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1,120 results on '"European sea bass"'

45. Fish Brain Cell Lines Can Be Infected with Adenoviral Vectors and Support Transgene Expression—An In Vitro Approach.

Author

Cuesta, Alberto and Valero, Yulema

Abstract

Host–pathogen interactions and the design of vaccines for aquaculture fish viruses are challenging and call for innovative approaches. This study explores the potential of adenoviral (Ad) vectors Ad5 and chimeric Ad5/40 as gene delivery tools for fish brain cells susceptible to neurotropic viruses. For this purpose, European sea bass (Dicentrarchus labrax) DLB-1 and gilthead seabream (Sparus aurata) SaB-1 brain cell lines were infected with Ad5 or Ad5/40 vectors expressing GFP, and we evaluated their capacity for infection by fluorescence microscopy and flow cytometry, as well as their antiviral innate immune response by the transcription of gene markers (irf3 and mx). We found that both vectors are able to infect DLB-1 and SaB-1 brain cell lines to similar levels, as demonstrated by fluorescence microscopy and flow cytometry, though the infection efficiency was low. In addition, infection with Ad vectors regulated the transcription of genes related to the interferon-mediated antiviral immune response. Our results indicate that the Ad5/40 vector achieves better infection and consistent cellular distribution. These findings suggest that these vectors may offer targeted gene delivery and local immune responses. [ABSTRACT FROM AUTHOR]

Published
2024
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46. Impact of Harvest Method on Development of European Sea Bass Skin Microbiome during Chilled Storage.

Author

Angelakopoulos, Rafael, Tsipourlianos, Andreas, Fytsili, Alexia E., Giannoulis, Themistoklis, and Moutou, Katerina A.

Abstract

European sea bass (Dicentrarchus labrax) is one of the most significant species farmed in the Mediterranean, yet a very perishable product. Its quality deteriorates rapidly as a result of three mechanisms: microbial activity, chemical oxidation, and enzymatic degradation. Microbial spoilage is the mechanism that contributes most to the quality deterioration of fresh and non-processed fish. To this end, our study aims to identify for the first time the combined effect of aquatic environment and harvest method on the composition and trajectory at storage at 0 °C of the European sea bass skin microbiome. Sampling was performed in two commercial fish farms in Western (WG) and Central Greece (CG) where fish were harvested using different methods: direct immersion in ice water or a mixture of slurry ice; application of electro-stunning prior to immersion in ice water. Samples were collected on harvest day and one week post-harvest. To profile the bacterial communities in the fish skin, 16S ribosomal RNA gene sequencing was used. The results and the following analyses indicated that the aquatic environment shaped the original composition of the skin microbiome, with 815 ASVs identified in the WG farm as opposed to 362 ASVs in the CG farm. Moreover, Pseudomonas and Pseudoalteromonas dominated the skin microbiome in the WG farm, unlike the CG farm where Shewanella and Psychrobacter were the dominant genera. All these genera contain species such as Shewanella putrefaciens, Pseudomonas aeruginosa, Pseudoalteromonas spp., and Psychrobacter sp., all of which have been implicated in the deterioration and spoilage of the final product. The different harvest methods drove variations in the microbiome already shaped by the aquatic environment, with electro-stunning favoring more diversity in the skin microbiome. The aquatic environment in combination with the harvest method appeared to determine the skin microbiome trajectory at storage at 0 °C. Although Shewanella had dominated the skin microbiome in all samples one week post-harvest, the diversity and the relative abundance of genera were strongly influenced by the aquatic environment and the harvest method. This study sheds light on the hierarchy of the factors shaping the fish skin microbiome and their importance for controlling post-harvest quality of fresh fish. [ABSTRACT FROM AUTHOR]

Published
2024
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47. Behavioural Monitoring Underlines Habituation to Repeated Stressor Stimuli in Farmed Gilthead Sea Bream (Sparus aurata) Reared at a High Stocking Density.

Author

Holhorea, Paul G., Naya-Català, Fernando, Domingo-Bretón, Ricardo, Moroni, Federico, Belenguer, Álvaro, Calduch-Giner, Josep À., and Pérez-Sánchez, Jaume

Subjects
*EUROPEAN seabass, *SPARUS aurata, *HABITUATION (Neuropsychology), *MUSCLE regeneration, *MUSCLE growth
Abstract

Simple Summary: Habituation is a strategy that involves several physiological and behavioural response mechanisms to make individuals less reactive to recurrent stimuli and cope with the challenges posed by a stressor. In order to better understand fish stress resilience and adaptive capability, it is important to assess adaptation and habituation to main aquaculture stressors, such as high stocking densities. With that purpose, in this study, a confinement stress test was designed and validated by evaluating stress response in gilthead sea bream and European sea bass. This test was further employed to explore behavioural parameters in gilthead sea bream with a different background in stocking density. Although animals reared at higher densities exhibited impaired growth performance, they also displayed physiological and behavioural adaptation strategies to partly overcome the negative effects of high-density environments. Interestingly, behavioural monitoring evidenced signs of habituation to high-density conditions in the same group of animals. Thus, evaluating habituation can help to ensure that fish are within acceptable welfare standards while optimizing industry profitability. A confinement stress test with 75% tank space reduction and behavioural monitoring through tri-axial accelerometers externally attached to the operculum was designed. This procedure was validated by demonstrating the less pronounced stress response in gilthead sea bream than in European sea bass (950–1200 g). Our study aimed to assess habituation to high stocking densities with such procedure in gilthead sea bream. Animals (420–450 g) were reared (June–August) in a flow-through system at two stocking densities (CTRL: 10–15 kg/m3; HD: 18–24 kg/m3), with natural photoperiod and temperature (21–29 °C), and oxygen levels at 5.2–4.2 (CTRL) and 4.2–3.2 ppm (HD). At the end, blood and muscle were sampled for haematology and transcriptomic analyses, and external tissue damage was assessed by image-based scoring. Four days later, fish underwent a 45 min confinement stress test over two consecutive days. HD fish showed reduced feed intake, growth rates and haematopoietic activity. Muscle transcriptome changes indicated a shift from systemic to local growth regulation and a primed muscle regeneration over protein accretion in HD animals with slight external injuries. After stress testing, HD fish exhibited a decreased recovery time in activity and respiration rates, which was shorter after a second stressor exposure, confirming habituation to high densities. [ABSTRACT FROM AUTHOR]

Published
2024
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