66 research outputs found
Behavioural stress responses predict environmental perception in European sea bass (Dicentrarchus labrax)
Individual variation in the response to environmental challenges depends partly on innate reaction norms, partly on experience-based cognitive/emotional evaluations that individuals make of the situation. The goal of this study was to investigate whether pre-existing differences in behaviour predict the outcome of such assessment of environmental cues, using a conditioned place preference/avoidance (CPP/CPA) paradigm. A comparative vertebrate model (European sea bass, Dicentrarchus labrax) was used, and ninety juvenile individuals were initially screened for behavioural reactivity using a net restraining test. Thereafter each individual was tested in a choice tank using net chasing as aversive stimulus or exposure to familiar conspecifics as appetitive stimulus in the preferred or non preferred side respectively (called hereafter stimulation side). Locomotor behaviour (i.e. time spent, distance travelled and swimming speed in each tank side) of each individual was recorded and analysed with video software. The results showed that fish which were previously exposed to appetitive stimulus increased significantly the time spent on the stimulation side, while aversive stimulus led to a strong decrease in time spent on the stimulation side. Moreover, this study showed clearly that proactive fish were characterised by a stronger preference for the social stimulus and when placed in a putative aversive environment showed a lower physiological stress responses than reactive fish. In conclusion, this study showed for the first time in sea bass, that the CPP/CPA paradigm can be used to assess the valence (positive vs. negative) that fish attribute to different stimuli and that individual behavioural traits is predictive of how stimuli are perceived and thus of the magnitude of preference or avoidance behaviour.European Commission [265957]; Portuguese Fundacao para a Ciencia e Tecnologia (FCT) [FRH/BPD/72952/2010]; FCT [SFRH/BD/80029/2011
Linking Fearfulness and Coping Styles in Fish
Consistent individual differences in cognitive appraisal and emotional reactivity, including fearfulness, are important personality traits in humans, non-human mammals, and birds. Comparative studies on teleost fishes support the existence of coping styles and behavioral syndromes also in poikilothermic animals. The functionalist approach to emotions hold that emotions have evolved to ensure appropriate behavioral responses to dangerous or rewarding stimuli. Little information is however available on how evolutionary widespread these putative links between personality and the expression of emotional or affective states such as fear are. Here we disclose that individual variation in coping style predicts fear responses in Nile tilapia Oreochromis niloticus, using the principle of avoidance learning. Fish previously screened for coping style were given the possibility to escape a signalled aversive stimulus. Fearful individuals showed a range of typically reactive traits such as slow recovery of feed intake in a novel environment, neophobia, and high post-stress cortisol levels. Hence, emotional reactivity and appraisal would appear to be an essential component of animal personality in species distributed throughout the vertebrate subphylum
Evoked potentials in the Atlantic cod following putatively innocuous and putatively noxious electrical stimulation: a minimally invasive approach
Aspects of peripheral and central nociception
have previously been studied through recording of
somatosensory evoked potentials (SEPs) to putative
noxious stimuli in specific brain regions in a few
freshwater fish species. In the present study, we
describe a novel, minimally invasive method for
recording SEPs from the central nervous system of the
Atlantic cod (Gadus morhua). Cutaneous electric
stimulation of the tail in 15 fish elicited SEPs at all
stimulus intensities (2, 5, 10 and 20 mA) with
quantitative properties corresponding to stimulus
intensity. In contrast to previous fish studies, the
methodological approach used in Atlantic cod in the
current study uncovered a number of additional
responses that could originate from multiple brain
regions. Several of these responses were specific to
stimulation at the highest stimulus intensities, possibly
representing qualitative differences in central processing
between somatosensory and nociceptive stimuli
Effects of putative stressors in public aquaria on locomotor activity, metabolic rate and cortisol levels in the Mozambique tilapia Oreochromis mossambicus
Mozambique tilapia Oreochromis mossambicus were housed individually during 7 days in
a continuous flow-trough respirometry system and daily exposed to one of three treatments: (1)
a series of knocks on the side of the aquarium, (2) a series of photo-flashes and (3) control
group. Exposure to photo-flashes did not change locomotor activity but decreased both nighttime
and daytime oxygen consumption throughout the experiment. Knocking induced a shortlived
increase in locomotor activity and tended to increase oxygen consumption, but this latter
effect was not significant. Night-time oxygen consumption was not affected by knocking
exposure. Cortisol levels assayed from fish-holding water collected at the end of the experiment
were significantly lower in subjects exposed to photo-flashes than in subjects exposed to knocks
or controls. Males did not respond differently than females to the treatments in any of the
measurements taken. In summary, the data reported here suggest that exposure to repetitive
photo-flashes, but not knocking, suppressed normal energy metabolism and cortisol levels.
These effects were present hours to a half day after exposure to the flashes
Effects of putative stressors in public aquaria on locomotor activity, metabolic rate and cortisol levels in the Mozambique tilapia Oreochromis mossambicus
Behavioural indicators of welfare in farmed fish
Behaviour represents a reaction to the environment as fish perceive it and is therefore a key element of fish welfare. This review summarises the main findings on how behavioural changes have been used to assess welfare in farmed fish, using both functional and feeling-based approaches. Changes in foraging behaviour, ventilatory activity, aggression, individual and group swimming behaviour, stereotypic and abnormal behaviour have been linked with acute and chronic stressors in aquaculture and can therefore be regarded as likely indicators of poor welfare. On the contrary, measurements of exploratory behaviour, feed anticipatory activity and reward-related operant behaviour are beginning to be considered as indicators of positive emotions and welfare in fish. Despite the lack of scientific agreement about the existence of sentience in fish, the possibility that they are capable of both positive and negative emotions may contribute to the development of new strategies (e. g. environmental enrichment) to promote good welfare. Numerous studies that use behavioural indicators of welfare show that behavioural changes can be interpreted as either good or poor welfare depending on the fish species. It is therefore essential to understand the species-specific biology before drawing any conclusions in relation to welfare. In addition, different individuals within the same species may exhibit divergent coping strategies towards stressors, and what is tolerated by some individuals may be detrimental to others. Therefore, the assessment of welfare in a few individuals may not represent the average welfare of a group and vice versa. This underlines the need to develop on-farm, operational behavioural welfare indicators that can be easily used to assess not only the individual welfare but also the welfare of the whole group (e. g. spatial distribution). With the ongoing development of video technology and image processing, the on-farm surveillance of behaviour may in the near future represent a low-cost, noninvasive tool to assess the welfare of farmed fish.Fundação para a Ciência e Tecnologia, Portugal [SFRH/BPD/42015/2007]info:eu-repo/semantics/publishedVersio
Effect of photoperiod stress assessment and locomotor activity of female lambari (Astyanax bimaculatu)
Evolutionary aspects of self- and world consciousness in vertebrates
Although most aspects of world and self-consciousness are inherently subjective, neuroscience studies in humans and non-human animals provide correlational and causative indices of specific links between brain activity and representation of the self and the world. In this article we review neuroanatomic, neurophysiological and neuropsychological data supporting the hypothesis that different levels of self and world representation in vertebrates rely upon (i) a \u201cbasal\u201d subcortical system that includes brainstem, hypothalamus and central thalamic nuclei and that may underpin the primary (or anoetic) consciousness likely present in all vertebrates; and (ii) a forebrain system that include the medial and lateral structures of the cerebral hemispheres and may sustain the most sophisticated forms of consciousness [e.g., noetic (knowledge based) and autonoetic, reflective knowledge]. We posit a mutual, bidirectional functional influence between these two major brain circuits. We conclude that basic aspects of consciousness like primary self and core self (based on anoetic and noetic consciousness) are present in many species of vertebrates and that, even self-consciousness (autonoetic consciousness) does not seem to be a prerogative of humans and of some non-human primates but may, to a certain extent, be present in some other mammals and bird
The role of predictability in the stress response of a cichlid fish
In recent years there has been an increasing interest in the cognitive abilities of fish with implications for
animal welfare and management of rearing operations. Although it is known that psychological factors can
modulate the stress response in mammals, this aspect has seldom been investigated within stress in fish. In
this study we investigate whether the perception (appraisal) that fish make of significant environmental
events modifies their behavioural and physiological response. For this purpose we have used a predictable vs.
unpredictable paradigm for positive (feeding) and negative (confinement) events using the cichlid fish
Oreochromis mossambicus as a model species.
Results show that there is a differential effect of predictability for the feeding and confinement events. In the
confinement experiment, predictability involved more attention to the visual cue and lower cortisol. The
feeding event triggered higher levels of anticipatory behaviour and a tendency for higher cortisol in the
predictable group. Therefore, predictable negative events reduce the cortisol response. Predictable positive
events may elicit an anticipatory response, and when there is a significant delay between the visual cue and
the actual occurrence of the event, it may also contain elements that can be interpreted as a stress response.
These findings demonstrate that fish can appraise relevant aspects of the environment, with welfare
implications for housing, husbandry and experimental procedures
Fish Intelligence, Sentience and Ethics
Fish are one of the most highly utilised vertebrate taxa by humans; they are harvested from wild stocks as part of global fishing industries, grown under intensive aquaculture conditions, are the most common pet and are widely used for scientific research. But fish are seldom afforded the same level of compassion or welfare as warm-blooded vertebrates. Part of the problem is the large gap between people’s perception of fish intelligence and the scientific reality. This is an important issue because public perception guides government policy. The perception of an animal’s intelligence often drives our decision whether or not to include them in our moral circle. From a welfare perspective, most researchers would suggest that if an animal is sentient, then it can most likely suffer and should therefore be offered some form of formal protection. There has been a debate about fish welfare for decades which centres on the question of whether they are sentient or conscious. The implications for affording the same level of protection to fish as other vertebrates are great, not least because of fishing-related industries. Here, I review the current state of knowledge of fish cognition starting with their sensory perception and moving on to cognition. The review reveals that fish perception and cognitive abilities often match or exceed other vertebrates. A review of the evidence for pain perception strongly suggests that fish experience pain in a manner similar to the rest of the vertebrates. Although scientists cannot provide a definitive answer on the level of consciousness for any nonhuman vertebrate, the extensive evidence of fish behavioural and cognitive sophistication and pain perception suggests that best practice would be to lend fish the same level of protection as any other vertebrate
- …