Search Results (355)

Plastic pollution is a major environmental concern. In humans, ingestion through contaminated seafood is a recognized exposure route to microplastics, which may impact gut health. However, the extent to which microplastics interfere with digestion and nutrient absorption remains unclear. To this end, the present work aimed to assess, for the first time, the influence of microplastic particles (polyethylene terephthalate, PET, and polylactic acid, PLA) on the digestibility of three selected seafood species (gilthead seabream, Sparus aurata; Atlantic salmon, Salmo salar; and hard clam, Mercenaria mercenaria) using an in vitro human digestion model. Furthermore, this study evaluated the potential degradability of microplastics along the gastrointestinal tract and examined how particle type and exposure level (10 or 20 particles) may influence seafood digestibility. Protein digestibility in S. aurata and S. salar filets was ~86%, while in M. mercenaria it was ~73%, regardless of microplastic presence or quantity. PET and PLA integrity was affected differently by digestion, with PLA showing greater surface degradation. These findings provide preliminary insight into the mutual interactions between microplastics and the human digestive process, highlighting the importance for further research into how the leaching of plastics additives may or may not influence the bioaccessibility of essential nutrients. Full article

Salmon farming has been affected by various bacterial diseases, and the use of antibiotics (such as oxytetracycline “OTC”) to control these diseases has become necessary and thus routine. This study aimed to determine how the gill cells are affected by OTC in Salmo salar. Gill tissue culture was performed in periods of 0.5, 1, 3, 6, 12, and 24 h, assessing the enzymatic activity and mRNA expression of catalase (CAT), cytochrome p450, glutathione peroxidase (GPx), glutathione reductase (Gr), and superoxide dismutase (SOD), HSP70 and HSP90, in response to two doses of OTC: 0.25 (low), and 3 µL/mL (high). The results indicated that the enzymatic activity of SOD and CAT showed low enzyme activity at both doses. At the same time, GR presented varied response patterns depending on the time and dose of OTC used, contrary to GPx, which just increased the enzyme activity at early times. Although the mRNA expression presented the most precise pattern of expression, they were not in line with the enzymatic activities. The HSP70 and HSP90 mRNA expression response (as a cellular damage marker) increased mRNA levels at low and high doses, respectively, but at different times, alluding to a differentiated response given by the size of the chaperone. These results suggest an oxidative response of the gills to OTC exposure and constitute significant information on the amount of OTC used in aquaculture and on methods for improving the optimal dose of drugs, fish health, and, consequently, environmental health. Full article

Water temperature is a key factor affecting the growth, feeding performance and physiological status of Atlantic salmon parr in aquaculture. To determine optimal conditions, parr (average weight 31.27 ± 0.35 g) were reared for 60 days at 10, 14, 18, and 22 °C. The survival and condition factors were similar across treatments. The growth rate and feed efficiency were highest at 14 °C, coinciding with elevated antioxidant activity. Feed intake was lowest at 10 °C. Whole-body protein and lipid contents remained unaffected, while moisture and ash contents were lowest at 14 °C. Most plasma biochemical indicators were stable; however, total protein was lowest at 14 °C. Glutathione peroxidase activity peaked at 14 °C, whereas cortisol levels remained unchanged. Heat shock proteins (HSP70, HSP90) increased with temperature, while insulin-like growth factor binding proteins (IGFBP1A, IGFBP1B) decreased at temperatures equal to or greater than 18 °C. Interferon alpha (IFNA) and thioredoxin (TRX) were lowest at 14 °C and highest at 22 °C. Overall, 14 °C appears optimal for growth and antioxidant capacity, although molecular stress markers suggest mild physiological trade-offs. These findings can inform temperature management strategies to enhance productivity and welfare in sustainable salmon aquaculture. Full article

Piscine orthoreovirus (PRV) is a globally distributed viral pathogen that causes heart and skeletal muscle inflammation (HSMI) in Atlantic salmon (Salmo salar) and affects other salmonids, yet no commercial vaccines are currently available. Major barriers to vaccine development include the inability to propagate PRV in cell lines and the low, variable immunogenicity of its proteins, particularly the outer capsid protein σ1, which mediates viral attachment. This protein is hypothesized to be immunologically relevant due to its homology with Mammalian orthoreoviruses. Recombinant σ1 expressed in conventional systems exhibits poor antibody recognition, whereas structural modifications such as lipidation or fusion with molecular chaperones improve epitope exposure. Formalin-inactivated vaccines have shown inconsistent protection, often failing to elicit robust innate or adaptive responses, especially under cohabitation challenge. In contrast, DNA vaccines encoding σ1 and the non-structural protein μNS have demonstrated partial efficacy, likely due to enhanced intracellular expression and antigen presentation. Nonetheless, the considerable variability observed in immune responses among individual fish and viral genotypes, together with suggestions that PRV may interfere with antiviral pathways, represent additional barriers to achieving consistent vaccine efficacy. This review summarizes the current status of PRV vaccine development and discusses future directions for rational design based on optimized antigens and intracellular delivery platforms. Full article

The large environmental and economic impact of sea lice infestation in the salmon industry has encouraged the development of non-medical methods and preventive strategies to combat sea lice infestation. Sea lice (Lepeophtheirus salmonis and Caligus elongatus) are sensitive to low salinities, and using fresh water as protection against infection may thus significantly reduce sea lice infestation of salmon while reducing the costs and impacts of traditional delousing methods. A new concept presented here is based on the manipulation of salinity within cages by adding fresh water to create an unfavourable environment for sea lice infestation. A full-scale set-up was tested in a salmon farm in northern Norway: two commercial-size cages with Atlantic salmon (Salmo salar) were enclosed with a 2 m deep tarpaulin skirt and supplied with fresh water at the centre to establish a surface layer with reduced salinity. Two reference cages had no skirt or fresh water supply. Time series of CTD-data showed that the fresh water supply caused a shallow and unstable salinity gradient, with salinities lower than 10 ppt measured for short periods in the upper 0.5 m. Despite these instabilities, significantly lower sea lice infestation in cages supplied with fresh water was observed, as infestation rates for pre-adult and adult stages of L. salmonis were reduced by 48% and 57%, respectively, in the treatment cages compared to controls. This preventive strategy is therefore very promising and deserves further development under more stable and controlled conditions. Future studies should focus on improving freshwater regulation, ensuring higher spatial resolution of salinity data in surface layers and documenting the effect on the more salinity-sensitive planktonic stages of L. salmonis. In addition, there is a need to examine the effectiveness of the technique at multiple sites and under a wide range of site conditions, especially various current rates through the site. Full article

The microbial community in a recirculating aquaculture system (RAS) is pivotal in fish health, contributing significantly to the productive performance during the growing-out phase. Classical and molecular methods using PCR for species-specific amplifications have traditionally been used for bacterial community surveillance. Unfortunately, these approaches mask the real bacterial diversity and abundance, population dynamics, and prevalence of pathogenic bacteria. In this study, we explored the use of Oxford Nanopore Technology to characterize the microbiota and functional metagenomics in a commercial freshwater RAS. Intestine samples from Atlantic salmon (Salmo salar (85 ± 5.7 g)) and water samples from the inlet/outlet water, settling tank, and biofilters were collected. The full-length 16S rRNA gene was sequenced to reconstruct the microbial community, and bioinformatic tools were applied to estimate the functional potential in the RAS and fish microbiota. The analysis showed that bacteria involved in denitrification processes were found in water samples, as well as metabolic pathways related to hydrogen sulfide metabolism. Observations suggested that fish classified as sick exhibited decreased microbial diversity compared with fish without clinical symptomatology (p < 0.05). Proteobacteria were predominant in ill fish, and pathogens of the genera Aeromonas, Aliivibrio, and Vibrio were detected in all intestinal samples. Notably, Aliivibrio wodanis was detected in fish showing abnormal clinical conditions. Healthy salmon showed higher contributions of pathways related to amino acid metabolism and short-chain fatty acid fermentation (p < 0.05), which may indicate more favorable fish conditions. These findings suggest the utility of nanopore sequencing methods in assessing the microbial community in RASs for salmon aquaculture. Full article

Black Soldier Fly Larvae Meal (BSFLM) has gained attention as a sustainable feed ingredient in aquaculture, yet its functional properties at the cellular level remain underexplored. This study evaluated the antioxidative and proliferative effects of BSFLM derived from larvae fed different waste-based substrates (Kitchen Waste (KW); Agricultural Waste (AW); Aquaculture Sludge (AS); Aquaculture Offal (AO); Mix (MX)), using the Atlantic salmon (Salmo salar) SHK-1 cell line as an in vitro model. BSFLM treatments were assessed through four assays: oxidative stress mitigation under H₂O₂ exposure, baseline cellular proliferation, proliferation under protein-standardized conditions, and recovery from serum starvation. Each assay was carried out in three independent experiments with three replicates per treatment, and changes in coloration were quantified using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide). The results showed that BSFLM from plant-based substrates, particularly MX and KW diets, significantly (p < 0.05) improved cell viability across all assays. Under oxidative stress, MX (121.1% ± 5.9) and AW (119.9% ± 6.1) treatments maintained viability levels comparable to Vitamin C (119.3% ± 3.8) (250 ppm of DSM Stay-C) and the control (137.5% ± 11.6). In proliferation assays, MX (207.6% ± 16.3) and KW (196.3% ± 11.1) outperformed animal-based treatments AO (122.6% ± 4.4) and AS (113.1% ± 3.7), and these effects persisted under protein-standardized conditions, although the statistical significance was reduced. In the recovery from serum starvation assay, cells treated with MX (45.5% ± 1.9) and KW (42.0% ± 0.4) exhibited markedly higher viability than AS (15.5% ± 1.9) and AO (14.8% ± 2.2). The biochemical composition of BSFL reared on different substrates, including proximate, amino acid, fatty acid, and polyphenol profiles, was analyzed to contextualize the observed cellular responses. These findings highlight the superior functional properties of BSFLM derived from plant-based substrates and support its potential use as a targeted functional feed ingredient in aquaculture feed formulations. Full article

Background/Objectives: Inactivation of the dnd gene involved in the development of primordial germ cells (PGCs) leads to the loss of gametes and halts reproductive development. Studies on sterile fish allow for the identification of genes and processes associated with GC differentiation. Methods: Atlantic salmon with GC-ablated testes were produced by temporal silencing of dnd. Gene expression was analyzed in sterile and fertile testes using 44k microarray and qPCR. Results: In sterile testes, transcripts of several GC markers were detected at low levels, suggesting the presence of cells with a GC-related expression profile that failed to initiate spermatogenesis. Expression of 260 genes was undetectable in the gonads of sterile males and females, and 61.5% of these were also inactivated during first maturation of fertile testes. This group was enriched with genes highly expressed in the brain, including those involved in endocrine and paracrine regulation, synaptic transmission, and numerous genes critical for brain development; among them, 45 genes encoding homeobox proteins. Another group of 229 genes showed increased expression in developing testes and included genes involved in neurosecretion and brain development regulation. GC-ablated testes showed increased expression of reproductive regulators such as amh and sdy and numerous immune genes, suggesting a reprogramming of GC-depleted testes. Temporal silencing of dnd indicated common developmental processes in the brains and gonads of Atlantic salmon testis that become inactive in testes at first maturation. These processes may play roles in PGC homing, the creation of a specific environment required for spermatogenesis, or facilitating communication between the gonads. Full article

Atlantic salmon aquaculture has become an important seafood producer, contributing to the human diet. The natural productivity of Atlantic salmon populations is not sufficient to meet even a fraction of current aquaculture production, and it has not been able to do so in the past. Alternative process technologies are needed to maintain aquaculture production at current levels while mitigating the environmental impact along the coasts. Future aquaculture development must align with the UN Sustainable Development Goals. This study describes an aquaculture process vessel operating in the open sea and powered largely by renewable energy. Production conditions are fully adapted to the biology of salmon, improving production reliability, reducing coastal environmental impacts, and enabling more sustainable production. This study specifies the biological and technological aspects, provides evidence of the technical and economic feasibility, and justifies the relocation of salmon aquaculture to a large oceanic ecosystem, the North Atlantic Ocean. Full article

This pilot study presents a sensor–actuator setup designed to evaluate tissue deformation in Atlantic Salmon (Salmo salar) during needle insertion. The system integrates three types of low-cost, commercially available force sensors to capture force profiles and identify biomechanical events associated with tissue layer transitions. Controlled insertions were performed on a deceased specimen, and the resulting force data were analyzed to quantify insertion dynamics and estimate tissue deformation. A simulation model based on the recorded force values was developed to calculate stress distribution and deformation, which ranged from 0.001 µm to 8.4 µm and from 0.3 N/m² to 4.9 N/m², respectively. The results indicate minimal biomechanical disruption, supporting the feasibility of using sensor–actuator systems for minimally invasive procedures in aquaculture. Although biological responses such as inflammation and healing could not be assessed, this study lays the basis for future research involving live specimens and blood sampling. The findings carry important implications for fish welfare, offering a pathway toward ethical and automated sampling techniques in aquaculture and livestock applications. Full article

This study evaluated the ability of a jasmine essential oil (JEO)-loaded nanoemulsion alone (WOM) and combined with modified atmosphere packaging (WOM-MAP) to extend the shelf life and maintain the quality of Atlantic salmon (Salmo salar) at 4 °C. The WOM was stabilized with oxidized corn starch (OCS) and whey protein (WP), and had a particle size of 255.7 nm and zeta potential of −25.43 mV. The treated salmon fillets were periodically analyzed for spoilage extent, texture, protein structure, and other quality parameters. The findings of this study showed that the salmon fillets treated with the WOM, particularly when combined with the MAP, was able to retain their original texture and taste to a great extent. Compared to the control check group (CK), the WOM and WOM-MAP treatments reduced bacterial counts by 2.1 log CFU/g and 2.4 log CFU/g, respectively, by the 20th day. Both the WOM and WOM-MAP treatments exhibited lower total volatile basic nitrogen and K values, prevented protein structural changes, and reduced free amino acid breakdown. These results indicate that the WOM effectively extends the shelf life and maintains the quality of Atlantic salmon, offering a promising natural preservative to preserve the quality and safety of seafood. Full article

The emergence and spread of pathogens pose significant challenges to the sustainability and productivity of aquaculture globally. For the Chilean salmon farming industry, salmonid rickettsial septicemia (SRS), caused by the facultative intracellular bacterium Piscirickettsia salmonis, constitutes one of the main disease challenges. In this study, the efficacy of various oral doses of florfenicol (FFC) (5, 7.5, and 10 mg/kg BW/day) against SRS was assessed in Atlantic salmon, when treatment was initiated at an early stage of infection. Since salmonids infected with P. salmonis typically lose appetite as the disease progresses, and the therapeutic FFC dose is dependent on a normal specific feeding rate (SFR), the treatments were administered 5 days post-challenge (DPC5). On the day of challenge, experimental fish were intraperitoneally (IP) injected with 0.2 mL of P. salmonis genogroup LF-89 inoculum (9.07 × 10⁷ CFU mL⁻¹). Fish mortality, behavior, clinical signs of disease, feed intake and SFR were monitored throughout the study. Conclusions: An important finding in this study was that all tested antibiotic doses halted disease progression and prevented mortality in fish challenged with P. salmonis when administered DPC5. In the control group, mortality reached 32.2% with fish displaying clinical signs of SRS. Full article

This study utilizes a discrete choice experiment (DCE) to estimate consumer valuation of sustainable aquaculture certification for Atlantic salmon (Salmo salar), one of the most important imported seafood products in South Korea. This experiment investigates consumer preferences across five product attributes: country of origin, product type, preparation method, sustainability certification, and price. Data were collected through an online survey administered by a professional research firm that yielded 24,000 valid choice observations from 1000 respondents. Conditional logit estimates revealed that all specified attributes significantly influenced consumer choices among seafood alternatives. Among the key product attributes, sustainability certification has emerged as the most influential factor affecting consumer decisions. The marginal willingness to pay for sustainably certified aquaculture is estimated to be USD 1.33 per 100 g. These findings provide valuable insights for seafood marketers and policymakers who seek to promote sustainable aquaculture in South Korea. Full article

A new polypeptide vaccine towards salmon lice (Lepeophtheirus salmonis) was given to experimental groups of 2 × 8000 Atlantic salmon parr (Salmo salar L.), following the vaccination of a total of 4 × 8000 parr with a common set of vaccines used in Norwegian aquaculture to prevent infestation in salmon growing at sea. The remaining 2 × 8000 salmon served as control. The trial was conducted at a sea farm research facility at Knappen-Solheim in Masfjorden, Norway. Natural infestation with sea lice were staged and counted once a week from January–December 2023. The infestation was never above two mature female lice per salmon, the maximum limit set specifically for the present trial by the Norwegian Food Safety Authorities, thus delousing with chemicals or other methods was avoided. Mortality, growth, feed consumption, sexual maturation, slaughter quality, and welfare quality parameters were not significantly different between vaccinated and control salmon. The effect size showed a moderate positive difference of 0.07 mature female salmon lice per salmon in favor of the vaccinated groups from a fish size above 600 g in May until November. All fish were slaughtered and marketed at a size of 5.8 kg (>83% superior quality). Full article

Chile is the second-largest producer of Atlantic salmon (Salmo salar), a key industry facing challenges such as infestations by Caligus rogercresseyi, which cause significant economic losses. However, there are no studies exploring how environmental variables in marine culture centers affect salmon’s immune response, considering their poikilothermic characteristics. This study analyzed the effect of the seasonal temperature on the skin transcriptome of Atlantic salmon infested with C. rogercresseyi in fjord-based farms in the Aysén Region during autumn and spring. Two different centers were analyzed (autumn: Farm-A; spring: Farm-S) to ensure the same age of the fish sampled in each season. RNA sequencing (RNA-seq) and functional network analysis revealed notable seasonal transcriptomic differences. In autumn, 253 differentially expressed genes (DEGs) were found, primarily associated with stress response and negative regulation of T-cell proliferation, suggesting an impaired response against the ectoparasite. In spring, 103 DEGs were detected, associated with protein synthesis and the activation of immune mechanisms, including complement activation, granulocyte chemotaxis, and antigen presentation. This is the first study to evaluate the transcriptomic response of healthy skin in C. rogercresseyi-infested salmon under farming conditions, highlighting the importance of considering seasonal variations for the development of more effective management strategies in the aquaculture industry. Full article