Stress coping styles (SCSs) are defined as coherent sets of individual physiological and behavioral differences in stress response consistent across time and context and are described in a wide range of taxa, including fishes. These... more
Stress coping styles (SCSs) are defined as coherent sets of individual physiological and behavioral differences in stress response consistent across time and context and are described in a wide range of taxa, including fishes. These differences in behavior and physiology are of great interest because they may have direct implications on animal health, welfare, and performance in farming systems, including aquaculture. In this study, the physiological responses of sea bream (Sparus aurata) from different SCSs following Vibrio anguillarum vaccination were monitored. Fish were first screened either bold or shy (proxy of proactive and reactive SCSs, respectively) using group risk-taking tests and were then injected with a vaccine against V. anguillarum. Following vaccination, the fish were implanted with an accelerometer tag to monitor their swimming activity (proxy of energy expenditure), and blood sampling was carried out to measure health and welfare parameters (e.g., cortisol, gluco...
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Viral haemorrhagic septicaemia virus (VHSV) and infectious haematopoietic necrosis virus (IHNV) are among the most important pathogens for freshwater aquaculture. They are RNA viruses belonging to the family Rhabdoviridae, which... more
Viral haemorrhagic septicaemia virus (VHSV) and infectious haematopoietic necrosis virus (IHNV) are among the most important pathogens for freshwater aquaculture. They are RNA viruses belonging to the family Rhabdoviridae, which constitutes the largest group of viruses listed by the Office International des Epizooties (OIE). Viral haemorrhagic septicaemia (VHS) and infectious haematopoietic necrosis (IHN) are predominantly diseases of freshwater salmonids, which may cause severe disease outbreaks with high mortality (Wolf 1988; Hoffmann et al. 2005). In particular, VHS is the most serious viral disease affecting the production of rainbow trout, Oncorhynchus mykiss (Walbaum), in continental Europe (Olesen, Lorenzen & LaPatra 1999), which may cause high mortalities rates in all sizes of fish. Infectious haematopoietic necrosis was originally endemic in North America and has been translocated to Europe and Asia by the movement of infected fish or eggs. The virus was first detected in Italy in 1987 (Bovo et al. 1987); it typically occurs in rainbow trout fry and fingerlings, but the disease has also been reported in various life stages of sockeye-, chinookand Atlantic salmon (Lapatra 1998). Moreover, both diseases are listed as being notifiable, according to the European legislation (2006/88/EC) and to the OIE. The infection is typically transmitted horizontally by the water route (Lorenzen & Lapatra 1999). Both gills and skin are thought to be important routes of infection. Infectious haematopoietic necrosis virus and VHSV exhibit a high affinity for epithelial cells, and once inside the fish, they spread in the body through the blood: this is how a systemic infection is established. Kidney, spleen and heart are major sites of replication, which in endothelial cells results in petechial haemorrhages in muscle tissue and in internal organs. Mortalities vary but may reach 90% or more in small fish (Wolf 1988; Smail & Munro 1989). In European aquaculture, IHNV and VHSV are mainly associated with salmonid host species, particularly rainbow trout, although outbreaks of VHSV in other species have been reported (Meier & Jørgensen 1980; Wizigmann, Baath & Hoffmann 1980; Ahne & Thomsen 1985; Skall, Correspondence F Pascoli, Fish Virology Department, Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell’Universit a, 10 35020 Legnaro, PD, Italy (e-mail: fpascoli@izsvenezie.it)
Research Interests: Zoology, Biology, Virology, Fish Diseases, Medicine, and 4 moreVirus, Fisheries Sciences, Veterinary Sciences, and Perch
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The primary basis for the concept of “animal welfare” is the belief that animals are sentient being capable to experience good or bad feelings or emotional states. Stress and stress-related responses should be considered as an adaptive... more
The primary basis for the concept of “animal welfare” is the belief that animals are sentient being capable to experience good or bad feelings or emotional states. Stress and stress-related responses should be considered as an adaptive condition of the organism that has the fundamental function of preserving the individual’s life. However, determination of animal welfare requires the selection, collection and interpretation of different parameters and validated indicators. The aspects of the fish’s condition that are often used in this context are its health status, its physiology and its behaviour.
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Abstract Stress coping style (SCS) is defined as a coherent set of individual physiological and behavioural differences in stress responses that are consistent across context and over time. SCS in fish has been studied, including because... more
Abstract Stress coping style (SCS) is defined as a coherent set of individual physiological and behavioural differences in stress responses that are consistent across context and over time. SCS in fish has been studied, including because it has direct implications for aquaculture productivity and welfare. The fish physiological responses upon stress between different SCS are overall well known. In contrast, the basal level of the physiological indicators of stress and welfare are understudied. Therefore, the purpose of our study was to investigate the relationship between SCS and the basal levels of stress, health and welfare indicators of sea breams (Sparus aurata). To this end, we first screened the fish SCS, by measuring the boldness behaviour of fish during both risk-taking and hypoxia tests. The tests were each run two times to evaluate the behavioural consistency over time (7 days). One week after the last behavioural measurement, a blood sample was taken to measure the basal level of several physiological stress indicators. We observed that the behavioural response in the hypoxia test was not consistent over time, while the behavioural response was consistent in the risk-taking test. Moreover, no behavioural consistency was observed between these two tests. Among fish that exited the safe area during risk taking test, bolder individuals displayed lower basal levels of cortisol, noradrenaline, and lactate while no correlation was found between physiological parameters and the behavioural response in the hypoxia test. In conclusion, the risk-taking test seems more appropriate for screening SCS in sea bream because the behavioural response is consistent over time. In addition, this behavioural response is linked with the basal level of the stress hormones (cortisol, noradrenaline, and lactate). This study contributes to bring new information about the link between behaviour and resting physiology of SCS.
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Research Interests: Genetics, Biology, Biodiversity, Medicine, Multidisciplinary, and 15 moreVirulence, Phylogeny, Applied Environmental Microbiology, Bacteria, Polymerase Chain Reaction, Gene, TYPING, Aeromonas, Phenotype, Microorganism, Gen, Genotype, Base Sequence, Multilocus sequence typing, and Molecular Sequence Data
Abstract Red mark syndrome (RMS) is a disease of farmed rainbow trout, Oncorhynchus mykiss (Walbaum, 1792), one of the most widespread freshwater farmed species in Europe. The disease emerges at water temperatures below 16 °C and consists... more
Abstract Red mark syndrome (RMS) is a disease of farmed rainbow trout, Oncorhynchus mykiss (Walbaum, 1792), one of the most widespread freshwater farmed species in Europe. The disease emerges at water temperatures below 16 °C and consists of one or more bright red skin lesions on the fish body. Mortality due to RMS is reportedly rare, but the disease leads to downgrading of the product and subsequent economic losses. Despite the disease impact, the causative agent for RMS is still formally undetermined although increasing evidence points to a bacterium ascribed to the Midichloriaceae family (order Rickettsiales), hereafter referred to as RMS-Midichloria like organism (RMS-MLO). Intriguingly, recently deposited sequences revealed the presence of RMS-MLO-like bacteria associated with Ichthyophthirius multifiliis, a common protozoan skin parasite of freshwater fish frequently harboring bacterial endosymbionts. Therefore, we hypothesized that I. multifiliis could be a vehicle for RMS-MLO. This was tested by infecting RMS-diseased rainbow trout with I. multifiliis theronts, and subsequently investigating the presence of RMS-MLO in tomonts detached from the fish. Real time PCR analyses showed clearly that I. multifiliis previously exposed to RMS-affected fish become positive to RMS-MLO suggesting that this bacterium can be at least transiently acquired and carried by the protozoan. Moreover, statistical analyses suggested a possible level of vertical transmission in I. multifiliis from one trophic stage to the next one. Further studies will be necessary to prove whether I. multifiliis has a role in the horizontal transfer of RMS-MLO bacteria from diseased RMS fish to healthy ones.
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The study was carried out to evaluate NIRS (Near Infrared Reflectance Spectroscopy) performance in predicting activity water (a ), pH, moisture, expressible drips (ED%) and Total Volatile Nitrogen (TVN) in common sole. Samples (n = 141)... more
The study was carried out to evaluate NIRS (Near Infrared Reflectance Spectroscopy) performance in predicting activity water (a ), pH, moisture, expressible drips (ED%) and Total Volatile Nitrogen (TVN) in common sole. Samples (n = 141) were submitted to instrumental analysis and minced wet muscle were scanned in reflectance mode using a NIRSystem 5000. NIRS technique showed a higher precision in predicting ED (fraction of explained variance, R 2 = 0.83 and fraction of explained variance in cross validation, 1-VR = 0.55), a (R 2 = 0.84; 1-VR = 0.69) and moisture (R 2 = 0.87; 1-VR = 0.67). The performance of calibration evidenced low SECV (standard error of cross validation) values. However, the data evidenced very low correlations between NIR and measurements of TVN. The principal component analysis (PCA), modified partial least square (MPLS) and SVM (support vector machine) were utilized in order to discriminate between fresh and frozen-thawed fish products. Results show that NIRS was able to distinguish fresh (98% samples recognized) and frozen-thawed (80% samples recognized) raw fillet according MPLS. The ConfMatrix (%) values obtained from SVM were 0.93 and 0.83 respectively.
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Eating raw or insufficiently cooked bivalve molluscs contaminated with human noroviruses (NVs) can result in acute cases of gastroenteritis in humans. Manila clams (Ruditapes philippinarum) are particularly prone to exposure to NVs due to... more
Eating raw or insufficiently cooked bivalve molluscs contaminated with human noroviruses (NVs) can result in acute cases of gastroenteritis in humans. Manila clams (Ruditapes philippinarum) are particularly prone to exposure to NVs due to the brackish environment in which they are farmed which is known to be susceptible to human faecal contamination. High hydrostatic pressure processing (HHP) is a food treatment technique that has been shown to inactivate NV. In this study we investigated the ability of HHP to inactivate murine norovirus (MNV-1), a recognised surrogate for NV, in experimentally contaminated manila clams. Pools of contaminated live clams were subjected to hydrostatic pressure ranging from 300 to 500 MPa for different time intervals of between one and 10 min. The trial was repeated three times, at monthly intervals. Virus vitality post-treatment was assessed and the data obtained indicates that the use of high hydrostatic pressures of at least 500 MPa for 1 min was effective in inactivating MNV-1. HHP results to be an effective technique that could be applied to industrial process to obtain safe Manila clams ready to eat.
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Ranaviruses have been isolated from Atlantic cod (Gadus morhua) and turbot (Scophthalmus maximus) in Denmark. Phylogenomic analyses revealed that these two ranaviruses are nearly identical and form a distinct clade at the base of the... more
Ranaviruses have been isolated from Atlantic cod (Gadus morhua) and turbot (Scophthalmus maximus) in Denmark. Phylogenomic analyses revealed that these two ranaviruses are nearly identical and form a distinct clade at the base of the ranavirus tree branching off near other fish ranaviruses.
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Nodular gill disease (NGD) is a serious parasitic condition associated with amoebic infection affecting farmed rainbow trout (Oncorhynchus mykiss) in several countries worldwide. Outbreaks of NGD have been recently observed in several... more
Nodular gill disease (NGD) is a serious parasitic condition associated with amoebic infection affecting farmed rainbow trout (Oncorhynchus mykiss) in several countries worldwide. Outbreaks of NGD have been recently observed in several rainbow trout farms in Italy, with clinical signs strongly indicative of respiratory distress and high mortality registered mainly during winter. From December 2013 to April 2015 a total of 494 rainbow trout were collected from 13 Italian farms and subjected to anatomo-pathological and histological exams. Gross gill lesions consisted in excessive mucus production, swelling, whitish nodules in the distal parts of filaments and presence of alternate discolored and congested areas. In 261 (52.8%) fish histology allowed to identify the presence of amoebae as showed also by the parasitological exam of fresh gill samples. Histological lesions, in presence of amoebae, consisted in strong hyperplasia of the gill epithelial cells producing extensive lamellar fusion with obliteration of interlamellar spaces. In more severe cases mucous cell hypertrophy, lamellar edema, necrosis and exfoliation of epithelial cells were observed. Among the epithelial cells, inflammatory infiltrate with numerous lymphocytes, macrophages and eosinophilic granule cells/mast cells was detected. Further analyses are in progress in order to identify the species of amoebae involved as causative agent of NGD in Italy
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Aquaculture significantly contributes to the growing demand for food worldwide. However, diseases associated with intensive aquaculture conditions, especially the skin related syndromes, may have significant implications on fish health... more
Aquaculture significantly contributes to the growing demand for food worldwide. However, diseases associated with intensive aquaculture conditions, especially the skin related syndromes, may have significant implications on fish health and industry. In farmed rainbow trout, red mark syndrome (RMS), which consists of multiple skin lesions, currently lacks recognized aetiological agents, and increased efforts are needed to elucidate the onset of these conditions. Most of the past studies were focused on analyzing skin lesions, but no study focused on water, a medium constantly interacting with fish. Indeed, water tanks are environmental niches colonized by microbial communities, which may be implicated in the onset of the disease. Here, we present the results of water and sediment microbiome analyses performed in an RMS-affected aquaculture facility, bringing new knowledge about the environmental microbiomes harbored under these conditions. On the whole, no significant differences in ...
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L’acquacoltura ha sempre rappresentato un’importante attività di allevamento animale e mai come oggi ha assunto un’importanza crescente dovuta ad una sempre maggior domanda di consumo annuo pro capite di pesce che, tuttavia, ha comportato... more
L’acquacoltura ha sempre rappresentato un’importante attività di allevamento animale e mai come oggi ha assunto un’importanza crescente dovuta ad una sempre maggior domanda di consumo annuo pro capite di pesce che, tuttavia, ha comportato una contestuale diminuzione dell’apporto della pesca. La movimentazione di pesce vivo è parte integrante della attività di piscicoltura in tutta Europa. Negli ultimi decenni in Italia l’allevamento del pesce e di altre specie acquatiche è stato in costante aumento, stabilizzandosi solo negli ultimi anni. Si è registrato un sempre maggiore interesse alle pratiche di acquacoltura utilizzate e ai relativi problemi di benessere dei pesci da parte del legislatore, nel campo della ricerca e da parte dei consumatori. I dati dimostrano che l’acquacoltura è un settore in crescita: nell’anno 2016 sono stati trasportati e introdotti in Italia oltre 72 milioni di Kg. di pesce vivo (35.5% trote – 14.6% spigole e orate – 4% pesce gatto e anguille) e si prevede...
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ABSTRACT An episode of mortality in farmed redclaw crayfish, Cherax quadricarinatus, reared in Sicily, is described. Histological and PCR methods were used to identify the oomycetes, Aphanomyces astaci, as the causative agent of the... more
ABSTRACT An episode of mortality in farmed redclaw crayfish, Cherax quadricarinatus, reared in Sicily, is described. Histological and PCR methods were used to identify the oomycetes, Aphanomyces astaci, as the causative agent of the disease. Mortality up to 30%, and haemocytic melanising response against hyphae in affected specimens, indicates a certain resistance of C. quadricarinatus towards A. astaci. Procambarus clarkii reared in the same facility is hypothesized to be the carrier of the pathogen. Evidence of mortality in redclaw crayfish held at higher temperatures than any previously investigated episodes is discussed in this paper.
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The genus Aeromonas has been described as comprising several species associated with the aquatic environment, which represents their principal reservoir. Aeromonas spp. are commonly isolated from diseased and healthy fish, but the... more
The genus Aeromonas has been described as comprising several species associated with the aquatic environment, which represents their principal reservoir. Aeromonas spp. are commonly isolated from diseased and healthy fish, but the involvement of such bacteria in human infection and gastroenteritis has frequently been reported. The primary challenge in establishing an unequivocal link between the Aeromonas genus and pathogenesis in humans is the extremely complicated taxonomy. With the aim of clarifying taxonomic relationships among the strains and phenotypes, a multilocus sequencing approach was developed and applied to characterize 23 type and reference strains of Aeromonas spp. and a collection of 77 field strains isolated from fish, crustaceans, and mollusks. All strains were also screened for putative determinants of virulence by PCR ( ast , ahh1 , act , asa1 , eno , ascV , and aexT ) and the production of acylated homoserine lactones (AHLs). In addition, the phenotypic fingerpr...
Research Interests: Biology, Biodiversity, Medicine, Multidisciplinary, Virulence, and 14 morePhylogeny, Applied Environmental Microbiology, Bacteria, Polymerase Chain Reaction, Gene, Aeromonas, Phenotype, Microorganism, Gen, Genotype, Base Sequence, Virulence Factors, Multilocus sequence typing, and Molecular Sequence Data
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RIASSUNTO Photobacterium damselae susbsp. piscicida (Ph.d.p.) e l’agente eziologico della fotobatteriosi o pasteurellosi ittica. Le principali specie ittiche delle quali sia stata documentata la sensibilita all’infezione sono la spigola... more
RIASSUNTO Photobacterium damselae susbsp. piscicida (Ph.d.p.) e l’agente eziologico della fotobatteriosi o pasteurellosi ittica. Le principali specie ittiche delle quali sia stata documentata la sensibilita all’infezione sono la spigola (Dicentrarchus labrax), l’orata (Sparus aurata) e il cefalo (Mugil cephalus). L’affermazione di alcune specie innovative nella maricoltura siciliana ci ha indotto a valutare la loro eventuale suscettibilita nei confronti di tale batterio. A tal fine, attraverso challenge sperimentali in microcosmo, e stata valutata la sensibilita al patogeno in soggetti di ombrina boccadoro (Argyrosomus regius) (n=10+10 controllo, peso medio 80 g), dentice (Dentex dentex) (n=10+10 controllo, peso medio 60 g) e spigola (n=10+10 controllo, peso medio 50 g) quale specie suscettibile al patogeno e utilizzata come controllo positivo. I pesci sono stati mantenuti in vasche da 110 litri, a temperatura di 24°C e salinita dell’acqua di 38‰. L’infezione e stata effettuata util...
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Many physiological and psychological factors govern the consumption and intake of fish. In addition, the perception that consumers have regarding the risks associated with the consumption of fish is also crucially influential. Several... more
Many physiological and psychological factors govern the consumption and intake of fish. In addition, the perception that consumers have regarding the risks associated with the consumption of fish is also crucially influential. Several studies have investigated the actual risks and benefits of consuming fish to human health. Among the investigated species, mercury concentrations were found to be higher in billfish than in other species. This implies that consuming billfish has potentially negative implications for human health. The present study aims to explore the billfish consumption habits and risk perception of fish consumers who live in the Western Central Atlantic, particularly in the Dominican Republic (DR) and Grenada (GR). Two online questionnaires were administered in the DR and GR between January and April of 2018. Among the 715 total respondents, 626 stated that they consumed fish and were thus included in the study––518 of these respondents were from the DR and 108 were ...
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Louisiana crayfish, an allochthonous species acclimatized to our latitudes, is present in almost all italian rivers and is subject to angling and consumption. The aim of this work was to evaluate the safety of about a hundred specimens... more
Louisiana crayfish, an allochthonous species acclimatized to our latitudes, is present in almost all italian rivers and is subject to angling and consumption. The aim of this work was to evaluate the safety of about a hundred specimens coming from Fimon lake (Vicenza). During the Spring and Summer period, microbiological and chemical assays were carried out weekly to evaluate fresh crayfish. The chemical results were favourable, but the presence of E. coli and salmonella confirmed a faecal contamination. For this reason it is necessary to apply a risk analysis for this kind of.
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The study was carried out to evaluate NIRS (Near Infrared Reflectance Spectroscopy) performance in predicting activity water (a ), pH, moisture, expressible drips (ED%) and Total Volatile Nitrogen (TVN) in common sole. Samples (n = 141)... more
The study was carried out to evaluate NIRS (Near Infrared Reflectance Spectroscopy) performance in predicting activity water (a ), pH, moisture, expressible drips (ED%) and Total Volatile Nitrogen (TVN) in common sole. Samples (n = 141) were submitted to instrumental analysis and minced wet muscle were scanned in reflectance mode using a NIRSystem 5000. NIRS technique showed a higher precision in predicting ED (fraction of explained variance, R 2 = 0.83 and fraction of explained variance in cross validation, 1-VR = 0.55), a (R 2 = 0.84; 1-VR = 0.69) and moisture (R 2 = 0.87; 1-VR = 0.67). The performance of calibration evidenced low SECV (standard error of cross validation) values. However, the data evidenced very low correlations between NIR and measurements of TVN. The principal component analysis (PCA), modified partial least square (MPLS) and SVM (support vector machine) were utilized in order to discriminate between fresh and frozen-thawed fish products. Results show that NIRS ...
The presence of enteric viruses (Hepatitis A and Norovirus) in mussels and manila clams was investigated in the delta area of Po river. Biomolecular assays were carried out with fortnightly cadence during one year in two lagoon areas and... more
The presence of enteric viruses (Hepatitis A and Norovirus) in mussels and manila clams was investigated in the delta area of Po river. Biomolecular assays were carried out with fortnightly cadence during one year in two lagoon areas and one sea area in front of the lagoon. Lagoon samples were analysed befon and after the purification treatment. All the checked samples were negative for Hepatitis A whereas n. 7 samples were positive for Norovirus. Positive samples correspond to the periods with increased flowing of the tributary river and the consequent remixing of the lagoon bottom. Absence of correlation between enteric viruses and E. coli was observed.
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The primary basis for the concept of “animal welfare” is the belief that animals are sentient being capable to experience good or bad feelings or emotional states. Stress and stress-related responses should be considered as an adaptive... more
The primary basis for the concept of “animal welfare” is the belief that animals are sentient being capable to experience good or bad feelings or emotional states. Stress and stress-related responses should be considered as an adaptive condition of the organism that has the fundamental function of preserving the individual’s life. However, determination of animal welfare requires the selection, collection and interpretation of different parameters and validated indicators. The aspects of the fish’s condition that are often used in this context are its health status, its physiology and its behaviour.
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The microsporidiosis of the endangered white-clawed crayfish Austropotamobius pallipes complex has generally been attributed to only one species, Thelohania contejeani, the agent of porcelain disease. Species identification was mostly... more
The microsporidiosis of the endangered white-clawed crayfish Austropotamobius pallipes complex has generally been attributed to only one species, Thelohania contejeani, the agent of porcelain disease. Species identification was mostly assessed by macroscopic examination or microscopic evaluation of muscle samples rather than by molecular or ultrastructural analyses. A survey conducted on A. pallipes complex populations in Northern Italy highlighted the presence of two different microsporidia causing similar muscular lesions, T. contejeani and an undescribed octosporoblastic species Vairimorpha austropotamobii sp. nov. Mature spores and earlier developmental stages of V. austropotamobii sp. nov. were found within striated muscle cells of the thorax, abdomen, and appendages of the crayfish. Only octosporoblastic sporogony within sporophorous vesicles (SPVs) was observed. Diplokaryotic sporonts separated into two uninucleate daughter cells, which gave rise to a rosette-shaped plasmodiu...
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Mortality in wild fish populations represents a challenging issue for public fish health inspectors. When a single fish species is involved, an infective aetiology is frequently suspected, with focus on viral notifiable diseases. However,... more
Mortality in wild fish populations represents a challenging issue for public fish health inspectors. When a single fish species is involved, an infective aetiology is frequently suspected, with focus on viral notifiable diseases. However, other viral agents not subjected to regulation and causing mortality in common carp have been reported such as carp edema virus (CEV). In mid-June 2020, a severe common carp mortality was observed in an artificial lake in north-east of Italy. Sleepy fish were noted some days before the beginning of the mortality itself, which lasted several days and involved over 340 adult specimens. During the outbreak, water temperature was around 15°C, water quality was normal, and no adverse meteorological events were reported in the area. Four specimens, which showed severe cutaneous hyperaemia and increased mucus production on skin and gills, were tested by bacteriological methods and virological analysis targeting the main carp pathogens. Molecular analysis performed on gills, kidney and brains from all the fish analysed resulted positive for CEV, which, based on anamnestic information and laboratory findings, was considered the responsible for the mortality event herein described.
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In aquaculture, fish species may experience stressful episodes caused by poor farming conditions. The exponential increase of global aquaculture has raised the number of research studies aimed at demonstrating the sensitivity of aquatic... more
In aquaculture, fish species may experience stressful episodes caused by poor farming conditions. The exponential increase of global aquaculture has raised the number of research studies aimed at demonstrating the sensitivity of aquatic animals in confined environments. The development of a real-time PCR and immunohistochemistry methods were investigated to evaluate the presence, localization, and quantity of biomarkers of oxidative stress in European sea bass ( Dicentrarchus labrax ). In particular, stress tests such as manipulation and temperature changes were conducted through molecular methods to identify the expression level of heat shock protein 70 (HSP70) in stressed animals compared with a control group. The immunohistochemical technique was also applied to locate and study the trends-levels of nitrotyrosine (NT), heat shock protein 70 (HSP70), malondialdehyde (MDA), and 4-hydroxy-2-nonenal (HNE) in different tissues from stressed animals and control group. The presence of the rodlet cell (RCs) was evaluated by histology in both a control and stressed group. Our results show that the real-time PCR method developed is specific for the evaluated target gene and that manipulation and temperature increase are strong stressors for animals. Relative quantification data revealed a gene expression increase of HSP70 in the stressed group of animals compared to the control group. The antibodies used for the immunohistochemical staining were efficient, and it was possible to appreciate the increase of immunoprecipitates in European sea bass either manipulated or stressed by temperature increase. The present study can be a starting point to allow the quantification of HSP70 and the identification of other stress biomarkers in D. labrax .
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In this small review, the most important contact-zoonotic bacteria and the diseases they cause in fish and humans are described. Especially, warmwaterornamental and fish culture professionals, owners, and processors are at risk in... more
In this small review, the most important contact-zoonotic bacteria and the diseases they cause in fish and humans are described. Especially, warmwaterornamental and fish culture professionals, owners, and processors are at risk in acquiring infections by Vibrio vulnificus, Photobacterium damselae subsp. damselae, Aeromonas hydrophila, Edwardsiella tarda, Mycobacterium marinum, Streptococcus iniae,or Streptococcusagalactiae, transmitted from their fish and fish water, in freshwater to marine environments. The chance of acquiring such a zoonosis is low, unless humans are immuno-compromised, and in case their skin is injured. These zoonoses are under reported, as in most countries they are non-notifiable. Strict hygiene for humans having direct contact with these fish in various fish holding and rearing facilities, and regular screening and health checks of imported warmwater ornamental fish at airports are recommended to avoid zoonosis and spread of potentially zoonotic, and often multiresistant bacteria.
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Background Telemetry applied to aquatic organisms has recently developed greatly. Physiological sensors have been increasingly used as tools for fish welfare monitoring. However, for the technology to be used as a reliable welfare... more
Background Telemetry applied to aquatic organisms has recently developed greatly. Physiological sensors have been increasingly used as tools for fish welfare monitoring. However, for the technology to be used as a reliable welfare indicator, it is important that the tagging procedure does not disrupt fish physiology, behaviour and performance. In this communication, we share our medium-term data on stress physiological profile and growth performance after surgical tag implantation in two important marine fish species for European aquaculture, the sea bream (Sparus aurata) and the European sea bass (Dicentrarchus labrax). Results Blood samples after surgical tag implantation (46 days for the sea bream and 95 days for the sea bass) revealed no differences between tagged and untagged fish in cortisol, glucose and lactate levels, suggesting that the tag implantation does not induce prolonged stress in these species. Moreover, the specific growth rates were similar in the tagged and unta...
Stocking density is considered a stress factor for fish and is therefore one of the numerous concerns about fish welfare in an aquaculture context. Stress coping styles (SCS) are defined as a coherent set of individual physiological and... more
Stocking density is considered a stress factor for fish and is therefore one of the numerous concerns about fish welfare in an aquaculture context. Stress coping styles (SCS) are defined as a coherent set of individual physiological and behavioral differences in stress responses that are consistent across time and context and appear to be promising for improving fish welfare in aquaculture. The aim of the present study was to describe the physiological and zootechnical performances of gilthead sea bream (Sparus aurata) at different stocking densities (low density, LD: 15 kg/m3 and high density, HD: 30 kg/m3), depending on individual SCS. To do so, the fish SCS were first screened by measuring boldness (prior to the experiment). Three consecutive samplings were performed over the experiment to measure several blood parameters, including hematocrit (Hct), red blood cell count (RBCC), hemoglobin (Hb), cortisol, adrenalin, noradrenalin, glucose, lactate, and lysozyme, to infer the consequence of the SCS profile on the welfare condition in response to stocking density. Finally, swimming activity was recorded in a subsample of individuals (9 BOLD and 9 SHY individuals per density), and BOLD individuals displayed higher swimming activity than SHY ones at HD, while the opposite pattern was observed at LD. According to principal component analysis, physiological parameters are linked to the SCS profile, mostly at the beginning of the experiment, while density effects on physiology remain during the entire experiment duration. In conclusion, regarding all the variables observed, fish SCS appeared to be promising criteria to select the most adaptive individuals relating to rearing conditions and therefore improve welfare.
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Cathelicidins are an important family of antimicrobial peptide effectors of innate immunity in vertebrates. Two members of this group, CATH-1 and CATH-2, have been identified and characterized in teleosts (ray-finned fish). In this study,... more
Cathelicidins are an important family of antimicrobial peptide effectors of innate immunity in vertebrates. Two members of this group, CATH-1 and CATH-2, have been identified and characterized in teleosts (ray-finned fish). In this study, we investigated the expression of these genes in different tissues of rainbow trout challenged with 4 different inactivated pathogens. By using qPCR, we detected a strong induction of both cath-1 and cath-2 genes within 24 hours after intraperitoneal inoculation with Lactococcus garvieae, Yersinia ruckeri, Aeromonas salmonicida, or Flavobacterium psychrophilum cells. Up to 700-fold induction of cath-2 was observed in the spleen of animals challenged with Y. ruckeri. Moreover, we found differences in the intensity and timing of gene up-regulation in the analyzed tissues. The overall results highlight the importance of cathelicidins in the immune response mechanisms of salmonids.
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Shewanella putrefaciens group consists of heterogeneous, Gram‐ negative, facultative anaerobe, rod‐shaped, motile microorganisms belonging to the γ‐subclass of Proteobacteria, Alteromonadaceae family. They are mainly diffuse in... more
Shewanella putrefaciens group consists of heterogeneous, Gram‐ negative, facultative anaerobe, rod‐shaped, motile microorganisms belonging to the γ‐subclass of Proteobacteria, Alteromonadaceae family. They are mainly diffuse in marine/brackish water and environs and in sediments. Even if generally defined as halophilic bacteria, some strains do not require NaCl for their growth (Buller, 2014; Pękala, Kozińska, Paździor, & Głowacka, 2015). Although the pathogenetic mechanisms are still to be defined and the infections are usually polymicrobic, Shewanella spp. is reported at increased frequency as an opportunistic human pathogen with a wide range of clinical manifestations (Janda & Abbott, 2014; Vignier et al., 2013). As part of the physiological microbiota of gills and intestine, S. putrefaciens group is now considered an opportunistic aetiological agent (shewanellosis) also in fishes (Pakingking, Palma, & Usero, 2015; Paździor, 2016). The first report was on a marine fish species (rabbitfish) (Saeed, Alamoudi, & Al‐Harbi, 1987). However, the microorganism is capable to spread to freshwater ecosystems, being able to grow also in pond water. The first isolation related to health disorders in freshwater fishes dates back to 2004 in Poland; since then, episodes of infection have been reported in different fresh and saltwater species, including koi (Cyprinus carpio L.). Skin necrotizing and ulcerative lesions and gill necrosis are the main gross pathologic findings, and polymicrobic infections have been recorded (Altun et al., 2014; El‐Barbary, 2017; Esteve, Merchán, & Alcaide, 2017; Korun, Akgun‐Dar, & Yazici, 2009; Kozińska & Pękala, 2004; Paździor, 2016; Pękala et al., 2015; Qin, Zhu, & Xu, 2014; Rusev, Rusenova, Simeonov, & Stratev, 2016). In January 2015 (supposed water temperature <10°C), an episode of mortality (5 out of 30 subjects) occurred in a group of koi (Cyprinus carpio L.). These koi were kept in a pond, supplied by freshwater and provided with a recirculating water system, with no recorded mortality. The owner referred the introduction of new subjects during the previous summer. The mortality involved the oldest of the group (11 years old) that showed lethargy, staying at the bottom, enophthalmos and poor body condition (Figure 1). Two dead koi (Cyprinus carpio L.) were kept refrigerated and referred for the necropsy to the Udine diagnostic laboratory, Istituto Zooprofilattico Sperimentale delle Venezie (Italy). The postmortem examination was performed on the day following mortality detection. The main gross findings in the subjects submitted were moderate, generalized oedema and severe ascites, with extensive visceral adherences and disseminated gas‐filled structures (Figure 2). The oedematous condition involved also the brain, the meninges were
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The microsporidiosis of the endangered white-clawed crayfish Austropotamobius pallipes complex has generally been attributed to only one species, Thelohania contejeani, the agent of porcelain disease. Species identification was mostly... more
The microsporidiosis of the endangered white-clawed crayfish Austropotamobius pallipes complex has generally been attributed to only one species, Thelohania contejeani, the agent of porcelain disease. Species identification was mostly assessed by macroscopic examination or microscopic evaluation of muscle samples rather than by molecular or ultrastructural analyses. A survey conducted on A. pallipes complex populations in Northern Italy highlighted the presence of two different microsporidia causing similar muscular lesions, T. contejeani and an undescribed octosporoblastic species Vairimorpha austropotamobii sp. nov. Mature spores and earlier developmental stages of V. austropotamobii sp. nov. were found within striated muscle cells of the thorax, abdomen, and appendages of the crayfish. Only octosporoblastic sporogony within sporophorous vesicles (SPVs) was observed. Diplokaryotic sporonts separated into two uninucleate daughter cells, which gave rise to a rosette-shaped plasmodiu...