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Microbiomes provide key ecological functions to their host; however, most host-associated microbiomes are too complicated to allow a model of essential host–microbe–microbe interactions. The intestinal microbiota of salmonids may offer a solution since few dominating species often characterize it. Healthy fish coexist with a mutualistic Mycoplasma sp. species, while stress allows the spread of pathogenic strains, such as Aliivibrio sp. Even after a skin infection, the Mycoplasma does not recover; Aliivibrio sp. often remains the dominant species, or Mycoplasma–Aliivibrio coexistence was occasionally observed. We devised a model involving interactions among the host immune system, Mycoplasma sp. plus a toxin-producing pathogen. Our model embraces a complete microbiota community and is in harmony with experimental results that host–Mycoplasma mutualism prevents the spread of pathogens. Contrary, stress suppresses the host immune system allowing dominance of pathogens, and Mycoplasma does not recover after stress disappears.

In the present study, the effects of dietary Halopithys incurva , a red macroalgae species, (0.25, 0.50, 1%) on whole-body serum and skin mucus immune system, antioxidant system and expression of various genes in zebrafish were investigated. At the end of the 8-week study, total protein, total immunoglobulin and lysozyme activities in whole-body serum and skin mucus increased in fish fed H. incurva (P < 0.05). While an increase was observed in superoxide dismutase (SOD), Catalase (CAT) and glutathione peroxidase (GPx) which are antioxidant enzyme activities in whole-body serum and skin mucus, a decrease in malondialdehyde (MDA) levels was detected (P < 0.05). All of the immune-related genes examined, such as Interleukin-1 beta (IL-1 beta), Tumor necrosis factor-alpha (TNF-alpha), Interferon-gamma (INF-gamma), were upregulated by the addition of 0.5% H. incurva (P < 0.05). While SOD and GPx, which are antioxidant enzyme-related genes, were remarkably upregulated in macroalgae fed fish (P < 0.05), no change was observed in CAT gene expression (P > 0.05). Based on the results of this study, it is considered that the addition of 0.5% H. incurva to the diets of commercially farmed fish will increase their immune and antioxidant defences and may contribute to the aquaculture sector for more sustainability.

Stress response is essential for the organism to quickly restore physiological homeostasis disturbed by various environmental insults. In addition to well-established physiological cascades, stress also evokes various brain and behavioral responses. Aquatic animal models, including the zebrafish (Danio rerio), have been extensively used to probe pathobiological mechanisms of stress and stress-related brain disorders. Here, we critically discuss the use of zebrafish models for studying mechanisms of stress and modeling its disorders experimentally, with a particular cross-taxon focus on the potential evolution of stress responses from zebrafish to rodents and humans, as well as its translational implications., Highlights • Aquatic animal models have been extensively used to study stress neurobiology. • Here, we discuss the use of zebrafish for studying mechanisms of stress-related brain disorders. • We focus on the evolution of stress responses in fish and mammals. • We also discuss translational implications of cross-taxon stress studies.

WOS:000681398200011; International audience; Gilthead seabream were equipped with intraperitoneal biologging tags to investigate cardiac responses to hypoxia and warming, comparing when fish were either swimming freely in a tank with conspecifics or confined to individual respirometers. After tag implantation under anaesthesia, heart rate (f(H)) required 60 h to recover to a stable value in a holding tank. Subsequently, when undisturbed under control conditions (normoxia, 21 degrees C), mean f(H) was always significantly lower in the tank than in the respirometers. In progressive hypoxia (100% to 15% oxygen saturation), mean f(H) in the tank was significantly lower than in the respirometers at oxygen levels down to 40%, with significant bradycardia in both holding conditions below this level. Simultaneous logging of tri-axial body acceleration revealed that spontaneous activity, inferred as the variance of external acceleration (VAR(m)), was low and invariant in hypoxia. Warming (21 to 31 degrees C) caused progressive tachycardia with no differences in f(H) between holding conditions. Mean VAR(m) was, however, significantly higher in the tank during warming, with a positive relationship between VAR(m) and f(H) across all temperatures. Therefore, spontaneous activity contributed to raising f(H) of fish in the tank during warming. Mean f(H) in respirometers had a highly significant linear relationship with mean rates of oxygen uptake, considering data from hypoxia and warming together. The high f(H) of confined seabream indicates that respirometry techniques may bias estimates of metabolic traits in some fishes, and that biologging on free-swimming fish will provide more reliable insight into cardiac and behavioural responses to environmental stressors by fish in their natural environment.

We investigated the gut microbiota of rabbit fish larvae at three locations in Vietnam (ThuanAn-northern, QuangNam-intermediate, BinhDinh-southern sampling site) over a three-year period. In the wild, the first food for rabbit fish larvae remains unknown, while the juveniles and adults are herbivores, forming schools near the coasts, lagoons, and river mouths, and feeding mainly on filamentous algae. This is the first study on the gut microbiota of the wild fish larvae and with a large number of individuals analyzed spatially and temporally. The Clostridiales order was the most predominant in the gut, and location-by-location alpha diversity showed significant differences in Chao-1, Hill number 1, and evenness. Analysis of beta diversity indicated that the location, not year, had an effect on the composition of the microbiota. In 2014, the gut microbiota of fish from QuangNam was different from that in BinhDinh; in 2015, the gut microbiota was different for all locations; and, in 2016, the gut microbiota in ThuanAn was different from that in the other locations. There was a time-dependent trend in the north-south axis for the gut microbiota, which is considered to be tentative awaiting larger datasets. We found limited variation in the gut microbiota geographically and in time and strong indications for a core microbiome. Five and fifteen OTUs were found in 100 and 99% of the individuals, respectively. This suggests that at this life stage the gut microbiota is under strong selection due to a combination of fish-microbe and microbe-microbe interactions. ispartof: MICROBIAL ECOLOGY vol:79 issue:3 pages:539-551 ispartof: location:United States status: published

DNA integrity is considered an important parameter of semen quality and is of significant value as a predictor of male fertility. Currently, there are several methods that can assess sperm DNA integrity. One such assay is the comet assay, or single-cell gel electrophoresis, which is a simple, sensitive, reliable, quick and low-cost technique that is used for measuring DNA strand breaks and repair at the level of individual cells. Although the comet assay is usually performed with somatic cells from different organs, the assay has the ability to detect genotoxicity in germ cells at different stages of spermatogenesis. Since the ability of sperm to remove DNA damage differs between the stages, interpretation of the results is dependent on the cells used. In this paper we give an overview on the use and applications of the comet assay on mature sperm and its ability to detect sperm DNA damage in both animals and humans. Overall, it can be concluded that the presence in sperm of significantly damaged DNA, assessed by the comet assay, is related to male infertility and seems to reduce live births. Although there is some evidence that sperm DNA damage also has a long-term impact on offspring's health, this aspect of DNA damage in sperm is understudied and deserves further attention. In summary, the comet assay can be applied as a useful tool to study effects of genotoxic exposures on sperm DNA integrity in animals and humans.

Driven by Regulation (EC) No. 1272/2008 and the European Water Framework Directive 2000/60/EC, we have re‐evaluated the available chronic freshwater ecotoxicity data for ionic silver (Ag) using strict data quality criteria. In addition, we generated new chronic ecotoxicity data for species potentially sensitive to Ag (the rotifer Brachionus calyciflorus, the cyanobacteria Anabaena flos‐aquae, and the aquatic plant Lemna minor) using Ag nitrate as the test substance. The 10% effect concentrations for the most sensitive endpoint per test species were 0.31 µg dissolved Ag/L for B. calyciflorus (population size), 0.41 µg dissolved Ag/L for A. flos‐aquae (growth rate), and 1.40 µg dissolved Ag/L for L. minor (root length). We included these values in the set of reliable chronic freshwater data, subsequently covering a total of 12 taxonomic groups and 15 species. Finally, we applied a species sensitivity distribution approach to the data set using various models. The best‐fitting model (Rayleigh distribution) resulted in a threshold value protective for 95% of the species of 0.116 µg dissolved Ag/L. This value is considered reliable and conservative in terms of species protection and can be used as a solid basis for setting thresholds for Ag in freshwater after application of an appropriate assessment factor. Furthermore, this value represents reasonable worst‐case conditions for bioavailability in European Union surface waters (low hardness and low dissolved organic carbon). Environ Toxicol Chem 2021;40:1678–1693. © 2021 European Precious Metals Federation. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

The new synthesized biphenyl-substituted chalcone derivatives were evaluated against the human carbonic anhydrase isoenzymes I and II (hCA I and hCA II), acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) enzymes. The synthesized biphenyl-substituted chalcone derivatives showed Ki values in range of 14.71-62.95 nM against hCA I, 31.69-47.20 nM against hCA II, 4.33-16.97 nM against AChE, and 3.72-6.74 nM against BChE enzymes. The synthesized biphenyl-substituted chalcone derivatives exhibited effective inhibition profiles against indicated metabolic enzymes when compared to acetazolamide (for hCA I and II) and tacrine (for AChE and BChE). Molecular docking, MD simulation, and MM/PB(GB)SA calculations were applied for nine compounds. The best dock scores were obtained from compounds 21, 22 and 24, and the lowest Delta GMM/PBSA energy were determined as 19, 21 and 22. All results may contribute to the development of new drugs particularly to treat some disorders, which widespread display in the world including glaucoma and Alzheimer's diseases. (C) 2022 Elsevier B.V. All rights reserved.

Background The Pacific bluefin tuna (Thunnus orientalis) is a regionally endothermic fish that maintains temperatures in their swimming musculature, eyes, brain and viscera above that of the ambient water. Within their skeletal muscle, a thermal gradient exists, with deep muscles, close to the backbone, operating at elevated temperatures compared to superficial muscles near the skin. Their heart, by contrast, operates at ambient temperature, which in bluefin tunas can range widely. Cardiac function in tunas reduces in cold waters, yet the heart must continue to supply blood for metabolically demanding endothermic tissues. Physiological studies indicate Pacific bluefin tuna have an elevated cardiac capacity and increased cold-tolerance compared to warm-water tuna species, primarily enabled by increased capacity for sarcoplasmic reticulum calcium cycling within the cardiac muscles. Results Here, we compare tissue-specific gene-expression profiles of different cardiac and skeletal muscle tissues in Pacific bluefin tuna. There was little difference in the overall expression of calcium-cycling and cardiac contraction pathways between atrium and ventricle. However, expression of a key sarcoplasmic reticulum calcium-cycling gene, SERCA2b, which plays a key role maintaining intracellular calcium stores, was higher in atrium than ventricle. Expression of genes involved in aerobic metabolism and cardiac contraction were higher in the ventricle than atrium. The two morphologically distinct tissues that derive the ventricle, spongy and compact myocardium, had near-identical levels of gene expression. More genes had higher expression in the cool, superficial muscle than in the warm, deep muscle in both the aerobic red muscle (slow-twitch) and anaerobic white muscle (fast-twitch), suggesting thermal compensation. Conclusions We find evidence of widespread transcriptomic differences between the Pacific tuna ventricle and atrium, with potentially higher rates of calcium cycling in the atrium associated with the higher expression of SERCA2b compared to the ventricle. We find no evidence that genes associated with thermogenesis are upregulated in the deep, warm muscle compared to superficial, cool muscle. Heat generation may be enabled by by the high aerobic capacity of bluefin tuna red muscle.

Littoral benthic primary production is considered the most important energy source of consumers in subarctic lakes. We analyzed essential fatty acid (EFA) and amino acid (EAA) content of 23 littoral benthic macroinvertebrate taxa as well as cladocerans and copepods from pelagic and littoral habitats of 8–9 subarctic lakes to compare their nutritional quality. Pelagic crustacean zooplankton had significantly higher EFA and total FA content (on average 2.6‐fold and 1.6‐fold, respectively) than littoral macroinvertebrates in all our study lakes. Specifically, docosahexaenoic acid (DHA), one of the most important EFA for juvenile fish, was almost exclusively found in pelagic copepods. In littoral macroinvertebrates, only Lymnaea (Gastropoda), Eurycercus (Cladocera), and Gammarus (Amphipoda) contained a low amount of DHA, whereas most littoral invertebrate taxa contained moderate amounts of eicosapentaenoic acid (EPA). The difference in DHA content may explain why so many generalist fish shift their diet to pelagic zooplankton at their peak abundance in mid/late‐summer. Meanwhile, the differences in EAA content between pelagic zooplankton and littoral invertebrates were much lower than for EFA suggesting a wider availability of EAA in subarctic lakes, except for methionine. In the studied subarctic lakes, EFA and EAA variation in consumers was more related to taxon‐specific than lake‐specific characteristics. This indicates that climate‐induced changes in the abundance and community structure of zooplankton vs. littoral macroinvertebrates will be important parameters in determining the availability of EFA and EAA to juvenile fish, and potentially fish production. peerReviewed

Key Points Zebrafish IL-4–like cytokines promote type 2 and suppress type 1 immunity. Zebrafish IL-10 is potently anti-inflammatory and essential for gill homeostasis., Mucosal surfaces such as fish gills interface between the organism and the external environment and as such are major sites of foreign Ag encounter. In the gills, the balance between inflammatory responses to waterborne pathogens and regulatory responses toward commensal microbes is critical for effective barrier function and overall fish health. In mammals, IL-4 and IL-13 in concert with IL-10 are essential for balancing immune responses to pathogens and suppressing inflammation. Although considerable progress has been made in the field of fish immunology in recent years, whether the fish counterparts of these key mammalian cytokines perform similar roles is still an open question. In this study, we have generated IL-4/13A and IL-4/13B mutant zebrafish (Danio rerio) and, together with an existing IL-10 mutant line, characterized the consequences of loss of function of these cytokines. We demonstrate that IL-4/13A and IL-4/13B are required for the maintenance of a Th2-like phenotype in the gills and the suppression of type 1 immune responses. As in mammals, IL-10 appears to have a more striking anti-inflammatory function than IL-4–like cytokines and is essential for gill homeostasis. Thus, both IL-4/13 and IL-10 paralogs in zebrafish exhibit aspects of conserved function with their mammalian counterparts.

Alzheimer's disease (AD) is one of the cognitive or memory-related impairments occurring with advancing age. Since its exact mechanism is not known, the full therapy has still not been found. Acetylcholinesterase (AChE) has been reported to be a viable therapeutic target for the treatment of AD and other dementias. To this end, acetylcholinesterase inhibitors (AChEIs) are commonly used. AChE is a member of the hydrolase enzyme family. A hydrolase is an enzyme that catalyzes the hydrolysis of a chemical bond. AChE is useful for the development of novel and mechanism-based inhibitors. It has a role in the breakdown of acetylcholine (ACh) neurotransmitters, such as acetylcholine-mediated neurotransmission. AChEIs are the most effective approaches to treat AD. AChE hydrolyzes ACh to acetate and choline, as an important neurotransmitter substance. Recently, Gulcin and his group explored new AChEIs. The most suggested mechanism for AD is the deficiency of ACh, which is an important neurotransmitter. In this regard, AChEIs are commonly used for the symptomatic treatment of AD. They act in different ways, such as by inhibiting AChE, protecting cells from free radical toxicity and beta-amyloid-induced injury or inhibiting the release of cytokines from microglia and monocytes. This review focuses on the role of AChEIs in AD using commonly available drugs. Also, the aim of this review is to research and discuss the role of AChEIs in AD using commonly available drugs. Therefore, in our review, related topics like AD and AChEIs are highlighted. Also, the latest work related to AChEIs is compiled. In recent research studies, novel natural and synthetic AChEIs, used for AD, are quite noteworthy. These studies can be very promising in detecting potent drugs against AD.

The generalized bioavailability model (gBAM) has been proposed as an alternative to the biotic ligand model (BLM) for modeling bioavailability and chronic toxicity of copper (Cu). The gBAM combines a log-linear effect of pH on free Cu2+ ion toxicity with BLM-type parameters for describing the protective effects of major cations (calcium [Ca]2+ , magnesium [Mg]2+ , and sodium [Na]+ ). In the present study, a Windermere Humic Aqueous Model (WHAM) VII-based gBAM for fish was parametrized based on an existing chronic (30-d) dataset of juvenile rainbow trout (Oncorhynchus mykiss). The model, with defined parameters (pH slope parameter [SpH ] = 0.4449 and biotic ligand competition constants [log KCaBL = 4.0, log KMgBL = 3.4, and log KNaBL = 3.0]), was shown to accurately predict the effects of pH, dissolved organic carbon, Ca, and Mg on chronic Cu toxicity to juvenile rainbow trout at the effect levels relevant for environmental risk assessment (i.e., median prediction error of 1.3-fold for 10 and 20% lethal concentrations). The gBAM predicted the effect of pH more accurately than a previously published Cu BLM for juvenile rainbow trout, especially at pH > 8. We also evaluated the cross-species and cross-life stage applicability of the newly developed juvenile rainbow trout gBAM using existing chronic Cu toxicity data with early life stages of fathead minnow (Pimephales promelas) and rainbow trout. We did this because using a single bioavailability model for all fish species and life stages is practical from a regulatory point of view. Although the early life stage datasets exhibit considerable uncertainties, 91% of the considered toxicity values at the effect levels most relevant in European environmental regulations (10% effect on survival or growth) were predicted within a 2-fold error. Overall, the chronic Cu gBAM we developed is a valuable alternative for the existing chronic Cu BLM for rainbow trout and performs sufficiently well to be used in risk assessment according to currently accepted standards of bioavailability model performance (from the current European regulatory point of view). However, our analysis also suggests that bioavailability relations differ between different fish life stages and between endpoints (e.g., mortality vs growth), which is currently not accounted for in environmental risk assessments. Environ Toxicol Chem 2020;39:2424-2436. © 2020 SETAC.

The aim of the present study was to determine the roles of externally versus internally oriented CO2/H+-sensitive chemoreceptors in promoting cardiorespiratory responses to environmental hypercarbia in the facultative air-breathing fish, Chitala ornata (the clown knifefish). Fish were exposed to environmental acidosis (pH 6.0) or hypercarbia (ae 30 torr PCO2) that produced changes in water pH equal to the pH levels of the acidotic water to distinguish the relative roles of CO2 versus H+. We also injected acetazolamide to elevate arterial levels of PCO2 and [H+] in fish in normocarbic water to distinguish between internal and external stimuli. We measured changes in gill ventilation frequency, air breathing frequency, heart rate and arterial blood pressure in response to each treatment as well as the changes produced in arterial PCO2 and pH. Exposure to normocarbic water of pH 6.0 for 1 h did not produce significant changes in any measured variable. Exposure to hypercarbic water dramatically increased air breathing frequency, but had no effect on gill ventilation. Hypercarbia also produced a modest bradycardia and fall in arterial blood pressure. Injection of acetazolamide produced similar effects. Both hypercarbia and acetazolamide led to increases in arterial PCO2 and falls in arterial pH although the changes in arterial PCO2/pH were more modest following acetazolamide injection as were the increases in air breathing frequency. The acetazolamide results suggest that the stimulation of air breathing was due, at least in part, to stimulation of internally oriented CO2/H+ chemoreceptors monitoring blood gas changes.

WOS: 000428835100026, Science Citation Index Expanded, This study was conducted on the microbial flora isolated from gills and intestine tissues of commercially important finfish species: saddled seabream (Oblada melanura), gilthead sea bream (Sparus amnia), Bogue (Boops boops), horse mackerel (Trachurus mediterraneus), red mullet (Mullus barbants), brushtooth lizardfish (Saurida undosquamis), grey mullet (Mugil cephalus), threadfin bream, (Nemipterus randalli), which were caught from the Iskenderun Bay at 6 different locations (local fishermen's fish market) were evaluated. The Serratia spp., Enterobacter aerogenes, Klebsiellu pneumoniae, and Enterobacter cloacae were isolated from the gill samples, while E. aerogenes, E. cloacae, Proteus vulgaris, K. pneumoniae and Pseudomonas fluorescens were isolated from the fish intestine samples. E. aerogenes (68.4%) Serratia spp. (53.3%), E. cloacae (50%) and K. pneumoniae (44.4%) showed high level of resistance against ampicillin. K. pneumoniae also showed high resistance against Cefepime (52.9%) and Ciprofloxacin (47.1%). Pseudomonus species exhibited high level of resistance against Cephalosporin., Scientific Research Projects Unit of Mustafa Kemal University [1303Y0105], This work was supported by Scientific Research Projects Unit of Mustafa Kemal University (Project Number: 1303Y0105). We thank Prof. Dr. Nizami Duran (Faculty of Medicine. Mustafa Kemal University) and Prof. Dr. Sefa Ayhan Demirhan (Faculty of Marine Sciences and Technology. Iskenderun Technical University) for their help.

WOS: 000414941000006, A 12-week feeding trial was conducted to estimate the effects of supplemented amino acids (lysine and methionine) with different dietary protein levels on growth, haematology and liver histology in meagre (Argyrosomus regius) at two different sizes: fingerling (15.2g) and juvenile (44.4g). Six practical diets were prepared, and three of these practical diets were formulated with 40 (P40), 44 (P44) and 48% (P48) crude protein without supplementation of amino acids. Other three diets having same protein levels were supplemented with lysine and methionine (P40AA, P44AA and P48AA) to bring these amino acids level up to that estimated to be at the least in the 48% protein diet. Final mean weight (FMW) and specific growth rate (SGR) of P48AA in fingerlings were higher than that of 40AA. According to FMW and SGR of juveniles, there was interaction found between dietary protein levels and the supplementation of amino acids. The FMW and SGR of meagre fed P44AA were higher than that of fish fed the other diets, except fish fed the P48. Economic profit index, packed cell volume and haemoglobin for juvenile meagre were significantly improved with the dietary protein level and amino acid supplementation. The liver tissues of the P48 group in both sizes displayed better structure compared with the other groups. In conclusion, dietary crude protein content of practical diets for juvenile meagre could be reduced from 48% to 44% by adding essential amino acids with an enhancement in growth, health and economic profit., T.C. Gida Tarim ve Hayvancilik Bakanligi [13/RD/31], T.C. Gida Tarim ve Hayvancilik Bakanligi, Grant/Award Number: 13/R&D/31

This work received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) and their support is gratefully acknowledged. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions. Much attention has been given to insulin-like growth factor (Igf) pathways that regulate the balance of skeletal muscle protein synthesis and breakdown in response to a range of extrinsic and intrinsic signals. However, we have a less complete understanding of how the same signals modulate muscle mass upstream of such signalling, through a family of functionally-diverse Igf-binding proteins (Igfbps) that modify the availability of Igfs to the cell receptor Igf1r. We exposed cultured myotubes from Atlantic salmon (Salmo salar L.) to treatments recapturing three catabolic signals: inflammation (interleukin-1β), stress (dexamethasone) and fasting (amino acid deprivation), plus one anabolic signal: recovery of muscle mass post-fasting (supplementation of fasted myotubes with Igf-I and amino acids). The intended phenotype of treatments was confirmed by significant changes in myotube diameter and immunofluorescent staining of structural proteins. We quantified the mRNA-level regulation of the full expressed Igf and Igfbp gene complement across a post-treatment time course, along with marker genes for muscle structural protein synthesis, as well as muscle breakdown, via the ubiquitin-proteasome and autophagy systems. Our results highlight complex, non-overlapping responses of Igfbp family members to the different treatments, suggesting that the profile of expressed Igfbps is differentially regulated by distinct signals promoting similar muscle remodelling phenotypes. We also demonstrate divergent regulation of salmonid-specific gene duplicates of igfbp5b1 and igfbp5b2 under distinct catabolic and anabolic conditions. Overall, this study increases our understanding of the regulation of Igfbp genes in response to signals that promote remodelling of skeletal muscle. Postprint

Recent studies reported positive effects of taurine supplementation to plant protein-based diets on fish growth performance and feed conversion ratio but the mechanisms involved remain unclear. The objective of this work was to provide a first insight on the importance of taurine on dietary protein and lipid absorption and utilisation, in Senegalese sole (Solea senegalensis) juveniles fed plant-based diets. Seven practical diets were tested: a fishmeal-based diet (FM) and a plant protein-based formula (PP85) to which taurine was added in graded levels: 0.2% (TAU1), 0.3% (TAU2), 0.4% (TAUS), 0.7% (TAU4) and 1.5% (TAU5). Short-term metabolic trials were performed by tube-feeding the different experimental diets labelled with different tracers: C-14-taurine, C-14-triolein (as tracer of dietary triacylglycerol) and a mixture of C-14-amino acids. Feeding sole juveniles with the PP85 diet affected taurine metabolism, since a higher proportion of dietary taurine was directed to gallbladder and probably used for bile salt synthesis. Consistent with this, fish receiving the plant-based low taurine-content diets (PP85 and TAU1) displayed a poor triacyglycerol digestion capacity. A higher proportion of C-14-amino acids was retained in fish muscle when fed the TAU5 compared to the PP85 diet. These short-term trials suggested that taurine supplementation to a plant-based diet might be beneficial to sole performance by enhancing bile salt synthesis and triacylglycerol digestion as well as muscle amino acid retention. However, this dietary supplementation should be tested in long-term trials to verify the effect on fish growth and to assess the beneficial effects on protein and lipid metabolism suggested here. Statement of relevance in the general field of aquaculture (limited to 60 characters): Adding taurine to a plant-based diet is beneficial for sole (C) 2016 Elsevier B.V. All rights reserved. National Funds through Fundacao para a Ciencia e Tecnologia [PTDC/MAR/117047/2010] Fundacao para a Ciencia e Tecnologia, Portugal [SFRH/BDP/65578/2009] info:eu-repo/semantics/acceptedVersion

In this study, a series of novel bis-sulfone compounds (2a-2j) were synthesized by oxidation of the bis-sulfides under mild reaction conditions. The bis-sulfone derivatives were characterized by H-1-NMR, C-13-NMR, Fourier-transform infrared spectroscopy, and elemental analysis techniques. Nuclear Overhauser effect experiments were performed to determine the orientation of the sulfonyl groups in bis-sulfone derivatives. Here, we report the synthesis and testing of novel bis-sulfone compound-based hybrid scaffold of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitors for the development of novel molecules toward the therapy of Alzheimer's disease. The novel synthesized bis-sulfone compounds demonstrated K-i values between 11.4 +/- 3.4 and 70.7 +/- 23.2 nM on human carbonic anhydrase I isozyme (hCA I), 28.7 +/- 6.6 to 77.6 +/- 5.6 nM on human carbonic anhydrase II isozyme (hCA II), 18.7 +/- 2.61 to 95.4 +/- 25.52 nM on AChE, and 9.5 +/- 2.1 to 95.5 +/- 1.2 nM on BChE enzymes. The results showed that novel bis-sulfone derivatives can have promising drug potential for glaucoma, leukemia, epilepsy, and Alzheimer's disease, which are associated with the high enzymatic activity of hCA I, hCA II, AChE, and BChE enzymes., Atatürk Üniversitesi Funding Source: Medline; Akdeniz Üniversitesi [FDK-2016-1541] Funding Source: Medline

In the present work, recent studies that contributed for improving dietary protein in practical microdiets for Senegalese sole larvae are revised, in an attempt to overcome some of the current problems in this species larviculture, such as the difficult early adaptation to inert diets and highly variable growth rates. Different diet formulation strategies were employed in an attempt to improve Senegalese sole larvae capacity to utilize and deposit protein throughout metamorphosis, to further maximize growth potential: (1) increasing indispensable amino acids (IAA) content (2) meeting the ideal IAA profile by adjusting the dietary AA profile to the larval body AA profile and (3) decreasing the complexity (molecular weight) of dietary protein to increase its digestibility. Either manipulating the quality or the complexity of dietary protein had impact on the larvae capacity to utilize protein and direct it for growth. Sole larvae seem to be able to adapt their digestive functions and metabolic capacity to dietary protein. Moreover, increasing the dietary IAA/DAA ratio and changing the degree of hydrolysis of dietary protein affected the expression pattern of muscle growth related genes, with consequences on muscle cellularity and potential for growth. The expression of DNA methyltransferases was altered in response to changes in dietary protein. The novelty of such information in fish may trigger further studies on the effect of dietary protein on the epigenetic regulation of growth. In conclusion, optimal protein quality for Senegalese sole seems to change during larval development. Whereas the inclusion of a moderately hydrolysed protein comes up as a promising way to improve growth in early larval stages, larger peptides and intact protein seem to be more suitable to sole post-larvae and young juveniles. Therefore, these results suggest that dietary protein fraction formulation of microdiets for Senegalese sole should be adapted to each developmental stage, what has important consequences for practical larval microdiets formulation and feeding protocols. POAlgarve 21 [13380] QREN [13380] European UnionEuropean Union (EU) [13380] FCT grant [SFRH/BD/82149/2011] FCT investigator grant - European Social Fund, the Operational Programme Human Potential [IF/00482/2014/CP1217/CT0005] FCT investigator grant - Foundation for Science and Technology of Portugal (FCT) [IF/00482/2014/CP1217/CT0005]

To understand the effect of low dietary phosphorus (P) intake on the vertebral column of Atlantic salmon Salmo salar, a primary P deficiency was induced in post-smolts. The dietary P provision was reduced by 50% for a period of 10 weeks under controlled conditions. The animal's skeleton was subsequently analysed by radiology, histological examination, histochemical detection of minerals in bones and scales and chemical mineral analysis. This is the first account of how a primary P deficiency affects the skeleton in S. salar at the cellular and at the micro-anatomical level. Animals that received the P-deficient diet displayed known signs of P deficiency including reduced growth and soft, pliable opercula. Bone and scale mineral content decreased by c. 50%. On radiographs, vertebral bodies appear small, undersized and with enlarged intervertebral spaces. Contrary to the X-ray-based diagnosis, the histological examination revealed that vertebral bodies had a regular size and regular internal bone structures; intervertebral spaces were not enlarged. Bone matrix formation was continuous and uninterrupted, albeit without traces of mineralization. Likewise, scale growth continues with regular annuli formation, but new scale matrix remains without minerals. The 10 week long experiment generated a homogeneous osteomalacia of vertebral bodies without apparent induction of skeletal malformations. The experiment shows that bone formation and bone mineralization are, to a large degree, independent processes in the fish examined. Therefore, a deficit in mineralization must not be the only cause of the alterations of the vertebral bone structure observed in farmed S. salar. It is discussed how the observed uncoupling of bone formation and mineralization helps to better diagnose, understand and prevent P deficiency-related malformations in farmed S. salar.

It is well known that healthy gut microbiota is essential to promote host health and well-being. The intestinal microbiota of endothermic animals as well as fish are classified as autochthonous or indigenous, when they are able to colonize the host’s epithelial surface or are associated with the microvilli, or as allochthonous or transient (associated with digesta or are present in the lumen). Furthermore, the gut microbiota of aquatic animals is more fluidic than that of terrestrial vertebrates and is highly sensitive to dietary changes. In fish, it is demonstrated that [a] dietary form (live feeds or pelleted diets), [b] dietary lipid (lipid levels, lipid sources and polyunsaturated fatty acids), [c] protein sources (soybean meal, krill meal and other meal products), [d] functional glycomic ingredients (chitin and cellulose), [e] nutraceuticals (probiotics, prebiotics, synbiotics and immunostimulants), [f] antibiotics, [g] dietary iron and [h] chromic oxide affect the gut microbiota. Furthermore, some information is available on bacterial colonization of the gut enterocyte surface as a result of dietary manipulation which indicates that changes in indigenous microbial populations may have repercussion on secondary host–microbe interactions. The effect of dietary components on the gut microbiota is important to investigate, as the gastrointestinal tract has been suggested as one of the major routes of infection in fish. Possible interactions between dietary components and the protective microbiota colonizing the digestive tract are discussed.

Chalcones and their derivatives are increasing attention due to numerous biochemical and pharmacological applications. In this study, a series of novel organohalogen chalcone derivatives (5-12) were tested towards alpha-glycosidase (alpha-Gly), acetylcholinesterase (AChE) human carbonic anhydrase I (hCA I), and carbonic anhydrase II (hCA II) enzymes. These compounds (5-12) showed K,s in ranging of 16.24 - 40.96 nM on hCA I, 29.61-67.15 nM on hCA II, 1.21-4.39 nM on AChE and 12.54-35.22 nM on alpha-glycosidase. The novel organohalogen chalcone derivatives (5-12) had effective inhibition profiles against all tested metabolic enzymes. Also, because of the enzyme inhibitory effects of the compounds (5-12), they have the potential of drug candidates to treat of some diseases including epilepsy, glaucoma, type-2 diabetes mellitus (T2DM), Alzheimer's disease (AD), and leukemia. Also, the chalcone derivatives with best inhibition score docked into the active site of indicated metabolic enzymes receptors. Bro-mobenzyle and chlorophenyl moieties of chalcone derivatives contribute to their inhibitor properties on the enzymes. (C) 2020 Published by Elsevier B.V.

International audience; Impacted marine environments lead to metal accumulation in edible marine fish, ultimately impairing human health. Nevertheless, metal accumulation is highly variable among marine fish species. In addition to ecological features, differences in bioaccumulation can be attributed to species-related physiological processes, which were investigated in two marine fish present in the Canary Current Large Marine Ecosystem (CCLME), where natural and anthropogenic metal exposure occurs. The European sea bass Dicentrarchus labrax and Senegalese sole Solea senegalensis were exposed for two months to two environmentally realistic dietary cadmium (Cd) doses before a depuration period. Organotropism (i.e., Cd repartition between organs) was studied in two storage compartments (the liver and muscle) and in an excretion vector (bile). To better understand the importance of physiological factors, the significance of hepatic metallothionein (MT) concentrations in accumulation and elimination kinetics in the two species was explored. Accumulation was faster in the sea bass muscle and liver, as inferred by earlier Cd increase and a higher accumulation rate. The elimination efficiency was also higher in the sea bass liver compared to sole, as highlighted by greater biliary excretion. In the liver, no induction of MT synthesis was attributed to metal exposure, challenging the relevance of using MT concentration as a biomarker of metal contamination. However, the basal MT pools were always greater in the liver of sea bass than in sole. This species-specific characteristic might have enhanced Cd biliary elimination and relocation to other organs such as muscle through the formation of more Cd/MT complexes. Thus, MT basal concentrations seem to play a key role in the variability observed in terms of metal concentrations in marine fish species.

The present study aimed to compare effects of increasing chronic stress load on the stress response of European seabass (Dicentrarchus labrax) and gilthead seabream (Sparus aurata) to identify neuroendocrine functions that regulate this response. Fish were left undisturbed (controls) or exposed to three levels of chronic stress for 3 weeks and then subjected to an acute stress test (ACT). Chronic stress impeded growth and decreased feed consumption in seabass, not in seabream. In seabass basal cortisol levels are high and increase with stress load; the response to a subsequent ACT decreases with increasing (earlier) load. Basal cortisol levels in seabream increase with the stress load, whereas the ACT induced a similar response in all groups. In seabass and seabream plasma a-MSH levels and brain stem serotonergic activity and turnover were similar and not affected by chronic stress. Species-specific molecular neuro-regional differences were seen. In-situ hybridization analysis of the early immediate gene cfos in the preoptic area showed ACT-activation in seabream; in seabass the expression level was not affected by ACT and seems constitutively high. In seabream, expression levels of telencephalic cif, crfbp, grl , and mr were downregulated; the seabass hypothalamic preoptic area showed increased expression of cif and gr1, and decreased expression of mr, and this increased the grl/mr ratio considerably. We substantiate species-specific physiological differences to stress coping between seabream and seabass at an endocrine and neuroendocrine molecular level. Seabass appear less resilient to stress, which we conclude from high basal activities of stress-related parameters and poor, or absent, responses to ACT. This comparative study reveals important aquaculture, husbandry, and welfare implications for the rearing of these species.

International audience; Chlorinated paraffins are industrial chemicals that can be subdivided into short-chain (SCCP), medium chain (MCCP), and long-chain (LCCP) chlorinated paraffins. The global production volumes of MCCPs are nowadays suspected to be much higher than those of S- and LCCPs, and the few available studies on the environmental occurrence of chlorinated paraffins report often higher MCCP concentrations than S- or LCCP concentrations in the environment. The present review focuses, therefore, on MCCPs specifically and provides a literature overview and a data analysis of the production volumes, PBT properties (persistence, bioaccumulation potential, and toxicity), and the worldwide measured concentrations of MCCP in environmental samples, biota, and humans. Furthermore, we include our own measurements of technical CP formulations from China, the major global producing country, to estimate the global production amounts of MCCPs. The key findings from this review are that (1) MCCPs are toxic to the aquatic environment, and the available data suggest that they are also persistent; (2) available time trends for MCCPs in soil, biota, and most of the sediment cores show increasing time trends over the last years to decades; and (3) MCCP concentrations in sediment close to local sources exceed toxicity thresholds (i.e., the PNEC). Our study shows that overall, MCCPs are of growing concern, and regulatory actions Should be considered seriously.

Although several efforts have been made to describe the immunoendocrine interaction in fish, there are no studies to date focusing on the characterization of the immune response and glucocorticoid synthesis using the host-pathogen interaction on larval stage as an early developmental stage model of study. Therefore, the aim of this study was to evaluate the glucocorticoid synthesis and the modulation of stress-and innate immune-related genes in European sea bass (Dicentrarchus labrax) larvae challenged with Vibrio anguillarum. For this purpose, we challenged by bath full-sibling gnotobiotic sea bass larvae with 107 CFU mL(-1) of V. anguillarum strain HI 610 on day 5 post-hatching (dph). The mortality was monitored up to the end of the experiment [120 hours post-challenge (hpc)]. While no variations were registered in non-challenged larvae maintained under gnotobiotic conditions (93.20% survival at 120 hpc), in the challenged group a constant and sustained mortality was observed from 36 hpc onward, dropping to 18.31% survival at 120 hpc. Glucocorticoid quantification and expression analysis of stress-and innate immunity-related genes were carried out in single larvae. The increase of cortisol, cortisone and 20 beta-dihydrocortisone was observed at 120 hpc, although did not influence upon the modulation of stress-related genes (glucocorticoid receptor 1 [gr1], gr2, and heat shock protein 70 [hsp70]). On the other hand, the expression of lysozyme, transferrin, and il-10 differentially increased at 120 hpc together with a marked upregulation of the pro-inflammatory cytokines (il-1 beta and il-8) and hepcidin, suggesting a late activation of defense mechanisms against V. anguillarum. Importantly, this response coincided with the lowest survival observed in challenged groups. Therefore, the increase in markers associated with glucocorticoid synthesis together with the upregulation of genes associated with the anti-inflammatory response suggests that in larvae infected with V. anguillarum a pro-inflammatory response at systemic level takes place, which then leads to the participation of other physiological mechanisms at systemic level to counteract the effect and the consequences of such response. However, this late systemic response could be related to the previous high mortality observed in sea bass larvae challenged with V. anguillarum.

In the current study, we investigated the effects of carp Il10 on phagocytes and lymphocytes. Carp Il10 shares several prototypical inhibitory activities on phagocytes with mammalian IL-10, including deactivation of neutrophils and macrophages, as shown by inhibition of oxygen and nitrogen radical production, as well as reduced expression of proinflammatory genes and mhc genes involved in Ag presentation. Similar to mammalian IL-10, carp Il10 acts through a signaling pathway involving phosphorylation of Stat3, ultimately leading to the early upregulation of socs3 expression. To our knowledge, this is the first study of the effects of Il10 on lymphocytes in fish. Although Il10 did not affect survival and proliferation of T cells from naive animals, it greatly promoted survival and proliferation of T cells in cultures from immunized animals, but only when used in combination with the immunizing Ag. Preliminary gene expression analysis suggests that, under these circumstances, carp Il10 stimulates a subset of CD8+ memory T cells while downregulating CD4+ memory Th1 and Th2 responses. In addition to the regulatory effect on T cells, carp Il10 stimulates proliferation, differentiation, and Ab secretion by IgM+ B cells. Overall, carp Il10 shares several prototypical activities with mammalian IL-10, including downregulation of the inflammatory response of phagocytes, stimulation of proliferation of subsets of memory T lymphocytes, and proliferation, differentiation, and Ab secretion by IgM+ B lymphocytes. To our knowledge, this is the first comprehensive analysis of biological activities of fish Il10 on both phagocytes and lymphocytes showing functional conservation of several properties of Il10.

A wide range of estrogenic endocrine disruptors (EDCs) are accumulating in the environment and may disrupt the physiology of aquatic organisms. The effects of EDCs on fish have mainly been assessed using reproductive endpoints and in vivo animal experiments. We used a simple non-invasive assay to evaluate the impact of estrogens and EDCs on sea bass (Dicentrarchus labrax) and tilapia (Oreochromis mossambicus) scales. These were exposed to estradiol (E2), two phytoestrogens and six anthropogenic estrogenic/anti-estrogenic EDCs and activities of enzymes related to mineralized tissue turnover (TRAP, tartrate-resistant acid phosphatase and ALP, alkaline phosphatase) were measured. Semi-quantitative RT-PCR detected the expression of both membrane and nuclear estrogen receptors in the scales of both species, confirming scales as a target for E2 and EDCs through different mechanisms. Changes in TRAP or ALP activities after 30 minute and 24 h exposure were detected in sea bass and tilapia scales treated with E2 and three EDCs, although compound-, time- and dose-specific responses were observed for the two species. These results support again that the mineralized tissue turnover of fish is regulated by estrogens and reveals that the scales are a mineralized estrogen-responsive tissue that may be affected by some EDCs. The significance of these effects for whole animal physiology needs to be further explored. The in vitro fish scale bioassay is a promising non-invasive screening tool for E2 and EDCs effects, although the low sensitivity of TRAP/ALP quantification limits their utility and indicates that alternative endpoints are required. info:eu-repo/semantics/submittedVersion

Homologous and heterologous (genogroup Ia) DNA vaccines against viral hemorrhagic septicemia virus (genogroup IVa) conferred partial protection in Pacific Herring Clupea pallasii. Early protection at 2 weeks postvaccination (PV) was low and occurred only at an elevated temperature (12.6°C, 189 degree days), where the relative percent survival following viral exposure was similar for the two vaccines (IVa and Ia) and higher than that of negative controls at the same temperature. Late protection at 10 weeks PV was induced by both vaccines but was higher with the homologous vaccine at both 9.0°C and 12.6°C. Virus neutralization titers were detected among 55% of all vaccinated fish at 10 weeks PV. The results suggest that the immune response profile triggered by DNA vaccination of herring was similar to that reported for Rainbow Trout Oncorhynchus mykiss by Lorenzen and LaPatra in 2005, who found interferon responses in the early days PV and the transition to adaptive response later. However, the protective effect was far less prominent in herring, possibly reflecting different physiologies or adaptations of the two fish species. Received August 1, 2016; accepted March 10, 2017.

[EN] Protocols for the cryopreservation of fish gametes have been developed for many different fish species, in special, freshwater salmonids and cyprinids. Methods for sperm freezing have progressed during the last decades due to the increasing number of potential applications: aquaculture (genetic improvement programs, broodstock management, helping with species having reproductive problems), biotechnology studies using model fish species (preservation of transgenic or mutant lines), cryobanking of genetic resources from endangered species, etc. This mini-review tries to give an overview of the present situation of this area of research, identifying the main challenges and perspectives, redirecting the reader to more in-depth reviews and papers., Partially funded by the European Training Network IMPRESS (Marie Sklodowska Curie Actions; Grant agreement nº: 642893), COST Office (Food and Agriculture COST Action FA1205: AQUAGAMETE), the Research Centre of Excellence- 9878-3/2016/FEKUT, KMR_12-1-2012-0436, NKFIH (OTKA) 109847, KLING 31-03-05-FEP-73, CRIOBIV 31-03-05-FEP-59, REPLING 31-03-05-FEP-69 all from PROMAR programme.

This study investigated the effect of dietary astaxanthin supplementation on egg quality and juvenile growth of long snout seahorse (Hippocampus guttulatus). Captive breed seahorse broodstock were fed four diets composed of frozen shrimp [Atlantic ditch shrimp, Palaemonetes varians) used as a vector to deliver artificial diets with increasing levels of astaxanthin (0, 75, 100 and 125 mg kg(-1) dry weight)]. The results indicated that the astaxanthin uptake into eggs from the enriched shrimp diets was highly efficient. Females fed unsupplemented astaxanthin diet produced similar-sized eggs with lower concentration of astaxanthin than females fed diets with astaxanthin. The lower concentration of astaxanthin in the eggs was correlated with the production of smaller juveniles in comparison with the juveniles hatched from parents fed supplemented astaxanthin diets. Juvenile growth and survival was limited by their size on release from the male's pouch as at the end of 28-day postparturition juveniles produced with the diet with no astaxanthin were still significantly smaller (P < 0.05) than those produced from parents fed astaxanthin-supplemented diets. These results demonstrate a significant benefit of dietary astaxanthin supplementation in long snout seahorse diets in terms of improved egg quality and juvenile growth and survival. FCT - Portugal [BPD/34816/2007] info:eu-repo/semantics/publishedVersion

Individual differences in physiological and behavioural responses to stressors are increasingly recognised as adaptive variation and thus raw material for evolution and fish farming improvements including selective breeding. Such individual variation has been evolutionarily conserved and is present in all vertebrate taxa including fish. In farmed animals, the interest in consistent trait associations, that is coping styles, has increased dramatically over the last years because many studies have demonstrated links to performance traits, health and disease susceptibility and welfare. This study will review (i) the main behavioural, neuroendocrine, cognitive and emotional differences between reactive and proactive coping styles in farmed fish; (ii) the methodological approaches used to identify coping styles in farmed fish, including individual (group) mass-screening tests; and (iii) how knowledge on coping styles may contribute to improved sustainability of the aquaculture industry, including welfare and performance of farmed fish. Moreover, we will suggest areas for future research, where genetic basis (heritability/epigene tic) of coping styles, and the neuroendocrine mechanisms behind consistent as well as flexible behavioural patterns are pinpointed as central themes. In addition, the ontogeny of coping styles and the influence of age, social context and environmental change in coping styles will also be discussed. European Commission under the 7th Framework Programme FP7-KBBE [265957]

Successful food consumption and digestion depend on specifics anatomical and behavioral characteristics and corresponding physiological functions that should be ready to work at the appropriate time. The physiological regulation of appetite and ingestion involves a complex integration of peripheral and central signals by the brain. Ghrelin is a peptide hormone involved in the control of energy homeostasis and increases food intake in mammals, however ghrelin has species-specific actions on food intake in fish. The aim of this study was to investigate whether this peptide has an orexigenic or anorexigenic role in Senegalese sole (Solea senegalensis) in order to improve the knowledge of the physiological basis underlying feeding activity. Feed intake was measured at several sampling points to determine the overall action time of the peptide and its effect in Senegalese sole food intake. Artemia protein digestibility and retention were determined in order to analyze the ghrelin effect in fed and fasted Senegalese sole post-larvae. Results suggested that ghrelin acts as orexigenic hormone in Senegalese sole, with a response time around 25 min. Results indicated that Senegalese sole post-larvae are able to maintain absorption and retention capacities independently of feeding rate and nutritional status. Furthermore, the present study gives insight for the first time of the fate of the retained amino acids, being mainly used for protein accretion (86.79% of retained amino acids recovered in protein and FAA fractions)., This work received national funds through FCT - Foundation for Science and Technology through project CCMAR/Multi/04326/2013 (Portugal), project SOLEAWIN (310305/FEP/71) partially supported by PROMAR Program (Portugal) with FEDER funds, and also through the Spanish Ministry of Economic Affairs and Competitiveness (MINECO) by project RIDIGEST (AGL2011-23722) with FEDER/ERDF contribution granted to M. Yúfera (Spain). Carmen Navarro-Guillén was supported by a doctoral fellowship (BES-2012-051956) from MINECO (Spain). Sofia Engrola acknowledges a FCT investigator grant IF/00482/2014/CP1217/CT0005 funded by the European Social Fund, the Operational Programme Human Potential and the Foundation for Science and Technology of Portugal (FCT – Portugal).

International audience; AbstractBackgroundIn breeding programs for aquaculture species, breeding goal traits are often weighted based on the desired gains but economic gain would be higher if economic values were used instead. The objectives of this study were: (1) to develop a bio-economic model to derive economic values for aquaculture species, (2) to apply the model to determine the economic importance and economic values of traits in a case-study on gilthead seabream, and (3) to validate the model by comparison with a profit equation for a simplified production system.MethodsA bio-economic model was developed to simulate a grow-out farm for gilthead seabream, and then used to simulate gross margin at the current levels of the traits and after one genetic standard deviation change in each trait with the other traits remaining unchanged. Economic values were derived for the traits included in the breeding goal: thermal growth coefficient (TGC), thermal feed intake coefficient (TFC), mortality rate (M), and standard deviation of harvest weight (σHW\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\sigma_{HW}$$\end{document}). For a simplified production system, improvement in TGC was assumed to affect harvest weight instead of growing period. Using the bio-economic model and a profit equation, economic values were derived for harvest weight, cumulative feed intake at harvest, and overall survival.ResultsChanges in gross margin showed that the order of economic importance of the traits was: TGC, TFC, M, and σHW\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\sigma_{HW}$$\end{document}. Economic values in € (kg production)−1 (trait unit)−1 were: 0.40 for TGC, −0.45 for TFC, −7.7 for M, and −0.0011 to −0.0010 for σHW\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\sigma_{HW}$$\end{document}. For the simplified production system, similar economic values were obtained with the bio-economic model and the profit equation. The advantage of the profit equation is its simplicity, while that of the bio-economic model is that it can be applied to any aquaculture species, because it can include any limiting factor and/or environmental condition that affects production.ConclusionsWe confirmed the validity of the bio-economic model. TGC is the most important trait to improve, followed by TFC and M, and the effect of σHW\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\sigma_{HW}$$\end{document} on gross margin is small.

Practical diets containing PP sources were elaborated. Increasing levels of di-calcium phosphate were added to diets leading to five different dietary available P levels: 2.5, 3.2, 6.0, 6.5 and 8.0 g kg−1 dry diet. The dietary treatments were tested in 13.5 g Senegalese sole juveniles throughout an 82-day experimental period. Dietary P content had no effect on the productive parameters, while nutrient intake was also similar among dietary treatments, except P intake. Dry matter ADC ranged between 54.9% and 64.0%, and the highest P ADCs value (47.2 ± 0.7%) was achieved in fish fed AP6.0. Dietary phosphorus level significantly influenced body lipid and P compositions. Regression analysis performed on whole-body P and ash contents fitted to quadratic models. Vertebral bone P content was low but increased significantly with increasing dietary P levels. Bone density and deformities occurrence were, however, similar between experimental conditions. An altered status of bone formation–resorption processes in soles fed the lowest P content diet might be inferred from ALP and TRAP activities. In conclusion, overall results state a high tolerance of Senegalese sole to low P content diets and support the utilization of practical diets with high plant protein content. © 2015 John Wiley & Sons This work was partially supported by NORTE‐07‐0124‐FEDER‐000038, in the context of the North Region Operational Programme (ON.2 – O Novo Norte), under the project Sustainable Aquaculture and Animal Welfare (AQUAIMPROV). There are no conflict of interests in connection with the present study.

Estrogens play well-recognized roles in reproduction across vertebrates, but also intervene in a wide range of other physiological processes, including mineral homeostasis. Classical actions are triggered when estrogens bind and activate intracellular estrogen receptors (ERs), regulating the transcription of responsive genes, but rapid non-genomic actions initiated by binding to plasma membrane receptors were recently described. A wide range of structurally diverse compounds from natural and anthropogenic sources have been shown to interact with and disrupt the normal functions of the estrogen system, and fish are particularly vulnerable to endocrine disruption, as these compounds are frequently discharged or run-off into waterways. The effect of estrogen disruptors in fish has mainly been assessed in relation to reproductive endpoints, and relatively little attention has been given to other disruptive actions. This review will overview the actions of estrogens in fish, including ER isoforms, their expression, structure and mechanisms of action. The estrogen functions will be considered in relation to mineral homeostasis and actions on mineralized tissues. The impact of estrogenic endocrine disrupting compounds on fish mineralized tissues will be reviewed, and the potential adverse outcomes of exposure to such compounds will be discussed. Current lacunae in knowledge are highlighted along with future research priorities. Foundation for Science and Technology of Portugal (FCT) [PTDC/AAG-GLO/4003/2012, PEst-C/MAR/LA0015/2011, SFRH/BPD/25247/2005] info:eu-repo/semantics/publishedVersion

The techno-functional properties of soy, lupine and rapeseed protein concentrates (SPC, LPC and RPC, respectively) in fish feed were evaluated relative to fish meal (FM). The effects were studied using a shear cell device and an extruder with emphasis on the added moisture content. Six diets were formulated: an SPC-based diet with 300 g SPC kg −1 , diets containing 100 and 200 g LPC kg −1 or 100 and 200 g RPC kg −1 and an FM-based diet with 450 g FM kg −1 . Each diet was extruded with an added moisture content of 29%, 25% and 22% of the mash feed rate. It was found that the technological properties of LPC closely resemble FM, being high solubility, low water-holding capacity (WHC) and low paste viscosity. The LPC 100 and 200 g kg −1 diets could be extruded at 22% moisture, which gives an extrudate with reduced drying requirements. In addition, less specific mechanical energy was needed for extrusion. In contrast, both SPC and RPC have high WHC and paste viscosity. This explains the higher feed moisture required during extrusion. The properties of the feeds containing RPC could be well within the ranges acceptable for commercial fish feed use at even higher moisture content compared with SPC. The results of the extrusion trials confirmed the observations made from the shear cell device. Thus, the shear cell device can be used to study processing conditions that are close to extrusion conditions.

Tryptophan (TRP) supplemented diets have been shown to have therapeutic effects in farmed animals including fish by modulating the activity of the neurotransmitter serotonin (5-hydroxytryptamine; 5-HT). The effects reported in fish have been obtained using individually-housed fish and include a reduction in stress response, aggression and stress-induced anorexia. In land farmed animals, TRP supplemented diets have also been shown to improve meat quality as a result of reduced stress during slaughter while in fish no data is currently available. This study aims at investigating whether short-term supplementation with TRP supplemented diets changes brain serotonergic activity and the stress response associated with slaughter handling in grouped-housed Nile tilapia Oreochromis niloticus. Adult fish (n = 108, 490.6 ± 4.0 g, 12 individuals per tank) were exposed to one of the three treatments (triplicates per treatment were used): control (0.48 g/100 g), TRP 4 × (1.87 g/100 g) and TRP 10 × (4.45 g/100 g) diets during 7 days. Afterwards, half of the fish in each tank were subjected to an acute stressor consisting of a combination of crowding and chasing, just prior to slaughter. The other half of the fish represented undisturbed conditions. Blood and brain samples were collected for cortisol and serotonergic activity analyses, respectively. Flesh quality was also assessed in both undisturbed and stressed fish for all treatments by measuring muscle pH and rigor mortis over a 72 h period. Results showed that the highest TRP supplemented diet (TRP 10 ×) induced a significant reduction in undisturbed plasma cortisol (10.57 ± 2.71 ng/ml) as compared to TRP 4 × (24.93 ± 3.19 ng/ml) and control diets (18.69 ± 2.94 ng/ml) and no effect on post-stress cortisol levels. After stress, the major 5-HT metabolite (5-hydroxyindoleacetic acid, 5-HIAA) was higher in the TRP 10 × (471.31 ± 60.95 ng/g) as compared to the other diets (TRP 4 ×: 313.52 ± 30.12 ng/g; control: 260.36 ± 19.65 ng/g). Stress before slaughter induced a significant increase in plasma cortisol (from 18.40 ± 1.76 ng/ml under undisturbed conditions to 80.34 ± 7.16 ng/ml), however, it was not sufficient to cause a faster deterioration of flesh quality. TRP supplement diets had also no effect on muscle pH and rigor mortis during the 72 h observation period. In conclusion, this study showed that only the highest levels of supplementation (10 × the control diet) affect serotonergic activity. However, these levels did not result in reduced stress responsiveness or improved flesh quality when an acute stressor is applied before slaughter. Therefore, these results underline the fact that effects of TRP on cortisol production are dose- and context-dependent, and further experiments are needed to determine under which conditions the optimal effect is obtained.

The aim of this study was to analyze the stress response during 3 hours net confinement stress and recovery period of 22 hours in normal (STD) and in 17 alpha-hydroxylase deficient common carp (E5). Fish were raised for 6 months and sampled at T-0 (control, unstressed), 5 minutes, 20 minutes, 1 hour and 3 hours of exposure to net confinement, and after 1 hour, 4 hours, and 22 hours of recovery. At every sampling time, blood was collected to determine cortisol, corticosterone, glucose, lactate and free fatty acids (FFA) levels (5 fish per strain). Fish and head kidney were weighed before and after dissection, respectively, to determine head kidney somatic Index (HKSI). Morphometric analysis of head kidney tissues indicated that the head kidney somatic index was significantly higher in E5 fish (0.076 +/- 0.021) compared with STD fish (0.045 +/- 0.015). Also, significant differences in cortisol and corticosterone as well as in glucose, lactate and FFA values were observed between the two strains of E5 and STD. Moreover, the pattern of changes of glucose and FFA during stress and afterward indicated a significant difference compared to the T-0. Results support the conclusion that the reduced capacity of ill fish to produce cortisol is caused by a deficiency in 17 alpha-hydroxylase activity. A reduced cortisol output leads to increased stimulation of adrenals by adrenocorticotropic Hormone (ACTH), resulting in increased outputs of corticosterone.

This review examines information generated over the past decade on the pollution of rivers in regions with a mediterranean-type climate (med-climate). Pollution has clearly increased in the last 100 years and is correlated with the development of industry, agriculture and human population. Important efforts have been made in some med-climate countries in order to characterise the chemical status of rivers. In addition, the number of chemical substances detectable in mediterranean-climate rivers (med-rivers), as well as the limits of detection, have improved from the development of better analytical methods. New substances detected in rivers are gaining attention. We discuss available knowledge regarding real and potential effects of pollutants on the biota and ecosystems in med-rivers, taking into account natural environmental characteristics of these rivers. The extreme seasonal conditions in med-rivers add to the potential risk because these characteristics can enhance pollutant effects. Efforts and policies to prevent or reduce pollution effects on med-rivers are linked to the knowledge about pollution pressures associated with the degree of economic development. Aquatic communities in med-rivers are more sensitive to pollutants because they are exposed to strong natural and human stressors.

00000 ăWOS:000382802100022; International audience; Human alteration of marine ecosystems is substantial and growing. Yet, no adequate methodology exists that provides reliable predictions of how environmental degradation will affect these ecosystems at a relevant level of biological organization. The primary objective of this study was to develop a methodology to evaluate a fish's capacity to face a well-established environmental challenge, an exposure to chemically dispersed oil, and characterize the long-term consequences. Therefore, we applied high-throughput, non-lethal challenge tests to assess hypoxia tolerance, temperature susceptibility and maximal swimming speed as proxies for a fish's functional integrity. These whole animal challenge tests were implemented before (1 month) and after (1 month) juvenile European sea bass (Dicentrarchus labrax) had been acutely exposed (48 h) to a mixture containing 0.08 g L-1 of weathered Arabian light crude oil plus 4% dispersant (Corexit(C) EC9500A), a realistic exposure concentration during an oil spill. In addition, experimental populations were then transferred into semi-natural tidal mesocosm ponds and correlates of Darwinian fitness (growth and survival) were monitored over a period of 4 months. Our results revealed that fish acutely exposed to chemically dispersed oil remained impaired in terms of their hypoxia tolerance and swimming performance, but not in temperature susceptibility for 1 month post-exposure. Nevertheless, these functional impairments had no subsequent ecological consequences under mildly selective environmental conditions since growth and survival were not impacted during the mesocosm pond study. Furthermore, the earlier effects on fish performance were presumably temporary because re-testing the fish 10 months post-exposure revealed no significant residual effects on hypoxia tolerance, temperature susceptibility and maximal swimming speed. We propose that the functional proxies and correlates of Darwinian fitness used here provide a useful assessment tool for fish health in the marine environment.

00000 ăWOS:000383801600012; International audience; Previous studies have shown that the amount of food influences fish otolith structure, opacity and shape and that diet composition has an effect on otolith chemical composition. This study investigated the potential correlation between diet and otolith shape in 5 wild marine fish species by addressing 4 complementary questions. First, is there a global relationship between diet and otolith shape? Second, which prey categories are involved in this relationship? Third, what are the respective contributions of food quantity and relative composition to diet-otolith shape co-variation? Fourth, is diet energetic composition related to otolith shape? For each species, we investigated how otolith shape varies with diet. These questions were tackled by describing diet in the analysis in 4 different ways, while also including individual-state variables to remove potential confounding effects. First, besides the strong effect of individual-state, a global relationship between diet and otolith shape was detected for 4 out of 5 fish species. Second, both main and secondary prey categories were related to variability in otolith shape, and otolith outline reconstructions revealed that both otolith global shape and its finer details co-varied with these prey categories. Third, the contribution of relative diet composition to diet-otolith shape co-variation was much higher than that of ingested food quantity. Fourth, the energetic composition of diet was related to otolith shape of only 1 species. These results suggest that diet in marine fish species may influence the quantity and composition of saccular endolymph proteins which play an important role in otolith biomineralization and their resulting 3D structure.

Data were compiled from the literature on the critical oxygen level (Pcrit), a hypoxia-tolerance trait, comprising 96 studies covering 151 fish species from 58 families. Salinity, temperature, body mass, and routine metabolic rate were highly correlated with Pcrit. The effects of temperature, CO2, acidification, metals and feeding are also assessed., Hypoxia is a common occurrence in aquatic habitats, and it is becoming an increasingly frequent and widespread environmental perturbation, primarily as the result of anthropogenic nutrient enrichment and climate change. An in-depth understanding of the hypoxia tolerance of fishes, and how this varies among individuals and species, is required to make accurate predictions of future ecological impacts and to provide better information for conservation and fisheries management. The critical oxygen level (Pcrit) has been widely used as a quantifiable trait of hypoxia tolerance. It is defined as the oxygen level below which the animal can no longer maintain a stable rate of oxygen uptake (oxyregulate) and uptake becomes dependent on ambient oxygen availability (the animal transitions to oxyconforming). A comprehensive database of Pcrit values, comprising 331 measurements from 96 published studies, covering 151 fish species from 58 families, provides the most extensive and up-to-date analysis of hypoxia tolerance in teleosts. Methodologies for determining Pcrit are critically examined to evaluate its usefulness as an indicator of hypoxia tolerance in fishes. Various abiotic and biotic factors that interact with hypoxia are analysed for their effect on Pcrit, including temperature, CO2, acidification, toxic metals and feeding. Salinity, temperature, body mass and routine metabolic rate were strongly correlated with Pcrit; 20% of variation in the Pcrit data set was explained by these four variables. An important methodological issue not previously considered is the inconsistent increase in partial pressure of CO2 within a closed respirometer during the measurement of Pcrit. Modelling suggests that the final partial pressure of CO2 reached can vary from 650 to 3500 µatm depending on the ambient pH and salinity, with potentially major effects on blood acid–base balance and Pcrit itself. This database will form part of a widely accessible repository of physiological trait data that will serve as a resource to facilitate future studies of fish ecology, conservation and management.

Several recent studies have highlighted how impaired cardiac performance at high temperatures and in hypoxia may compromise the capacity for oxygen transport. Thus, at high temperatures impaired cardiac capacity is proposed to reduce oxygen transport to a degree that lowers aerobic scope and compromises thermal tolerance (the oxygen- and capacity-limited thermal tolerance (OCLTT) hypothesis). To investigate this hypothesis, we measured aerobic and cardiac performance of a eurythermal freshwater teleost, the European perch (Perca fluviatilis). Rates of oxygen consumption were measured during rest and activity at temperatures between 5 degrees C and 27 degrees C, and we evaluated cardiac function by in vivo measurements of heart rate and in vitro studies to determine contractility of myocardial strips. Aerobic scope increased progressively from 5 degrees C to 21 degrees C, after which it levelled off. Heart rate showed a similar response. We found little difference between resting and active heart rate at high temperature suggesting that increased cardiac scope during activity is primarily related to changes in stroke volume. To examine the effects of temperature on cardiac capacity, we measured isometric force development in electrically paced myocardial preparations during different combinations of temperature, pacing frequency, oxygenation and adrenergic stimulation. The force-frequency product increased markedly upon adrenergic stimulation at 21 and 27 degrees C (with higher effects at 21 degrees C) and the cardiac preparations were highly sensitive to hypoxia. These findings suggest that at (critically) high temperatures, cardiac output may diminish due to a decreased effect of adrenergic stimulation and that this effect may be further exacerbated if the heart becomes hypoxic. Hence cardiac limitations may contribute to the inability to increase aerobic scope at high temperatures in the European perch (Perca fluviatilis).