Viral nervous necrosis in gilthead sea bream (Sparus aurata) caused by reassortant betanodavirus RGNNV/SJNNV : an emerging threat for Mediterranean aquaculture

Viral nervous necrosis (VNN) certainly represents the biggest challenge for the sustainability and the development of aquaculture. A large number of economically relevant fish species have proven to be susceptible to the disease. Conversely, gilthead sea bream has generally been considered resistant to VNN, although it has been possible to isolate the virus from apparently healthy sea bream and sporadically from affected larvae and postlarvae. Unexpectedly, in 2014-2016 an increasing number of hatcheries in Europe have experienced mass mortalities in sea bream larvae. Two clinical outbreaks were monitored over this time span and findings are reported in this paper. Despite showing no specific clinical signs, the affected fish displayed high mortality and histological lesions typical of VNN. Fish tested positive for betanodavirus by different laboratory techniques. The isolates were all genetically characterized as being reassortant strains RGNNV/SJNNV. A genetic characterization of all sea bream betanodaviruses which had been isolated in the past had revealed that the majority of the strains infecting sea bream are actually RGNNV/SJNNV. Taken together, this information strongly suggests that RGNNV/SJNNV betanodavirus possesses a particular tropism to sea bream, which can pose a new and unexpected threat to the Mediterranean aquaculture

Detection and characterization of a rhabdovirus causing mortality in black bullhead catfish, Ameiurus melas

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Feebly-Interacting Particles:FIPs 2020 Workshop Report

With the establishment and maturation of the experimental programs searching for new physics with sizeable couplings at the LHC, there is an increasing interest in the broader particle and astrophysics community for exploring the physics of light and feebly-interacting particles as a paradigm complementary to a New Physics sector at the TeV scale and beyond. FIPs 2020 has been the first workshop fully dedicated to the physics of feebly-interacting particles and was held virtually from 31 August to 4 September 2020. The workshop has gathered together experts from collider, beam dump, fixed target experiments, as well as from astrophysics, axions/ALPs searches, current/future neutrino experiments, and dark matter direct detection communities to discuss progress in experimental searches and underlying theory models for FIPs physics, and to enhance the cross-fertilisation across different fields. FIPs 2020 has been complemented by the topical workshop "Physics Beyond Colliders meets theory", held at CERN from 7 June to 9 June 2020. This document presents the summary of the talks presented at the workshops and the outcome of the subsequent discussions held immediately after. It aims to provide a clear picture of this blooming field and proposes a few recommendations for the next round of experimental results.Comment: 240 pages, 71 figure

Welfare assessment in sea bass (Dicentrarchus labrax) reared under organic aquaculture

During the last years, fish welfare is receiving increasing attention in public and therefore in the world of research, industry and governments. In aquaculture, fishes are often exposed to stress conditions, due to practices such as manipulation, grading, high stocking densities, transport, pre-slaughter conditions and slaughter methods. In order to reduce this stressors and to increase both fish welfare and production needs, it is seeking to introduce organic agriculture principles to the conventional aquaculture. Organic aquaculture is still relatively new in concept and development all over the World. Consumers expect organic producers to follow higher animal welfare standards. In this study, fish welfare was investigated in European sea bass (Dicentrarchus labrax) reared under organic aquaculture in a standard commercial farm, comparing it with a parallel conventional farming. At the beginning of the trial, the main difference between the two rearing systems was in the diet. Welfare was evaluated through different stress and immunological parameters, besides growing performances. Particularly, stress response was evaluated through the analysis of both serum and muscle cortisol, and oxidative stress was investigated with an histochemical (melanomacrophage centres count and relative pigments content) and an immunohistochemical approach, using an antibody anti-HNE (a lipid peroxidation marker), besides glutathione analysis. Hematological and innate immunity parameters was also carried out, such as hematocrit, leucocrit and serum lysozyme activity. The aims of the study were to investigate both differences in fish welfare between the two rearing systems and the seasonal variations of the parameters carried out. Concerning differences between rearing systems, this study highlighted a different growing trend, in which conventional fishes were longer and heavier than organic ones. On the other hand, stress and immunological parameters didn’t show any significant differences, if not in some samplings, suggesting that more severe conditions may be required to affect these activities. Since this was a monitoring study on a commercial farming, potential differences in the investigated parameters may have been mitigated, as the two systems didn’t differed so pronounced. Concerning seasonality, all parameters investigated exhibited some seasonal trend, probably correlated to water temperature and photoperiod or to their combination.Negli ultimi anni, il benessere dei pesci o “fish welfare” sta ricevendo crescente attenzione nel pubblico e quindi nel mondo della ricerca, dell'industria e dei governi. In acquacoltura, i pesci sono spesso esposti a condizioni di stress, a causa di pratiche di allevamento come la manipolazione, la selezione, l’alta densità di allevamento, il trasporto, le condizioni di pre-macellazione e i metodi di macellazione. Al fine di ridurre questo stress e per aumentare sia il benessere dei pesci sia le esigenze di produzione, si sta cercando di introdurre i principi dell'agricoltura biologica nell’acquacoltura tradizionale. L'acquacoltura biologica è un concetto ancora relativamente nuovo nel mondo dell’acquacoltura. I consumatori si aspettano che i produttori biologici seguano standard più elevati per quanto riguarda il benessere animale. In questo studio, il benessere dei pesci è stato valutato in branzini (Dicentrarchus labrax) allevati secondo disciplinare biologico in un allevamento commerciale. Contemporaneamente, gli stessi parametri sono stati studiati in branzini allevati in un parallelo allevamento convenzionale. All'inizio della sperimentazione, la differenza principale tra i due sistemi di allevamento riguardava il mangime utilizzato nella dieta. Il benessere è stato valutato attraverso parametri immunologici e di stress, oltre alle performance di crescita. In particolare, la risposta allo stress è stata valutata attraverso l'analisi di cortisolo sierico e muscolare e lo stress ossidativo è stato studiato con un approccio sia istochimico (conteggio dei centri melanomacrofagici e relativo contenuto in pigmenti) sia immunoistochimico, utilizzando un anticorpo anti-HNE (un marker della perossidazione lipidica), oltre all’analisi del glutatione totale. Inoltre si sono investigati parametri ematologici e immunitari, come l’ematocrito, il leucocrito e l'attività lisozimatica del siero. Gli obiettivi dello studio hanno riguardato sia la valutazione di eventuali differenze nel benessere dei pesci tra i due sistemi di allevamento sia lo studio delle variazioni stagionali dei parametri ricercati. Per quanto riguarda le differenze tra i sistemi di allevamento, questo studio ha evidenziato un diverso trend di crescita, per il quale i pesci allevati in modo convenzionale hanno mostrato un accrescimento maggiore sia in termini di peso che di lunghezza rispetto a quelli biologici. D'altra parte, lo stress e i parametri immunologici non hanno evidenziato particolari differenze significative, se non in alcuni campionamenti, suggerendo che condizioni più severe sarebbero necessarie per incidere su questi indicatori. Dal momento che questo è stato uno studio di monitoraggio su una azienda ittica a fini commerciali e non un allevamento sperimentale di ricerca, eventuali differenze nei parametri indagati potrebbero essere state mitigate, considerando anche che i due sistemi non differivano in modo pronunciato. Per quanto riguarda la stagionalità, tutti i parametri indagati hanno mostrato un trend stagionale, probabilmente correlato alla temperatura dell'acqua e al fotoperiodo o alla loro combinazione

Flexible polyimide electrodes for ECoG in chicken embryos

Electrocorticography (ECoG) is a valuable tool used to investigate brain activity with a better spatial resolution compared to the EEG system. We describe the fabrication of new polyimide electrodes for EcoG recording, used to research the development of wake-sleep cycles in chicken embryos. The microelectrodes are connected to a dedicated system for data acquisition. Current ECoG recordings in birds are usually made with metallic wire electrodes placed on the dura surface though a hole on the skull. This approach is not reliable for long term acquisitions (a few days) as the electrodes may generate signal artefacts and cause bleeding. Recently, flexible polymer electrodes have been proposed to avoid the stiffness of the metal wire and to improve compliance with brain surface. The electrodes are fabricated on a 75µm thick polyimide film substrate. Gold lines are used as conductive wires to read the brain potentials and transfer them to the acquisition system. To protect and isolate gold tracks, a protective spinnable polyimide layer (Hitachi PI2610) is subsequently deposited. Then, an aluminium hard mask is deposited and patterned by a lithographic step, to protect and to open a window by oxygen plasma etch in the protective layers, so that the gold pads are exposed. Finally, the electrodes are ready and are detached from the carrier tape. Preliminary insertion tests have showed the feasibility of flexible electrodes insertion in the chicken brain

Assessment in Statistics Using the Personal Computer

In Italian universities, students ’ performance is usually assessed by oral examinations. Although this system offers some advantages, it also has a number of weaknesses regarding both objectivity and efficiency, especially for crowded courses. One method of assessment which can be considered objective is true/false testing. Thi

Comparison of European sea bass (Dicentrachus labrax) from organic and semi-intensive rearing systems

The study aimed to compare biometric and rheological traits and chemical composition of sea bass coming from the organic and semiintensive rearing systems of an Italian fish farm (Veneto Agricoltura). The two systems differed for the diet, organic and conventional, while water conditions and stocking density were similar. After 18 months of rearing, 40 specimens (20 per rearing system) were slaughtered by immersion in ice slurry and analysed the day after catch. Biometric traits, dressing percentage and fillet pH, CIE L*a*b* colour and texture were measured. Chemical composition and fatty acid profile of the diets and sea bass fillets were analysed. Individual data were submitted to ANOVA by GLM procedure of SAS. Sea bass showed similar weight at slaughter (447 vs 421 g; P>0.05) and no difference in biometric traits or dressing percentage. Fillets showed similar texture profile, pH and L* and a* indexes, while b* index was higher in organic sea bass than in semi-intensive sea bass (1.39 vs 0.54; P<0.01). Fillet proximate composition did not change, while fatty acid profile differed according to the composition of the diets: in particular, organic sea bass showed higher proportion of saturated fatty acids (FA) (23.7 vs 22.2%), monounsaturated FA (33.4 vs 31.3%) and n-3 polyunsaturated FA (22.7 vs 14.4%) and a lower proportion of n-6 polyunsaturated FA (16.0 vs 29.1%) compared to semiintensive sea bass (P<0.001). The n3/n6 ratio was higher in the organic fish (1.42 vs 0.49; P<0.001). In conclusions, differences between organic and semi-intensive sea bass concerned their nutritional value and exclusively depended on the feeding regime