Contemporary topics in laboratory animal science最新文献

Hematologic and serum biochemical values are of great importance in assessing animal health. Normal reference ranges for vervet monkeys (Chlorocebus aethiops sabaeus) have seldom been reported, making it difficult for clinicians to interpret blood values. The purpose of this study was to determine what effects age and sex have on hematologic and serum biochemical values of vervet monkeys and to establish clinically relevant reference ranges for all life stages of each gender. Blood samples were collected from 140 healthy vervet monkeys of Caribbean origin consisting of 60 females and 80 males. Male and female data were displayed separately within six life-stage categories (yearlings, juveniles, adolescents, young adults, adults, and aged). The effects of sex and age on these values were examined statistically. Significant age-related factors included red blood cell count, hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, alkaline phosphatase, albumin, total protein, globulin, direct bilirubin, blood urea nitrogen, creatinine, glucose, calcium, phosphorus, potassium, albumin/globulin ratio, blood urea nitrogen/creatinine ratio, and sodium/potassium ratio values. Significant sex-related values included red blood cell count, hemoglobin, hematocrit, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, neutrophil count, total bilirubin, direct bilirubin, creatinine, glucose, calcium, phosphorus, total carbon dioxide, chloride, potassium, and sodium/potassium ratio values.

The urine concentration test is a potentially stressful procedure used to assess renal function. Historically, animals have been deprived of water for 24 h or longer during this test, creating the potential for distress. Refinement of the technique to lessen distress may involve decreasing the water-deprivation period. To determine the feasibility of reduced water-deprivation time, 10 male and 10 female rats were food- and water-deprived for 22 h. Clinical condition and body weights were recorded, and urine was collected every 2 h, beginning 16 h after the onset of food and water deprivation. All rats lost weight (P < 0.001). All rats were clinically normal after 16 h, but 90% of the males and 30% of the females appeared clinically dehydrated after 22 h. After 16 h, mean urine specific gravities were 1.040 and 1.054 for males and females, respectively, and mean urine osmolalities were 1,362 and 2,080 mOsm/kg, respectively, indicating the rats were adequately concentrating urine. The rats in this study tolerated water deprivation relatively well for 16 h but showed clinical signs of dehydration after 22 h. Based on this study, it was concluded that the urine concentration test can be refined such that rats are not deprived of water for more than 16 h without jeopardizing test results.

Cardiovascular research in mouse models can lead to respiratory insufficiency with the need for temporary mechanical ventilation to reduce mortality. We developed a noninvasive method for brief ventilation in which a balloon-tipped cannula is inserted into the oral cavity of the mouse. The rubber balloon is constructed in such a way that it becomes inflated when the pressure in the tube rises. We tested the cannula in ten C57BL/6J mice which underwent mechanical ventilation by a membrane-pump-driven ventilator. Results of blood gas analyses in the ten cannulated animals were in the normal range after 1 h of mechanical ventilation and did not differ significantly from those of anesthetized and spontaneously breathing mice (n = 5) and mice mechanically ventilated via tracheal intubation (n = 5). Noninvasive mechanical ventilation by using the balloon-tipped cannula is a useful method which is quick and easy to manipulate.

Testing for the induction of maternal behavior in rats involves the use of adult nulliparous experimental females, lactating donor dams, and their pups. In the present study, the effects of reducing the daily pup exposure from 23 h to 1 h on maternal induction latencies were assessed. In addition, because a 1-h daily exposure would reduce the non-nutritive period and potential discomfort in the pups, the effect of the reduction in pup exposure on animal use numbers was compared under these two conditions. Exposure to test young for 23 h daily for 15 days significantly increased the proportion of test animals that became maternal compared with 1 h of exposure (92% versus 35%). Moreover, animals in the 23-h group that became maternal had shorter latencies (5 days versus 11 days) and responded faster to the pups on the first day that maternal behavior was displayed than did the 1-h exposure group. A mathematical comparison of numbers of rats required to induce maternal behavior in 30 nulliparous rats under both exposure conditions revealed that the 1-h group requires 2.6 times more animals. These findings indicate that compared with the 1-h scheme, the 23-h exposure protocol is significantly more efficient in both inducing maternal care as well as reducing the overall use of animals. Therefore, when selecting an animal testing protocol, one must consider the effect of reducing potential pup discomfort in light of the implications on the number of animals used and the behavioral outcome in a given test paradigm.

This study evaluated the gross and microscopic effects of serial blood collection from six ball pythons (Python regius) by using cardiocentesis. We collected 39 blood samples from each snake over a 120-day period. Cardiocentesis was performed on manually restrained snakes, with each sample requiring approximately 15 sec to collect. No clinically apparent complications were noted in any of the snakes after the cardiocentesis procedures, and all snakes survived until they were euthanized 73 days after the last blood sample. Minimal gross lesions were noted at necropsy; faint brown pigmentation of the pericardium was present in five of six snakes, and three snakes had approximately 0.5 ml dark pigmented fluid in the pericardial space. One snake had a small, organized hematoma in the pericardial space. Microscopic findings were limited to moderate and regularly arranged collagen fibrosis and focal thickening of the epicardium. The pericardial sac in all snakes had a mild infiltrate of hemosiderin-laden macrophages and small numbers of heterophils. The results suggest that serial cardiocentesis is well tolerated in ball pythons.

Three male, wild-caught northern leopard frogs (Rana pipiens) died over a 1-week period with no previous history of clinical illness or disease. Noteworthy necropsy findings in one of the three frogs included depleted fat bodies in the coelomic cavity, indicating a poor nutritional condition, and a heavy parasite burden in the lungs. The location of infection and morphologic characteristics of the parasite were consistent with infection by the common lung fluke, Haematoloechus sp. In contrast to the heavy fluke load, only minor microscopic changes were observed in the lungs. Lesions included mild hypertrophy of the bronchiolar epithelium, with few submucosal inflammatory cells consisting predominantly of lymphocytes. Subsequent review of the literature revealed little about the pathologic effects of these parasites except that small numbers are thought to cause the host little harm. Our findings suggest that even with a large number of parasites, there is minimal pathologic impact in the lungs. We conclude that heavy lung-fluke infection should not be diagnosed as the sole or major etiology of death or illness in leopard frogs.

Successful cleft palate repair (palatoplasty) was accomplished in a male canine pup from a kindred with autosomal recessive transmission for a complete cleft palate phenotype. This case represents the potential application of a new animal model for cleft palate repair. This reproducible congenital defect provides a clinically relevant model to improve research into the human anomaly, as compared with previous iatrogenic or teratogenically induced animal models. This case report presents the basis for new repair techniques and for studying the genetic basis of the cleft palate defect.

The reported case describes how an orphaned infant rhesus macaque (Macaca mulatta) was adopted by a non-lactating female animal from the same breeding group. Experience at our institution over the last 27 years has indicated that fostering infant rhesus macaques on to other females is unsuccessful. However, the described infant was held and carried by another female in his breeding group when his mother was sick. After the death of his natural mother, fostering on to a lactating female was attempted but failed, and he was returned to his breeding group and was adopted by the non-lactating female. The infant was hand-fed by animal care staff, and the feeding regimen is described. The fostering was successful, and the infant has had access to a mother figure and peers, although extensive contact with humans initially was necessary for feeding. This contact did not, however, appear to be detrimental to the mother-infant and peer-infant bond, as the infant did not preferentially seek human contact over monkey contact, and he was at no point rejected by mother or group. The disruption caused by removal and replacement of the infant did not cause agitation or increased fighting within the group. We anticipate that the contact with a matriarchal figure in a primate breeding group will minimize the psychological disturbances frequently found with hand-reared macaques.

Eighty published studies were appraised to document the potential stress associated with three routine laboratory procedures commonly performed on animals: handling, blood collection, and orogastric gavage. We defined handling as any non-invasive manipulation occurring as part of routine husbandry, including lifting an animal and cleaning or moving an animal's cage. Significant changes in physiologic parameters correlated with stress (e.g., serum or plasma concentrations of corticosterone, glucose, growth hormone or prolactin, heart rate, blood pressure, and behavior) were associated with all three procedures in multiple species in the studies we examined. The results of these studies demonstrated that animals responded with rapid, pronounced, and statistically significant elevations in stress-related responses for each of the procedures, although handling elicited variable alterations in immune system responses. Changes from baseline or control measures typically ranged from 20% to 100% or more and lasted at least 30 min or longer. We interpret these findings to indicate that laboratory routines are associated with stress, and that animals do not readily habituate to them. The data suggest that significant fear, stress, and possibly distress are predictable consequences of routine laboratory procedures, and that these phenomena have substantial scientific and humane implications for the use of animals in laboratory research.

The objective of this study was to evaluate whether an 240-ml water bottle provided to individually housed mice would remain potable for a 2-week interval (based on absence of coliforms). The study used inbred C57BL/6 mice and CB6F1 x C3D2F1 hybrid mice. Test groups were assigned to minimize the variables of strain, caging type (non-ventilated static versus ventilated) and building location. A 3-cc sample of drinking water was removed aseptically from the bottles and vacuum-filtered using a 250-ml filter funnel with a 0.45-mum pore size. The membrane filter was removed using sterile forceps and placed on a blood agar plate for 10 min. The plate was streaked and incubated at 37 degrees C for 5 days. The plates were observed daily, and if growth had occurred, further testing was done to determine specific organisms. Of the 148 samples only 23 had any bacterial growth. Typical bacteria were unspeciated gram-positive bacilli and Staphylococcus, Micrococcus, Streptococcus, and Pantoea species. The absence of coliforms and low percentage of bacterial contamination suggest that drinking water will remain potable for 2 weeks when supplied to an individual mouse.