No abstract

The single housing of laboratory rats may be recommended in some situations such as hypothesis-driven or test-specific studies, during electroencephalogram recording of phases of sleep and after surgical procedures. However, as single housing of laboratory rats has been shown to be stressful, modification of the housing environment is needed to improve the welfare of these animals. This experiment was carried out to investigate the long-term effects of environmental enrichment on some behavioural, physiological, pathological and psychological measures of welfare. With two batches of animals, 24 rats were housed singly in either enriched cages (EC) (n ¼ 12 cages) or unenriched cages (UC) (n ¼ 12 cages). Behaviour was sampled every week and so was body weight and weight gain over a six-week observation period. Behaviours of the rats in the elevated plus-maze were recorded on the seventh week, whereas organ weights were recorded postmortem. The results revealed that long-term single housing of rats in super-enriched cages increased levels of indicators of good welfare including sleep, exploration, movement and feeding behaviour, body weights, weight gains and the relative weights of the thymus gland and spleen, and decreased levels of indicators of poor welfare such as stationary behaviour and the relative weight of adrenal glands. Thus, enrichment of conventional cages of newly weaned singly-housed laboratory rats with multiple physical structures appeared to improve their ability to control the environment and to promote their species-specific behaviour; changes that can ultimately result in good welfare.

No abstract

Although the effects of monochromatic light on behaviour and performance of birds have been extensively studied, it is not known how rearing Mulard ducks in different monochromatic lights affects their fear reactions, physiological responses to stress and welfare. A total of 108 newly hatched Mulard ducks, representing three replicates, were housed in either blue light (BL), green light (GL), red light (RL) or white light (WL) for 12 weeks. Ducks were exposed to a light/dark schedule of 23 L/1 D, and food and water were provided ad libitum. At the beginning of the 13th week of the rearing period, behavioural measurements of fear were assessed by using a tonic immobility test, open field test and fear of man test. Physiological responses of the birds to stress such as heterophil : lymphocyte ratio, total leukocyte count and plasma concentrations of corticosterone were also assessed. Results demonstrated that birds exposed to both RL and WL displayed higher levels of behavioural indicators of fear including tonic immobility durations (P < 0.01), latency to first immobilisation (P < 0.001) and avoidance of man index (P < 0.001), and higher levels of physiological indicators of stress such as heterophil : lymphocyte ratios (P < 0.001) and plasmas concentrations of corticosterone (P < 0.001), and lower total leukocytic counts (P < 0.01) compared with birds exposed to either BL or GL. Rearing Mulard ducks in BL or GL appeared to reduce their fear reactions and physiological responses to stress and to enhance their ability to cope with the environment and may therefore improve their welfare.

No abstract

No abstract

No abstract

). Tel. 002 (0)162557996Fax. 002 (0)502379952 Highlights  The study examined whether effects of environmental enrichment are due to novelty or complexity.  Behavioural, performance and pathological indicators of welfare were used.  The effects of enrichment are mainly due to complexity of the cages by multiple items.  The type of environmental enrichment protocol affects welfare of laboratory rats. AbstractAlthough experimental work on environmental enrichment has answered many important questions, it is not yet known whether beneficial effects of enrichment are more strongly influenced by regular provision of novel objects, or by the diversity of objects present at any one time. In a five-replicate study, 80 newly weaned male Wistar rats were housed in groups of four in: a 'novelty' condition (NC) in which five copies of the same object were provided in the home cage during the first week of the study followed by five copies of a different, novel, object over each of the next 4 weeks; a 'complexity' condition (CC) in which one example of each of the five objects used in NC was always present in the cage across the 5-week study period. Behaviour was collected in two 2-hrs sessions every week, once during the light phase of the light/dark cycle and once during the dark phase. Body weight and weight gain were measured over the five weeks and organ weights were recorded postmortem. Rats in the CC displayed elevated levels of measures suggestive of improved welfare such as sleep, enrichment-directed behaviour, enrichment contact, weight gain and relative thymus weight, and decreased levels of indicators denoting poor welfare including aggression, awake-non active and audible vocalizations. It appears that CC may have the potential to increase the frequency and diversity of behaviours, to express different types of behaviour when desired, and to augment the ability of the animals to exert some control over their environment, findings that may improve their welfare. Provision of novelty per se in the absence of diversity of objects at any one time seems to be less beneficial. Order (replicate) effects in the NC group indicated that responses of the animals towards the enrichment regimen appeared to depend on the type of object supplied, thus drawing attention to the importance of object characteristics when designing enrichment protocols for laboratory animals.