Enriched Housing Research Articles

Complex assessment of distinct cognitive impairments following ouabain injection into the rat dorsoloateral striatum

A stroke in humans may induce focal injury to the brain tissue resulting in various disabilities. Although motor deficits are the most discernible, cognitive impairments seem to be crucial for patients mental well-being. The current lack of effective treatments encourages scientists and clinicians to develop novel approaches. Before applying them in clinic, testing for safety and effectiveness in non-human models is necessary. Such animal model should include significant cognitive impairments resulting from brain lesion.We used ouabain stereotactic injection into the right dorsolateral striatum of male Wistar rats, and enriched environment housing. To confirm the brain injury before cognitive testing, rats were given a beam-walking task to evaluate the level of sensorimotor deficits. To determine the cognitive impairment after focal brain damage, rats underwent a set of selected tasks over an observation period of 30 days.Brain injury induced by ouabain significantly impaired the acquisition of the T-maze habit learning task, where ‘win–stay’ strategy rules were applied. The injured rats also showed significant deficits in the performance of the T-maze switching task, which involved shifting from multiple clues previously relevant to the only one important clue. Focal brain injury also significantly changed ‘what – where’ memory, tested in the object exploration task, in which a novel object consecutively appeared in the same place while the location of a familiar item was continuously changed.In conclusion, we developed an animal model of distinct cognitive impairments after focal brain injury that provides a convenient method to test the effectiveness of restorative therapies.

Environmental assessment of three egg production systems–Part I: Monitoring system and indoor air quality

To comprehensively assess conventional vs. some alternative laying-hen housing systems under U.S. production conditions, a multi-institute and multi-disciplinary project, known as the Coalition for Sustainable Egg Supply (CSES) study, was carried out at a commercial egg production farm in the Midwestern United States over two single-cycle production flocks. The housing systems studied include a conventional cage house (200,000 hen capacity), an aviary house (50,000 hen capacity), and an enriched colony house (50,000 hen capacity). As an integral part of the CSES project, continual environmental monitoring over a 27-month period described in this paper quantifies indoor gaseous and particulate matter concentrations, thermal environment, and building ventilation rate of each house. Results showed that similar indoor thermal environments in all three houses were maintained through ventilation management and environmental control. Gaseous and particulate matter concentrations of the enriched colony house were comparable with those of the conventional cage house. In comparison, the aviary house had poorer indoor air quality, especially in wintertime, resulting from the presence of floor litter (higher ammonia levels) and hens’ activities (higher particulate matter levels) in it. Specifically, daily mean indoor ammonia concentrations had the 95% confidence interval values of 3.8 to 4.2 (overall mean of 4.0) ppm for the conventional cage house; 6.2 to 7.2 (overall mean of 6.7) ppm for the aviary house; and 2.7 to 3.0 (overall mean of 2.8) ppm for the enriched colony house. The 95% confidence interval (overall mean) values of daily mean indoor carbon dioxide concentrations were 1997 to 2170 (2083) ppm for the conventional cage house, 2367 to 2582 (2475) ppm for the aviary house, and 2124 to 2309 (2216) ppm for the enriched colony house. Daily mean indoor methane concentrations were similar for all three houses, with 95% confidence interval values of 11.1 to 11.9 (overall mean of 11.5) ppm. The 95% confidence interval values (overall mean) of daily mean PM10 and PM2.5 concentrations, in mg/m3, were, respectively, 0.57 to 0.61 (0.59) and 0.033 to 0.037 (0.035) for the conventional cage house, 3.61 to 4.29 (3.95) and 0.374 to 0.446 (0.410) for the aviary house, and 0.42 to 0.46 (0.44) and 0.054 to 0.059 (0.056) for the enriched colony house. Investigation of mitigation practices to improve indoor air quality of the litter-floor aviary housing system is warranted.

Effects of housing system on the costs of commercial egg production

This article reports the first publicly available egg production costs compared across 3 hen-housing systems. We collected detailed data from 2 flock cycles from a commercial egg farm operating a conventional barn, an aviary, and an enriched colony system at the same location. The farm employed the same operational and accounting procedures for each housing system. Results provide clear evidence that egg production costs are much higher for the aviary system than the other 2 housing systems. Feed costs per dozen eggs are somewhat higher for the aviary and lower for the enriched house compared with the conventional house. Labor costs are much lower for the conventional house than the other 2, and pullet costs are much higher for the aviary. Energy and miscellaneous costs are a minimal part of total operating costs and do not differ by housing system. Total capital investments per hen-capacity are much higher for the aviary and the enriched house. Capital costs per dozen eggs depend on assumptions about appropriate interest and depreciation rates. Using the same 10% rate for each housing system shows capital costs per dozen for the aviary and the enriched housing system are much higher than capital costs per dozen for the conventional house. The aviary has average operating costs (feed, labor, pullet, energy, and miscellaneous costs that recur for each flock and vary with egg production) about 23% higher and average total costs about 36% higher compared with the conventional house. The enriched housing system has average operating costs only about 4% higher compared with the conventional house, but average total costs are 13% higher than for the conventional house.

Environmental assessment of three egg production systems — Part II. Ammonia, greenhouse gas, and particulate matter emissions

As an integral part of the Coalition for Sustainable Egg Supply (CSES) Project, this study simultaneously monitored air emissions of 3 commercially operated egg production systems at the house level and associated manure storage over 2 single-cycle flocks (18 to 78 wk of age). The 3 housing systems were 1) a conventional cage house (CC) with a 200,000-hen capacity (6 hens in a cage at a stocking density of 516 cm2/hen), 2) an enriched colony house (EC) with a 50,000-hen capacity (60 hens per colony at a stocking density of 752 cm2/hen), and 3) an aviary house (AV) with a 50,000-hen capacity (at a stocking density of 1253 to 1257 cm2/hen). The 3 hen houses were located on the same farm and were populated with Lohmann white hens of the same age. Indoor environment and house-level gaseous (ammonia [NH3] and greenhouse gasses [GHG], including carbon dioxide [CO2], methane [CH4], and nitrous oxide [N2 O]) and particulate matter (PM10, PM2.5) emissions were monitored continually. Gaseous emissions from the respective manure storage of each housing system were also monitored. Emission rates (ERs) are expressed as emission quantities per hen, per animal unit (AU, 500 kg live BW), and per kilogram of egg output. House-level NH3 ER (g/hen/d) of EC (0.054) was significantly lower than that of CC (0.082) or AV (0.112) (P < 0.05). The house-level CO2 ER (g/hen/d) was lower for CC (68.3) than for EC and AV (74.4 and 74.0, respectively), and the CH4 ER (g/hen/d) was similar for all 3 houses (0.07 to 0.08). The house-level PM ER (mg/hen/d), essentially representing the farm-level PM ER, was significantly higher for AV (PM10 100.3 and PM2.5 8.8) than for CC (PM10 15.7 and PM2.5 0.9) or EC (PM10 15.6 and PM2.5 1.7) (P < 0.05). The farm-level (house plus manure storage) NH3 ER (g/hen/d) was significantly lower for EC (0.16) than for CC (0.29) or AV (0.30) (P < 0.05). As expected, the magnitudes of GHG emissions were rather small for all 3 production systems. Data from this study enable comparative assessment of conventional vs. alternative hen housing systems regarding air emissions and enhance the U.S. national air emissions inventory for farm animal operations.

Impaired spatial working memory after anterior thalamic lesions: recovery with cerebrolysin and enrichment.

Lesions to the anterior thalamic nuclei (ATN) in rats produce robust spatial memory deficits that reflect their influence as part of an extended hippocampal system. Recovery of spatial working memory after ATN lesions was examined using a 30-day administration of the neurotrophin cerebrolysin and/or an enriched housing environment. As expected, ATN lesions in standard-housed rats given saline produced severely impaired reinforced spatial alternation when compared to standard-housed rats with sham lesions. Both cerebrolysin and enrichment substantially improved this working memory deficit, including accuracy on trials that required attention to distal cues for successful performance. The combination of cerebrolysin and enrichment was more effective than either treatment alone when the delay between successive runs in a trial was increased to 40s. Compared to the intact rats, ATN lesions in standard-housed groups produced substantial reduction in c-Fos expression in the retrosplenial cortex, which remained low after cerebrolysin and enrichment treatments. Evidence that multiple treatment strategies restore some memory functions in the current lesion model reinforces the prospect for treatments in human diencephalic amnesia.

Group composition for fattening entire male pigs under enriched housing conditions—Influences on behaviour, injuries and boar taint compounds

In organic farming, the production of pork from entire male pigs seems to be the most promising alternative to castration, as organic animal husbandry aims at high standards of animal welfare and elimination of mutilations. However, previous research on behaviour of entire male pigs was mostly carried out under barren housing conditions and is thus not entirely transferrable to enriched housing conditions. In the present study, we investigated single-sex and mixed-sex groups of entire male pigs and compared them with mixed-sex groups of castrated male pigs under organic housing conditions. On a commercial farm, 362 pigs (average weight 22.7kg, average age 80 days) were assigned to pens with groups of 20 (+1) pigs according to three treatments: single-sex groups with entire males (EE), mixed-sex groups with entire males and females (EF) and mixed-sex groups with castrated males and females (CF). Skin and tail lesions, lameness and the behaviours ‘head knocking/biting’, ‘fighting’ and ‘mounting’ were assessed on five days during the fattening period. Average carcass weight for all sexes was 92kg. After slaughter, female reproductive organs were inspected for signs of pregnancy. Fat samples of entire male pigs were analysed for concentrations of androstenone and skatole. Entire males showed more aggressive and mounting behaviours than castrated males (p<0.001), and no difference was found between entire males from the EE and EF treatments. Welfare of female pigs was not impaired when penned together with entire males compared to when penned together with castrates, neither in terms of skin lesions nor in terms of received aggressive behaviour. Pigs in the EE treatment had higher lesion scores than those in the EF and CF treatments (p<0.05 and p<0.01, respectively), while the two latter treatments did not differ. In the inspected female reproductive organs, no pregnancy could be detected. The concentration of androstenone in fat indicated that the presence or absence of females in a group did not have an effect on the male pigs. Of the 177 slaughtered entire male pigs, only one carcass was classified as containing boar taint by a human nose test. Our findings suggest that under enriched housing conditions, entire males can be kept in single–sex groups as well as in mixed-sex groups with females without compromise in animal welfare.

Aggression and affiliation during social conflict in pigs.

Social conflict is mostly studied in relation to aggression. A more integral approach, including aggressive and affiliative behaviour as well as physiology, may however give a better understanding of the animals' experience during social conflict. The experience of social conflict may also be reflected in the spatial distribution between conspecifics. The objective was to assess the relationship between behaviour, physiology, and spatial integration in pigs (Sus scrofa) during social conflict. Hereto, 64 groups of pigs (9 wk of age) were studied in a 24 h regrouping test whereby pairs of familiar pigs were grouped with 2 unfamiliar pairs, in either barren or straw-enriched housing. Data on aggressive and affiliative behaviour, skin lesions, body weight, and haptoglobin could be summarized into three principal component analysis factors. These three factors were analysed in relation to spatial integration, i.e. inter-individual distances and lying in body contact. Pigs stayed up to 24 h after encounter in closer proximity to the familiar pig than to unfamiliar pigs. Pigs with a high factor 1 score were more inactive, gave little social nosing, had many skin lesions and a high body weight. They tended to space further away from the familiar pig (b = 1.9 cm; P = 0.08) and unfamiliar ones (b = 0.7 cm; P = 0.05). Pigs that were involved in much aggression (factor 2), and that had a strong increase in haptoglobin (factor 3), tended to be relatively most far away from unfamiliar pigs (b = 0.03 times further; P = 0.08). Results on lying in body contact were coherent with results on distances. Pigs in enriched housing spaced further apart than pigs in barren housing (P<0.001). The combined analysis of measures revealed animals that may either promote or slow down group cohesion, which may not have become clear from single parameters. This emphasizes the importance of an integral approach to social conflict.

What is the impact of low testosterone levels on the anatomical and behavioral repertoire of long-term enriched housing of male mice?

Environmental enrichment is a strategy to improve animal welfare, providing brain plasticity with changes at cellular, molecular and behavioral levels. In order to test the long-term effects of enriched housing and the importance of testosterone levels for the expression of behavioral plasticity, 28 categories were assessed in 45 adult Swiss mice, subdivided in prepubertal castrated and non-castrated groups, maintained for seven months as three non-sibling mates. Enrichment consisted of introducing insets for gnawing, climbing and hiding. Tests of spontaneous exploration (barrier), territoriality (intruder) and hierarchical organization (group) were applied at once. Measurements of body weight and the relative weight of key organs were done at the end of the experiment. Mice kept in enriched cages, either castrated or non-castrated, showed more spontaneous exploration than those raised in standard cages. Non-castrated mice housed in structured cages had a lower frequency of attack in the resident-intruder test than the non-castrated standard caged mice, indicating a decrease in territoriality in the first group. Independent of the housing conditions, castrated mice showed reduction of offensive, defensive, and social contacts, as well as low frequency of attack in both agonistic tests. The well-known importance of testes to ensure the expression of aggressive and social contact behaviors was therefore not challenged by the enrichment condition. Behavioral repertoire at the home cage, performance in the group-test, and organometric measurements were not significantly different between the groups kept in enriched and non-enriched cages. Our results suggest that the experience in enriched environment does not increase aggressiveness in their routine in the home-cage nor negatively influence physiological parameters, independently of the testosterone level.

Anterior thalamic lesions reduce spine density in both hippocampal CA1 and retrosplenial cortex, but enrichment rescues CA1 spines only.

Injury to the anterior thalamic nuclei (ATN) may affect both hippocampus and retrosplenial cortex thus explaining some parallels between diencephalic and medial temporal lobe amnesias. We found that standard-housed rats with ATN lesions, compared with standard-housed controls, showed reduced spine density in hippocampal CA1 neurons (basal dendrites, -11.2%; apical dendrites, -9.6%) and in retrospenial granular b cortex (Rgb) neurons (apical dendrites, -20.1%) together with spatial memory deficits on cross maze and radial-arm maze tasks. Additional rats with ATN lesions were also shown to display a severe deficit on spatial working memory in the cross-maze, but subsequent enriched housing ameliorated their performance on both this task and the radial-arm maze. These enriched rats with ATN lesions also showed recovery of both basal and apical CA1 spine density to levels comparable to that of the standard-housed controls, but no recovery of Rgb spine density. Inspection of spine types in the CA1 neurons showed that ATN lesions reduced the density of thin spines and mushroom spines, but not stubby spines; while enrichment promoted recovery of thin spines. Comparison with enriched rats that received pseudo-training, which provided comparable task-related experience, but no explicit spatial memory training, suggested that basal CA1 spine density in particular was associated with spatial learning and memory performance. Distal pathology in terms of reduced integrity of hippocampal and retrosplenial microstructure provides clear support for the influence of the ATN lesions on the extended hippocampal system. The reversal by postoperative enrichment of this deficit in the hippocampus but not the retrosplenial cortex may indicate region-specific mechanisms of recovery after ATN injury.

Enriched Housing Enhances Recovery of Limb Placement Ability and Reduces Aggrecan-Containing Perineuronal Nets in the Rat Somatosensory Cortex after Experimental Stroke

Stroke causes life long disabilities where few therapeutic options are available. Using electrical and magnetic stimulation of the brain and physical rehabilitation, recovery of brain function can be enhanced even late after stroke. Animal models support this notion, and housing rodents in an enriched environment (EE) several days after experimental stroke stimulates lost brain function by multisensory mechanisms. We studied the dynamics of functional recovery of rats with a lesion to the fore and hind limb motor areas induced by photothrombosis (PT), and with subsequent housing in either standard (STD) or EE. In this model, skilled motor function is not significantly enhanced by enriched housing, while the speed of recovery of sensori-motor function substantially improves over the 9-week study period. In particular, this stroke lesion completely obliterates the fore and hind limb placing ability when visual and whisker guidance is prevented, a deficit that persists for up to 9 weeks of recovery, but that is markedly restored within 2 weeks by enriched housing. Enriched housing after stroke also leads to a significant loss of perineuronal net (PNN) immunoreactivity; detection of aggrecan protein backbone with AB1031 antibody was decreased by 13–22%, and labelling of a glycan moiety of aggrecan with Cat-315 antibody was reduced by 25–30% in the peri-infarct area and in the somatosensory cortex, respectively. The majority of these cells are parvalbumin/GABA inhibitory interneurons that are important in sensori-information processing. We conclude that damage to the fore and hind limb motor areas provides a model of loss of limb placing response without visual guidance, a deficit also seen in more than 50% of stroke patients. This loss is amenable to recovery induced by multiple sensory stimulation and correlates with a decrease in aggrecan-containing PNNs around inhibitory interneurons. Modulating the PNN structure after ischemic damage may provide new therapies enhancing tactile/proprioceptive function after stroke.

Enrichment and individual housing reinforce the differences in aggressiveness and amphetamine response in 129S6/SvEv and C57BL/6 strains

As different kinds of enrichment equipment are applied to standard rodent laboratory housing conditions in Europe (Directive 2010/63/EU) and worldwide, it is essential to understand how it may influence the brain and behaviour of animals. We observed common inbred mouse strains 129S6/SvEv/Tac (129) and C57BL/6 Bkl (B6) reared in 3 different environments: standard housing (SH), individual housing (IH) and enriched environment (EE). We measured common behavioural parameters, social behaviour and BDNF mRNA expression in hippocampus and frontal cortex. Our results demonstrate that the robust behavioural differences between B6 and 129 mouse strains which are well studied in the literature persist in varied housing conditions, but the response to these conditions has different directionality in studied strains. EE appears to reinforce the existing coping strategies in both strains: B6 became more agile, sensitive and venturous in behavioural models, whereas 129 became even more inhibited than they are in standard conditions. The stimulating effect of amphetamine is decreased in 129 animals that have been reared in EE. This may indicate desensitisation or inhibition of their dopamine system by EE. A frequently used biomarker in enrichment studies, BDNF, is a likely mediator for the long-term phenotype effects of EE. In this paper we demonstrate the differences of BDNF expression pattern in 129 and B6 mice.

Effects of an enriched housing environment on sensory aspects and fatty-acid composition of the longissimus muscle of light-weight finished lambs

We analysed the effect of enriched housing on the sensory meat quality and fatty acid composition of longissimus muscle in 60 entire Rasa Aragonesa lambs, housed indoors for 5weeks in six pens (10 lambs/pen, 0.95m2/lamb, initial weight 17.13±0.18kg and carcass mean 12.23±0.23kg); three control pens (barren) and three enriched pens (straw, platform with ramps and a small ramp). The final weight, carcass weight, fatness scores and cooking losses of meat from enriched lambs (EG) were higher and pH24 was lower (P≤0.05). The EG lambs had more C18:0 and total SFA (P≤0.05). Lamb odour and grass odour were more intense in EG (P≤0.05). Overall liking was higher for EG (P≤0.05) and associated with tenderness (P≤0.0001). The results suggest that environmental enrichment can have effects on fatty acid composition and sensory meat quality.

Enriched housing down-regulates the Toll-like receptor 2 response in the mouse brain after experimental stroke

Post-ischemic inflammation plays an important role in the evolution of brain injury, recovery and repair after stroke. Housing rodents in an enriched environment provides multisensory stimulation to the brain and enhances functional recovery after experimental stroke, also depressing the release of cytokines and chemokines in the peri-infarct. In order to identify targets for late stroke treatment, we studied the dynamics of inflammation and the contribution of resident Toll-like receptor 2 (TLR2) expressing microglia cells.We took advantage of the biophotonic/bioluminescent imaging technique using the reporter mouse-expressing luciferase and GFP reporter genes under transcriptional control of the murine TLR2 promoter (TLR2-luc/GFP mice) for non-invasive in vivo analysis of TLR2 activation/response in photothrombotic stroke after differential housing.Real-time imaging at 1day after stroke, revealed up-regulation of TLR2 in response to photothrombotic stroke that subsequently declined over time of recovery (14days). The inflammatory response was persistently down-regulated within days of enriched housing, enhancing recovery of lost sensori-motor function in TLR2-luc mice without affecting infarct size. The number of YM1-expressing microglia in the peri-infarct and areas remote from the infarct was also markedly attenuated.Using a live imaging approach, we demonstrate that multisensory stimulation rapidly, persistently and generally attenuates brain inflammation after experimental stroke, reducing the TLR2 response and leading to improved neurological outcome. TLR2-expressing microglia cells may provide targets for new stroke therapeutics.

Effect of enriched housing on welfare, production performance and meat quality in finishing lambs: The use of feeder ramps

This study analyses the effect of environmental enrichment on the welfare, productive traits and meat quality of lambs housed in feedlots. Sixty lambs were placed in enriched (EE) or conventional (CO) pens (3 pens for each treatment, 10lambs/pen) where EE had a wooden platform with ramps that provided access to a concentrate hopper, cereal straw as bedding and forage, and one play ramp. The CO pen was barren, similar to commercial feedlots. The physiological adaptation response of EE lambs was more efficient than CO, since the latter mobilised more body reserves (i.e., increased NEFA, P<0.05), and had lower levels of immunity (i.e., increased N/L, P<0.05), which indicate chronic stress, probably associated with the barren environment. The EE lambs had a higher (P<0.05) average daily gain, with heavier carcasses and higher fattening scores, as well as lower pHult, higher L* and b* values, and lower values of texture (P<0.05).

Environmental enrichment attenuates nicotine behavioral sensitization in male and female rats.

Environmental enrichment decreases nicotine reactivity in male rats, but these effects have not been examined in females. This research was conducted to examine the effects of enrichment on nicotine behavioral sensitization (i.e., nicotine reactivity) in male and female rats. One hundred forty-four Sprague-Dawley rats (72 male, 72 female) were raised in isolation, social enrichment (groups of three rats [SE]), or combined physical enrichment and social enrichment (groups of three rats with novel toys [PESE]) housing conditions. As adults, they received daily subcutaneous injections of saline or nicotine (0.1, 0.5, or 1.0 mg/kg) for 12 days; locomotor activity was measured on drug days 1, 5, 9, and 12. Before drug administration, PESE and SE decreased activity in males; only PESE decreased activity in females, F(2, 120) = 6.51, p < .01. In the drug phase, nicotine behavioral sensitization occurred, F(8.46, 341.04) = 20.71, p < .001, and was greater in females than males, F(8.340, 319.715) = 2.072, p < .05. Enrichment decreased nicotine behavioral sensitization in both sexes, F(16.91, 341.04) = 2.48, p < .01. In conclusion, nicotine behavioral sensitization occurred in male and female rats and was attenuated by environmental enrichment. This research has implications for treatment and prevention strategies in humans. Programs that incorporate aspects of social and environmental stimulation may have enhanced effectiveness in preventing and reducing cigarette smoking and may have implications for relapse prevention.

How Enrichment Affects Exploration Trade-Offs in Rats: Implications for Welfare and Well-Being

We propose that a comparative approach to well-being could be the key to understanding ‘the good life.’ Inspired by current theories of human well-being and animal welfare, we designed a novel test of exploration behavior. Environmentally and socially enriched Long-Evans female rats (N = 60) were trained in four simultaneously presented arms of an eight-arm radial-maze. They learned to expect successes in two arms and failures in the other two. After training, 20 animals remained in enriched housing (enrichment-maintenance) while 40 animals were re-housed in standard, isolated conditions (enrichment-removal). Two weeks later, all animals were re-tested in the maze, initially with access to the four familiar arms only. In the final minute, they also had access to the unfamiliar ambiguous-arms. Though both groups showed significant interest in the ambiguous-arms (P<.0001), the enrichment-maintenance group showed a significantly greater exploratory tendency (P<.01) despite having equivalent levels of activity (P>.3). Thus, we show not only that rats will abandon known rewards and incur risk in order to explore, indicating that exploration is valuable in its own right, but also that individuals with (vs. without) enriched housing conditions are more likely to engage in such exploratory behavior. This novel test contributes to the body of knowledge examining the importance of exploration in humans and other animals; implications for animal welfare and human well-being are discussed.

Comparative lipidomics of mouse brain exposed to enriched environment

Several studies have shown that housing conditions and environmental exposure to a series of stimuli lead to behavior improvement in several species. While more works have been focused on illustrating changes of the proteome and transcriptome following enriched environment exposure in mice, little has been done to understand changes in the brain metabolome in this paradigm due to the complexity of this type of analysis. In this paper, lipidomics focused on phospholipids and gangliosides were conducted for brain tissues of mice exposed to enriched or impoverished conditions. We optimized previously reported method and established a reliable relative comparison method for phospholipids and gangliosides in brain tissue using prefractionation with weak anion exchange cartridge. We used liquid chromatography mass spectrometry to explore metabolic signatures of the cerebral cortex and hippocampus after confirming the animals had significant memory differences using the fear conditioning paradigm and brain immunohistochemistry. Although both cerebral cortex and hippocampus regions did not show major alterations in ganglioside composition, we found significant differences in a series of phospholipids containing 22:6 fatty acid in the prefrontal cortex, indicating that environmental enrichment and impoverished housing conditions might be a relevant paradigm to study aberrant lipid metabolism of docosahexaenoic acid consumption. Our study highlights the hypothesis-generating potential of lipidomics and identifies novel region-specific lipid changes possibly linked not only to change of memory function in these models, but also to help us better understand how lipid changes may contribute to memory disorders.

Effects of Environmental Enrichment on Repetitive Behaviors in the BTBR T+tf/J Mouse Model of Autism

Lower order and higher order repetitive behaviors have been documented in the BTBR T+tf/J (BTBR) mouse strain, a mouse model that exhibits all three core behavioral domains that define autism. The purpose of this study was to evaluate the effectiveness of environmental enrichment for reducing repetitive behaviors in BTBR mice. Lower order behaviors were captured by assaying the time and sequence of grooming, while higher order behaviors were measured using pattern analysis of an object exploration task from digital recordings. Baseline scores were established at 7 weeks of age, followed by 30 days of housing in either a standard or enriched cage. As expected, BTBR mice spent significantly more time grooming and had a more rigid grooming sequence than control C57BL/6J mice did at baseline. After 30 days of enrichment housing, BTBR mice demonstrated a significant reduction in time spent grooming, resulting in levels that were lower than those exhibited by BTBR mice in standard housing. However, no changes were noted in the rigidity of their grooming sequence. In contrast to previous findings, there was no difference in repetitive patterns of exploration at baseline between BTBR and C57BL/6J mice in the object exploration test. Subsequently, enrichment did not significantly alter the number of repetitive patterns at posttest. Overall, the results suggest that environmental enrichment may be beneficial for reducing the time spent engaging in lower order repetitive behaviors, but may not change the overall quality of the behaviors when they do manifest.

Modelling ventilation rate, balance temperature and supplemental heat need in alternative vs. conventional laying-hen housing systems

An Excel-based spreadsheet model has been developed to delineate ventilation rate (VR), supplemental heat need ( H s ), balance temperature ( t bal , outdoor temperature below which H s is required to maintain the desired indoor temperature), energy use and cost for H s in alternative (aviary and enriched colony) vs. conventional cage laying-hen houses. The model was applied to the Midwestern U.S. housing characteristics (same land footprint) and winter weather conditions (−30 °C to 5 °C ambient temperature, and a constant relative humidity or RH of 70%). Effects of hen stocking density, target indoor temperature and RH ( t i , RH i ), building insulation, and light period vs. dark period on VR, t bal and H s were examined. For the housing characteristics considered and target indoor condition of 25 °C and 60% RH, t bal for the alternative housing systems was found to be 2.0–2.6 °C higher than that for the conventional cage counterpart. The supplemental heater capacity would need to be 20.5–22.0 kW per 10,000 hens for the aviary houses (107,000-hen capacity) and 17.6 kW per 10,000 hens for the enriched colony house (124,000-hen capacity). Annual H s was estimated to be 0.09 and 0.12 MJ [kg egg] −1 for the enriched and aviary houses, respectively. The corresponding H s cost (in US dollars) would be, respectively, 0.11 and 0.15 US cent [kg egg] −1 at a wholesale liquid propane (LP) fuel price of $0.32 l −1 ($1.21 gal −1 ) or 0.26 and 0.35 US cent [kg egg] −1 at a retail LP fuel price of $0.75 l −1 ($2.84 gal −1 ). Among all the influencing factors considered, t i and RH i setpoints had more pronounced impacts on t bal and H s . The analysis indicated that H s energy cost for the alternative housing systems in the Midwestern USA is less than 0.3% of the total production cost. The simulation model was validated with measured heating energy use by a commercial aviary house in northern Iowa and the difference between the predicted and field-measured H s values was less than 5%. This interactive model can be readily used for analysis of other laying-hen housing, climatic conditions, and/or management scenarios.

Effects of neonatal castration on social behaviour, human–animal relationship and feeding activity in finishing pigs reared in a conventional or an enriched housing

Raising entire males is already common in a few European countries. It has the advantage of avoiding the pain of castration. Entire males have also a better food conversion. However, they would be more aggressive than castrates which causes welfare troubles. The consequences for human–animal relationship are not clear. We thus wanted to determine the effects of raising entire males in stable groups compared to castrated males on their social behaviour (including agonistic behaviour, non-agonistic behaviour, play, belly-nosing), the human–animal relationship and the feeding behaviour during the fattening period. We also determined the effects of an enrichment of the housing (space, outdoor run, straw) on the same behavioural activities. Eighty males (groups of 10) were studied: 40 castrated (surgically) at 5–6 days of age and 40 left entire, half of each reared in a barren (1m2/animal, slatted floor) and half in an enriched (2.5m2/animal, straw bedding and outdoor run) housing. We observed their social activity by continuous sampling three times a month for 1h from 3 to 5 months of age. We also measured their feeding activity three times a month for 24h. The three observations for a same month were pooled. We evaluated their relationship to humans at 80 and 150 days of age by measuring the manageability (during displacement, saliva collection and weighing) and the reaction to the presence and departure of an unfamiliar human after isolation in a test pen (1m×6m). Entire males expressed more social activities and were more aggressive than castrates only at 3 months of age. They were more attracted by the unfamiliar human but not aggressive towards him, and not more difficult to handle. They expressed a reduced feeding activity. Whatever the gonadal status, pigs from the enriched environment were observed more often playing, were less attracted by an unfamiliar human in a test pen. They were also easier to handle during weighing. Enriching the environment reduced agonistic behaviour of castrates and induced more difficulties to handle castrates during saliva collection, but had no effect on these behaviours in entire males. However, it decreased the feeding activity of entire males. In conclusion, we did not show any strong behavioural negative consequences of rearing entire males in stable groups. Our enrichment did not modulate so much the social behaviour of entire males, but decreased their feeding activity.