Environmental Enrichment Research Articles

The impact of enriched environments on cerebral oxidative balance in rodents: a systematic review of environmental variability effects

IntroductionThe present review aimed to systematically summarize the impacts of environmental enrichment (EE) on cerebral oxidative balance in rodents exposed to normal and unfavorable environmental conditions.MethodsIn this systematic review, four databases were used: PubMed (830 articles), Scopus (126 articles), Embase (127 articles), and Science Direct (794 articles). Eligibility criteria were applied based on the Population, Intervention, Comparison, Outcomes, and Study (PICOS) strategy to reduce the risk of bias. The searches were carried out by two independent researchers; in case of disagreement, a third participant was requested. After the selection and inclusion of articles, data related to sample characteristics and the EE protocol (time of exposure to EE, number of animals, and size of the environment) were extracted, as well as data related to brain tissues and biomarkers of oxidative balance, including carbonyls, malondialdehyde, nitrotyrosine, oxygen-reactive species, and glutathione (reduced/oxidized).ResultsA total of 1,877 articles were found in the four databases, of which 16 studies were included in this systematic review. The results showed that different EE protocols were able to produce a global increase in antioxidant capacity, both enzymatic and non-enzymatic, which are the main factors for the neuroprotective effects in the central nervous system (CNS) subjected to unfavorable conditions. Furthermore, it was possible to notice a slowdown in neural dysfunction associated with oxidative damage, especially in the prefrontal structure in mice.DiscussionIn conclusion, EE protocols were determined to be valid tools for improving oxidative balance in the CNS. The global decrease in oxidative stress biomarkers indicates refinement in reactive oxygen species detoxification, triggering an improvement in the antioxidant network.

A modified rehabilitation paradigm bilaterally increased rat extensor digitorum communis muscle size but did not improve forelimb function after stroke.

Malnutrition after stroke may lessen the beneficial effects of rehabilitation on motor recovery through influences on both brain and skeletal muscle. Enriched rehabilitation (ER), a combination of environmental enrichment and forelimb reaching practice, is used preclinically to study recovery of skilled reaching after stroke. However, the chronic food restriction typically used to motivate engagement in reaching practice is a barrier to using ER to investigate interactions between nutritional status and rehabilitation. Thus, our objectives were to determine if a modified ER program comprised of environmental enrichment and skilled reaching practice motivated by a short fast would enhance post-stroke forelimb motor recovery and preserve forelimb muscle size and metabolic fiber type, relative to a group exposed to stroke without ER. At one week after photothrombotic cortical stroke, male, Sprague-Dawley rats were assigned to modified ER or standard care for 2 weeks. Forelimb recovery was assessed in the Montoya staircase and cylinder task before stroke and on days 5-6, 22-23, and 33-34 after stroke. ER failed to improve forelimb function in either task (p > 0.05). Atrophy of extensor digitorum communis (EDC) and triceps brachii long head (TBL) muscles was not evident in the stroke-targeted forelimb on day 35, but the area occupied by hybrid fibers was increased in the EDC muscle (p = 0.038). ER bilaterally increased EDC (p = 0.046), but not TBL, muscle size; EDC muscle fiber type was unchanged by ER. While the modified ER did not promote forelimb motor recovery, it does appear to have utility for studying the role of skeletal muscle plasticity in post-stroke recovery.

Assessing the influence of seasonal precipitation patterns on groundwater quality in the coal rich environment of Enugu, Nigeria

As the impacts of climate change continue to be felt around the world, understanding the effects on groundwater quality and quantity has become an important area of investigation. As a global source of water that contributes to preserving the environment, a better understanding of the effect of precipitation seasonal pattern on these systems is crucial; though studies connected to groundwater quality in this era of environmental crisis are at infancy. This study aims to evaluate the effect of precipitation seasonal pattern on groundwater quality in a coal enriched environment of developing city of west African sub-region with particular reference to Enugu, a coal city in Nigeria. Three residential areas (Abakpa, Achara, and Independence Layout) were randomly selected from high, medium, and low neighbourhood densities in the metropolis. Within the period spanning from April 2018 to March 2019, a physiochemical analysis was conducted on twelve deep wells utilizing weighted arithmetic index method. This technique was implemented in order to facilitate the assessment of the degree of water quality by translating a number of variables to just one metric value. The results of the investigation showed that the groundwater resources in the study region are mildly acidic, presumably as a result of the presence of pyrite, which is a byproduct of coal weathering, and chloride-ion-charged rains. Additionally, noticeable distinctions in the properties of water samples were observed between the dry and rainy seasons. Specifically, just 1% of the sampled water had excellent ratings, while 58.3% were considered good, 29.1% were deemed poor, and 8.3% of samples were categorized as very poor. The study concluded that coupled with climate crisis, seasonal precipitation patterns affect groundwater resources by reducing recharge, discharge, and the overall quality of water. These results have important implications for the management of groundwater resources in the region and highlight the need for continued monitoring and assessment of water quality in the face of ongoing environmental changes.

Study on Sedimentary Environment and Organic Matter Enrichment Model of Carboniferous–Permian Marine–Continental Transitional Shale in Northern Margin of North China Basin

The shales of the Taiyuan Formation and Shanxi Formation in the North China Basin have good prospects for shale gas exploration and development. In this study, Well KP1 at the northern margin of the North China Basin was used as the research object for rock mineral, organic geochemical, and elemental geochemical analyses. The results show that brittle minerals in the shales of the Taiyuan Formation and Shanxi Formation are relatively rare (<40%) and that the clay mineral content is high (>50%). The average TOC content is 3.68%. The organic matter is mainly mixed and sapropelic. The source rocks of the Taiyuan Formation and Shanxi Formation are mainly felsic, and the tectonic background lies in the continental island arc area. The primary variables that influenced the enrichment of organic materials during the sedimentary stage of the Taiyuan Formation were paleosalinity and paleoproductivity. Paleosalinity acted as the primary regulator of organic matter enrichment during the sedimentary stage of the Shanxi Formation.

Effects of simple cage enrichment and its removal on the behavior and welfare of American mink (Neogale vison)

ABSTRACT Environmental enrichment may reduce stereotypies in fur-farmed mink. North American mink standards require manipulable enrichment objects within cages. However, mink can rapidly destroy objects inhibiting continuous enrichment presence, which may have negative welfare impacts. This experimental study determined the effects of removing simple cage manipulable enrichments (plastic chains and dumbbells), either short-term or longer-term, on the behavioral expression of welfare in fur-farmed mink. Locomotor stereotypies, normal activity, sub-types of inactivity related to boredom, and tail fur-chewing were recorded across four treatment groups with either (1) no enrichment, (2) continuous enrichment, (3) short (temporary), or (4) long-term enrichment removal. Contrary to predictions, locomotor stereotypies, and scrabbling were not reduced by the enrichments, nor affected by the enrichment removal. Observations at the beginning of the trial showed the non-enriched mink spent the least amount of time lying with their eyes open (i.e., the least bored). The lack of enrichment may have increased fur-chewing on the tail, but larger sample sizes would be needed for statistical confirmation. This research contributes to the literature on evaluating simple, practical enrichments for improving fur-farmed mink welfare.

The Role of the Sensory Input Intervention in Recovery of the Motor Function in Hypoxic Ischemic Encephalopathy Rat Model.

Motor disturbances predominantly characterize hypoxic-ischemic encephalopathy (HIE). Among its intervention methods, Environmental Enrichment (EE) is strictly considered a form of sensory intervention. However, limited research employs EE as a single sensory input intervention to validate outcomes post-intervention. A Sprague-Dawley rat model subjected to left common carotid artery ligation and exposure to oxygen-hypoxic conditions use in this study. EE was achieved by enhancing the recreational and stress-relief items within the cage, increasing the duration of sunlight, colorful items exposure, and introducing background music. JZL184 (JZL) was administered as a neuroprotective drugs. EE was performed 21 days postoperatively and the rats were randomly assigned to the standard environment and EE groups, the two groups were redivided into control, JZL, and vehicle injection subgroups. The western blotting and behavior test indicated that EE and JZL injections were efficacious in promoting cognitive function in rats following HIE. Additionally, the motor function performance in the EE-alone intervention group and the JZL-alone group after HIE was significantly improved compared to the control group. The combined EE and JZL intervention group exhibited even more pronounced improvements in these performances. EE may enhance motor function through sensory input different from the direct neuroprotective effect of pharmacological treatment.

Sex-Specific Differences and the Role of Environmental Enrichment in the Expression of Hippocampal CB1 Receptors following Chronic Unpredictable Stress

Stress-related mental disorders have become increasingly prevalent, thus endangering mental health worldwide. Exploring stress-associated brain alterations is vital for understanding the possible neurobiological mechanisms underlying these changes. Based on existing evidence, the brain endogenous cannabinoid system (ECS) plays a significant role in the stress response, and disruptions in its function are associated with the neurobiology of various stress-related disorders. This study primarily focuses on investigating the impact of chronic unpredictable stress (CUS) on the expression of hippocampal cannabinoid type 1 (CB1) receptors, part of the ECS, in adult male and female Wistar rats. Additionally, it explores whether environmental enrichment (EE) initiated during adolescence could mitigate the CUS-associated alterations in CB1 expression. Wistar rats, shortly after weaning, were placed in either standard housing (SH) or EE conditions for a duration of 10 weeks. On postnatal day 66, specific subgroups of SH or EE animals underwent a 4-week CUS protocol. Western blot (WB) analysis was conducted in the whole hippocampus of the left brain hemisphere to assess total CB1 protein expression, while immunohistochemistry (IHC) was performed on the right hemisphere to estimate the expression of CB1 receptors in certain hippocampal areas (i.e., CA1, CA3 and dentate gyrus-DG). The WB analysis revealed no statistically significant differences in total CB1 protein levels among the groups; however, reduced CB1 expression was found in specific hippocampal sub-regions using IHC. Specifically, CUS significantly decreased CB1 receptor expression in the CA1 and DG of both sexes, whereas in CA3 the CUS-associated decrease was limited to SH males. Interestingly, EE housing proved protective against these reductions. These findings suggest a region and sex-specific endocannabinoid response to chronic stress, emphasizing the role of positive early experiences in the protection of the adolescent brain against adverse conditions later in life.

Lytic/Lysogenic Transition as a Life-History Switch

Abstract The transition between lytic and lysogenic life cycles is the most important feature of the life history of temperate viruses. To explain this transition, an optimal life-history model is offered based a discrete-time formulation of phage/bacteria population dynamics that features infection of bacteria by Poisson sampling of virions from the environment. The time step is the viral latency period. In this model density-dependent viral absorption onto the bacterial surface produces virus/bacteria coexistence and density-dependence in bacterial growth is not needed. The formula for the transition between lytic and lysogenic phases is termed the “fitness switch”. According to the model, the virus switches from lytic to lysogenic when its population grows faster as prophage than as virions produced by lysis of the infected cells, and conversely for the switch from lysogenic to lytic. A prophage that benefits the bacterium it infects automatically incurs lower fitness upon exiting the bacterial genome, resulting in its becoming locked into the bacterial genome in what is termed here as a “prophage lock”. The fitness switch qualitatively predicts the ecogeographic rule that environmental enrichment leads to microbialization with a concomitant increase in lysogeny, fluctuating environmental conditions promote virus-mediated horizontal gene transfer, and prophage-containing bacteria can integrate into the microbiome of a eukaryotic host forming a functionally integrated tripartite holobiont. These predictions accord more with the “Piggyback-the-Winner” hypothesis than with the “Kill-the-Winner” hypothesis in virus ecology.

Dynamics of changes in broiler spatial distribution induced by a robot with autonomous navigation along the growing cycle

Welfare problems in broiler chickens are associated with accelerated growth in high density and barren environments. Encouraging broiler movement yields benefits by increasing locomotion, foraging, and environmental exploration. Robot sensors with autonomous navigation capabilities developed to collect husbandry information could collaterally induce movement of birds while traversing the chicken houses. This study examines the short-time dynamic of changes in broiler spatial distribution within the robot's zone of influence throughout the growing cycle. Two batches of mixed-sex Cobb-500 were raised in a commercial broiler farm until 42 d of age, in 2 houses divided into 4 equally sized sectors. In half of the sectors an AviSense robot sustained 2-h per day of autonomous navigation. The minute prior and the 4 min following the robot entering the zone of influence were video recorded weekly. Control sectors without a robot were analyzed equivalently. Number of individuals within the zone of influence of the robot were obtained at 1-s intervals and relative density (%) was estimated. Physical interactions between broilers and the robot, as well as interactions with the environment were also recorded. The entrance of the robot triggers within seconds a strong depopulation of the zone with birds walking to neighboring areas (P < 0.03, in all ages). The decreases in relative density induced by the robot appears more pronounced, and repopulation of the zone was slower, in younger than in older birds (P < 0.05). Broilers´ showed physical interactions towards the robot and were also touched and/or slightly pushed by the robots (19 and 84% of videos recorded, respectively). They were also found scratching and/or pecking the ground after the robot passed (64% of videos). Findings strongly suggest that robots, beyond their specific capabilities as environmental sensors, were effective in promoting increased movement in broilers along the growing cycle and could also favor additional exploratory behaviors. Thus, these robots could be considered as environmental enrichment elements that contribute to welfare improvements during intensive rearing.

Boosting Decision-Making in Rat Models of Early-Life Adversity with Environmental Enrichment and Intranasal Oxytocin

Impaired decision-making constitutes a fundamental issue in numerous psychiatric disorders. Extensive research has established that early life adversity (ELA) increases vulnerability to psychiatric disorders later in life. ELA in human neonates is associated with changes in cognitive, emotional, as well as reward-related processing. Maternal separation (MS) is an established animal model of ELA and has been shown to be associated with decision-making deficits. On the other hand, enriched environment (EE) and intranasal oxytocin (OT) administration have been demonstrated to have beneficial effects on decision-making in humans or animals. Given these considerations, our investigation sought to explore the impact of brief exposure to EE and intranasal OT administration on the decision-making abilities of adolescent rats that had experienced MS during infancy.The experimental protocol involved subjecting rat pups to the MS regimen for 180minutes per day from postnatal day (PND) 1 to PND 21. Then, from PND 22 to PND 34, the rats were exposed to EE and/or received intranasal OT (2μg/μl) for seven days. The assessment of decision-making abilities, using a rat gambling task (RGT), commenced during adolescence. Our findings revealed that MS led to impaired decision-making and a decreased percentage of advantageous choices. However, exposure to brief EE or intranasal OT administration mitigated the deficits induced by MS and improved the decision-making skills of maternally-separated rats. Furthermore, combination of these treatments did not yield additional benefits. These results suggest that EE and OT may hold promise as therapeutic interventions to enhance certain aspects of cognitive performance.

Effects of environmental enrichment on GLUT expression in the visual cortex of amblyopic rats

ObjectiveTo investigate the potential changes of glucose metabolism and glucose transporter protein (GLUT) in the visual cortex of formally deprived amblyopic rats, as well as the effects of enriched environments on the levels of nerve conduction and glucose metabolism in the visual cortex of amblyopic rats. Methods36 rats were randomly divided into three groups: CON + SE (n = 12), MD + SE (n = 12) and MD + EE (n = 12). The right eyelids of both MD + SE and MD + EE groups were sutured. After successful modelling, the MD + EE group was maintained in an enriched environment, and the other two groups were kept in the same environment. Pattern visual evoked potentials (PVEP) was used to confirm models' effect, glucose metabolism was analyzed by Micro-PET/CT (18F-FDG), and the protein as well as mRNA expression levels of GLUT were detected by Western Blot and quantitative RT-PCR (quantitative Reverse Transcription-Polymerase Chain Reaction) analyses, site of GLUT expression by immunofluorescence (IF). ResultsAfter suture modelling, both the MD + EE and MD + SE groups objective visual nerve conduction function decreased, the glucose metabolism in the visual cortex was markedly lower. After the enriched environment intervention, it recovered in the MD + EE group. The expression levels of GLUT1 and GLUT3 were increased in the MD + EE group in comparison with the MD + SE group. GLUT1 was primarily expressed on astrocytes and endothelial cells, but GLUT3 was mainly expressed on neurons. ConclusionEnrichment of the environment exhibited a therapeutic effect on amblyopia, which could be related to the enhancement of glucose metabolism and GLUT expression in the visual cortex.

Effects of housing systems on behaviour and welfare of autochthonous laying hens and a commercial hybrid

The welfare of laying hens is crucial for a sustainable and ethical food industry. Free-range systems offer a more natural and stimulating environment, while dual-purpose autochthonous breeds and crossbreeding could address ethical concerns and improve productivity. In this study, behaviour, plumage status, and leg health of five genotypes (two local breeds, two crossbreeds with a medium growth hybrid, and one commercial hybrid) in two different housing systems (enriched cage/free-range) were evaluated. The animals were filmed with professional cameras for three consecutive days at 30 and 64 weeks of age. Each day the recording session lasted 20minutes, resulting in a total of 120minutes per pen (20min X 6 days recorded). A total of 16 behaviours divided into six categories (feeding, movement, social, resting, comfort, stretching) were scored. In addition, the tonic immobility test was performed, and the plumage status and footpad dermatitis of the birds were assessed. The results revealed a significant influence of the housing system on the behaviour, plumage status, and foot health of laying hens. While the housing system affected all behaviours, mainly feeding and comfort behaviours were influenced by the genotype of the hens and the interaction between the housing system and genotype. All genotypes displayed a similar behavioural pattern within the two housing systems, except for the commercial hybrid, which differed in its behaviour from the others adapting better to the enriched cage environment. In particular, the free-range system provided hens with more opportunities to engage in movement and comfort behaviour, and social interactions. Furthermore, hens in the free-range system exhibited better plumage conditions and lower rates of footpad dermatitis, indicating a positive impact on their overall welfare.

In-situ construction of 1D β-FeOOH nanobelts/2D porous g-C3N4 heterojunction for enhanced “signal-on” photoelectrochemical aptasensing

Bisphenol A (BPA), a prevalent organic pollutant found in wastewater environment, is notorious for its resistance to natural degradation, raising significant ecological and human health concerns. In this study, a “signal-on” photoelectrochemical aptasensing system was designed for detecting BPA in real water samples with high specificity and sensitivity. One-dimensional (1D) β-FeOOH nanobelts were synthesized on a two-dimensional (2D) porous carbon nitride (g-C3N4) through an in-situ growth procedure. The β-FeOOH/g-C3N4 nanocomposites demonstrated superior photoelectric conversion efficiency due to several factors: (i) The 1D nanobelt-like structure of β-FeOOH shortens the charge transfer path within the nanocomposite, enabling directional and rapid migration of photoinduced charges from the interior to the surface. (ii) β-FeOOH possesses strong visible absorption capabilities, enhancing the utilization of g-C3N4 under photoexcitation, resulting in the generation of numerous photo-induced carriers. (iii) The in-situ formation of the β-FeOOH/g-C3N4 heterojunction establishes an intimate interfacial contact, facilitating the rapid separation and transfer of charges between β-FeOOH and g-C3N4. A photoelectrochemical aptasensing platform based on the photoactive material of β-FeOOH/g-C3N4 detects BPA with reduced photocurrent owing to the presence of BPA-aptamer macromolecules on the electrode surface. This BPA detection system exhibits excellent linearity over a wide concentration range from 10 pM to 10nM, with high sensitivity (a detection limit of 3.5 pM), stability, specificity, and repeatability. Furthermore, this research offers a straightforward and rapid sensing platform for monitoring BPA enriched water environments.

Comb size, shape complexity and laterality of laying hens reared in environments varying in resource choice

The comb is an ornament involved in signalling condition in domestic fowl. We hypothesised that comb size, comb shape complexity (i.e., rugosity, the comb perimeter jaggedness), and comb laterality of laying hens would be influenced by the degree of environmental enrichment experienced during juvenile development in the form of resource choice. We conducted a 2 x 2 factorial crossover experiment with pullets reared in pens containing four perches of equal length and four litter areas of equal size. Pullets were exposed to a single choice versus multiple choices of perch and litter types (i.e., all the same versus all different) during Weeks 1 - 4 (Period 1) and/or Weeks 5 - 15 (Period 2) of rearing (n = 4 pens/treatment combination) prior to transfer to standard adult laying pens for Weeks 16 - 27 (Period 3). In Week 27, combs were photographed, and comb laterality (hanging on left or right side) was noted. Using a custom-made image analysis programme, we captured comb area (mm2), perimeter length (mm), and rugosity ((perimeter length – horizontal length) / horizontal length) from comb photographs of 6 - 7 randomly-selected hens/pen. We predicted that hens reared in the multi-choice environment during Periods 1 and 2 would have larger, more complex, and left-side-biased combs than those in the other treatment groups, reflecting lower allostatic load. The predicted comb side bias was based on a possible bias in head posture/movements associated with greater right eye/ear use and left-brain hemispheric dominance. Contrary to our predictions, we detected an overall right-side bias in comb laterality, and no associations between resource choice treatment in Period 1 or 2 and comb area, perimeter length, rugosity, or laterality of the adult hens. Thus, variation in allostatic load resulting from the rearing treatments was insufficient to modify the trajectory of comb morphological development, possibly due to a ceiling effect when comparing environmental treatments on the positive end of the welfare spectrum. We found that left-lopping combs had shorter perimeters than right-lopping combs. However, among hens with left-lopping combs, those with larger combs were heavier and had less feather damage, while among hens with right-lopping combs, those with longer-perimeter combs were heavier and tended to have less comb damage. In conclusion, comb characteristics were related to physical condition at the individual level but did not serve as sensitive integrated indicators of hen welfare in response to basic versus enhanced resource choice during rearing.

Environmental enrichment improves mice motor performance.

Environmental enrichment improves mice motor performance.

Effects of Therapeutic Dosing through Enriched Environment on Gross Motor Function in Spastic Quadriplegic Cerebral Palsy

Background: Cerebral palsy differs in every child in terms of impairments, activity limitations and participation restrictions, so intervention should be designed in a way which is specific to every child and is constantly adjusted according to the needs of the child. Level appropriate selection of dosage (frequency, type, time, intensity) of treatment plays a vital role in treatment efficacy. Objective: To investigate the effects of therapeutic dosing through age-appropriate enriched environment on gross motor function in spastic quadriplegic cerebral palsy. Methods:  In this RCT, 82 spastic cerebral palsy children were randomly allocated to two groups. Group A received level appropriate enriched environmental inputs consisting of motor and sensory enriched play environment with therapeutic dosing (20-25 minutes intermittently, 5 hours per day, 5 days a week for 24 weeks) along with Neurodevelopmental Technique. The goal was to promote participant’s self-generated movements, exploration of the environment and successful task completion. Group B received clinical based regular physical therapy consisting of NDT. Guidance was given to parents on how to carry out a home program. Data was collected at the end of 5 months on GMFM scale to check improvement in gross motor function. Results: The data was analyzed using Mann Whitney U test. There was statistically significant difference between the two groups. Group A showed improvement in gross motor function (p value&lt;0.05) whereas improvement in group B was not as significant (p-value&gt;0.05). Conclusion: This study concluded that optimal dosage of an intervention along with parent/caregiver education started at an early age resulted in significant functional improvements in spastic quadriplegic cerebral palsy children. These improvements were observed not only in body functions but also in active involvement and participation of the child.

Preventive interventional strategies mitigate age-associated degeneration of dorsal hippocampal neural cells in naturally ageing mice

Objectives: The objective of this study was to investigate the effectiveness and potential protective effects of various intervention strategies, such as choline and docosahexaenoic acid (Ch-DHA) supplementation, Clitoria ternatea root extract (CTR) supplements, human embryonic kidney stem cell conditioned media (HEK-CM) treatment and exposure to enriched environments (EEs), in mitigating neural cell degeneration in dorsal hippocampal subregions of naturally ageing mice brain. Materials and Methods: Twelve–fifteen-month-old CF1 male mice were subdivided (n = 6/group) into normal age-matched control, Ch-DHA supplemented, EE exposed, HEK-CM administered and CTR-supplemented groups. Neuro morphological alterations in the dorsal hippocampus were assessed using cresyl violet staining. Results: Higher neural cell degeneration was observed in the CA1–CA3 dorsal hippocampal subregions in normal ageing mice brains. Notably, interventions such as HEK-CM administration, Ch-DHA supplementation, exposure to an EE and CTR supplementation significantly reduced degeneration, particularly in the CA3 and CA2 regions. Conclusion: Ch-DHA supplementation and HEK-CM treatment are observed to significantly reduce age-dependent degeneration of dorsal hippocampal CA3 and CA2 neurons in naturally ageing mice compared to EE exposure or CTR supplementation.

Effects of Environmental Enrichment on Stress and Welfare in Laboratory Animals

Purpose: The general purpose of this study was to examine the effects of environmental enrichment on stress and welfare in laboratory animals.&#x0D; Methodology: The study adopted a desktop research methodology. Desk research refers to secondary data or that which can be collected without fieldwork. Desk research is basically involved in collecting data from existing resources hence it is often considered a low cost technique as compared to field research, as the main cost is involved in executive’s time, telephone charges and directories. Thus, the study relied on already published studies, reports and statistics. This secondary data was easily accessed through the online journals and library.&#x0D; Findings: The findings reveal that there exists a contextual and methodological gap relating to the effects of environmental enrichment on stress and welfare in laboratory animals. Preliminary empirical review revealed that that enriching their living environments significantly improved their well-being. They found that interventions such as physical, social, cognitive, and sensory enrichment reduced stress levels, promoted natural behaviors, and enhanced cognitive function. Tailoring enrichment programs to specific species' needs and considering factors like environmental complexity and novelty proved crucial. Moreover, these interventions not only benefited animal welfare but also improved research outcomes by reducing stress and enhancing the validity of preclinical studies. Overall, the research underscored the importance of implementing evidence-based enrichment strategies to ensure the ethical treatment of laboratory animals and enhance the reliability of scientific research.&#x0D; Unique Contribution to Theory, Practice and Policy: The Biophilia Hypothesis, Optimal Stimulation theory and Stress Inoculation theory may be used to anchor future studies on stress and welfare in laboratory animals. The study made significant contributions to theory, practice, and policy in the field of laboratory animal welfare. It provided valuable insights into the underlying mechanisms of environmental enrichment's influence on animal well-being, contributing to existing theoretical frameworks such as the Biophilia Hypothesis, Optimal Stimulation Theory, and Stress Inoculation Theory. Additionally, the study offered practical recommendations for implementing evidence-based enrichment programs tailored to the needs of different animal species. These findings informed policy development by guiding the establishment of standards for enrichment in laboratory animal facilities, enhancing the protection and welfare of laboratory animals across institutional and national levels.&#x0D; Keywords: Environmental Enrichment, Laboratory Animals, Stress, Welfare, Mechanisms, Biophilia Hypothesis, Optimal Stimulation Theory, Stress Inoculation Theory, Implementation, Standards, Well-Being

Welfare Implications for Tigers in Travelling Circuses.

There are very few studies that have focused on species-specific welfare implications for tigers in a travelling circus. The absence of scientific evidence to inform nationwide legislation means that tigers are still commonly used in travelling circuses across the world. A systematic review of relevant published studies was conducted using the bibliographic databases Web of Science and Scopus, supplemented by a narrative search. In total, 42 relevant studies were identified that assessed the welfare of tigers in captivity, including circuses and zoos. Only eight papers assessed the welfare implications for tigers in circuses directly, evidencing the lack of research in this area. Given that circuses provide a sub-optimal environment compared to zoos, implications for tiger welfare were also inferred from zoo research, within the Five Domains framework. Collectively, these papers infer that the travelling nature of a circus often negatively impacts the welfare domains of nutrition, physical environment, health, and mental state. This is due to limitations in enclosure size, as well as in both environmental and behavioural enrichment. There is also often difficulty in sourcing appropriate food and specialised routine veterinary care. The literature is divided concerning behavioural interactions, specifically whether training can improve welfare by offering mental stimulation. However, circus performances are often associated with negative welfare due to noise disruption from spectators. The collective scientific evidence indicates that tigers are not well suited to circus living, due to the inability of a travelling circus to provide for their species-specific psychological, physiological, and behavioural needs.

Probing Denitrifying Anaerobic Methane Oxidation via Antimicrobial Intervention: Implications for Innovative Wastewater Management.

Methane emissions present a significant environmental challenge in both natural and engineered aquatic environments. Denitrifying anaerobic methane oxidation (N-DAMO) has the potential for application in wastewater treatment plants. However, our understanding of the N-DAMO process is primarily based on studies conducted on environmental samples or enrichment cultures using metagenomic approaches. To gain deeper insights into N-DAMO, we used antimicrobial compounds to study the function and physiology of 'Candidatus Methanoperedens nitroreducens' and 'Candidatus Methylomirabilis oxyfera' in N-DAMO enrichment cultures. We explored the effects of inhibitors and antibiotics and investigated the potential application of N-DAMO in wastewater contaminated with ammonium and heavy metals. Our results showed that 'Ca. M. nitroreducens' was susceptible to puromycin and 2-bromoethanesulfonate, while the novel methanogen inhibitor 3-nitrooxypropanol had no effect on N-DAMO. Furthermore, 'Ca. M. oxyfera' was shown to be susceptible to the particulate methane monooxygenase inhibitor 1,7-octadiyne and a bacteria-suppressing antibiotic cocktail. The N-DAMO activity was not affected by ammonium concentrations below 10 mM. Finally, the N-DAMO community appeared to be remarkably resistant to lead (Pb) but susceptible to nickel (Ni) and cadmium (Cd). This study provides insights into microbial functions in N-DAMO communities, facilitating further investigation of their application in methanogenic, nitrogen-polluted water systems.