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Abstract Microalgae are emerging as functional feed ingredients in aquaculture due to their immune-stimulating and stress-modulating properties. We investigated the potential of the microalgae Chlorella vulgaris as a feed supplement to improve the health and modulate microbiota and stress responses of Atlantic salmon. Triplicate groups of Atlantic salmon (~ 126 g) were reared in a recirculating aquaculture system (RAS) at 15 °C and received diets supplemented with 2% (CV2) or 14% (CV14) spray-dried C. vulgaris daily, 14% once weekly (CV14w), or a control diet (CD) for 8 weeks. Subsequently, all groups were exposed to an acute one-hour peracetic acid (CH3CO3H; PAA) treatment, a commonly used disinfectant in RAS. While CV14 increased feed conversion (FCR) significantly, feeding the diets CV2 and CV14w improved protein retention efficiency. CV14 significantly modulated beta-diversity in the intestinal digesta and mucosa, but this effect was already visible in fish fed CV2. Feeding CV14 and, to a lesser degree, CV2 increased the relative abundances of Paenarthrobacter and Trichococcus in the digesta and mucosa, which are able to metabolize complex carbohydrates. However, the same diets reduced the abundance of the lactic acid bacteria Lactobacillus and Weissella in the digesta and Floricoccus in the mucosa. Peracetic acid exposure induced systemic stress (increase in plasma glucose and cortisol) and a local immune response in the gill, with the most prominent upregulation of several immune- and stress-regulated genes (clra, cebpb, marco, tnfrsf14, ikba, c1ql2, drtp1) 18 h after exposure in fish fed the control diet. Fish receiving CV14 once a week showed a reduced transcriptional response to PAA exposure. Catalase protein abundance in the liver increased following exposure to PAA, while superoxide dismutase abundance in the gill and liver was increased in response to C. vulgaris inclusion before stress. Overall, the results highlight that a high (14%) inclusion rate of C. vulgaris in feed for Atlantic salmon impairs feed conversion and shifts the intestinal microbiota composition in digesta and mucosa. Weekly feeding of C. vulgaris proves a viable approach in improving protein retention and improving transcriptional resilience towards oxidative stress in increasingly intensive production systems. Thereby this study may motivate future studies on optimizing temporal feeding schedules for health-promoting aquafeeds.

Smoltification was found to impact both immune and stress responses of farmed Atlantic salmon (Salmo salar), but little is known about how salinity change affects salmon months after completed smoltification. Here, we examined (1) the effect of salinity change from brackish water to seawater on the stress and immune responses in Atlantic salmon and (2) evaluated if functional diets enriched with microalgae can mitigate stress- and immune-related changes. Groups of Atlantic salmon were fed for 8 weeks with different microalgae-enriched diets in brackish water and were then transferred into seawater. Samples of the head kidney, gill, liver and plasma were taken before seawater transfer (SWT), 20 h after SWT, and 2 weeks after SWT for gene-expression analysis, plasma biochemistry and protein quantification. The salmon showed full osmoregulatory ability upon transfer to seawater reflected by high nkaα1b levels in the gill and tight plasma ion regulation. In the gill, one-third of 44 investigated genes were reduced at either 20 h or 2 weeks in seawater, including genes involved in cytokine signaling (il1b) and antiviral defense (isg15, rsad2, ifit5). In contrast, an acute response after 20 h in SW was apparent in the head kidney reflected by increased plasma stress indicators and induced expression of genes involved in acute-phase response (drtp1), antimicrobial defense (camp) and stress response (hspa5). However, after 2 weeks in seawater, the expression of antiviral genes (isg15, rsad2, znfx1) was reduced in the head kidney. Few genes (camp, clra, c1ql2) in the gill were downregulated by a diet with 8% inclusion of Athrospira platensis. The results of the present study indicate that salinity change months after smoltification evokes molecular stress- and immune responses in Atlantic salmon. However, microalgae-enriched functional diets seem to have only limited potential to mitigate the related changes.

Microalgae are increasingly being investigated as functional feed additives in a variety of fish species, but our knowledge on how microalgae supplementation affects Atlantic salmon remains limited. We hypothesized that microalgae inclusion of 8% in the feed would improve performance, fatty acid and pigment deposition as well as health and immunity of Atlantic salmon reared in recirculating aquaculture systems (RAS). We fed Atlantic salmon smolts with five different microalgae enriched diets containing Tetraselmis chuii (TC), Arthrospira platensis (AP), Schizochytrium limacinum (SL) or Chlorella vulgaris, either intact (CVI) or as broken cell wall derivative (CVB) or a control diet (CD). After eight weeks of feeding in brackish water (13 psu), all groups were transferred to seawater (32 psu) for additional two weeks. Our results indicate that CVB improved feed conversion and protein retention, but reduced condition factor (p < 0.05) compared to fish fed with a control diet. Voluntary feed intake decreased in seawater, but was similar among diet groups. The amount of docosahexaenoic acid was particularly high in SL-fed fish and alpha-linolenic acid was enriched in fish fed CVI, CVB and TC (p < 0.05). Following seawater transfer, fat content and monounsaturated fatty acids decreased in the muscle, while polyunsaturated fatty acids increased. Lutein was present in all muscle samples, but highest concentrations were found in CVB-, CVI- and TC-fed fish. In the anterior intestine, microalgae supplementation induced differentially regulated trout protein 1 (drtp1) expression in CVI- and CVB-fed fish, but reduced the expression of interleukin 1 and 10 receptor (il1r2 & il10rb) in CVI-fed fish. In the liver, feeding CVI and SL induced complement C1q like 2 (c1ql2) expression, while reducing serum amyloid A5 (saa5) expression. Superoxide-dismutase protein concentration was induced in the liver of fish fed SL, while myeloperoxidase was reduced in most microalgae-fed groups. In conclusion, we show that commercially relevant microalgae can be used as functional feed additives for Atlantic salmon promoting different health aspects without negatively affecting their growth performance when cultivated in RAS.

Atlantic herring (Clupea harengus) has a complex population structure and displays a variety of reproductive strategies. Differences in reproductive strategies among herring populations are linked to their time of spawning, as well as to their reproductive investment which can be an indicator for migratory vs. stationary behavior. These differences are reflected in the number of oocytes (fecundity) and the size of the oocytes prior spawning. We studied potential mixing of herring with different reproductive strategies during the spring spawning season on a coastal spawning ground. It has been hypothesized that both spring and autumn spawning herring co-occur on this specific spawning ground. Therefore, we investigated the reproductive traits oocyte size, fecundity, fertilization success as well as length of the hatching larvae during the spring spawning season from February to April. We used a set of 11 single nucleotide polymorphism markers (SNPs), which are associated with spawning season, to genetically identify autumn and spring spawning herring. Reproductive traits were investigated separately within these genetically distinct spawning types. Furthermore, we used multivariate analyses to identify groups with potentially different reproductive strategies within the genetic spring spawners. Our results indicate that mixing between ripe spring and autumn spawners occurs on the spawning ground during spring, with ripe autumn spawners being generally smaller but having larger oocytes than spring spawners. Within spring spawners, we found large variability in reproductive traits. A following multivariate cluster analysis indicated two groups with different reproductive investment. Comparisons with other herring populations along the Norwegian coastline suggest that the high variability can be explained by the co-occurrence of groups with different reproductive investments potentially resulting from stationary or migratory behavior. Fertilization success and the length of the hatching larvae decreased with progression of the spawning season, with strong inter-individual variation, supporting our findings. Incorporating such complex population dynamics into management strategies of this species will be essential to build its future population resilience.

BACKGROUND: We recently compared the effects of bedside and outside the room ward rounds on patients’ knowledge about their medical care. Here, we report preferences of medical and nursing staff members regarding outside versus bedside ward rounds. METHODS: Within this ancillary project of a large multicentre randomised controlled trial, we prospectively conducted a survey of medical and nursing staff members participating in the weekly consultant ward rounds in the internal medicine division of three Swiss teaching hospitals between July 2017 and October 2019. Participants were asked about their preferences on outside versus bedside ward rounds. The primary endpoint was satisfaction of healthcare workers with the ward round measured with a visual analogue scale from 0 to 100. RESULTS: Between July 2017 and October 2019, 919 patients were included in the trial, and we received 891 survey responses (nurses 15.6%, residents 26.8%, attending physicians 29.6%, consultants 7.8% and chief physicians 20.2%. In the overall analysis, mean (± standard deviation) satisfaction of healthcare workers was higher with outside the room than bedside ward rounds (78.03 ± 16.96 versus 68.25 ± 21.10 respectively; age-, gender- and centre-adjusted difference of –10.46, 95% confidence interval [CI] –12.73 to –8.19; p

Introduction Intensive care unit patients are at risk for post-intensive care syndrome (PICS), which includes psychological, physical and/or cognitive sequelae after their hospital stay. Our aim was to investigate PICS in adult patients with out-of-hospital cardiac arrest (OHCA). Methods In this prospective observational cohort study, we assessed risks for PICS at 3 and 12-month follow-up within the following domains: a) physical impairment (EuroQol [EQ-5D-3L]), b) cognitive functioning (Cerebral Performance Category [CPC] score >1, modified Rankin Scale [mRS] >2) and c) psychological burden (Hospital Anxiety and Depression Scale [HADS], Impact of Event Scale-Revised [IES-R]). Results At 3 months, 69/139 patients (50%) met the definition of PICS including 37% in the physical domain, 25% in the cognitive domain and 13% in the psychological domain. Intubation (OR 2.3, 95%CI 1.1 to 5,0 p = 0.03), sedatives (OR 3.4, 95%CI 1 to 11, p = 0.045), mRS at discharge (OR 4.3, 95%CI 1.70 to 11.01, p = 0.002), CPC at discharge (OR 3.3, 95%CI 1.4 to 7.6, p = 0.005) and post-discharge work loss (OR 13.4, 95%CI 1.7 to 107.5, p = 0.014) were significantly associated with PICS. At 12 months, 52/110 (47%) patients had PICS, which was associated with prolonged duration of rehabilitation, higher APACHE scores, and higher mRS and CPC scores at hospital discharge. Conclusions Nearly half of long-term OHCA survivors show PICS after 3 and 12 months. These high numbers call for more emphasis on appropriate screening and treatment in this patient population. Future studies should evaluate whether early identification of these patients enables preventive strategies and treatment options.

IntroductionIntensive care unit patients are at risk for post-intensive care syndrome (PICS), which includes psychological, physical and/or cognitive sequelae after their hospital stay. Our aim was to investigate PICS in adult patients with out-of-hospital cardiac arrest (OHCA).MethodsIn this prospective observational cohort study, we assessed risks for PICS at 3 and 12-month follow-up within the following domains: a) physical impairment (EuroQol [EQ-5D-3L]), b) cognitive functioning (Cerebral Performance Category [CPC] score >1, modified Rankin Scale [mRS] >2) and c) psychological burden (Hospital Anxiety and Depression Scale [HADS], Impact of Event Scale-Revised [IES-R]).ResultsAt 3 months, 69/139 patients (50%) met the definition of PICS including 37% in the physical domain, 25% in the cognitive domain and 13% in the psychological domain. Intubation (OR 2.3, 95%CI 1.1 to 5,0 p = 0.03), sedatives (OR 3.4, 95%CI 1 to 11, p = 0.045), mRS at discharge (OR 4.3, 95%CI 1.70 to 11.01, p = 0.002), CPC at discharge (OR 3.3, 95%CI 1.4 to 7.6, p = 0.005) and post-discharge work loss (OR 13.4, 95%CI 1.7 to 107.5, p = 0.014) were significantly associated with PICS. At 12 months, 52/110 (47%) patients had PICS, which was associated with prolonged duration of rehabilitation, higher APACHE scores, and higher mRS and CPC scores at hospital discharge.ConclusionsNearly half of long-term OHCA survivors show PICS after 3 and 12 months. These high numbers call for more emphasis on appropriate screening and treatment in this patient population. Future studies should evaluate whether early identification of these patients enables preventive strategies and treatment options.

AIMS OF THE STUDY: There is increasing interest in better understanding of long COVID, a condition characterised by long-term sequelae — appearing or persisting after the typical convalescence period — of coronavirus disease 2019 (COVID-19). Herein, we describe long-term outcomes regarding residual symptoms and psychological distress in hospitalised patients 1 year after COVID-19. METHODS: This prospective cohort study included consecutive adult patients hospitalised for confirmed COVID-19 in two Swiss tertiary-care hospitals between March and June 2020. The primary endpoint was evidence of long COVID 1 year after discharge, defined as ≥1 persisting or new symptom related to COVID-19, from a predefined list of symptoms. Secondary endpoints included psychological distress and symptoms of post-traumatic stress disorder (PTSD). RESULTS: Among 90 patients included in the study, 63 (70%) had symptoms of long COVID 1 year after hospitalisation, particularly fatigue (46%), concentration difficulties (31%), shortness of breath (21%) and post-exertion malaise (20%). Three predictors, namely duration of hospitalisation (odds ratio [OR] 1.11, 95% confidence interval [CI] 1.00–1.22; p = 0.041), severity of illness (OR 1.19, 95% CI 1.04–1.37; p = 0.013), and self-perceived overall health status 30 days after hospitalisation (OR 0.97, 95% CI 0.94–1.00; p = 0.027) were associated with long COVID. Regarding secondary endpoints, 16 (18%) experienced psychological distress and 3 (3.3%) patients had symptoms of PTSD. CONCLUSION: A high proportion of COVID-19 patients report symptoms of long COVID 1 year after hospitalisation, which negatively affects their quality of life. The most important risk factors were severe initial presentation of COVID-19 with long hospital stays.

Summary: In vitro differentiation of pluripotent cells into β cells is a promising alternative to cadaveric-islet transplantation as a cure for type 1 diabetes (T1D). During the directed differentiation of human embryonic stem cells (hESCS) by exogenous factors, numerous genes that affect the differentiation process are turned on and off autonomously. Manipulating these reactions could increase the efficiency of differentiation and provide a more complete control over the final composition of cell populations. To uncover in vitro autonomous responses, we performed single-cell RNA sequencing on hESCs as they differentiate in spherical clusters. We observed that endocrine cells and their progenitors exist beside one another in separate compartments that activate distinct genetic pathways. WNT pathway inhibition in the endocrine domain of the differentiating clusters reveals a necessary role for the WNT inhibitor APC during islet formation in vivo. Accordingly, WNT inhibition in vitro causes an increase in the proportion of differentiated endocrine cells. : In vitro differentiation of pluripotent cells into β cells is a promising alternative to cadaveric islet transplantation as a cure for type 1 diabetes. Sharon et al. use scRNA-seq to identify the cell populations that form during the process and uncover a role for WNT pathway inhibition during endocrine differentiation. Keywords: Single-cell RNA sequencing, human embryonic stem cells, hESCs, in vitro differentiation, β cells, insulin, diabetes, pancreas development, WNT pathway, APC