The Influence of a Reflective Identity Leadership Intervention on Perceived Identity Leadership, Social Identity, and Psychological Safety in Cricket.

The purpose of this study was to investigate the influence of an identity leadership-framed reflective practice intervention on perceptions of leadership, social identity, and psychological safety in cricket. Building on previous evidence, an eight-week design included three intervention group coaches and their athletes (n = 32) and three control group coaches and their athletes (n = 34). Measurements of perceived coach identity leadership, social identity, and psychological safety were completed by cricket athletes at week 0 and week 8 for both groups. Intervention group coaches completed three identity leadership-framed reflective tasks in weeks one, three, and five, while the control group coaches continued their regular practices. Controlling for baseline scores, our analysis indicated that compared to the control group, the intervention group athletes reported significantly greater coach identity leadership behaviours, social identity, and psychological safety following the intervention. Social validation data highlighted shared identity, relationships, and learning as potential mechanisms for the positive results seen.

Doppler ultrasound surveillance of recently formed haemodialysis arteriovenous fistula: the SONAR observational cohort study.

Background: Arteriovenous fistulas are considered the best option for haemodialysis provision, but as many as 30% fail to mature or suffer early failure. Objective: To assess the feasibility of performing a randomised controlled trial that examines whether, by informing early and effective salvage intervention of fistulas that would otherwise fail, Doppler ultrasound surveillance of developing arteriovenous fistulas improves longer-term arteriovenous fistula patency. Design: A prospective multicentre observational cohort study (the 'SONAR' study). Setting: Seventeen haemodialysis centres in the UK. Participants: Consenting adults with end-stage renal disease who were scheduled to have an arteriovenous fistula created. Intervention: Participants underwent Doppler ultrasound surveillance of their arteriovenous fistulas at 2, 4, 6 and 10 weeks after creation, with clinical teams blinded to the ultrasound surveillance findings. Main outcome measures: Fistula maturation at week 10 defined according to ultrasound surveillance parameters of representative venous diameter and blood flow (wrist arteriovenous fistulas: ≥ 4 mm and > 400 ml/minute; elbow arteriovenous fistulas: ≥ 5 mm and > 500 ml/minute). Mixed multivariable logistic regression modelling of the early ultrasound scan data was used to predict arteriovenous fistula non-maturation by 10 weeks and fistula failure at 6 months. Results: A total of 333 arteriovenous fistulas were created during the study window (47.7% wrist, 52.3% elbow). By 2 weeks, 37 (11.1%) arteriovenous fistulas had failed (thrombosed), but by 10 weeks, 219 of 333 (65.8%) of created arteriovenous fistulas had reached maturity (60.4% wrist, 67.2% elbow). Persistently lower flow rates and venous diameters were observed in those fistulas that did not mature. Models for arteriovenous fistulas' non-maturation could be optimally constructed using the week 4 scan data, with fistula venous diameter and flow rate the most significant variables in explaining wrist fistula maturity failure (positive predictive value 60.6%, 95% confidence interval 43.9% to 77.3%), whereas resistance index and flow rate were most significant for elbow arteriovenous fistulas (positive predictive value 66.7%, 95% confidence interval 48.9% to 84.4%). In contrast to non-maturation, both models predicted fistula maturation much more reliably [negative predictive values of 95.4% (95% confidence interval 91.0% to 99.8%) and 95.6% (95% confidence interval 91.8% to 99.4%) for wrist and elbow, respectively]. Additional follow-up and modelling on a subset (n = 192) of the original SONAR cohort (the SONAR-12M study) revealed the rates of primary, assisted primary and secondary patency arteriovenous fistulas at 6 months were 76.5, 80.7 and 83.3, respectively. Fistula vein size, flow rate and resistance index could identify primary patency failure at 6 months, with similar predictive power as for 10-week arteriovenous fistula maturity failure, but with wide confidence intervals for wrist (positive predictive value 72.7%, 95% confidence interval 46.4% to 99.0%) and elbow (positive predictive value 57.1%, 95% confidence interval 20.5% to 93.8%). These models, moreover, performed poorly at identifying assisted primary and secondary patency failure, likely because a subset of those arteriovenous fistulas identified on ultrasound surveillance as at risk underwent subsequent successful salvage intervention without recourse to early ultrasound data. Conclusions: Although early ultrasound can predict fistula maturation and longer-term patency very effectively, it was only moderately good at identifying those fistulas likely to remain immature or to fail within 6 months. Allied to the better- than-expected fistula patency rates achieved (that are further improved by successful salvage), we estimate that a randomised controlled trial comparing early ultrasound-guided intervention against standard care would require at least 1300 fistulas and would achieve only minimal patient benefit. Trial Registration: This trial is registered as ISRCTN36033877 and ISRCTN17399438. Funding: This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: NIHR135572) and is published in full in Health Technology Assessment; Vol. 28, No. 24. See the NIHR Funding and Awards website for further award information.

For people with advanced kidney disease, haemodialysis is best provided by an 'arteriovenous fistula', which is created surgically by joining a vein onto an artery at the wrist or elbow. However, these take about 2 months to develop fully ('mature'), and as many as 3 out of 10 fail to do so. We asked whether we could use early ultrasound scanning of the fistula to identify those that are unlikely to mature. This would allow us to decide whether it would be practical to run a large, randomised trial to find out if using early ultrasound allows us to 'rescue' fistulas that would otherwise fail. We invited adults to undergo serial ultrasound scanning of their fistula in the first few weeks after it was created. We then analysed whether we could use the data from the early scans to identify those fistulas that were not going to mature by week 10. Of the 333 fistulas that were created, about two-thirds reached maturity by week 10. We found that an ultrasound scan 4 weeks after fistula creation could reliably identify those fistulas that were going to mature. However, of those fistulas predicted to fail, about one-third did eventually mature without further intervention, and even without knowing what the early scans showed, another third were successfully rescued by surgery or X-ray-guided treatment at a later stage. Performing an early ultrasound scan on a fistula can provide reassurance that it will mature and deliver trouble-free dialysis. However, because scans are poor at identifying fistulas that are unlikely to mature, we would not recommend their use to justify early surgery or X-ray-guided treatment in the expectation that this will improve outcomes.

Early Ultrasound Surveillance of Newly-Created Hemodialysis Arteriovenous Fistula.

Introduction: We assess if ultrasound surveillance of newly-created arteriovenous fistulas (AVFs) can predict nonmaturation sufficiently reliably to justify randomized controlled trial (RCT) evaluation of ultrasound-directed salvage intervention. Methods: Consenting adults underwent blinded fortnightly ultrasound scanning of their AVF after creation, with scan characteristics that predicted AVF nonmaturation identified by logistic regression modeling. Results: Of 333 AVFs created, 65.8% matured by 10 weeks. Serial scanning revealed that maturation occurred rapidly, whereas consistently lower fistula flow rates and venous diameters were observed in those that did not mature. Wrist and elbow AVF nonmaturation could be optimally modeled from week 4 ultrasound parameters alone, but with only moderate positive predictive values (PPVs) (wrist, 60.6% [95% confidence interval, CI: 43.9-77.3]; elbow, 66.7% [48.9-84.4]). Moreover, 40 (70.2%) of the 57 AVFs that thrombosed by week 10 had already failed by the week 4 scan, thus limiting the potential of salvage procedures initiated by that scan's findings to alter overall maturation rates. Modeling of the early ultrasound characteristics could also predict primary patency failure at 6 months; however, that model performed poorly at predicting assisted primary failure (those AVFs that failed despite a salvage attempt), partly because patency of at-risk AVFs was maintained by successful salvage performed without recourse to the early scan data. Conclusion: Early ultrasound surveillance may predict fistula maturation, but is likely, at best, to result in only very modest improvements in fistula patency. Power calculations suggest that an impractically large number of participants (>1700) would be required for formal RCT evaluation.

Measuring leadership in sport: Development and validation of the Identity Leadership Inventory - Youth (ILI-Y).

The social identity approach to leadership posits that leaders' effectiveness depends on their ability to represent, advance, create, and embed a shared sense of social identity among their followers. Although significant progress has been made in investigating the benefits of identity leadership in adult sports, research in youth sports is still in its infancy. One reason is the lack of a youth-centric inventory that adequately measures identity leadership in this population. To bridge this gap, we developed and validated a long (16 items) and short (5 items) version of the Identity Leadership Inventory for Youth Sport (ILI-Y or ILI-Y-Short-Form) through five studies conducted in three phases of research. Data were primarily collected in football in the United Kingdom, involving a total of 1096 participants. Results of Phase I of this study provided little to no evidence that the ILI - originally developed for adults - was understandable (Study 1) and had factor validity and internal consistency (Study 2) in a sample of youth athletes. Therefore, in Phase II, the ILI was revised, leading to the development of the ILI-Y, which was understandable for youth athletes (Study 3). Results from Phase II (Study 4) also indicated that the ILI-Y exhibited a unidimensional factor structure, which was subsequently confirmed in Phase III (Study 5). This last phase offered additional evidence for the discriminant, criterion, and incremental validity of the ILI-Y and its short form, along with their measurement invariance across genders and age groups, and internal consistency. This study provides sports psychology researchers and practitioners with a valid measure to assess identity leadership in youth sports.

Potential of alginate, chitosan and polyethylene glycol as substances for colloidal drug delivery as determined by protein release and digestion.

Colloidal encapsulations can be applied as protective matrices in aquaculture feeds. They promise an ideal approach to protect bioactive substances such as oral vaccines, pre- or probiotics against degradation due to acidic environments or untimely lixiviation. Alginate, chitosan and polyethylene glycol (PEG) are substances frequently applied in encapsulations as protective matrices. However, essential information on their direct and comparable characteristics and their effects on digestion speeds after oral application in aquaculture are lacking. The current study evaluated in vitro release and retention profiles of a model protein bovine serum albumin (BSA) after encapsulation with four experimental formulations of protective matrices: ALG - alginate; AC -alginate and chitosan, AP - alginate and PEG and APC - alginate, PEG and chitosan. The iron marked treatment diets were fed to juvenile rainbow trout and digestion speed was investigated using radiographic imaging. Digestion speeds did not differ significantly between treatments, with all test diets reaching the anterior fish intestine 10 h after feeding. The BSA retention under low pH was highest for the alginate-chitosan PM (84.7 ± 5.8 %). The inclusion of PEG reduced the retention rate in low pH but significantly increased the absolute BSA release. An oil coating significantly reduced the BSA release during the initial burst for the alginate, alginate-PEG and alginate-chitosan-PEG treatments and significantly reduced retention potential under neutral pH conditions. The feeding simulation trial showed that an oil-coated diet containing alginate-chitosan as a protective matrix can be used to protect the model protein during feeding (release to the water) and against the harmful milieu of the fish stomach. Different combinations of the investigated encapsulation substances can be used to achieve optimal encapsulation and protective characteristics depending on the application objective.

Examination of cognitive appraisals, irrational beliefs, and challenge and threat evaluations in the prediction of tournament affective states and performance of competitive elite Indian golfers.

Researchers have intimated that cognitions and emotions can change in the lead up to important events. However, previous research has adopted atemporal cross-sectional designs, making it challenging to understand how cognitions and emotions unfold in the lead up to a competition. In the current study, we extended previous research by examining the temporal patterns of cognitive appraisals, irrational beliefs, and challenge and threat evaluations in predicting pre-competitive affective states (hedonic balance and anxiety) in the lead up to an actual competition, among competitive elite Indian golfers (N = 107). We adopted a within-subjects repeated-measures design and collected data in the lead up to an actual golf tournament, at three timepoints; 1 week before (T1), the night before (T2), and an hour prior (T3). Self-reported measures of cognitive appraisals, irrational beliefs, challenge and threat evaluations, affect, and anxiety were completed. Also, objective golf performance was collected from participants. Crossed-lagged path analysis did not find a causal effect for irrational beliefs on any of the variables across the three time points. On the other hand, hierarchical multiple regression analysis determined that changes in irrational beliefs predicted changes in cognitive appraisals, threat evaluation, cognitive and somatic anxiety, and the directional interpretation of anxiety. The findings of temporal patterns in the current research indicated that sport psychologists should consider the dynamic nature of antecedent cognitions and affective states in the lead up to competition, and accordingly provide adequate support to the athletes. Further, limitations and future research is discussed with reference to the results.

The role of social support and social identification on challenge and threat cognitive appraisals, perceived stress, and life satisfaction in workplace employees.

There is an emergent literature highlighting the positive role of social support and social identification in buffering against the deleterious effects of psychological stressors. Yet, we have limited understanding of how exactly these social factors fit within contemporary stress and coping theory. To advance and gain a greater understanding of these social factors, we explore the associations of social support and social identification on individuals' challenge and threat cognitive appraisals and how this then relates to perceived stress, life satisfaction, turnover intentions, and job performance. A total of 412 workplace employees from private and public sector occupations completed state measures around a recent most stressful experience at work. Results revealed atemporal associations between cognitive resource appraisals with both social support and social identification. Specifically, greater identification with colleagues and lower threat were related to less perceived stress, while having greater social identification (with colleagues and organisation), social support, and lower threat, were related to greater life satisfaction. Greater perceived stress, and lower social identification and life satisfaction, were also related to greater turnover intentions. While greater identification with the organisation and life satisfaction, along with lower perceived stress were related to greater job performance. Taken together, this research provides evidence that social support and social identification play a positive role when trying to promote more adaptive responses to stressful situations.

Cardiorespiratory Optimisation By Arteriovenous fistula Ligation after renal Transplantation (COBALT): study protocol for a multicentre randomised interventional feasibility trial.

INTRODUCTION: Cardiovascular events are a major cause of mortality following successful kidney transplantation.Arteriovenous fistulas (AVFs) are considered the best option for haemodialysis, but may contribute to this excess mortality because they promote adverse cardiac remodelling and ventricular hypertrophy. This raises the question whether recipients with a well-functioning kidney transplant should undergo elective AVF ligation. METHODS AND ANALYSIS: The COBALT feasibility study is a multicentre interventional randomised controlled trial (RCT) that will randomise renal transplant patients with stable graft function and a working AVF on a 1:1 basis to standard care (continued conservative management) or to AVF ligation. All patients will perform cardiopulmonary exercise testing (CPET) on recruitment and 6 months later. Daily functioning and quality of life will be additionally assessed by questionnaire completion and objective measure of physical activity. The primary outcome-the proportion of approached patients who complete the study (incorporating rates of consent, receipt of allocated intervention and completion of both CPETs without withdrawal)-will determine progression to a full-scale RCT. Design of the proposed RCT will be informed by an embedded qualitative assessment of participant and healthcare professional involvement. ETHICS AND DISSEMINATION: This study has been approved by the East Midlands-Derby Research Ethics Committee (22/EM/0002) and the Health Research Authority. The results of this work will be disseminated academically through presentation at national and international renal meetings and via open access, peer-reviewed outputs. Existing networks of renal patient groups will also be used to disseminate the study findings to other key stakeholders. TRIAL REGISTRATION NUMBER: ISRCTN49033491.

Public Conceptions of Scientific Consensus.

Despite decades of concerted efforts to communicate to the public on important scientific issues pertaining to the environment and public health, gaps between public acceptance and the scientific consensus on these issues remain stubborn. One strategy for dealing with this shortcoming has been to focus on the existence of scientific consensus on the relevant matters. Recent science communication research has added support to this general idea, though the interpretation of these studies and their generalizability remains a matter of contention. In this paper, we describe results of a qualitative interview study on different models of scientific consensus and the relationship between such models and trust of science, finding that familiarity with scientific consensus is rarer than might be expected. These results suggest that consensus messaging strategies may not be effective.

Addition of Molasses Ameliorates Water and Bio-Floc Quality in Shrimp Pond Water.

Suspended particulate matter, phytoplankton and bacteria can be exploited to form larger aggregates, so-called bio-flocs. These serve as feeds for cultured shrimps, govern inorganic nutrients and load bacteria including pathogens. The current study aimed to simulate aggregate formation from available particulate matter in shrimp pond water and investigate quality of aggregates as well as possible impact to the pond water. Molasses was added to cylindrical tanks containing shrimp pond waters, and the tanks were rolled for 48 h. Besides water quality (inorganic nutrients and physical parameters), the researchers investigated and separated bacterial community compositions (BCC) to free-living (FL) and bio-flocs/particle-attached (PA) bacteria via 16S rRNA amplicon sequencing, and measured macro-molecules contents (carbohydrates, lipids and proteins) in the bio-flocs. Molasses addition increased bacterial numbers in the bio-flocs to two-fold higher than the FL's. Moreover, potential probiotics such as Halomonas, Psychrobacter, Mesonia and Chromohalobacter were detected associated to bio-flocs and dominated the BCC. In contrast, bio-flocs without molasses showed 4-fold less carbohydrates and harboured elevated potential pathogens such as Vibrio and Alteromonas. Results show that molasses (at C/N ratio 1:2) increases pH (to 8.2 ± 0.09 and 8.0 ± 0.04 after 24 h and 48 h, respectively) in pond water, improving beneficial biofloc formation. Molasses also increased carbohydrates and proteins in bio-flocs and maintained abundances of beneficial bacteria resulting in low inorganic nutrient concentrations. Thus, molasses is suitable for shrimp farming to improve rearing processes.

Using Personal-Disclosure Mutual-Sharing (PDMS) with first-year undergraduate students transitioning to higher education.

BACKGROUND: Using Personal-Disclosure Mutual-Sharing (PDMS) with students transitioning to Higher Education (HE) has yet to be researched in education. AIMS: In two studies, we aimed to explore the immediate effects of a Coping Oriented Personal-Disclosure Mutual-Sharing (COPDMS) intervention on first-year undergraduate students' relational and organizational identification, perceived social support availability, and self-efficacy for learning and performance. In our second study, we also aimed to examine student-perceptions of participating in a COPDMS intervention. SAMPLE AND METHODS: At the beginning of induction week in both studies, first-year undergraduate students on the same degree programme at a HE provider in England received an education session where COPDMS was introduced. Students participated in a COPDMS session a few days later. During COPDMS sessions, students mutually-shared and disclosed personal information and/or stories relating to transitional experiences. RESULTS: Across both studies, students' relational identification with staff and perceived emotional, esteemed, and informational support availability from others on the degree programme significantly increased from pre- to post-COPDMS phases. Findings relating to relational identification with other Year 1 students and perceived availability of tangible support were mixed. No significant changes occurred for organizational identification with the university and self-efficacy for learning and performance. In Study 2, five higher-order themes relating to students' perceptions of COPDMS were found: (1) emotionality; (2) personal development; (3) storytelling; (4) enhanced group processes; and (5) task appropriateness and value. CONCLUSIONS: Study findings provide evidence that COPDMS is a useful psychological intervention to deliver to students transitioning to HE. Practical considerations, limitations, and future research suggestions are provided.

Extreme winter cold-induced osmoregulatory, metabolic, and physiological responses in European seabass (Dicentrarchus labrax) acclimatized at different salinities.

Despite climate-change challenges, for most aquaculture species, physiological responses to different salinities during ambient extreme cold events remain unknown. Here, European seabass acclimatized at 3, 6, 12, and 30 PSU were subjected to 20 days of an ambient extreme winter cold event (8 °C), and monitored for growth and physiological performance. Growth performance decreased significantly (p < 0.05) in fish exposed at 3 and 30 PSU compared to 6 and 12 PSU. During cold stress exposure, serum Na+, Cl-, and K+ concentrations were significantly (p < 0.05) increased in fish exposed at 30 PSU. Serum cortisol, glucose, and blood urea nitrogen (BUN) were increased significantly (p < 0.05) in fish exposed at 3 and 30 PSU. In contrast, opposite trends were observed for serum protein, lactate, and triglycerides content during cold exposure. Transaminase activities [glutamic-pyruvate transaminase (GPT), glutamic oxaloacetic transaminase (GOT), lactic acid dehydrogenase (LDH), gamma-glutamyl-transaminase (γGGT)] were significantly higher in fish exposed at 3 and 30 PSU on days 10 and 20. The abundance of heat shock protein 70 (HSP70), tumor necrosis factor-α (TNF-α), cystic fibrosis transmembrane conductance (CFTR) were significantly (p < 0.05) increased in fish exposed at 3 and 30 PSU during cold shock exposure. In contrast, insulin-like growth factor 1 (Igf1) expression was significantly lower in fish exposed at 3 and 30 PSU. Whereas, on day 20, Na+/K+ ATPase α1 and Na+/K+/Cl- cotransporter-1 (NKCC1) were significantly upregulated in fish exposed at 30 PSU, followed by 12, 6, and 3 PSU. Results demonstrated that ambient extreme winter cold events induce metabolic and physiological stress responses and provide a conceivable mechanism by which growth and physiological fitness are limited at cold thermal events. However, during ambient extreme cold (8 °C) exposure, European seabass exhibited better physiological fitness at 12 and 6 PSU water, providing possible insight into future aquaculture management options.

Low turbidity in recirculating aquaculture systems (RAS) reduces feeding behavior and increases stress-related physiological parameters in pikeperch (Sander lucioperca) during grow-out.

There is a tendency to farm fish in low turbidity water when production takes place in the land-based recirculating aquaculture systems (RAS). However, the effect of water turbidity on stress and performance is unknown for many species cultured in RAS. The effect of different turbidity treatments as Formazine Attenuation Units (0 FAU, 15 FAU, and 38 FAU) on feed intake performance (latency, total feeding time, and total feed intake) and physiological blood stress parameters (cortisol, lactate, and glucose) in medium-sized pikeperch ((Sander lucioperca) n = 27, undetermined sex and age) of initial body weights of 508.13 g ± 83 g (at FAU 0, 15, and 38, respectively) was investigated. The rearing system consisted of 9 rectangular tanks (200 L per tank). Fish were housed individually (n = 1, per tank, n replicates per treatment = 9). All tanks were connected to a recirculation system equipped with a moving bed biofilter. Feed intake in pikeperch kept at low turbidity (0 FAU) was 25% lower than pikeperch kept at high turbidity (38 FAU) (P < 0.01) and also significantly (10.5%) lower compared to feed intake in pikeperch kept at intermediate turbidity (15 FAU) (P < 0.01 for 0 FAU vs. 15 FAU, feed intake sign. Value as the main effect is P < 0.01). Pikeperch kept at low turbidity showed significantly slower feeding response (latency time) towards pellets entering the tank, shorter feeding times (both P < 0.05), and higher glucose blood concentration (73%) in contrast to pikeperch kept at highest turbidity. A reduction of 25% feed intake has obvious economic consequences for any fish farm and present data strongly emphasize the importance of considering the species-specific biology in future RAS farming.

An exploration of the organisational stressors encountered by international disability footballers.

Presently, disability athletes remain under-represented in organisational stressor research. Our study sought to bring novel insights to this area by determining the organisational stressors experienced by international disability footballers. Twelve current international disability footballers (10 male, 2 female) from a range of UK impairment squads took part in the study. Semi-structured interviews were completed with each participant, and data were analysed by content analysis procedures. Organisational stressors data were abstracted into Arnold, Wagstaff, Steadman and Pratt's (2017) concepts, and Arnold and Fletcher's (2012) four general dimensions: leadership and personnel issues, cultural and team issues, logistical and environmental issues, and performance and personal issues, revealing a series of football-specific nuances. Our study is the first exploration of the prevalence of organisational stressors within international disability football. Our study also provides practitioners with an understanding of the common and unique organisational stressors faced by international disability footballers. Finally, we suggest a series of practical recommendations for policy development within disability football organisations to aid athletes to effective manage organisational stressors.

More positive group memberships are associated with greater resilience in Royal Air Force (RAF) personnel.

In the current project, we examined how perceived group memberships (number, and characteristics, of), social and relational identification, and social identity leadership are associated with resilience in Royal Air Force (RAF) personnel. Based on social identity theorizing, we hypothesized positive associations between the number of groups, perceptions of their characteristics (e.g., positivity), and how they relate to each other (i.e., compatibility) and resilience (H1). We also hypothesized positive associations between both social identity leadership (H2) and resilience, and social and relational identification (H3) and resilience. Two hundred and forty-three personnel from 18 RAF bases completed an identity mapping exercise and measures of leadership, social and relational identification, and resilience. Our findings highlighted the importance of the association between positive group memberships and resilience, and social identification and resilience. Counter to our hypothesis, belonging to more groups was negatively associated with resilience, and there were non-significant relationships between three principles of social identity leadership and resilience, with embedding identity being significantly negatively associated with resilience. In support of social identity theorizing, the number of positive groups was positively associated with resilience, as was social identification. These findings indicate that, for RAF personnel, it is belonging to positive groups, both within and outside work, along with social identification, that is positively associated with resilience.

What metabolic, osmotic and molecular stress responses tell us about extreme ambient heatwave impacts in fish at low salinities: The case of European seabass, Dicentrarchus labrax.

Unprecedented shifts in temperature and precipitation patterns in recent decades place multiple abiotic stressors on the fish. In teleosts, metabolic, osmoregulatory, and molecular potential as tolerance responses to extreme ambient heatwave events at different salinities are poorly understood. The study was performed to evaluate the physio-biochemical stress responses and acclimation potential of European seabass, Dicentrarchus labrax maintained at four different salinities followed by an extreme ambient heatwave exposure. Fish were kept at 32, 12, 6, and 2 psu for 35 days followed by a simulated extreme ambient heatwave (33 °C) exposure for 10 days. Fish growth performances, physio-biochemical and molecular responses were recorded. Fish acclimated at 32 and 2 psu exhibited significantly (p < 0.05) decreased growth performance. Serum [Na+] and [Cl-] ions were significantly lowered (p < 0.05) in 32 psu fish on day 10 of heatwave exposure. While serum glucose, triglycerides, and protein tended to decrease during the extreme ambient heatwave exposure, lactate content increased significantly (p < 0.05) in 32 psu fish on day 10. In 32 and 2 psu fish, serum metabolic enzymes, and cortisol levels increased significantly (p < 0.05) during the extreme heatwave exposure. On days 5 and 10, HSP70 mRNA was significantly (p < 0.05) upregulated in kidneys and gills of 32 and 2 psu fish, while Igf1 showed downregulation. In gills of 2 psu fish, ATPase Na+/K+-α1 and NKCC1 expression decreased significantly (p < 0.05) in 2 psu, in contrast, significant upregulation was observed at 32 psu fish during extreme ambient heatwave exposure. On days 5 and 10, cystic fibrosis transmembrane conductance (CFTR) upregulation was significantly lower (p < 0.05) in 32 and 2 psu fish. Results suggest that European seabass held at 12 and 6 psu water fare better physiological fitness during the tested extreme ambient heatwave event (33 °C), providing possible insights into options for future aquaculture management in a warming environment.

Effects of extreme ambient temperature in European seabass, Dicentrarchus labrax acclimated at different salinities: Growth performance, metabolic and molecular stress responses.

Extreme weather events are becoming more intense and frequent as a result of climate change. The modulation of hemato-physiological potential as a compensatory response to extreme warm events combined with different salinities is poorly understood. This study aimed to assess the hemato-physiological and molecular response of European seabass, Dicentrarchus labrax exposed to extreme warm temperature (33 °C) after prior acclimatization at 32 psu, 12 psu, 6 psu, and 2 psu water. Fish were acclimated to 32 psu, 12 psu, 6 psu, and 2 psu followed by 10 days extreme warm (33 °C) exposure. Along with growth performance and survival, hemato-physiological response and molecular response of fish were recorded. Fish held at 32 psu and 2 psu exhibited significantly lower growth performance and survival than those at 12 psu and 6 psu (p < 0.05). Red blood cells (RBC), hematocrit, and hemoglobin content were significantly decreased, while white blood cells (WBC), erythrocytic cellular abnormalities (ECA) and erythrocytic nuclear abnormalities (ENA) were found to increase significantly in 32 psu and 2 psu fish (p < 0.05). Plasma lactate was found to increase significantly in 32 psu fish on day 10 (p < 0.05). Activities of glutathione peroxidase (GPx), glutathione reductase (GR), superoxide dismutase (SOD), catalase (CAT), and TNF-α expression increased significantly in 32 psu and 2 psu fish (p < 0.05). Most of the repeated measured parameters indicated limited acclimation capacity during the extreme warm exposure at all four salinity groups. However, overall results indicate that European seabass acclimatized at 12 psu and 6 psu salinities, can cope better during extreme warm exposure (33 °C).