain group-housed mice of both sexes for training veterinarians and technicians in husbandry, medication, and sampling procedures. Mice kept in all-male groups may experience poor welfare due to fighting. Castrated mice may be used to replace gonadally intact males for such training programs. In this prospective cohort study, 80 castrated and 80 control (intact) male mice were studied over 3 mo to monitor aggression frequency and injury levels. Behavioral observations were performed twice weekly by using an all-occurrences sampling method to quantify behavioral events and the number and severity of bite wounds. Under these housing conditions, group-housed male mice castrated postpubertally exhibited significantly less aggression than did intact male mice. Castration therefore improves welfare in group-housed male mice and thus provides a husbandry alternative to individually housing animals in nonstudy situations.

The suprachiasmatic nucleus is synchronized by the light:dark cycle and is the master biologic clock that serves as a pacemaker to regulate circadian rhythms. We explored the hypothesis that spectral transmittance (tint) of light through caging alters circadian rhythms of endocrine and metabolic plasma constituents in nonpigmented Sprague–Dawley rats. Rats (Crl:SD; n = 12 per group) were housed in a 12:12-h light:dark environment (300 lx; 123.0 μ W/cm²; lights on, 0600) in either clear-, amber-, blue-, or red-tinted rodent cages. Blood was collected at 0400, 0800, 1200, 1600, 2000, and 2400 and measured for melatonin, total fatty acids, pH, glucose, lactic acid, corticosterone, insulin, and leptin. As expected, plasma melatonin levels were low during the light phase but higher during the dark phase in all groups; however, when compared with the clear-cage group, rats in amber-, blue-, and red-tinted cages had 29%, 74%, and 48%, respectively, greater total daily melatonin levels due to an increased duration and, in some cases, amplitude of the nocturnal melatonin signal. No differences were found in dietary and water intake, body growth rates, total fatty acids, pH, or glucose among groups. Disruptions in circadian rhythms, manifesting as alterations in phase timing, amplitude, or duration, occurred in the melatonin, lactic acid, corticosterone, insulin, and leptin levels of rats in tinted compared with clear cages. Therefore, the use of variously tinted animal cages significantly alters circadian rhythms in plasma measures of metabolism and physiology in laboratory rats, thus potentially altering the outcomes of scientific investigations.

Housing enrichment for rodents continues to be a discussion topic within the animal care community. The objective of this study was to determine the extent to which a complex housing environment affects heart rate, blood pressure, and activity of rats when undisturbed and after exposure to stressful challenges and whether autonomic controls of heart rate would be affected. Male and female Sprague–Dawley and Wistar rats with radiotelemetry transmitters were evaluated under nonenriched single-housing conditions and after acclimation to a complex environment of dim light and cohabitation with 3 conspecifics in large cages with hiding, food foraging, and nesting items. Telemetry data were collected when rats were undisturbed, after acute challenges (cage change, intraperitoneal injections, restraint), during a forced running protocol, and after cholinergic or adrenergic blockade. The complex environment reduced heart rate and increased activity in undisturbed rats but did not affect blood pressure. Heart rate responses to challenges were unaffected, decreased, or increased by complex housing, depending on the stock and sex of rats. Forced running was either unaffected or decreased, depending on the stock and sex of rats. Heart rate responses to cholinergic or β1-adrenergic blockade were not affected. We conclude that the complex housing did not reduce indices of stress (for example, heart rate) as compared with simpler housing. However, the possibility that some environmental elements interact negatively with each other must be considered in future studies.

The pole-and-collar method is one of several techniques that enable the safe transfer of a nonhuman primate from its home environment into a restraint chair without the need for sedation. It has been used within the scientific community for decades. Traditional methods to train animals for pole-and-collar use rely primarily on aspects of negative reinforcement, with very little incorporation of positive-reinforcement techniques. With increasing emphasis on animal training and welfare, research facilities are incorporating positive-reinforcement training into husbandry and experimental procedures. Here we demonstrate the feasibility of training rhesus macaques (Macaca mulatta; n = 8) to cooperate for pole-and-collar transfer to a primate restraint chair. By using predominantly positive-reinforcement techniques, with supplemental elements of negative reinforcement, macaques were trained in a mean of 85 training sessions (a mean of 1085 min of training time). We also provide tools for investigators using the pole-and-collar method to help them successfully incorporate positive-reinforcement training into their procedures. This refinement has the potential to improve animal welfare and enhance the value of nonhuman primate models in research.

Our study evaluated and compared the false-negative rates (FNR) of a wide array of fur-mite diagnostic tests, including 2 postmortem tests (pelt exam and sticky paper) and 3 antemortem tests (adhesive tape, fur pluck, and PCR). Past publications examining fur-mite diagnostic techniques primarily used paired comparisons, evaluating tests by their level of agreement with only one other test. However, different combinations or pairs of diagnostics are used in the different studies, making the results of these comparisons difficult to interpret across all available diagnostics. In the current study, mice from a conventionally maintained colony endemic for Myobia musculi were identified as positive based on at least one positive diagnostic test. From this pool of positive animals, the FNR of all tests were quantified. The PCR assay and the pelt exam performed the best, with 0% and 2% FNR respectively, whereas tape, fur-pluck, and sticky-paper tests showed 24%, 26%, and 36% FNR, respectively. Our study shows that for mice in a colony naturally infested with Myobia musculi, PCR testing can be used for reliable antemortem detection, and pelt exam performed by experienced examiners is reliable for postmortem detection.

Objective monitoring of the level of anesthesia is crucial in carefully controlled translational neuroscience studies. The usefulness of bispectral index (BIS) in monitoring human anesthesia is well established. However, the validity of its application remains unproven in laboratory animals. We assessed whether BIS could be used reliably in monitoring the depth of deep anesthesia in 8 New Zealand white rabbits. Experimental baseline anesthesia was maintained with continuous infusion of propofol and administration of isoflurane, both of which were titrated to EEG activity. The rabbits were allocated randomly to receive 3 increasing concentrations of common anesthetic drugs (etomidate, propofol, and isoflurane) aimed to produce burst suppression of EEG activity yielding at least 10 s of sustained EEG silence. Rabbits had a 20-min recovery interval between challenges. Transient cerebral hypoperfusion to produce reversible EEG silence due to ischemia was induced as a fourth challenge, followed by terminal arrest, in each animal. BIS, EEG, and physiologic data were analyzed for each rabbit. We observed stable BIS values in the range of 40 to 60 during the administration of baseline anesthesia. However, as the depth of anesthesia deepened with the anesthetic drug challenges, the BIS value paradoxically increased with increasing doses. The BIS signal quality index declined while the total power decreased. In contrast to these unexpected results, BIS values decreased rapidly to near 0 during terminal arrest, as expected. Therefore, we do not consider BIS to be a useful method for monitoring deep levels of anesthesia in laboratory rabbits.

This study was designed to evaluate the maximal amount of blood that can be safely collected in healthy, adult male and female cynomolgus macaques for 4 consecutive weeks with minimal effect on animal wellbeing. General guidelines for blood collection volumes in laboratory animals are not species-specific, and currently there are few evaluations of blood collection in macaques. In this study, blood was removed at 7.5%, 10%, 12.5%, 15%, or 17.5% of total blood volume (TBV) for 4 consecutive weeks. Hematologic parameters and body weights were evaluated immediately prior to each blood collection time point and for an additional 4 consecutive weeks following the last collection. Male and female macaques tolerated removal of as much as 15% TBV with minor clinical effects, whereas macaques in the 17.5% TBV group exhibited an increased incidence of emesis and anorexia during the first 24 h after blood collection. According to these results, we recommend collecting no more than 15% TBV weekly for 4 consecutive weeks from healthy, adult male and female cynomolgus macaques.

The naked mole rat (NMR) is a small eusocial rodent. Because of its remarkable longevity (maximal lifespan, 32 y) and resistance to cancer, the NMR has emerged as a valuable model for aging and cancer research. However, breeding NMR can be difficult. Here, we report the successful introduction and acceptance of pups into a foreign colony with existing pups of different ages. Among the 7 NMR colonies in our satellite facility, one had a consistently poor record of pup viability, with nearly 100% preweaning mortality in multiple litters born over the course of 2 y. The queen of this colony gave birth to 18 pups in January 2013; by 2 d after parturition, it was evident that the pups were not receiving sufficient nourishment. To salvage the litter, the most vigorous pups were cross-fostered to another queen that had recently given birth. On postparturition day 1 (PD1), two pups from the poorly nourished donor litter were bathed with warm water, rolled in recipient colony bedding, and transferred to the recipient colony, which included 8 PD14 pups. The new pups were accepted by the recipient queen, who continued to produce milk in response to suckling by the donor pups well past the weaning of her own litter. This case report provides evidence of successful cross-fostering of NMR pups despite age differences between donor pups and those in the recipient litter; this technique may prove beneficial to researchers struggling with NMR breeding issues.

A colony of rainbow trout (Oncorhynchus mykiss) in a decentralized aquatic animal facility was noted to have an increase in morbidity and mortality (from 4 or 5 fish each month to 3 or 4 fish daily) approximately 2 wk after experimental procedures began. The primary clinical signs were erratic swimming behavior and 'flashing' of fish against surfaces within housing enclosures. Moribund and normal rainbow trout were presented alive for diagnostic evaluation; samples of water from housing enclosures were provided for water quality assessment. The trout were determined to be infected with gyrodactylids, a common monogenean ectoparasite of the skin and gills in both marine and freshwater fish. This case report describes the diagnosis, pathology, and treatment of gyrodactylids and husbandry modifications associated with the resolution of this clinical aquatic-animal case.