Browsing by Author "Millot, Sandie"
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- Are coping styles consistent in the teleost fish Sparus aurata through sexual maturation and sex reversal?Publication . Castanheira, Maria Filipa; Martinez Paramo, S.; Figueiredo, F.; Cerqueira, Marco; Millot, Sandie; Oliveira, Catarina C. V.; Martins, Catarina I. M.; Conceicao, Luis E. C.Individual differences in behaviour and physiological responses to stress are associated with evolutionary adaptive variation and thus raw material for evolution. In farmed animals, the interest in consistent trait associations, i.e. coping styles, has increased dramatically over the last years. However, one of limitations of the available knowledge, regarding the temporal consistency, is that it refers always to short-term consistency (usually few weeks). The present study used an escape response during a net restraining test, previously shown to be an indicative of coping styles in seabream, to investigate long-term consistency of coping styles both over time and during different life history stages. Results showed both short-term (14 days) consistency and long-term (8 months) consistency of escape response. However, we did not found consistency in the same behaviour after sexual maturation when the restraining test was repeated 16, 22 and 23 months after the first test was performed. In conclusion, this study showed consistent behaviour traits in seabream when juveniles, and a loss of this behavioural traits when adults. Therefore, these results underline that adding a life story approach to data interpretation as an essential step forward towards coping styles foreground. Furthermore, a fine-tuning of aquaculture rearing strategies to adapt to different coping strategies may need to be adjusted differently at early stages of development and adults to improve the welfare of farmed fish.
- Are personality traits consistent in fish? The influence of social contextPublication . Castanheira, Maria Filipa; Cerqueira, Marco; Millot, Sandie; Gonçalves, Rui A.; Oliveira, Catarina C. V.; Conceição, Luis E. C.; Martins, Catarina I. M.Individual differences in behavioural and physiological responses to challenges are progressively accepted as adaptive variation and reveal a strong degree of evolutionary conservation throughout the vertebrate taxa. Previous studies in gilthead seabream (Sparus aurata) suggested that individual differences in behaviour reflect distinct coping styles or personality, contrasting consistent traits associations. One of the traits that have been shown to be consistent over time and across context is the escape response under a restraining test. Using this trait as a proxy of personality in seabream the influence of social context in the consistency of escape behaviour was investigated. Individually tagged juvenile seabream (n = 360; 70.18 +/- 11.44 g; mean +/- SD) were subjected to a restraining test that consisted of keeping each fish in an emerged net for one minute. Behaviours measured in the net (latency to escape; number of escape attempts and total time spent on escaping) were collapsed into first principal component scores using Principal Components Analysis (PCA). Using the PCA scores the individuals were distributed into homogeneous groups (n = 30 each group) of proactive, reactive and intermediate. Control groups consisted of mixed groups with 1/3 of each coping style. After one month the same individuals were exposed to the same test (restraining test) to assess consistency of behavioural responses. Results indicate that homogenous groups of proactive (p = 0.086) and reactive (p = 0.159) individuals did not exhibit consistent behavioural responses as opposed to the intermediate (p = 0.028) and control groups (p < 0.001). This study thus confirms that the social context in which fish are kept significantly influence personality traits. (C) 2016 Elsevier B.V. All rights reserved.
- Behavioural stress responses predict environmental perception in European sea bass (Dicentrarchus labrax)Publication . Millot, Sandie; Cerqueira, Marco; Castanheira, Maria Filipa; Overli, Oyvind; Oliveira, Rui F.; Martins, Catarina I. M.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.
- Coping styles in farmed fish: consequences for aquaculturePublication . Castanheira, Maria Filipa; Conceicao, Luis; Millot, Sandie; Rey, Sonia; Begout, Marie-Laure; Damsgard, Borge; Kristiansen, Tore; Hoglund, Erik; Overli, Oyvind; Martins, CatarinaIndividual differences in physiological and behavioural responses to stressors are increasingly recognised as adaptive variation and thus raw material for evolution and fish farming improvements including selective breeding. Such individual variation has been evolutionarily conserved and is present in all vertebrate taxa including fish. In farmed animals, the interest in consistent trait associations, that is coping styles, has increased dramatically over the last years because many studies have demonstrated links to performance traits, health and disease susceptibility and welfare. This study will review (i) the main behavioural, neuroendocrine, cognitive and emotional differences between reactive and proactive coping styles in farmed fish; (ii) the methodological approaches used to identify coping styles in farmed fish, including individual (group) mass-screening tests; and (iii) how knowledge on coping styles may contribute to improved sustainability of the aquaculture industry, including welfare and performance of farmed fish. Moreover, we will suggest areas for future research, where genetic basis (heritability/epigene tic) of coping styles, and the neuroendocrine mechanisms behind consistent as well as flexible behavioural patterns are pinpointed as central themes. In addition, the ontogeny of coping styles and the influence of age, social context and environmental change in coping styles will also be discussed.
- Stressor controllability modulates the stress response in fishPublication . Cerqueira, Marco; Millot, Sandie; Silva, Tomé; Félix, Ana S.; Castanheira, Maria Filipa; Rey, Sonia; MacKenzie, Simon; Oliveira, Gonçalo A.; Oliveira, Catarina; Oliveira, Rui F.Background In humans the stress response is known to be modulated to a great extent by psychological factors, particularly by the predictability and the perceived control that the subject has of the stressor. This psychological dimension of the stress response has also been demonstrated in animals phylogenetically closer to humans (i.e. mammals). However, its occurrence in fish, which represent a divergent vertebrate evolutionary lineage from that of mammals, has not been established yet, and, if present, would indicate a deep evolutionary origin of these mechanisms across vertebrates. Moreover, the fact that psychological modulation of stress is implemented in mammals by a brain cortical top-down inhibitory control over subcortical stress-responsive structures, and the absence of a brain cortex in fish, has been used as an argument against the possibility of psychological stress in fish, with implications for the assessment of fish sentience and welfare. Here, we have investigated the occurrence of psychological stress in fish by assessing how stressor controllability modulates the stress response in European seabass (Dicentrarchus labrax). Results Fish were exposed to either a controllable or an uncontrollable stressor (i.e. possibility or impossibility to escape a signaled stressor). The effect of loss of control (possibility to escape followed by impossibility to escape) was also assessed. Both behavioral and circulating cortisol data indicates that the perception of control reduces the response to the stressor, when compared to the uncontrollable situation. Losing control had the most detrimental effect. The brain activity of the teleost homologues to the sensory cortex (Dld) and hippocampus (Dlv) parallels the uncontrolled and loss of control stressors, respectively, whereas the activity of the lateral septum (Vv) homologue responds in different ways depending on the gene marker of brain activity used. Conclusions These results suggest the psychological modulation of the stress response to be evolutionary conserved across vertebrates, despite being implemented by different brain circuits in mammals (pre-frontal cortex) and fish (Dld-Dlv).