| Accueil | << 1 2 >> |
|
Alfonso, S., Gesto, M., & Sadoul, B. (2020). Temperature increase and its effects on fish stress physiology in the context of global warming. J. Fish Biol., .
Résumé: The capacity of fishes to cope with environmental variation is considered to be a main determinant of their fitness and is partly determined by their stress physiology. By 2100, global ocean temperature is expected to rise by 1-4 degrees C, with potential consequences for stress physiology. Global warming is affecting animal populations worldwide through chronic temperature increases and an increase in the frequency of extreme heatwave events. As ectotherms, fishes are expected to be particularly vulnerable to global warming. Although little information is available about the effects of global warming on stress physiology in nature, multiple studies describe the consequences of temperature increases on stress physiology in controlled laboratory conditions, providing insight into what can be expected in the wild. Chronic temperature increase constitutes a physiological load that can alter the ability of fishes to cope with additional stressors, which might compromise their fitness. In addition, rapid temperature increases are known to induce acute stress responses in fishes and might be of ecological relevance in particular situations. This review summarizes knowledge about effects of temperature increases on the stress physiology of fishes and discusses these in the context of global warming.
|
|
Li, X., Blancheton, J. - P., Liu, Y., Triplet, S., & Michaud, L. (2014). Effect of oxidation-reduction potential on performance of European sea bass (Dicentrarchus labrax) in recirculating aquaculture systems. Aquaculture International, 22(4), 1263–1282.
Résumé: The direct impact of oxidation-reduction potential (ORP) on fish welfare and water quality in marine recirculating aquaculture systems (RAS) is poorly documented. In this study, the effects of the fish size (S-1, S-2, S-3) and ORP level (normal, four successive levels) on the performance of European sea bass (Dicentrarchus labrax) were investigated. Three size fish were distributed into two RAS (RAS and RAS O-3). Ozone was injected into RAS O-3 to increase the ORP level. The ORP was stabilized to four successive levels: 260-300, 300-320, 320-350, and 300-320 mV in fish tanks during four periods (P1-4). At the last day of each period, the hematological parameters, plasma protein and mortality of sea bass were analyzed. Two-way ANOVA revealed that several hematological parameters, including pH, hematocrit, concentrations of oxygen, carbon dioxide, glucose (Glu), ionized calcium, kalium, and hemoglobin, were significantly influenced by the increased ORP levels over the experimental period. The alteration in blood Glu and plasma protein concentration showed that ORP around 300-320 mV started to stress sea bass. Once the ORP exceeded 320 mV in the tanks during the P-3 period, mortality occurred even when total residual oxidants/ozone-produced oxidants was only 0.03-0.05 mg L-1 in the fish tanks. At the same time, plasma protein decreased notably due to appetite depression. After the decrease in ORP during the P-4 period, mortality continued. In conclusion, the results strongly suggest that for European sea bass in RAS, the ORP should not exceed 320 mV in the tanks. Once ozonation damaged fish, the effect seemed to be irreversible. However, how ORP affected related hematological parameters still need the further investigations.
|
|
Marras, S., Killen, S. S., Claireaux, G., Domenici, P., & McKenzie, D. J. (2011). Behavioural and kinematic components of the fast-start escape response in fish: individual variation and temporal repeatability. J. Exp. Biol., 214(18), 3102–3110.
Résumé: Inter-individual variation in physiological performance traits, which is stable over time, can be of potential ecological and evolutionary significance. The fish escape response is interesting in this regard because it is a performance trait for which inter-individual variation may determine individual survival. The temporal stability of such variation is, however, largely unexplored. We quantified individual variation of various components of the escape response in a population of European sea bass (Dicentrarchus labrax), considering both non-locomotor (responsiveness and latency) and locomotor (speed, acceleration, turning rate, turning angle and distance travelled in a fixed time, D(esc)) variables. We assessed whether variation in performance was temporally stable and we searched for any trade-offs among the components of the response that might explain why the variation persisted in the population. The coefficient of variation was high for all components, from 23% for turning rate to 41% for D(esc), highlighting the non-stereotypic nature of the response. Individual performance for all variables was significantly repeatable over five sequential responses at 30min intervals, and also repeatable after a 30 day interval for most of the components. This indicates that the variation is intrinsic to the individuals, but there was no evidence for trade-offs amongst the components of the response, suggesting that, if trade-offs exist, they must be against other ecologically important behavioural or performance traits.
Mots-Clés: anaerobic performance; anaerobic swimming performance; body form; dicentrarchus-labrax; escape response; european sea bass; fast start; fish; gambusia-affinis; individual variation; locomotor performance; morphology; poecilia-reticulata; rainbow-trout; repeatability; sea bass; stereotype; swimming performance; teleost fish
|
|
McKenzie, D. J., Belao, T. C., Killen, S. S., & Rantin, F. T. (2015). To boldly gulp: standard metabolic rate and boldness have context-dependent influences on risk-taking to breathe air in a catfish. J. Exp. Biol., 218(23), 3762–3770.
Résumé: The African sharptooth catfish Clarias gariepinus has bimodal respiration, it has a suprabranchial air-breathing organ alongside substantial gills. We used automated bimodal respirometry to reveal that undisturbed juvenile catfish (N=29) breathed air continuously in normoxia, with a marked diurnal cycle. Air breathing and routine metabolic rate (RMR) increased in darkness when, in the wild, this nocturnal predator forages. Aquatic hypoxia (20% air saturation) greatly increased overall reliance on air breathing. We investigated whether two measures of risk taking to breathe air, namely absolute rates of aerial O-2 uptake ((M) over dotO(2), air) and the percentage of RMR obtained from air (% (M) over dotO(2), air), were influenced by individual standard metabolic rate (SMR) and boldness. In particular, whether any influence varied with resource availability (normoxia versus hypoxia) or relative fear of predation (day versus night). Individual SMR, derived from respirometry, had an overall positive influence on (M) over dotO(2), air across all contexts but a positive influence on % (M) over dotO(2), air only in hypoxia. Thus, a pervasive effect of SMR on air breathing became most acute in hypoxia, when individuals with higher O-2 demand took proportionally more risks. Boldness was estimated as time required to resume air breathing after a fearful stimulus in daylight normoxia (T-res). Although T-res had no overall influence on (M) over dotO(2), air or % (M) over dotO(2), air, there was a negative relationship between Tres and % (M) over dotO(2), air in daylight, in normoxia and hypoxia. There were two Tres response groups, 'bold' phenotypes with Tres below 75 min (N= 13) which, in daylight, breathed proportionally more air than 'shy' phenotypes with Tres above 115 min (N= 16). Therefore, individual boldness influenced air breathing when fear of predation was high. Thus, individual energy demand and personality did not have parallel influences on the emergent tendency to take risks to obtain a resource; their influences varied in strength with context.
Mots-Clés: african catfish; animal personality; Bimodal respiration; clarias-gariepinus; ecological consequences; Energy metabolism; european sea bass; Hypoxia; individual variation; oncorhynchus-mykiss; Personality; personality-traits; predation risk; Respiratory partitioning; Risk-taking; wild-type zebrafish
|
|
Pérez-Pascual, D., Estellé, J., Dutto, G., Rodde, C., Bernardet, J. - F., Marchand, Y., et al. (2020). Growth Performance and Adaptability of European Sea Bass (Dicentrarchus labrax) Gut Microbiota to Alternative Diets Free of Fish Products. Microorganisms, 8(9), 1346.
Résumé: Innovative fish diets made of terrestrial plants supplemented with sustainable protein sources free of fish-derived proteins could contribute to reducing the environmental impact of the farmed fish industry. However, such alternative diets may influence fish gut microbial community, health, and, ultimately, growth performance. Here, we developed five fish feed formulas composed of terrestrial plant-based nutrients, in which fish-derived proteins were substituted with sustainable protein sources, including insect larvae, cyanobacteria, yeast, or recycled processed poultry protein. We then analyzed the growth performance of European sea bass (Dicentrarchus labrax L.) and the evolution of gut microbiota of fish fed the five formulations. We showed that replacement of 15% protein of a vegetal formulation by insect or yeast proteins led to a significantly higher fish growth performance and feed intake when compared with the full vegetal formulation, with feed conversion ratio similar to a commercial diet. 16S rRNA gene sequencing monitoring of the sea bass gut microbial community showed a predominance of Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes phyla. The partial replacement of protein source in fish diets was not associated with significant differences on gut microbial richness. Overall, our study highlights the adaptability of European sea bass gut microbiota composition to changes in fish diet and identifies promising alternative protein sources for sustainable aquafeeds with terrestrial vegetal complements.
Mots-Clés: bacteria; European sea bass; fish gut microbiota
|