The personality axis ‘exploration-avoidance’ is often measured using an open field test (OFT) from which measurements such as mobility level (e.g. distance travelled) and space use (e.g. area ...covered) in an unknown environment are extracted. Recently developed tracking software surprisingly includes only a measure of mobility level in their output summary. Consequently, recent articles using these software programs started to ignore a measure of space use in their determination of exploration. In this short communication, we show briefly why it is important to not overlook a measure of space use, provide an easy way to calculate such a measure, with adjustable resolution, from the available position data provided by the software and a method to determine a proxy for exploration.
•The personality trait ‘exploration’ is commonly measured using an open field test•‘Distance travelled’ and ‘area covered’ are two measures influencing exploration•Tracking software only provides distance travelled in their summary statistics•A way to calculate ‘area covered’ from position data from the software is presented
La pandémie a installé les objets technologiques dans nos vies, les rendant indispensables. Le pouvoir qu’ils nous confèrent crée une certaine hubris qui réveille en nous le sentiment de la ...toute-puissance infantile. À partir de là, l’auteur convoque deux auteurs qui développent deux positions complètement opposées sur le virtuel et ses vertus. Le premier parle de mutation anthropologique contemporaine et voit dans la cyberculture un processus d’hominisation qui éclaire le développement de l’histoire humaine. Le second voit dans la société de communication dans laquelle nous vivons une lourde menace qui pèse sur la parole vivante.
Behavioural traits have been shown to have implications in fish welfare and growth performances in aquaculture. If several studies have demonstrated the existence of repeatable and heritable ...behavioural traits (i.e., animal personality), the methodology to assess personality in fishes is often carried out in solitary context, which appears to somewhat limit their use from a selective breeding perspective because these tests are too time consuming. To address this drawback, group-based tests have been developed. In Nordic country, Arctic charr (Salvelinus alpinus) is widely used in aquaculture, but no selection effort on behavioural traits has yet been carried out. Specifically, in this study we examined if risk-taking behaviour was repeatable and correlated in group and solitary context and if the early influences of physical environment affect the among-individual variation of behavioural trait across time in order to verify whether a group risk-taking test could be used as a selective breeding tool. Here, we found that in both contexts and treatments, the risk-taking behaviour was repeatable across 7 days. However, no cross-context consistency was found between group and solitary, which indicates that individual Arctic charr express different behavioural trait in group and solitary.
•Risk-taking behaviour was assessed in the Arctic charr.•Fish were raised in plain versus enriched environments.•Risk-taking were tested in solitary versus group contexts.•Risk-taking behaviour was repeatable across 7 days in both contexts.•No consistency was found between the solitaryand groupcontexts.
Personality is now recognized as an ecologically and evolutionarily significant phenomenon because it can affect fitness directly. However, empirical studies specifically tackling the importance of ...personality in the processes of adaptive divergence and speciation are scarce. Whether selection favours plasticity or canalization of personality traits in specific contexts and how ecological conditions affect the presence and the structure of personalities remain to be elucidated. We used five populations of Arctic charr, Salvelinus alpinus, chosen along a gradient of genetic and phenotypic divergence: an anadromous population supposedly close to the ancestral population and two pairs of sympatric lake morphs. Fish were raised individually from eggs in a common garden experiment to specifically assess the genetic bases of the boldness trait in these populations. Thirty-two individuals per morph were repeatedly tested at 11 months old in an open field test with a shelter to assess boldness. The repeatability of the boldness trait (i.e. personality), within- and among-individual variation and temporal variation were assessed within each population. Then, the temporal plasticity in boldness and boldness mean score were assessed among populations. The results show differences between populations for the three variables, with the highest repeatability in the most diverged population, an increase in boldness over time and a lower mean value (especially the first time they were exposed to the novel environment) in the anadromous population. This suggests that boldness and temporal plasticity differ between the anadromous population and the more diverged lake populations under a controlled embryonic/juvenile environment. Further research is needed to verify the contribution of temporal plasticity for personality traits in the context of rapid adaptive radiation such as that seen in Arctic charr.
•Boldness and related parameters were measured in five populations of Arctic charr.•Temporal variation in boldness was assessed by repeated measures.•Lower boldness and higher temporal plasticity are shown in the ancestral population.•Contribution of temporal plasticity in adaptive radiation remains to be elucidated.
Atlantic salmon aquaculture is expanding, and with it, the need to find suitable replacements for conventional protein sources used in formulated feeds. Torula yeast (Cyberlindnera jadinii), has been ...identified as a promising alternative protein for feed and can be sustainably cultivated on lignocellulosic biomasses. The present study investigated the impact of torula yeast on the growth performance and gut microbiome of freshwater Atlantic salmon. A marine protein base diet and a mixed marine and plant protein base diet were tested, where conventional proteins were replaced with increasing inclusion levels of torula yeast, (0%, 10%, 20%). This study demonstrated that 20% torula yeast can replace fish meal without alteration to growth performance while leading to potential benefits for the gut microbiome by increasing the presence of bacteria positively associated with the host. However, when torula yeast replaced plant meal in a mixed protein diet, results suggested that 10% inclusion of yeast produced the best growth performance results but at the 20% inclusion level of yeast, potentially negative changes were observed in the gut microbial community, such as a decrease in lactic acid bacteria. This study supports the continued investigation of torula yeast for Atlantic salmon as a partial replacement for conventional proteins.
Animal personality has been shown to be influenced by both genetic and environmental factors and shaped by natural selection. Currently, little is known about mechanisms influencing the development ...of personality traits. This study examines the extent to which personality development is genetically influenced and/or environmentally responsive (plastic). We also investigated the role of evolutionary history, assessing whether personality traits could be canalized along a genetic and ecological divergence gradient. We tested the plastic potential of boldness in juveniles of five Icelandic Arctic charr morphs (
), including two pairs of sympatric morphs, displaying various degrees of genetic and ecological divergence from the ancestral anadromous charr, split between treatments mimicking benthic versus pelagic feeding modalities. We show that differences in mean boldness are mostly affected by genetics. While the benthic treatment led to bolder individuals overall, the environmental effect was rather weak, suggesting that boldness lies under strong genetic influence with reduced plastic potential. Finally, we found hints of differences by morphs in boldness canalization through reduced variance and plasticity, and higher consistency in boldness within morphs. These findings provide new insights on how behavioural development may impact adaptive diversification.
Animals show among‐individual variation in behaviors, including migration behaviors, which are often repeatable across time periods and contexts, commonly termed “personality.” These behaviors can be ...correlated, forming a behavioral syndrome. In this study, we assessed the repeatability and correlation of different behavioral traits, i.e., boldness, exploration, and sociality, and the link to feeding migration patterns in Atlantic cod juveniles. To do so, we collected repeated measurements within two short‐term (3 days) and two long‐term (2 months) intervals of these personality traits and genotypes of the Pan I locus, which is correlated with feeding migration patterns in this species. We found high repeatabilities for exploration behavior in the short‐ and long‐term intervals, and a trend for the relationship between exploration and the Pan I locus. Boldness and sociality were only repeatable in the second short‐term interval indicating a possible development of stability over time and did not show a relation with the Pan I locus. We found no indication of behavioral syndromes among the studied traits. We were unable to identify the existence of a migration syndrome for the frontal genotype, which is the reason that the link between personality and migration remains inconclusive, but we demonstrated a possible link between exploration and the Pan I genotype. This supports the need for further research that should focus on the effect of exploration tendency and other personality traits on cod movement, including the migratory (frontal) ecotype to develop management strategies based on behavioral units, rather than treating the population as a single homogeneous stock.
By collecting repeated behavioral measurements of exploration, boldness, and sociality and the feeding migration‐linked Pan I genotype, we studied the link between personality and feeding migration in Atlantic cod juveniles. The results show that personality is apparent and that exploration shows a trend to be linked to the Pan I locus, which might have implications for fisheries management.
•Impact of triploidy is assessed in juvenile Salmon raised at low temperature.•Farming performances, behavioural traits and gut microbiome are compared.•Differences between triploid and diploid ...salmon are reduced by low temperature.•Diploid and triploid fish display similar swimming activity and boldness traits.•Gut microbiome seems to be quite similar between both fish categories.
Triploid Atlantic salmon (Salmo salar) aquaculture has been extensively considered for many years, but its development has so far remained very limited. This is mostly due to poorer farming performances of triploid fish (3 N) in comparison with their diploid (2 N) counterparts, with temperature seen as a key explanatory factor. Furthermore, there are many inconsistencies between studies and considerable knowledge gaps exist in triploid physiology and performance, especially at early life stages. The present work is a pilot experiment in which the temperature was kept constantly low (8 °C) during 149 days from 81 to 229 days post hatching (dph). We used a multi-trait approach with an emphasis on behaviour to investigate the performance of 3 N and 2 N Atlantic salmon. Specifically, we compared growth, survival, prevalence of malformation, gut microbiome, and behavioural traits such as swimming activity in response to a stressor, and boldness. Reared at a cold and constant temperature, juvenile triploid and diploid fish showed similar growth from 81 to 165 dph but a difference occurred at 221 dph. Interestingly, triploids outperformed diploids in terms of survival. The prevalence of deformity was low in both diploid and triploid fish and no lower jaw skeletal abnormalities were observed in live fish at the end of the experiment. Triploid and diploid fish displayed very similar swimming activity and boldness traits as well as a very similar gut microbiome. This multi-trait approach reveals that when raised at low temperature, triploid and diploid fish performed equally well, with even a better survival for triploids towards the end of the experiment. Our study emphasizes the need for developing different rearing protocols for diploid and triploid Atlantic salmon. Applying a lower temperature at early developmental stages in ectotherms inevitably slows their developmental rate and may allow fine tuning of key developmental structures, decreasing deformities at early and later life stages of triploids. Further research comparing different temperature profiles is needed to find the best compromise between growth performance and low malformation rate and to examine the long-term effect of low temperatures applied at an early stage of development. This is a crucial step to improve both triploid salmon performance and welfare.
Atlantic salmon (Salmo salar) is one of the worlds most domesticated fish. As production volumes increase, access to high quality and sustainable protein sources for formulated feeds of this ...carnivorous fish is required. Soybean meal (SBM) and soy-derived proteins are the dominant protein sources in commercial aquafeeds due to their low-cost, availability and favorable amino acid profile. However, for Atlantic salmon, the inclusion of soybean meal (SBM), and soy protein concentrate (SPC) in certain combinations can impact gut health, which has consequences for immunity and welfare, limiting the use of soy products in salmonid feeds. This study sought to address this challenge by evaluating two gut health-targeted enhancements of SBM for inclusion in freshwater phase salmon diets: enzyme pre-treatment (ETS), and addition of fructose oligosaccharide (USP). These were compared with untreated soybean meal (US) and fish meal (FM). This study took a multi-disciplinary approach, investigating the effect on growth performance, gut microbiome, and behaviors relevant to welfare in aquaculture. This study suggests that both enhancements of SBM provide benefits for growth performance compared with conventional SBM. Both SBM treatments altered fish gut microbiomes and in the case of ETS, increased the presence of the lactic acid bacteria Enterococcus. For the first time, the effects of marine protein sources and plant protein sources on the coping style of salmon were demonstrated. Fish fed SBM showed a tendency for more reactive behavior compared with those fed the FM-based control. All fish had a similar low response to elicited stress, although ETS-fed fish responded more actively than US-fed fish for a single swimming measure. Furthermore, SBM-fed fish displayed lower repeatability of behavior, which may indicate diminished welfare for intensively farmed fish. The implications of these findings for commercial salmonid aquaculture are discussed.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
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