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1.
Previous studies on environmental enrichment have generally placed a purported enrichment in the cage and observed changes in behavioural and physiological indicators of welfare. However, many of these ‘enrichments’ are not purposely designed, or appear to be designed with anthropomorphic or anthropocentric concerns, which have little biological relevance. The aim of this study was to screen the behavioural responses of mice to a range of 24 potential enrichments (PEs) considered by an expert panel to have characteristics most biologically relevant to mice. Female mice (64 C57/Bl/6 and 64 ICR(CD-1)) were housed in groups of four and observed three days per week for 12 weeks whilst provided with a different PE weekly. The overall time-budgets of the two strains differed significantly. ICR(CD-1) mice performed more bar chewing, digging, manipulation of PEs, and rearing in the cage. They were also more likely to be hidden in the cage. C57/Bl/6 mice performed more drinking, cage sniffing and social interaction, and showed three times more bar climbing. The two strains responded differently to the PEs, with the ICR(CD-1) mice making more use of PEs, particularly those that could be manipulated or which provided additional hiding places. The higher trait anxiety of the C57/Bl/6 mice may have reduced their utilisation of novel PEs. We conclude that, whilst enrichment can significantly improve animal welfare, those types of enrichments that work well for all strains need to be identified, or strain-specific enrichment policies devised.  相似文献   

2.
Abstract: Changes in levels of extracellular noradrenaline (NA), 3,4-dihydroxyphenylacetic acid (DOPAC), and 5-hydroxyindole-3-acetic acid (5-HIAA) in the frontal cortex, induced by exposure of unrestrained, conscious rats to novel environments, were compared using in vivo microdialysis. NA efflux increased when rats were transferred to a novel cage, but this was not significant when compared with either basal efflux or with changes after equivalent handling in their home cage. Increasing the intensity of illumination of the novel cage by fivefold significantly increased NA efflux with respect to basal efflux but not handled controls. However, a sustained and significant increase in NA efflux (cf. basal efflux or handled controls) was found when an unfamiliar conspecific was also present in the novel cage. In all cases, basal efflux was restored within 1 h of returning rats to their home cage. Neither handling nor environmental stimuli described above affected DOPAC efflux. 5-HIAA efflux was increased (cf. basal) in the presence of an unfamiliar conspecific, but this increase was no greater than that in handled rats. It is concluded that different naturalistic stimuli cause incremental changes in the levels of extracellular NA in the frontal cortex; these changes affect both phasic and tonic components of the response.  相似文献   

3.
Stress strongly alters the physiology and behavior of some individuals, while others are little or not affected. The causes of this individual variability have remained unknown. Here, we hypothesize that epigenetically induced levels of trait anxiety predict the stress response of individual mice in a genetically homogeneous population. Inbred C57BL/6 male mice were selected for their latency to freely enter from their home cage into an unfamiliar arena and classified as having high or low levels of trait anxiety. Mice were then exposed to acute stress (1-h olfactory contact with a rat) or control conditions. After 24 h, acute stress enhanced state anxiety measured in the elevated-plus maze test only in mice previously classified as having high levels of trait anxiety. This anxiogenic effect of acute stress was paralleled by enhanced novelty-induced plasma corticosterone secretion and increased messenger RNA (mRNA) expression for glucocorticoid and mineralocorticoid receptors in the hippocampus. No effects of acute stress were observed in mice classified as having low levels of trait anxiety. Under unstressed control conditions, mice only differed in basal levels of hippocampal mRNA for the glucocorticoid receptor, which were higher in mice with high trait anxiety than in mice with low trait anxiety. In summary, inbred C57BL/6 mice display a remarkably high interindividual variability in their trait anxiety that predicts the behavioral and neuroendocrine response to an acute stressor, indicating that expression of extremely different coping strategies can develop also between genetically identical individuals.  相似文献   

4.
目的探讨4种不同品系小鼠在3种实验(空场实验、悬尾实验及强迫游泳实验)中的行为学差异,为抗抑郁新药研究中的实验动物选择提供参考。方法利用空场实验检测C57BL/6、BALB/c、ICR、和昆明小鼠的自主活动能力和对新奇环境的探索能力;利用悬尾实验和强迫游泳实验检测它们在应激刺激下的行为绝望状态。结果在空场实验中,BALB/c、ICR和昆明小鼠的运动总路程、运动速度和运动时间明显高于C57BL/6小鼠(P〈0.05),ICR和昆明小鼠的直立次数也明显高于C57BL/6小鼠(P〈0.05);悬尾实验C57BL/6小鼠的不动时间显著长于其他3种品系小鼠(P〈0.05),但是4种品系小鼠在强迫游泳实验中的不动时间差异无显著性。结论 C57BL/6小鼠自发活动量低,对新奇环境的探索能力差,并且在急性应激刺激下容易造成行为绝望,因此C57BL/6小鼠可能适合作为急性应激抑郁模型动物。  相似文献   

5.
Previous studies have indicated that neonatal handling influences development of hypothalamic-pituitary-adrenal (HPA) control of corticosterone. In addition, corticosterone influences memory consolidation processes in contextual fear conditioning. Therefore, neonatal handling may affect hippocampal-dependent memory processes present in contextual fear conditioning by influencing the development of HPA control of corticosterone. To investigate the effects of neonatal handling on early learning, rat pups were either handled (15-min removal from home cage) on the first 15 days after birth or left undisturbed in their home cage. Handled rats and nonhandled rats were fear conditioned at 18, 21, or 30 days of age and then tested at two time points--24 h following conditioning and at postnatal day 45. Subsequently, at approximately postnatal day 60, rats were exposed to restraint stress and corticosterone levels were assessed during restraint and recovery. Handled and nonhandled rats did not differ significantly in their freezing response immediately following footshock on the conditioning day. However, when tested for contextual fear conditioning at 24 h following conditioning and at postnatal day 45, handled rats showed more freezing behavior than nonhandled rats. When exposed to restraint stress, handled rats had a more rapid return of corticosterone to basal levels than nonhandled rats. These results indicate that neonatal handling enhances developmentally early memory processes involved in contextual fear conditioning and confirms previously reported effects of neonatal handling on HPA control of corticosterone.  相似文献   

6.
Behavior of male mice of C57Bl/6J and CBA/Lac strains was tested in the elevated plus-maze and open field in order to estimate state anxiety in novel conditions. The cube and partition tests were used to reveal trait anxiety in the familiar conditions of the home cage. It is concluded that genetically defined state anxiety is more pronounced in CBA/Lac mice and trait anxiety in C57Bl/6J strain.  相似文献   

7.
Postweaning management strategies that include an element of social enrichment may reduce weaning stress and improve welfare and productive performance. We analyzed the effect of postweaning handling strategies on welfare and production traits in lambs. After weaning, 36 lambs were assigned to 3 experimental groups with 12 lambs each (control [C], fattening with gentle human female contact [H], and fattening with 2 adult ewes [E]). The average daily gain (ADG) was estimated. Blood samples were taken, and infrared thermography was used to estimate stress variables. There were significant differences among treatments (in favor of alternative strategies) regarding production and stress variables (cortisol, glucose, and creatine kinase). The results suggest that the lambs handled gently during the fattening were less reactive and better able to modulate their physiological stress. The E group adapted better to acute stress than the C group but was less efficient in modulating chronic stress. Both treatments showed higher slaughter live weights and better ADGs compared with the control. The use of social enrichment at weaning, especially to establish a positive human–nonhuman animal bond, alleviates lamb weaning stress and improves welfare and performance.  相似文献   

8.
The influence of ApoE gene deletion on the anxiety state has not been previously investigated. The elevated plus maze was used in this study to determine differences in anxiety-related behavior between apoE-deficient and wild type C57BL/6 mice. The apoE-deficient mice demonstrated less anxiety on the elevated plus maze by spending more time in the open arms of the elevated plus maze compared to wild type mice (p<0.001). Additionally, female apoE-deficient mice visited the open arm of the maze more often than their apoE-deficient male counterpart (p<0.05). The anxiety state and/or sex are possible variables to be considered when designing physiological and/or behavioral studies involving mice that are apoE-deficient.  相似文献   

9.
A recent study reported lower anxiety in the 5xFAD transgenic mouse model of Alzheimer's disease, as measured by reduced time on the open arms of an elevated plus maze. This is important because all behaviors in experimental animals must be interpreted in light of basal anxiety and response to novel environments. We conducted a comprehensive anxiety battery in the 5xFAD transgenics and replicated the plus‐maze phenotype. However, we found that it did not reflect reduced anxiety, but rather abnormal avoidance of the closed arms on the part of transgenics and within‐session habituation to the closed arms on the part of wild‐type controls. We noticed that the 5xFAD transgenics did not engage in the whisker‐barbering behavior typical of mice of this background strain. This is suggestive of abnormal social behavior, and we suspected it might be related to their avoidance of the closed arms on the plus maze. Indeed, transgenic mice exhibited excessive home‐cage social behavior and impaired social recognition, and did not permit barbering by wild‐type mice when pair‐housed. When their whiskers were snipped the 5xFAD transgenics no longer avoided the closed arms on the plus maze. Examination of parvalbumin (PV) staining showed a 28.9% reduction in PV+ inhibitory interneurons in the barrel fields of 5xFAD mice, and loss of PV+ fibers in layers IV and V. This loss of vibrissal inhibition suggests a putatively aversive overstimulation that may be responsible for the transgenics' avoidance of the closed arms in the plus maze .  相似文献   

10.
Early life events lead to behavioral and neurochemical changes in adulthood. The aim of this study is to verify the effects of neonatal handling on spatial memory, nitric oxide (NO) production, antioxidant enzymatic activities and DNA breaks in the hippocampus of male and female adult rats. Litters of rats were non-handled or handled (10 min/day, days 1–10 after birth). In adulthood they were subjected to a Morris water maze or used for biochemical evaluations. Female handled rats showed impairment in spatial learning. They also showed decreased NO production, while no effects were observed in these parameters in male rats. No effects were observed on the number of hippocampal NADPH diaphorase positive cells. In the Comet Assay, male handled rats showed increased DNA breaks index when compared to non-handled ones. We conclude that neonatal handling impairs learning performance in a sex-specific manner, what may be related to NO decreased levels.  相似文献   

11.
Veterinary and management procedures often are aversive to the animals, resulting in physiological and behavioural stress reactions, which increase the risk of accidents and might lower performance. We investigated the effects of previous positive handling and of gentle interactions during the procedure on behaviour and heart rate in dairy cows during rectal palpation with sham insemination. Twenty cows were allocated randomly into two groups of 10 animals: handling, received additional positive handling over a period of four weeks by one person (handler); control, only routine handling by different caretakers. The week after the handling period, tests lasting 9 min, including 4 min rectal palpation, were carried out with each animal on four successive days in four situations in a balanced order: cow is alone during the test, with the handler, with an usual caretaker, or with an unknown person. Behaviour and heart rate were recorded.Previously handled animals had lower heart rate during tests (P≤0.05, n=19), kicked less when alone (P≤0.05, n=19) and tended to show less restless behaviour (P≤0.1, n=19). Cows were further calmed by gentle interactions during the test, but people differed remarkably. Cows showed less restless behaviour when gentled by the handler, both in the 4 min of rectal palpation and in the 9 min test period (each: P≤0.001, n=19). No significant stress reducing effect was found for the other two persons.In conclusion, stress reactions of cows during rectal palpation/insemination can be reduced by previous positive handling as well as by a person providing positive, gentle interactions during the procedure. The results underline the importance of positive, gentle interactions with the animals to enhance animal welfare and reduce the risk of accidents. They also show that people differ in the success to calm down the animals in aversive situations and indicate the need to investigate the characteristics responsible for the differences and identify the preconditions for a stress reducing effect in future research.  相似文献   

12.
This study examined emotionality, activity, learning and memory, as well as the influence of emotionality and activity on learning and memory performance in C57BL/6 and DBA/2 mice using a mouse-test battery. DBA/2 mice performed more poorly than C57BL/6 mice in complex learning tasks such as the water maze and object recognition tasks. In contrast, C57BL/6 mice showed attenuated habituation to novelty in the open field apparatus and poorer performance in the step-down passive avoidance task. The C57BL/6 mice were less exploratory and more anxious than the DBA/2 mice. The anxiety score (open arm entries in the elevated plus maze) was significantly correlated with all measures of learning and memory in the object recognition task, and some measures in the passive avoidance and water maze tasks. Analysis of covariance (with open arm entries as a covariate) revealed that some measures on trial 1 of the object recognition task, but not the memory scores on trial 2, were confounded by anxiety. No confounding factors of anxiety were found in the water maze or passive avoidance tasks. Similar results were obtained with the activity scores (line crossing and rearing in the open field). In conclusion, strain differences in activity and anxiety did not account for strain differences in learning and memory performance of C57BL/6 and DBA/2 mice. Nonetheless, the importance of using complete behavioural test batteries should be stressed to ensure that strain differences in learning and memory tasks are not confounded by non-cognitive factors.  相似文献   

13.
In the laboratory rat and mouse, neonatal handling enhances hippocampal-dependent learning in adulthood, an effect mediated by changes in maternal behavior toward the handled young. In the present study, we examined the interaction between neonatal handling and biparental care during the early postnatal period and its effect on cognitive function in adult California mice (Peromyscus californicus). We characterized the parental behavior of handled and nonhandled father-present and father-absent families over the first 15 days of life. We then assessed cognitive performance of male and female offspring in the Barnes maze and object recognition test after they were 60 days of age. We found that the amount of licking and grooming received by pups was decreased in father-absent families. By postnatal days 12-15, licking and grooming in handled, father-absent families were equivalent to that of nonhandled, father-present families. Handling enhanced novel object recognition in father-present male mice with no effect in females. In the nonhandled group, the presence of the father had no effect on object recognition learning in male or female mice. Handling also enhanced spatial learning in the Barnes maze. In nonhandled families, the presence of the father appeared to have no effect on spatial learning in the male offspring. Interestingly, spatial learning in nonhandled, father-absent, female offspring was similar to that of handled animals. The average amount of licking and grooming received by pups was negatively correlated with the average number of errors made on the first day of reversal training in the Barnes maze. These data support previous findings that neonatal handling facilitates learning and memory in adulthood, suggest that under certain environmental conditions, there is a sex difference in the response of pups to paternal care, and further demonstrate the importance of active parental investment for offspring cognitive development.  相似文献   

14.
The minimalistic environment of standard laboratory cages can adversely influence the responses of animals in standard behavioural tests and other aspects of the animals' biology. To avoid this, cages should provide for the animals' species-specific behavioural characteristics. We hypothesized that, given their possible capacity for colour vision, laboratory mice, Mus musculus, would show preferences between cages of different colours. Studies show that environmental colour can influence emotionality and task performance in humans, suggesting that cage colour could also affect emotionality and performance of mice in behavioural tests. Seventy-two mice were housed in home cages painted red, black, green or white. Five weeks later, 24 mice were placed individually into an apparatus allowing them to choose between cages of each of the home cage colours. Each mouse showed a highly significant preference, which overall, was unrelated to home cage colour. White cages were most preferred and red were least. Home cage colour had a significant effect on body weight and food consumption as well as on behaviour in a raised plus maze. Mice from red home cages spent most time in the closed arms, indicating greater anxiety, possibly suggesting that the reduced occupancy of the red preference cages resulted from avoidance of environmental conditions that induced a negative mental state. These findings show that laboratory mice have strong preferences between cages of different colours. We also found that an apparently inconsequential environmental variable, home cage colour, can influence responses in standard behavioural tests, which should be considered in assessing the external validity of such tests. Copyright 2003 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.  相似文献   

15.
水迷宫实验中三种品系小鼠学习记忆能力的比较   总被引:4,自引:0,他引:4  
目的探讨三种品系小鼠在Morris水迷宫实验中的学习记忆能力差异,为与改善学习记忆能力相关新药研究的实验动物选择提供参考。方法选用C57BL/6小鼠、昆明种小鼠和ICR小鼠,进行定位航行实验(5d)、空间搜索实验(1d)和工作记忆实验(4d),考察其学习记忆能力。结果定位航行实验从第3天起C57BL/6小鼠的潜伏期明显小于昆明种小鼠和ICR小鼠(P0.01);空间搜索实验C57BL/6小鼠穿过原平台位置的次数、在原平台象限游程比率和时间比率均明显多于昆明种小鼠和ICR小鼠(P0.05);动物每天工作记忆实验的潜伏期随测试次数增加而缩短,C57BL/6小鼠缩短的较昆明种小鼠和ICR小鼠稍多。结论C57BL/6小鼠的空间参考记忆能力与工作记忆能力均优于昆明种小鼠和ICR小鼠,且非空间因素对其学习记忆能力的评价干扰较小,可作为优先选择的水迷宫实验动物。  相似文献   

16.
The behavioral characterization of rodent strains in different studies and laboratories can provide unreplicable results even when genotypes are kept constant and environmental control is maximized. In the present study, the influence of common laboratory environmental variables and their interaction with genotype on the results of behavioral tests of anxiety/emotionality were investigated. To this end, the inbred rat strains Lewis (LEW) and spontaneously hypertensive rats (SHR), which are known to differ for numerous emotionality-related behaviors, were tested in the open field (OF), elevated plus maze (EPM) and black/white box (BWB), while three environmental factors were systematically controlled and analyzed: (1) the experimenter handling the animal (familiar or unfamiliar); (2) the position of the home cage (top or bottom shelf of the rack) and (3) the behavioral state of the animal immediately before the test (arousal or rest). Experimenter familiarity did not alter the behavior of rats in the OF. Cage position, on the other hand, influenced the behavior in the OF and BWB, with rats housed in top cages appearing less anxious than those housed in the bottom. In the BWB (but not in the OF), these effects were genotype dependent. Finally, the behavioral state of the animals prior to testing altered the results of the EPM in a strain-dependent manner, with some anxiety-related genotypic differences being found only among rats that were aroused in their home cages. This study showed that common variations in the laboratory environment interact with genotype in behavioral tests of anxiety/emotionality. Recognizing and understanding such variations can help in the design of more effective experiments.  相似文献   

17.
Genetic material for polymerase chain reaction (PCR) and Southern blot analysis on transgenic mice is normally obtained by tail biopsy. Additionally, it may be necessary to tattoo the mice, as it is essential to have a good and permanent identification. The aim of this study was to evaluate the effects of amputating the tip of the tail to obtain a biopsy for genetic analysis and of ink tattooing on welfare in C57BL/6J mice, a strain often used as genetic background for transgenes. The behaviour of the animals, fluctuating asymmetry (FA, a measure of developmental instability) and the level of restitution in the remaining part of the tail were evaluated and used for an assessment of the impact of these procedures on the welfare of the animals. One group of mice was marked by tail tattooing at various ages. Another group of mice were tail amputated at 12 or 20 days of age. Body weight and FA were followed, and at the end of the experiment, the level of fear/anxiety was assessed using a light-dark box. In the group of tail-amputated animals observation of climbing behaviour and a beam walking test for balance was performed. Seven weeks after tail amputation, the animals were euthanized. The remaining part of the tail was evaluated histopathologically. Body weight, behaviour in the light-dark box and balance test results were not influenced by tail amputation or tattooing. FA was only transiently increased by tattooing. Climbing behaviour was reduced just after tail amputation at 20 days of age. No signs of neuromas were found in the amputated tails, but seven weeks after amputation a significant number of mice did not have fully regenerated glandular tissue and hair follicles in the tail. It is concluded that both tail amputation and tail tattooing seem to have minor short-term negative effects on welfare and that the tissues on the tail probably do not regenerate fully after amputation.  相似文献   

18.
目的:探索二氢杨梅素(DHM)对慢性社会挫败应激小鼠认知与情感障碍的作用及其可能机制。方法:将C57BL/6J小鼠随机分成对照组(Control)、慢性社会挫败应激组(CSDS)和慢性社会挫败应激+DHM组(CSDS+DHM),每组14只,每天将两个应激组小鼠放入ICR攻击鼠的饲养笼中10 min,之后取出放于ICR攻击鼠饲养笼的旁边笼中,连续应激10 d,在应激5 d后,每天按10 ml/kg的量分别腹腔注射一次2%的DMSO或20 mg/kg的DHM(分散于2% DMSO中),连续注射5 d,之后每组取10只小鼠进行新颖物体识别测试、Y迷宫测试、社会交互和旷场测试、行为学测试,剩余4只小鼠于实验结束后24 h内断头取脑,采用Western blot法检测海马组织SIRT1水平。结果:与Control组比较,CSDS组小鼠的学习记忆显著降低,焦虑水平显著升高,在悬尾测试(TST)和强迫游泳测试(FST)中的不动时间显著升高,海马SIRT1蛋白水平显著降低(P均<0.05或P<0.01);与CSDS组比较,CSDS+DHM组小鼠学习记忆显著提高,小鼠焦虑水平显著降低,在TST和FST中不动时间显著降低,海马SIRT1蛋白水平显著升高(P均<0.05或P<0.01)。结论:DHM可改善CSDS诱导小鼠的认知障碍、焦虑样行为和抑郁样行为,并提高海马SIRT1蛋白的表达水平。  相似文献   

19.
We have previously reported severely impaired spatial learning in mutant mice underexpressing a shortened variant of the beta-amyloid precursor protein (beta-APPtheta/theta). This targeted mutation is functionally equivalent to a null mutation. It also disturbs behavioral and neurological maturation with deficits emerging mainly between postnatal day (pd) 11 and 19. Such early tested mice exhibited almost no genotype-related difference in Morris water maze learning, raising the possibility that early handling might have compensated for genetic deficits. To verify this effect, we compared watermaze learning and open field behavior of 66 adult mutant and wildtype mice having been handled during pd 3-27 with that of 70 non-handled mutant and wildtype mice. Neurological testing during pd 3-27 markedly reduced time near wall and improved spatial retention of adult mutants, restoring their learning capabilities to wildtype levels. Early handling did not cure the mutation associated activity deficit in the open field, but mainly increased center field exploration in both mutants and wildtypes. In a follow-up experiment we analyzed whether an early (pd 3-10, n = 22) or middle (pd 11-19, n = 24) period of handling in form of neurological testing had differential effects on adult behavior. Mice handled during pd 11-19 had slightly shorter escape times than mice handled during pd 3-10 but were not significantly different in other behavioral measures. There were no sex related differences. Correlational and factor analysis showed that both the mutation and early handling had pleiotropic behavioral effects, resulting in differentially impaired mutants depending on the test situation. Likewise, early handling affected not only thigmotactic tendencies but also, more subtly, other behavioral components underlying water maze learning. We conclude that early postnatal stimulation can prevent mutation induced learning deficits in adult mice, but probably through other developmental mechanisms than those affected by the mutation. This implies that some behavioral impairments related to beta-APP malfunction may be corrected through simple treatments.  相似文献   

20.
Rabbits are commonly kept in a variety of settings, including homes, laboratories, and veterinary clinics. Despite the popularity of keeping this prey species, little research has investigated current methods of handling. The aim of this study was to examine the experience of caregivers (owners and keepers) in using five handling methods commonly referred to in books written for companion animal (pet) owners and veterinary and/or laboratory personnel. An online survey was completed by 2644 respondents, representing all three of these groups, and breeders. Data were acquired to determine sources that participants used to gain knowledge of different handling methods, the methods they used and for what purposes they used them, and their perceptions of any associated difficulties or welfare concerns. Results indicated that participants most frequently used the method of supporting a rabbit’s body against a person’s chest, which was considered the easiest and most welfare-friendly method of the handling methods explored. “Scruffing with rear support” was the least used method and was considered to be distressing and painful for the rabbit. As rabbits are a terrestrial prey species, being picked up is likely an innately stressful experience. Additional research is encouraged to explore the experience of rabbits during handling to identify methods that can be easily used with the fewest welfare compromises.  相似文献   

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