Quantitative immunoenzymatic detection of viral encephalopathy and retinopathy virus (betanodavirus) in sea bass Dicentrarchus labrax

2015 ◽  
Vol 39 (7) ◽  
pp. 821-831 ◽  
Author(s):  
N Nuñez-Ortiz ◽  
V Stocchi ◽  
A Toffan ◽  
F Pascoli ◽  
N Sood ◽  
...  
2021 ◽  
Vol 58 (4) ◽  
Author(s):  
Rosvita Sitar ◽  
Tanja Švara ◽  
Aleksandra Grilc Fajfar ◽  
Sabina Šturm ◽  
Marko Cvetko ◽  
...  

Abstract: Viral encephalopathy and retinopathy (VER) is considered a serious disease of several marine fish species, caused by RNA virus belonging to the family Nodaviridae, genus Betanodavirus. The disease is spread almost worldwide and causes significant losses among diseased fish. It is characterised by vacuolation of the central nervous system and the retina. In July 2018, behavioural abnormalities i.e. altered swimming, swirling and vertical floating as well as lethargy and anorexia were observed in farmed sea bass (Dicentrarchus labrax) in the Gulf of Piran (Slovenia), associated with significant mortality. The disease initially occurred in juvenile sea bass, but later market-sized fish also became affected. Diseased fish displayed ocular opacity and multifocal skin ulceration on the head. Emaciation in some fish was also evident. Histopathology revealed characteristic vacuolation in the brain and retina. Performing a RT-PCR and RT-qPCR techniques, we have identified and confirmed the presence of betanodavirus nucleic acid in ocular and brain tissues. In addition, concentrations of the causative agent of VER in spleen and kidney did result in significantly higher viral yield than expected. Phylogenetic analysis showed that Slovenian isolate belongs to RGNNV species of betanodaviruses. Based on the clinical signs, gross and typical microscopic lesions and results of molecular analyses, we can conclude that farmed sea bass from the Gulf of Piran were affected with VER. To the best of our knowledge, this is the first report of VER in Slovenia.Key words: viral encephalopathy and retinopathy; betanodavirus; sea bass; histopathology; RT-qPCR PRVI IZBRUH VIRUSNE ENCEFALOPATIJE IN RETINOPATIJE PRI GOJENIH BRANCINIH (Dicentrarchus labrax) V SLOVENIJI Izvleček: Virusna encefalopatija in retinopatija (VER) je nevarna bolezen številnih vrst morskih rib, ki jo povzroča nevrotropni RNA virus iz družine Nodaviridae, rod Betanodavirus. Bolezen je razširjena skoraj po vsem svetu in povzroča visok pogin okuženih rib. Zanjo so značilne vakuole v centralnem živčnem sistemu in retini. Konec julija 2018 so v ribogojnici v Piranskem zalivu pri brancinih opazili nepravilno plavanje, vrtenje in postavljanje v vertikalno smer ter letargijo in neješčnost, brancini so množično poginjali. Bolezen se je najprej pojavila pri mladicah, nato tudi pri konzumnih kategorijah brancinov. Obolele ribe so imele sivo-motna očesna zrkla ter multifokalne kožne razjede na glavi, posamezne so bile shujšane. S histopatološko preiskavo smo ugotovili značilne vakuole v možganih in retini. Z molekularnima metodama RT-PCR in RT-qPCR smo potrdili prisotnost nukleinske kisline betanodavirusa v očesnem zrklu in možganih. Koncentracije virusa, ki so bile signifikantno višje od pričakovanih, smo ugotovili tudi v vranici in ledvicah. Na podlagi kliničnih znakov, makroskopskih in tipičnih histopatoloških sprememb ter rezultatov molekularnih preiskav lahko zaključimo, da so gojeni brancini v ribogojnici v Piranskem zalivu zboleli za VER. Opisani izbruh je prvi potrjeni primer te bolezni v Sloveniji.Ključne besede: virusna encefalopatija in retinopatija; betanodavirus; brancin; histopatologija; RT-qPCR


This study concentrated on the assessment of the prevailing parasitic fish diseases in some marine fishes at Ismailia province and how to control the infestation using microalgae. This study was carried out on 1080 pre-mature fish (360 D. labrax (225±25 g) and 360 S aurata (150±25 g) and 360 M. cephalus (125±25 g) collected from similar ponds of studies to be examined at the end of treatment. In addition to that we followed non-treated fish (1080 premature). The infested fish showed dark colour and respiratory signs. Post mortem lesions were a presence of congestion or paleness and destruction of gill filaments. The total prevalence of infestation was the total prevalence of parasitic infection of non-treated fishes was 45.83 %. The highest percentage was in D. labrax 56.94 % followed by S. aurata 47.22%, the lowest percentage in M. cephalus 33.33. The total prevalence of parasitic infection in premature treated with 2 g algae was 28.79%, followed by 3 g algae was 23.60 %, while the lowest percentage with 5 g algae was 20.37 % respectively. The detected species of parasites were protozoal parasites, Amyloodinium ocellatum and Riboscyphidia in additions of marine monogenea, Lamellodiscus diplodicus isolated from D Labrex, Mugil Cephalus and S aurata. The present study concluded that, the use of microalgae instead of fish meal decreased parasitic infestation in marine fish. The histopathological alteration of natural infested examined fishes was also recorded.


2019 ◽  
Vol 90 ◽  
pp. 317-327 ◽  
Author(s):  
Shay Ravid-Peretz ◽  
Angelo Colorni ◽  
Galit Sharon ◽  
Michal Ucko

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 392
Author(s):  
Lydia Katsika ◽  
Mario Huesca Flores ◽  
Yannis Kotzamanis ◽  
Alicia Estevez ◽  
Stavros Chatzifotis

This study was conducted to elucidate the interaction effects of temperature and dietary lipid levels (2 × 2 factorial experiment) on the growth performance, muscle, and liver composition in adult farmed European sea bass (Dicentrarchus labrax). Two groups of fish (190 g; 60 fish per group) were distributed in 12 tanks in triplicates and kept at two different temperature regimes; one starting at 23 °C and then changed to 17 °C for 61 days, and the other starting at 17 °C and then changed to 23 °C for 39 days. Two commercial diets containing both ~44% crude protein but incorporating different dietary lipid levels, 16.5% (D16) and 20.0% (D20) (dry matter (DM)), were fed to the fish to apparent satiation; the type of diet fed to each fish group remained constant throughout the experiment. Final body weight, weight gain, and specific growth rate were significantly higher for the fish group held at 23 °C compared to the fish group at 17 °C (before the temperature changes), while the dietary fat content did not have any profound effect in both groups. Furthermore, the different temperature regimes did not affect muscle or liver composition, but, on the contrary, dietary lipids affected hepatosomatic, perivisceral fat, and visceral indexes. Feed conversion ratio and specific growth rate were not affected by the dietary lipid level. An interaction of temperature and dietary lipid content was observed in daily feed consumption (DFC) and final body weight (FBW).


2017 ◽  
Vol 19 (1) ◽  
pp. 102-115 ◽  
Author(s):  
Daniel Żarski ◽  
Thaovi Nguyen ◽  
Aurélie Le Cam ◽  
Jérôme Montfort ◽  
Gilbert Dutto ◽  
...  

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