Search Results (43)

The yellowtail kingfish (Seriola aureovittata), a commercially important marine species, encounters significant survival challenges under low-temperature conditions during winter aquaculture. To elucidate its molecular adaptation mechanisms, this study employed RNA-Seq to analyze transcriptional responses in juvenile muscle tissues under acute cold stress (10 °C) at 0, 6, 12, and 24 h. Differential gene expression analysis revealed time-dependent patterns, with 269, 863, and 984 differentially expressed genes (DEGs) identified at 6, 12, and 24 h, respectively. Key pathways were identified, including lipid metabolism, carbohydrate metabolism, and stress response. Sestrin3 upregulation implicated AMPK-mediated energy homeostasis in cold adaptation. These findings provide novel insights into the molecular strategies underlying cold adaptation in yellowtail kingfish, offering potential targets for breeding cold-resistant strains and improving aquaculture resilience. Full article

In this study, a kinetic analysis was conducted to clarify the thermal inactivation behavior of AMP deaminase and IMPase, enzymes involved in the generation and degradation of inosine 5′-monophosphate (IMP) in the dorsal ordinary muscle (OM) and dark muscle (DM) of yellowtail Seriola quinqueradiata. Both enzymes were extracted from each part of the fish muscle, heated in the range of 50–60 °C, and then measured for residual enzyme activity. Based on these data, kinetic analysis was performed. When comparing fish muscle types, the thermal stability at 50 °C and 55 °C and the temperature dependence of both AMP deaminase and IMPase tended to be higher in the DM. When comparing the two enzymes, the thermal stability of IMPase was higher than that of AMP deaminase at 50 °C in both muscle types. These results suggest that to prepare heated yellowtail muscle with a high IMP content, it is important to consider the thermal inactivation behavior of enzymes and use slow heating to maintain AMP deaminase activity and produce sufficient IMP in OM. For DM, rapidly increasing the product temperature to ≥60 °C to inactivate IMPase is required to preserve the IMP content. Full article

Popular foods such as sushi and sashimi depend on the quality of raw fish meat to maintain consumer satisfaction. Recently, dietary insect meal and insect-derived substances have been extensively studied for application in aquaculture as a protein alternative or immunostimulant. However, the impact of insect functional substances on the fish meat quality of teleosts remains unclear. Here, we investigated the influence of dietary inclusion of silkrose-BM, a novel bioactive polysaccharide derived from the silkworm, Bombyx mori, on the meat quality of yellowtail (Seriola quinqueradiata). This study was conducted by comparing two groups given different feeds, commercial EP and feeds containing Silkrose-BM (0.1%), after a culture period of six months in separate floating-net cages. The yellowtail were specifically cut into loins and several meat quality parameters were observed, including proximate, meat color changes, total collagen, drip loss, muscle histology, and gene expression (qRT-PCR). The results of the color-change analysis showed that discoloration of red muscle in the EP feed group occurred faster than in the silkrose-BM group, indicating an antioxidant property of silkrose-BM. Dietary silkrose-BM also significantly reduced drip loss and increased the total collagen content of yellowtail meat. Furthermore, qRT-PCR analysis showed that genes related to lipid and protein degradation were downregulated in the muscles of fish fed on silkrose-BM. In contrast, proximate analysis indicated no significant change in the nutritional composition of the meat between the groups. Taken together, our results suggest that dietary silkrose-BM could improve fish meat quality by minimizing protein denaturation and inhibiting lipid oxidation during fish meat storage. Full article

The storage temperature is important for maintaining the quality of raw fish meat. The characteristics of ordinary muscle (OM) and dark muscle (DM) differ. This study aimed to clarify the effects of storage temperature (refrigeration, ice storage, and super-chilled (SC) storage) on the bacterial flora and quality (biochemical changes, volatile organic compounds (VOCs), and off-flavor development) of both muscles of yellowtail (Seriola quinqueradiata). SC storage effectively extended the shelf life of the dorsal part of ordinary muscle (OM) and DM by reducing bacterial proliferation, VOC changes, and off-flavor formation. However, their effects on the inhibition of trimethylamine (TMA) accumulation and lipid oxidation are limited. (E,E)-2,4-octadienal and (E,E)-3,5-octadien-2-one were identified as candidate markers of OM quality deterioration, whereas 1-hexanol was identified as a potential marker for DM. Alcohols, esters, and ketones are potential spoilage indicators of yellowtail muscles (OM and DM). Pseudomonas was the dominant spoilage bacterium in OM and DM across all storage conditions, with Acinetobacter, Brochothrix, and Shewanella appearing in later storage stages. These findings highlight the importance of storage at lower temperatures and understanding the dynamics of spoilage-causing bacteria and changes in VOCs in raw fish meat (OM and DM) to prevent spoilage and maintain meat quality. Full article

The rapid development of mining activities, the shipping industry, and public transportation across the land and water areas of Boedingi Village can have both positive and negative impacts on the water quality of this area. This study aimed to determine the heavy metal content in yellowtail fish (Caesio cuning), a type of fish that is generally consumed by Boedingi villagers in North Konawe, Indonesia. A descriptive method with an environmental health risk assessment (EHRA) was employed to measure metal profiles (Pb, Cd, and Hg). The results showed that the metal levels in the water exceeded the thresholds, indicating significant heavy metal pollution. In addition, the Cd levels of the fish surpassed the food safety standard according to the USA Food and Drug Administration (FDA). Since Indonesia began its large-scale shift from conventional to electrical transportation, global and government collaboration have become critical in managing the environmental and health impacts of the related industries. This is especially important because this area is one of the largest nickel producers (the raw material of electrical transportation) both nationally and globally. Full article

Skin aging is intrinsic and extrinsic. Intrinsic, or chronological, skin aging is an inevitable process of chronological and physiological alterations. The factors contributing to extrinsic skin aging involve sunlight, nutrients, and stress. Thus, extrinsic aging is thought to be superimposed over intrinsic aging and depends on the intensity and duration of environmental exposure and skin type (e.g., dry skin, oily skin, or eczema). The most significant extrinsic aging factor is UV radiation, which causes cellular senescence in a process known as photoaging. This study aimed to illuminate the mechanism whereby solubilized elastin peptide lotion (EL) from the bulbus arteriosus of yellowtail (Seriola quinqueradiata) prevents skin photoaging in hairless mice. EL reduced wrinkle formation, epidermal skin thickness, and Ki67 (cell growth marker) mRNA expression in skin tissues from ultraviolet B (UVB)-irradiated mice. EL treatment also reduced glyoxalase-1 (key enzyme of glucose metabolism) levels in skin tissue. Although no significant differences in collagen and elastin contents were found in dermal areas, matrix metalloproteinase-12 (wrinkle-related marker) expression was reduced following EL application. Furthermore, skin DPP-IV/CD26 (new senescence marker) levels decreased following EL treatment in photoaging model mice. These results suggest that EL moderates skin damage caused by UVB irradiation by regulating senescence-related molecule expression. Full article

Yellowtail snapper Ocyurus chrysurus has great potential as a production fish in aquaculture, yet there is very limited information on its nutritional requirements. To establish baseline data, two trials were conducted to evaluate the effects of dietary protein and lipid levels in practical diets on growth and protein retention. The first trial, conducted over 14 weeks, used a series of diets with varying levels of protein (36%, 40%, and 44%) and lipids (6%, 10%, and 14%). The second trial, conducted for 10 weeks, used a series of diets with 36% protein and scaled lipid levels (7%, 10%, 13%, and 16%). Additionally, a commercial reference diet with 44% protein and 12% lipids was included. Growth performance and feed utilization parameters for Trial 1 indicated that the yellowtail snapper were able to effectively utilize practical diets containing 36% protein and 10% lipids, which produced the highest apparent net protein retention (ANPR; %) and survival. No significant differences were found in growth performance metrics, though there were numerical differences in final weight, weight gain, and survival. Similarly, in Trial 2, most growth metrics did not show significant differences. There were variations in weight gain, feed offered, and ANPR, with the highest performance observed in the fish given feed with 13% lipids. Based on the growth performance and ANPR values across these trials, we recommend 36% protein and dietary lipid levels of 7–13%, which are lower than the currently used commercial diets for marine finfish. The data gathered from the current study may be helpful for nutritionists in formulating feed to include more sustainable and cheaper feedstuffs and promote sustainable yellowtail snapper aquaculture production. Full article

The farming mode of yellowtail kingfish (Seriola aureovittata) in China tends to be mature. However, there are some problems with environmental impact and economic benefits that cannot be ignored in the sustainable farming process. This study focused on a yellowtail kingfish aquaculture company in Dalian, China, and carried out a life cycle environmental and cost assessment (LCA and LCC) study to evaluate the environmental impact and economic benefits of the yellowtail kingfish farming process. According to the LCA and LCC results, the environmental impact is significantly influenced by fossil energy consumption and feed production. Moreover, five improvement scenarios were proposed and discussed, and the results show that replacing coal and thermal power generation with wind power generation will comprehensively (scenario 5) reduce environmental impact by 82.14% and decrease costs by 24.25%. The results of this study can provide effective improvement scenarios for yellowtail kingfish aquaculture enterprises and enrich the international aquaculture LCA basic database with data support. Full article

We evaluated the changes in the quality and microflora of yellowtail flesh cold-stored until spoilage. Based on the sensory evaluation, odor palatability was deemed unacceptable for dark muscle (DM) and the dorsal part of the ordinary muscle (OD) after >10 days and 14 of storage, respectively. Log 7 CFU/g in DM as well as OD was obtained on days 10 (Aeromonas spp.) and 14 (Enterobacteriaceae and Pseudomonas spp.) of storage, whereas log 5 (Brocothrix thermosphacta) and 6 (H₂S-producing bacteria) CFU/g in them were obtained on day 14 of storage. In these bacteria, the viable bacterial counts of Pseudomonas spp. and Aeromonas spp. in DM were significantly higher than those in OD only at some storage times. Amplicon sequencing revealed that in both muscles, Pseudomonas became predominant after storage, with greater than 90% recorded after more than 10 days of storage. The relative abundances of Acinetobacter, Unclassified Gammaproteobacter, and Shewanella were relatively high in both muscles after more than 10 days of storage; however, these values were less than 5%. Ethyl butyrate in the OD and DM and 2,3-butanedione in the OD were first detected on days 14 and 10 of storage, respectively. Acetoin in the OD increased by 81-fold after 14 days of storage and was significantly increased in the DM after more than 10 days compared with the amount detected pre-storage. Volatiles, such as (E)-2-pentenal in the OD and 1-pentanol in the DM, decreased and increased linearly, respectively, throughout the 14-day storage period. Altogether, these volatile components may cause quality deterioration due to spoilage and/or lipid oxidation during cold storage of the OD and DM. Full article

The yellowtail kingfish is a highly active and fast-growing marine fish with promising potential for aquaculture. In this study, essential insights were gained into the energy economy of this species by heart rate and acceleration logging during a swim-fitness test and a subsequent stress challenge test. Oxygen consumption values of the 600–800 g fish, when swimming in the range of 0.2 up to 1 m·s⁻¹, were high—between 550 and 800 mg·kg⁻¹·h⁻¹—and the heart rate values—up to 228 bpm—were even among the highest ever measured for fishes. When swimming at these increasing speeds, their heart rate increased from 126 up to 162 bpm, and acceleration increased from 11 up to 26 milli-g. When exposed to four sequential steps of increasing stress load, the decreasing peaks of acceleration (baseline values of 12 to peaks of 26, 19 and 15 milli-g) indicated anticipatory behavior, but the heart rate increases (110 up to 138–144 bpm) remained similar. During the fourth step, when fish were also chased, peaking values of 186 bpm and 44 milli-g were measured. Oxygen consumption and heart rate increased with swimming speed and was well reflected by increases in tail beat and head width frequencies. Only when swimming steadily near the optimal swimming speed were these parameters strongly correlated. Full article

Fishmeal and fish oil substitution in aquafeeds might have adverse effects on fish growth and health, mainly in carnivorous species, such as Mediterranean yellowtail (Seriola dumerili). Mediterranean yellowtail shows great potential as an alternative aquaculture species due to its fast growth and high price on the market, but the need for high-quality protein and fatty acid content in its diets is limiting its production. In order to improve the sustainability of its production, this study was conducted with 360 fish of 35 g to evaluate the effects on fish growth and health. Six diets were used: one control diet without replacement, three with FM replacement (FM66, FM33, and FM0) (33%, 66%, and 100% FM replacement), and two with FO replacement (FO50 and FO0) (50% and 100% FO replacement). The substitution of FM was with vegetable (VM) (corn gluten) and animal (AM) (krill and meat meal) meals. The reductions in FM and FO of up to 33 and 0%, respectively, did not affect the growth and survival of S. dumerili at the intestinal morphology level, except for the anterior intestine regarding the lower villi length and width and the posterior intestine regarding the lower width of the lamina propria. On the other hand, the substitution of fish ingredients in the diet affects liver morphology, indicating alterations in the major diameter of hepatocytes or their nuclei. Finally, diet did not affect the gut microbiota with respect to the control, but significant differences were found in alpha and beta diversity when FO and FM microbiota were compared. A 66% FM replacement and total FO replacement would be possible without causing major alterations in the fish. Full article

Diseases pose a significant and pressing concern for the sustainable development of the aquaculture sector, particularly as their impact continues to grow due to climatic shifts such as rising water temperatures. While various approaches, ranging from biosecurity measures to vaccines, have been devised to combat infectious diseases, their efficacy is disease and species specific and contingent upon a multitude of factors. The fields of genetics and genomics offer effective tools to control and prevent disease outbreaks in aquatic animal species. In this study, we present the key findings from our recent research, focusing on the genetic resistance to three specific diseases: White Spot Syndrome Virus (WSSV) in white shrimp, Bacterial Necrotic Pancreatitis (BNP) in striped catfish, and skin fluke (a parasitic ailment) in yellowtail kingfish. Our investigations reveal that all three species possess substantial heritable genetic components for disease-resistant traits, indicating their potential responsiveness to artificial selection in genetic improvement programs tailored to combat these diseases. Also, we observed a high genetic association between disease traits and survival rates. Through selective breeding aimed at enhancing resistance to these pathogens, we achieved substantial genetic gains, averaging 10% per generation. These selection programs also contributed positively to the overall production performance and productivity of these species. Although the effects of selection on immunological traits or immune responses were not significant in white shrimp, they yielded favorable results in striped catfish. Furthermore, our genomic analyses, including shallow genome sequencing of pedigreed populations, enriched our understanding of the genomic architecture underlying disease resistance traits. These traits are primarily governed by a polygenic nature, with numerous genes or genetic variants, each with small effects. Leveraging a range of advanced statistical methods, from mixed models to machine and deep learning, we developed prediction models that demonstrated moderate-to-high levels of accuracy in forecasting these disease-related traits. In addition to genomics, our RNA-seq experiments identified several genes that undergo upregulation in response to infection or viral loads within the populations. Preliminary microbiome data, while offering limited predictive accuracy for disease traits in one of our studied species, underscore the potential for combining such data with genome sequence information to enhance predictive power for disease traits in our populations. Lastly, this paper briefly discusses the roles of precision agriculture systems and AI algorithms and outlines the path for future research to expedite the development of disease-resistant genetic lines tailored to our target species. In conclusion, our study underscores the critical role of genetics and genomics in fortifying the aquaculture sector against the threats posed by diseases, paving the way for more sustainable and resilient aquaculture development. Full article

Harmful algal blooms (HABs) can produce a variety of noxious effects and, in some cases, the massive mortality of wild and farmed marine organisms. Some HAB species produce toxins that are released into seawater or transferred via food webs (particulate toxin fraction). The objective of the present study was to identify the toxicological effects of subacute exposure to saxitoxin (STX) during embryonic and early larval stages in Seriola rivoliana. Eggs were exposed to dissolved 19 STX (100 μg L⁻¹). The toxic effects of STX were evaluated via the hatching percentage, the activity of three enzymes (protein and alkaline phosphatases and peroxidase), and the expression of four genes (HSF2, Nav1.4b, PPRC1, and DUSP8). A low hatching percentage (less than 5%) was observed in 44 hpf (hours post fertilization) embryos exposed to STX compared to 71% in the unexposed control. At this STX concentration, no oxidative stress in the embryos was evident. However, STX induced the expression of the NaV1.4 channel α-subunit (NaV1.4b), which is the primary target of this toxin. Our results revealed the overexpression of all four candidate genes in STX-intoxicated lecithotrophic larvae, reflecting the activation of diverse cellular processes involved in stress responses (HSF2), lipid metabolism (PPRC1), and MAP kinase signaling pathways associated with cell proliferation and differentiation (DUSP8). The effects of STX were more pronounced in young larvae than in embryos, indicating a stage-specific sensitivity to the toxin. Full article

Aquaculture practices expose fish to several factors that may generate stress, modifying the balance between the production of reactive oxygen species (ROS) and the activity of antioxidant defenses that induce cell damage. Alpha-tocopherol (VE) improves the antioxidant capacity against ROS production in fish. A 50-day trial with longfin yellowtail (Seriola rivoliana) juveniles was conducted to compare the dietary supplementation of 500 mg/kg of VE against a control diet without VE supplementation on growth, lymphoid tissue enzymatic activity, immune-system-related gene expression, and the histology of the liver and spleen. Growth, weight gain, specific growth rate, feed conversion rate, and survival did not show significant differences (p > 0.05) among treatments. Fish fed with an α-tocopherol-enriched diet showed a higher enzymatic activity of superoxide dismutase in the liver (p < 0.05) and a lower percentage of melanomacrophage coverage area in the lymphoid organs (p < 0.05). Overexpression was observed of MyD88 and il-10 in the spleen, and il-1b in the liver in fish fed 500 mg/kg of VE, as well as overexpression of Toll-like 3 in the head kidney, spleen, and liver in fish fed the control diet. Dietary supplementation with VE reduces the effects of oxidative stress and improves lymphoid tissue defense and immune-related gene expression in S. rivoliana. Full article

Rockfishes (Sebastes spp.) are a long-lived, understudied, multi-species fish assemblage in inland Washington (USA) waters. Driven by large-scale fishery removals in the 1970s, their numbers declined and have yet to recover, perhaps due to slow maturation and rare recruitment success. Since then, rockfish fishing restrictions have increased within Puget Sound, culminating in a 2010 total ban. Here, we analyze rockfish community trends (abundance and Shannon Diversity) within Puget Sound from 2009 to 2023. Our dataset includes 157 recorded dive transects from nine rocky or artificial reef habitats at depths 5–24 m throughout four Puget Sound basins: Admiralty Inlet (2 sites), Central Puget Sound (4 sites), Hood Canal (2 sites), and South Puget Sound (1 site). Significant differences in community species composition between basins were observed; we noted more Black (S. melanops), Yellowtail (S. flavidus), and Puget Sound (S. emphaeus) rockfish and fewer Brown rockfish (S. auriculatus) at sites in Admiralty Inlet vs. Central Puget Sound. Adult rockfish counts and Shannon Diversity varied seasonally, with higher rockfish counts and diversity indices in summer/autumn vs. winter/spring. Notably, we observed that total adult rockfish count per survey tended downward over time, driven partly by significant downward trends in Hood Canal Copper rockfish (S. caurinus) counts. We recommend continued monitoring and additional investigation into what factors besides fishing may be driving the trends reported here. Full article