Search

Carry-over effects describe the phenomenon whereby an animal's previous conditions influence its subsequent performance. Carry-over effects are unlikely to affect individuals uniformly, but the factors modulating their strength are poorly known. Variation in the strength of carry-over effects may reflect individual differences in pace-of-life: slow-paced, shyly behaved individuals are thought to favour an allocation to self-maintenance over current reproduction, compared to their fast-paced, boldly behaved conspecifics (the pace-of-life syndrome hypothesis). Therefore, detectable carry-over effects on breeding should be weaker in bolder individuals, as they should maintain an allocation to reproduction irrespective of previous conditions, while shy individuals should experience stronger carry-over effects. We tested this prediction in black-legged kittiwakes breeding in Svalbard. Using miniature biologging devices, we measured non-breeding activity of kittiwakes and monitored their subsequent breeding performance. We report a number of negative carry-over effects of non-breeding activity on breeding, which were generally stronger in shyer individuals: more active winters were followed by later breeding phenology and poorer breeding performance in shy birds, but these effects were weaker or undetected in bolder individuals. Our study quantifies individual variability in the strength of carry-over effects on breeding and provides a mechanism explaining widespread differences in individual reproductive success.

Background: Zebrafish (Danio rerio) are an increasingly popular model species within a variety of biomedical and neurobiological contexts. Researchers are required to prevent any negative states, such as pain, when using experimental animals to optimise fish welfare but analysis tools for zebrafish are lacking., New Method: The chromatic fish analyser (CFA) is a computer-based monitoring system that has the potential to identify changes in fish behaviour via spatial chromatic analysis of video images. The CFA was used to monitor the behaviour of groups of six fish, where none, one, three or six fish were given a fin clip. Additionally a drug with pain-relieving properties, lidocaine, was administered to determine if this ameliorated any alterations in behaviour. The CFA measured hue horizontally and vertically reflecting the position of the fish in their tank. Saturation (indicates clustering distribution) and lightness were measured to reflect overall zebrafish activity., Results: Changes in vertical hue demonstrated that all fin clipped animals were closer to the bottom of the tank relative to pre-treatment; this was not observed in control groups, and was alleviated in those treated with lidocaine. Saturation (clustering) and lightness alterations indicated fin clipped groups reduced activity after receiving the fin clip. Lidocaine was effective in preventing the behavioural changes when 1 or 3 fish were clipped., Conclusions: The CFA proved powerful enough to identify significant changes in behaviour taken directly from video images. With further development this monitoring tool represents a step forward in detecting behavioural changes in groups of zebrafish indicating welfare., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Fish are used in a variety of experimental contexts often in high numbers. To maintain their welfare and ensure valid results during invasive procedures it is vital that we can detect subtle changes in behaviour that may allow us to intervene to provide pain-relief. Therefore, an automated method, the Fish Behaviour Index (FBI), was devised and used for testing the impact of laboratory procedures and efficacy of analgesic drugs in the model species, the zebrafish. Cameras with tracking software were used to visually track and quantify female zebrafish behaviour in real time after a number of laboratory procedures including fin clipping, PIT tagging, and nociceptor excitation via injection of acetic acid subcutaneously. The FBI was derived from activity and distance swum measured before and after these procedures compared with control and sham groups. Further, the efficacy of a range of drugs with analgesic properties to identify efficacy of these agents was explored. Lidocaine (5 mg/L), flunixin (8 mg/L) and morphine (48 mg/L) prevented the associated reduction in activity and distance swum after fin clipping. From an ethical perspective, the FBI represents a significant refinement in the use of zebrafish and could be adopted across a wide range of biological disciplines.

Both adult and larval zebrafish have been demonstrated to show behavioural responses to noxious stimulation but also to potentially stress- and fear or anxiety- eliciting situations. The pain or nociceptive response can be altered and modulated by these situations in adult fish through a mechanism called stress-induced analgesia. However, this phenomenon has not been described in larval fish yet. Therefore, this study explores the behavioural changes in larval zebrafish after noxious stimulation and exposure to challenges that can trigger a stress, fear or anxiety reaction. Five-day post fertilization zebrafish were exposed to either a stressor (air emersion), a predatory fear cue (alarm substance) or an anxiogenic (caffeine) alone or prior to immersion in acetic acid 0.1%. Pre- and post-stimulation behaviour (swimming velocity and time spent active) was recorded using a novel tracking software in 25 fish at once. Results show that larvae reduced both velocity and activity after exposure to the air emersion and alarm substance challenges and that these changes were attenuated using etomidate and diazepam, respectively. Exposure to acetic acid decreased velocity and activity as well, whereas air emersion and alarm substance inhibited these responses, showing no differences between pre- and post-stimulation. Therefore, we hypothesize that an antinociceptive mechanism, activated by stress and/or fear, occur in 5dpf zebrafish, which could have prevented the larvae to display the characteristic responses to pain.

Research has recently demonstrated that larval zebrafish show similar molecular responses to nociception to those of adults. Our study explored whether unprotected larval zebrafish exhibited altered behaviour after exposure to noxious chemicals and screened a range of analgesic drugs to determine their efficacy to reduce these responses. This approach aimed to validate larval zebrafish as a reliable replacement for adults as well as providing a high-throughput means of analysing behavioural responses. Zebrafish at 5 days post-fertilization were exposed to known noxious stimuli: acetic acid (0.01%, 0.1% and 0.25%) and citric acid (0.1%, 1% and 5%). The behavioural response of each was recorded and analysed using novel tracking software that measures time spent active in 25 larvae at one time. Subsequently, the efficacy of aspirin, lidocaine, morphine and flunixin as analgesics after exposure to 0.1% acetic acid was tested. Larvae exposed to 0.1% and 0.25% acetic acid spent less time active, whereas those exposed to 0.01% acetic acid and 0.1-5% citric acid showed an increase in swimming activity. Administration of 2.5 mg l -1 aspirin, 5 mg l -1 lidocaine and 48 mg l -1 morphine prevented the behavioural changes induced by acetic acid. These results suggest that larvae respond to a noxious challenge in a similar way to adult zebrafish and other vertebrates and that the effect of nociception on activity can be ameliorated by using analgesics. Therefore, adopting larval zebrafish could represent a direct replacement of a protected adult fish with a non-protected form in pain- and nociception-related research., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2017. Published by The Company of Biologists Ltd.)

We review the evidence for a link between consistent among-individual variation in behaviour (animal personality) and the ability to win contests over limited resources. Explorative and bold behaviours often covary with contest behaviour and outcome, although there is evidence that the structure of these 'behavioural syndromes' can change across situations. Aggression itself is typically repeatable, but also subject to high within-individual variation as a consequence of plastic responses to previous fight outcomes and opponent traits. Common proximate mechanisms (gene expression, endocrine control and metabolic rates) may underpin variation in both contest behaviour and general personality traits. Given the theoretical links between the evolution of fighting and of personality, we suggest that longitudinal studies of contest behaviour, combining behavioural and physiological data, would be a useful context for the study of animal personalities., (© 2015 The Author(s) Published by the Royal Society. All rights reserved.)

In the present study, our aim was to compare physiological and behavioural responses to different noxious stimuli to those of a standardized innocuous stimulus, to possibly identify aversive responses indicative of injury detection in a commercially important marine teleost fish, the Atlantic cod. Individual fish were administered with a noxious stimulus to the lip under short-term general anaesthesia (MS-222). The noxious treatments included injection of 0.1% or 2% acetic acid, 0.005% or 0.1% capsaicin, or piercing the lip with a commercial fishing hook. Counts of opercular beat rate (OBR) at 10, 30, 60, 90 and 120 min and observations of behaviour at 30 and 90 min post-treatment were compared with pre-treatment values and with control fish injected with physiological saline, an innocuous stimulus. Circulatory levels of physiological stress indicators were determined in all fish at 120 minutes post-treatment. All treatments evoked temporarily increased OBR that returned to pre-treatment levels at 60 minutes (saline, 0.005% capsaicin, hook), 90 minutes (0.1% acetic acid, 0.1% capsaicin), or 120 minutes (2% acetic acid), but with no significant differences from the control group at any time point. Fish treated with 0.1% and 2% acetic acid and 0.1% capsaicin displayed increased hovering close to the bottom of the aquaria and fish given 2% acetic acid and 0.1% capsaicin also displayed a reduced use of shelter. The only effect seen in hooked fish was brief episodes of lateral head shaking which were not seen pre-treatment or in the other groups, possibly reflecting a resiliency to tissue damage in the mouth area related to the tough nature of the Atlantic cod diet. There were no differences between groups in circulatory stress indicators two hours after treatment. This study provides novel data on behavioural indicators that could be used to assess potentially aversive events in Atlantic cod.

Bold, risk-taking animals have previously been putatively linked with a proactive stress coping style whereas it is suggested shyer, risk-averse animals exhibit a reactive coping style. The aim of this study was to investigate whether differences in the expression of bold-type behaviour were evident within and between two lines of rainbow trout, Oncorhynchus mykiss, selectively bred for a low (LR) or high (HR) endocrine response to stress, and to link boldness and stress responsiveness with the expression of related candidate genes. Boldness was determined in individual fish over two trials by measuring the latency to approach a novel object. Differences in plasma cortisol concentrations and the expression of eight novel candidate genes previously identified as being linked with divergent behaviours or stress were determined. Bold and shy individuals, approaching the object within 180 s or not approaching within 300 s respectively, were evident within each line, and this was linked with activity levels in the HR line. Post-stress plasma cortisol concentrations were significantly greater in the HR line compared with the LR line, and six of the eight tested genes were upregulated in the brains of LR fish compared with HR fish. However, no direct relationship between boldness and either stress responsiveness or gene expression was found, although clear differences in stress physiology and, for the first time, gene expression could be identified between the lines. This lack of correlation between physiological and molecular responses and behavioural variation within both lines highlights the complexity of the behavioural-physiological complex., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Recent evidence has shown that fish display aversive behavioral and physiological reactions and a suspension of normal behavior in response to noxious stimuli that cause pain in other animals and humans. In addition to these behavioral responses, scientists have identified a peripheral nociceptive system and recorded specific changes in the brain activity of fish during noxious stimulation. As a result of these observations teleost fish are now considered capable of nociception and, in some opinions, pain perception. From both an experimental and an ethical perspective, it is important that scientists be able to assess possible pain and minimize discomfort that may result from invasive or other noxious procedures. If scientists accept that the definition of pain in animals cannot include direct measurement of subjective experience (the standard for humans), then fish fulfill the criteria for animal pain. In this review, recent evidence for pain is discussed in terms of the physiological properties of nociceptors, central responses to noxious stimulation, and changes in behavior and physiology that are indicative of nociception and are responsive to analgesia. To enable the assessment of potential pain, there are descriptions of newly identified robust indicators and species-specific responses that are easily measurable. The article concludes with a discussion of humane endpoints and of the need for alleviation of pain through the use of analgesia and anesthesia.

Theoreticians predict that animal 'personality' traits may be maladaptive if fixed throughout different contexts, so the present study aimed to test whether these traits are fixed or plastic. Rainbow trout (Onchorhyncus mykiss) were given emboldening or negative experiences in the forms of watching bold or shy individuals responding to novelty or winning or losing fights to examine whether prior experience affected boldness. Bold individuals that lost fights or watched shy demonstrators became more shy by increasing their latency to approach a novel object, whereas shy observers that watched bold demonstrators remained cautious and did not modify their responses to novelty. Shy winners became bolder and decreased their latency to approach a novel object, but shy losers also displayed this shift. In comparison, control groups showed no change in behaviour. Bold fishes given negative experiences reduced their boldness which may be an adaptive response; however, shy fishes may base their strategic decisions upon self-assessment of their relative competitive ability and increase their boldness in situations where getting to resources more quickly ensures they outcompete better competitors.

Microarrays, or gene chips, are transforming the way that gene expression is measured by allowing us to determine the expression of thousands of genes from a sample. This gives immense power to examine gene expression on a global scale within individual animals and between animals. The scope for analysing complex animal functions at the molecular level is within our grasp. Relatively few studies have examined complex behaviours and correlated them with gene expression in the central nervous system. Here, we review the use of microarray technology in the dissection of behaviour and focus specifically on dominance status. A cDNA library using suppression subtraction hybridisation on rainbow trout Oncorhynchus mykiss of differing status has been produced to enrich the cDNA library for genes that are differentially expressed between individuals of different dominance status. A preliminary analysis demonstrated that there were 1,165 genes that differed between fish of different dominance status. Therefore, there is the potential of correlating gene expression profile with rank position within dominance hierarchies, thus identifying targets for candidate gene approaches.