Adequate nutrient intake is critical in the maintenance of normal physiologic activity of rodents in biomedical studies. Vitamin K is an essential nutrient in rodent diets and functions as a cofactor for the γ-carboxylation of various proteins involved in blood coagulation and bone metabolism. Several forms of vitamin K are used in rodent diets, with a shift during the last decade towards the use of phylloquinone, the predominant form in human diets, and a concomitant increase in concentrations. This review summarizes current recommendations for vitamin K in rodent diets relative to our evolving knowledge about this fat-soluble vitamin.

Sprague–Dawley rats are often the background stock for transgenic rats, and rats from various sources may differ in their physical development and behavior. In 1990, the Institute of Cytology and Genetics in Novosibirsk obtained Sprague–Dawley rats from a commercial vendor and bred them in a closed colony. To study various aspects of the physical development and behavior of male F1 progeny of the Novosibirsk colony (Nov:SD) and commercial colony (Crl:SD) raised in identical environments, we evaluated body weight; food and water consumption; behavior in the elevated-plus maze (X maze), open field, free exploration paradigm, hole board, and the rotarod; and serotonin content in brain regions. Crl:SD rats were heavier and consumed more food than did the Nov:SD rats, which displayed a higher level of motor activity in all tests without displaying differences in anxiety-related behavior in the X maze or open-field test. In the free exploration paradigm, more Nov:SD rats explored the outside and started exploration earlier; they also were more active and showed less habituation in the hole-board test. Brain serotonin content was higher in the Crl:SD rats. In conclusion, prolonged isolated breeding of 2 stocks of Sprague–Dawley rats led to populations that differed in their exploratory and anxiety-related behavior, physical development, and serotonergic neurotransmission. Therefore, rats of the same stock but obtained from different breeders should be used with caution in research involving these measures.

The use of swine in cardiopulmonary resuscitation (CPR) research has increased in the last decades. Landrace–Large White (LLW) swine are a farm breed of pigs. The aims of the present study were to describe the baseline hemodynamics of this breed and to demonstrate that it is suitable for CPR research. The systolic and diastolic pressures of the descending aorta (mean ± 1 standard deviation; n = 29) were 111.72 ± 13.61 and 79.03 ± 12.08 mm Hg, respectively, whereas the mean systolic and diastolic pressures of the left ventricle were 108.97 ± 12.06 and 8.88 ± 1.81 mm Hg, respectively. The mean pressures of the right atrium were 10.93 ± 1.36 mm Hg (systolic) and 4.10 ± 1.01 mm Hg (diastolic), whereas the value obtained by using near-infrared spectroscopy to determine brain regional oxygen saturation was 64.55% ± 3.88%. LLW can be considered a suitable breed for CPR research because of the close similarity of its hemodynamic values to those of humans.

We assessed the concentrations of 2 antibiotic combinations, amoxicillin-clavulanic acid and trimethoprim-sulfamethoxazole when compounded in reverse osmosis [RO] (pH 6.0), tap (pH 6.7), and acidified water (pH 2.6) over 7 d, and pre- and post-pelleting, post-gamma irradiation and shipping, and monthly until 180 d post-milling in feed. Amoxicillin concentrations in RO and tap water varied between 1.18 and 1.29 mg/ml, and 1.09 and 1.22 mg/ml, respectively. The concentration of amoxicillin declined immediately and remained between 0.43 and 0.50 mg/ml in acidified water. Clavulanic acid exhibited a slow time-dependent decrease in concentration to 0.05 mg/ml at day 7 in RO water, immediately declined and varied from 0.02 to 0.05 mg/ml in tap water, and was undetectable in acidified water. Trimethoprim and sulfamethoxazole concentrations were near expected in RO, tap, and acidified water. In food, amoxicillin, trimethoprim, and sulfamethoxazole concentrations were each reduced to approximately 60% of expected after pelleting, but remained stable thereafter for 180 d. The initial clavulanic acid concentration in feed was less than 10% of expected and was undetectable after 1 mo. Plasma drug concentrations were determined in C57BL/6NCrl mice at 4 h after commencement of the dark and light cycles following administration of antibiotic food for at least 72 h. Plasma amoxicillin and sulfamethoxazole concentrations were 3- and 10-fold greater, respectively, during the dark period. Plasma levels of clavulanic acid and trimethoprim were consistent at both time points. These results indicate that the antibiotic concentration can be in uenced by compounding in feed and water, and differs in plasma during the light and dark phases of the photoperiod.

The Guide for the Care and Use of Laboratory Animals recommends environmental enrichment for all laboratory animals, including amphibians. In this study, we evaluated the effect of adding environmental enrichment in the form of acrylonitrile–butadiene–styrene (ABS) pipes as covered refuge for laboratory Xenopus laevis housed in 2 pond-style tanks (capacity, 300 l; stocking density, approximately 150 frogs/tank; dimensions, 1.3 × 1.8 × 1.3 m). Medical records from animals housed in these 2 ponds between 1 January 2001 to 31 December 2003 revealed the incidence of bite wounds to be 5.0%, 4.0%, and 5.0% annually, respectively, and indicated 2 episodes of cannibalism (in 2003). In January 2004, we added ABS pipes as refuge housing to these tanks and continued to monitor the number of bite wounds and cannibalism. Over the following 24 mo (1 January 2004 to 1 January 2006), the incidence of bite wounds declined to 0.3% and 0.7% annually, respectively; no episodes of cannibalism were reported. The results of this investigation indicate that environmental enrichment in the form of ABS pipes for refuge cover has a quantifiable beneficial effect on the physical and social wellbeing of laboratory Xenopus laevis.

Rodents are very susceptible to hypothermia during anesthetic events because of their high body surface-to-mass ratio. This study examined the effectiveness of 2 heating devices, a heatpad and a circulating hot-water blanket, during 60 min of isoflurane general anesthesia in rats and mice (n = 6 per treatment). In addition, 1 control group of animals for each species was anesthetized with no heat source (n = 6). Both devices carried minimal risk of causing thermal burns or hyperthermia. Rats on the circulating water blanket showed a slight decrease (0.11 ± 0.19 °C) from the initial (time 0) body temperature (mean ± standard error), whereas the heatpad was associated with a significant increase (0.96 ± 0.10 °C). Mice on the circulating water blanket showed a significant decrease (0.46 ± 0.05 °C) in body temperature. The trend in mice on the heatpad was similar to that in rats, with a significant increase (0.94 ± 0.13 °C) from the body temperature at time 0. Although statistically significant, these deviations from baseline body temperature were not considered physiologically relevant. In comparison, body temperatures decreased significantly in rats and mice (4.42 ± 0.60 and 9.90 ± 0.35 °C, respectively) with no heat source. Both heating devices were safe and effective, but the low cost, ease of maintenance, and portability of the heatpad may make it a more desirable choice in some facilities.

The ¹⁸F isotope of fluoro-2-deoxy-D-glucose (FDG) is a radiotracer commonly used in positron emission tomography (PET) for determining regional metabolic activity in the brain. However, in rats and many other species with nictitating membranes, harderian glands located just behind the eyes aggressively incorporate ¹⁸F-FDG to the extent that PET images of the brain become obscured. This radioactive spillover, or 'partial volume error,' combined with the limited spatial resolution of microPET scanners (1.5 to 2 mm) may markedly reduce the ability to quantify neuronal activity in frontal brain structures. Theoretically, surgical removal of the harderian glands before ¹⁸F-FDG injection would eliminate the confounding uptake of the radioactive tracer and thereby permit visualization of glucose metabolism in the frontal brain. We conducted a pilot study of unilateral harderian gland adenectomy, leaving the contralateral gland intact for comparison. At 1 wk after surgery, each rat was injected intravenously with ¹⁸F-FDG, and 40 min later underwent brain microPET for 20 min. Review of the resulting images showed that the frontal cortex on the surgical side was defined more clearly, with only background ¹⁸F-FDG accumulation in the surgical bed. Activity in the frontal cortex on the intact side was obscured by intense accumulation of ¹⁸F-FDG in the harderian gland. By reducing partial volume error, this simple surgical procedure may become a valuable tool for visualization of the frontal cortex of rat brain by ¹⁸F-FDG microPET imaging.

Standards for the reproductive management of captive chimpanzees stipulate that chimpanzees admitted into the National Chimpanzee Sanctuary System must undergo vasectomy followed by laboratory confirmation of azoospermia. In light of the observations of ourselves and others, we questioned whether azoospermia is a necessary indicator of successful vasectomy. Therefore, the objectives of the present study were to assess how much time is required between vasectomy and semen evaluation for azoospermia to be reached and to determine the percentage of vasectomized chimpanzees that actually are azoospermic. The study population comprised 39 adult male chimpanzees that underwent vasectomy and subsequent semen examination at 0.5 to 24 mo afterward. Overall, spermatozoa were found in the semen of at least 1 chimpanzee in almost every month in which animals were evaluated. Of the animals evaluated repeatedly after vasectomy, 20% had no sperm at any examination, 60% were azoospermic then positive during at least 1 subsequent examination, 13.3% were positive at least once and then azoospermic, and 6.7% were positive at every examination. After 0.5 mo postvasectomy, all sperm observed were nonmotile. The results suggest that azoospermia is not a necessary indicator of successful vasectomy.

Infections of Trypanoxyuris spp. pinworms in Aotus nancymae and other New World primates are typically subclinical, but infection during experimental use could confound interpretation of experimental data. Further, Trypanoxyuris species are highly infective, and rapid diagnosis is important to prevent an outbreak in the animal colony. This study sought to determine whether a fecal flotation technique was sensitive enough to replace the perianal tape test for diagnosis of Trypanoxyuris spp., thereby reducing stress to the animal and sample collection time. On days 0 and 3, we collected fecal samples from 45 animals confirmed to be infected with Trypanoxyuris spp. by perianal tape testing. Fecal samples were evaluated by both a commercial analysis system and by sucrose flotation with centrifugation. For both detection methods, no significant difference in sensitivity was detected between tests conducted on day 0 versus day 3. The sensitivity of repeated commercial tests was 80%, significantly higher than the 60% for sucrose flotation. The commercial test was significantly more sensitive than sucrose flotation, indicating that the commercial system was a better method for detecting Trypanoxyuris spp. However, sensitivity of only 80% confers a considerable risk of false negatives, thereby potentially delaying treatment and further contributing to environmental contamination. In our opinion, neither method of fecal analysis was a suitable replacement for the perianal tape test to diagnose Trypanoxyuris spp. in owl monkeys.

Macaques are important models for menopause and associated diseases in women. A sensitive, noninvasive technique for quantifying changes in ovarian morphology would facilitate longitudinal studies focused on the health-related sequelae of naturally occurring or experimentally induced alterations in ovarian structure and function. Multidetector computed tomography (MDCT) is a fast, non-invasive imaging technique that uses X-rays, multiple rows of detectors, and computers to generate detailed slice images of structures. The purpose of this study was to describe the utility of MDCT for reliably characterizing ovarian morphology in macaques. Five macaques were scanned using contrast-enhanced MDCT. The following characteristics were described: 1) appearance of ovaries and adjacent landmarks, 2) effects of varying technical protocols on ovarian image quality, 3) radiation doses delivered to the pelvic region during scanning, and 4) MDCT estimates of ovarian volume and antral follicle counts versus those measured directly in ovarian tissue. Ovaries were distinguishable in all MDCT scans and exhibited heterogeneous contrast enhancement. Antral follicles appeared as focal areas of nonenhancement. Ovarian image quality with 5 pediatric scanning protocols was sufficient for discriminating ovarian margins. Pelvic region radiation doses ranged from 0.5 to 0.7 rad. Antral follicles counted using MDCT ranged from 3 to 5 compared with 3 to 4 counted using histology. Ovarian volumes measured using MDCT ranged from 0.41 to 0.67 ml compared with 0.40 to 0.65 ml by water displacement. MDCT is a promising technique for measuring longitudinal changes in macaque ovarian morphology reliably and noninvasively.

Although halogenated gas anesthetics are indispensable in laboratory animal medicine, they are hazardous when present in the working environment. A simple technique of real-time leak detection and environmental spot monitoring can provide valuable adjunct information to current techniques of time-weighted monitoring. We investigated the minimal limit of detection of halothane, isoflurane, sevoflurane, and desflurane of a leak detector for halogenated gas refrigerants which provides a qualitative response only. We connected a container to an infrared gas analyzer to create a 135-l closed-circuit system and injected liquid halothane, isoflurane, sevoflurane, and desflurane to create calculated gas concentrations of 0.7 to 3.4 parts per million (ppm). The infrared absorbance and response of the leak detector were recorded, and a total of 5 measurements were made per concentration. The actual gas concentrations were calculated by comparison with the agent-specific absorbance standard curve. The leak detector clearly and consistently responded to halothane, isoflurane, sevoflurane, and desflurane from minimal concentrations of 2.1 ± 0.2, 1.4 ± 0.04, 0.8 ± 0.04, and 1.2 ± 0.4 ppm, respectively, as determined by infrared analysis. Although the detector does not provide numerical and time-weighted results, leak testing of equipment and repeated monitoring of the environment (spot monitoring) can provide valuable real-time information. In addition, with appropriate consideration of the methodological limitations, spot monitoring can be used to predict the likelihood of compliance with time-weighted exposure recommendations. A leak detector therefore represents a simple, effective, and inexpensive instrument for monitoring the leakage of halogenated anesthetic gases from equipment and into the working environment.

A 3-y-old female Flemish Giant pet rabbit developed a papilloma on the right nictitating membrane. Although the papilloma was excised surgically, it promptly recurred. Examination of the eye 10 wk after surgery revealed that in addition to the initial mass, 2 smaller papillomas were present on the lower eyelid. All 3 masses were excised, and histology revealed papillomatous hyperplasia of the conjunctival epithelium, koilocytosis, and intranuclear viral inclusions. Polymerase chain reaction amplified papillomaviral DNA from the largest papilloma. Sequencing of the amplicon revealed 99.3% homology with rabbit oral papillomavirus (ROPV). All 3 masses recurred after removal. In addition, the rabbit was noted to be losing weight. Weight loss continued until the rabbit died 3 mo later. All 3 papillomas persisted until death. This article provides the first description of ROPV causing conjunctival papillomas and is the first report of ROPV from the southern hemisphere. The persistence of the papillomas in this case is also unusual and may suggest that ROPV-induced conjunctival papillomas are less likely than oral papillomas to spontaneously regress. Alternatively, the death of this rabbit may indicate a compromised immune system that allowed papillomaviral persistence.

This report describes congenital radial and thumb aplasia in a neonatal owl monkey. Congenital limb deformities in human neonates and Old World primate species have been well characterized. The many probable causes of these congenital defects in skeletal structure include fetal exposure to environmental toxins and genetic in uences. In nonhuman primates, the cause frequently remains undetermined. In the case we present, the neonate presented for examination because of inability to cling to the dam. The forelimbs were contracted distally, and thumbs were absent. Radiographs indicated complete radial aplasia and other skeletal abnormalities. This description is the first case study of congenital radial and thumb aplasia in a New World primate species.