Search

Deep-sea mariculture, particularly copper (Cu) alloy fence mariculture, is increasingly regarded as a sustainable model for future mariculture development. However, limited research has been conducted on its impact on seawater and sediment. To investigate variations in environmental factors induced by large-scale enclosure aquaculture of the large yellow croaker (Larimichthys crocea), a comprehensive quarterly analysis was conducted in the sea area near Dachen Island, China, from 2021 to 2023. This study focused on changes in pH, dissolved oxygen (DO), Cu, chlorophyll a, dissolved inorganic nitrogen (DIN), and labile phosphate ( PO 4 3 - ) in seawater. Additionally, variations in total nitrogen (TN), total phosphorus (TP), and total organic carbon (TOC) content and pollution levels in the sediment were examined. The Nemerow index was used to assess the quality of both seawater and sediment. In 2021 and 2022, the highest DIN content in seawater was observed during the summer, reaching 0.491 ± 0.161 mg·L−1 and 0.485 ± 0.101 mg·L−1, respectively. Contrastingly, in 2023, the peak DIN concentration occurred in autumn, escalating to 0.597 ± 0.054 mg·L−1. Over the three years, the content of PO 4 3 - in seawater exhibited elevated levels during summer and autumn, with the highest concentration of 0.087 ± 0.009 mg·L−1 observed in autumn 2023. Notably, the Cu content in spring 2023 was 4.09 ± 0.36 μg·L−1, making the highest quarterly value within the three-year period. This data indicated a discernible accumulation trend for DIN, PO 4 3 - , and Cu in seawater. Additionally, TN, TP, and TOC levels in the sediment demonstrated an increasing trend over the three years. The maximum TN content recorded in the sediment was 0.69 ± 0.15 mg·L−1 in 2021, 0.74 ± 0.12 mg·L−1 in 2022, and 0.90 ± 0.15 mg·L−1 in 2023. For TP, the highest content was 0.66 ± 0.17 mg·L−1 in 2021, 0.60 ± 0.18 mg·L−1 in 2022, and 0.85 ± 0.12 mg·L−1 in 2023. The maximum TOC content was 0.74 ± 0.15% in 2021, 0.74 ± 0.13% in 2022, and 0.95 ± 0.12% in 2023. The Nemerow index for both seawater and sediment showed a consistent increasing trend over the three-year period. Although seawater quality remained at Class III (mild pollution) for most of this period, it approached Class IV (moderate pollution) during the summer and autumn of 2023. During these three years, sediment quality reached Class II (relatively clean) only in the winter of 2021 and the spring of 2022; however, it remained Class III (mild pollution) during the other seasons. The findings suggested that Cu alloy fence mariculture did not fundamentally address the pollution issue caused by aquaculture. And the development of an ecological mariculture model with a low-carbon footprint and sustainable practices may be the primary direction for future advancements in aquaculture. This study complemented basic data on the environmental impact of Cu alloy fence mariculture and provided theoretical support for the development of sustainable farming models. [ABSTRACT FROM AUTHOR]

The preservation of harvested fish is important in fisheries production. To investigate the effect of acute cold stress on preserving the freshness of large yellow croaker, which has the highest expression of ISP2 mRNA in its muscle, under ice-temperature storage and frozen storage, acute cold stress durations were investigated first. According to the results of the above test, large yellow croakers were subjected to acute cold stress for 40 min, followed by ice-temperature storage or frozen storage. The K values, sensory attributes, and protein compositions of large yellow croaker under ice-temperature storage or frozen storage for different durations were investigated in this study. The results showed that acute cold stress treatment affects the ice-temperature storage and frozen storage of large yellow croaker. In the muscle of large yellow croaker under ice-temperature storage for 1, 2, 3, and 5 d, the K values of the acute cold stress groups were significantly lower than those of the control groups (not subjected to acute cold stress). In the muscle of large yellow croaker under frozen storage, the sensory evaluation scores of the acute cold stress groups were greater than those of the control group until a storage time of 60 d. With an extension of frozen storage, there were changes in the contents of myofibrillar protein, myogen, muscle matrix protein, and alkali-soluble protein. The myofibrillar protein, myogen, and muscle matrix protein contents of the acute cold stress groups were greater than those of the control groups after short-term frozen storage, while the alkali-soluble protein contents of the acute cold stress groups were lower than those of the control groups, except for durations of 1, 3, 15, 19, and 22 d. In addition, the K values of the acute cold stress groups were significantly lower than those of the control groups after frozen storage for 1, 2, 3, 5, 9, 15, 19, and 22 d. The results indicate that treatment with acute cold stress for 40 min affects the preservation of large yellow croaker. [ABSTRACT FROM AUTHOR]

Exploring the influence of dietary L-carnitine (LC) supplementation in fish diets with varying lipid levels is essential for comprehending its effects. The present study assessed the effect of dietary LC supplementation on growth performance, feed utilization, body composition, and antioxidant capacity of large yellow croaker (Larimichthys crocea) at two dietary lipid levels. Two diets were formulated with 100 g kg−1 and 140 g kg−1 lipid levels as control diets, which were each supplemented with four LC levels at 0, 0.2, 0.3, and 0.4 g kg−1 to make the experimental diets. These diets were fed to fish weighing 10.80 ± 0.40 g for eight weeks. The results showed that dietary lipid and LC levels, and their interaction affected final body weight and weight gain of fish. The fish fed at 140 g kg−1 dietary lipid level supplemented with 0.2 (HC2) and 0.3 (HC3) g kg−1 LC increased weight gain by 5% and 23%, respectively, compared to those fed on the control diet (HC0). Moreover, the fish fed at 100 g kg−1 dietary lipid level supplemented with 0.2 (LC2), 0.3 (LC3), and 0.4 (LC4) g kg−1 LC increased weight gain by 12.6%, 5.8%, and 8.3% compared to those fed the control diet (LC0). Independently, dietary lipid and LC levels affected serum superoxide dismutase and liver catalase activities. Dietary lipid level affected body lipid and energy contents, serum malondialdehyde content, and liver glutathione peroxidase activity. The optimum dietary LC required for maximum weight gain was 0.31 g kg−1 for fish fed the diet containing 140 g kg−1 lipid level. The present study reveals that the effect of dietary LC varies at different lipid levels. We recommend adding 0.31 g kg−1 LC during the formulation of diets containing 140 g kg−1 lipid to improve growth performance of large yellow croaker during commercial farming. [ABSTRACT FROM AUTHOR]

The liver metabolomics and related biochemical indices of large yellow croaker were investigated during packaging and oxygenation transport. The large yellow croaker was packed into bags and transported at a constant temperature of 20 ℃. Serum and liver samples were collected after 0, 6, 12, 18, and 24 h of transportation for subsequent analysis. The results showed that transport time had a significant effect on serum creatinine (CR) and glutamine transaminase (AST) levels, suggesting that the kidney and liver tissues of large yellow croaker were affected. Transport stress impacted the antioxidant capacity of large yellow croaker liver, indicated by increased activities of catalase (CAT), malondialdehyde (MDA), and alkaline phosphatase (AKP), which altered immune capacity. In the liver metabolome, we identified five metabolic pathways that were enriched based on differential metabolites and compared across different transport times. These pathways include biosynthesis, lipid, cofactor and vitamin, amino acid, and carbohydrate metabolism. These pathways may impact the morphology of liver cells, as well as the antioxidant and immune abilities of large yellow croaker. Additionally, the statistical analysis of the metabolites at each transportation time revealed that histidylarginine and 3-(4-hydroxyphenyl) pyruvate were consistently downregulated which serve as signature metabolites during live large yellow croaker transportation. [ABSTRACT FROM AUTHOR]

Seafood is highly perishable after being caught, making effective preservation technology essential. A few studies have explored the mechanisms of near-freezing storage combined with high-voltage electric fields for seafood preservation. This study uses near-freezing storage at −1 °C in conjunction with three high-voltage electric fields (5 kV/m, 8 kV/m, and 16 kV/m) to store large yellow croakers for 21 days and assesses their quality through sensory evaluation, pH values, malondialdehyde, total volatile basic nitrogen, and total viable counts. The results indicate that high-voltage electric fields effectively inhibit endogenous enzyme activity and microbial growth while reducing lipid oxidation in large yellow croakers. The preservation effect is optimal at an electric field strength of 16 kV/m, extending their shelf life by 9 days. These findings offer valuable theoretical and data-driven insights for applying near-freezing storage and electric field preservation technology in cross-regional fish transportation. [ABSTRACT FROM AUTHOR]

Fishmeal is over-represented in the diets of large yellow croaker (Larimichthys crocea), and this farming mode, which relies heavily on fishmeal, is highly susceptible to the price of fishmeal and is unsustainable. Therefore, more and more studies on the large yellow croaker tend to replace fishmeal with land-based animal or plant proteins, but few studies have considered it from the genomic selection. In this study, we evaluated the survival rate (SR), final body weight (FBW), body weight gain (BWG), weight gain rate (WGR), and specific growth rate (SGR) of the large yellow croaker GS7 strain, which was obtained through genomic selection for tolerance to plant proteins and analyzed the differences in plant protein utilization between the GS7 strain and unselected commercial large yellow croaker (control group). The results of separate feeding for 60 days showed that although there was no significant difference in SR between the control and GS7 strains (P > 0.05), the BWG, WGR, and SGR of the control were significantly lower (P < 0.05) than those of the GS7 group. Results of mixed feeding after PIT marking showed that compared to the control fish, the GS7 strain had significantly higher BWG, WGR, and SGR (P < 0.0001). To make the experimental results more precise, we compared fishes with equivalent initial body weight (IBW) in the GS7 strain and the control group. The final fish body weight (FBW) of Ctrl-2 (IBW 300–399 g) and Ctrl-4 (IBW 500–599 g) was significantly lower than those of the corresponding GS7-2 and GS7-4 (P < 0.05), while the FBW of Ctrl-1 (IBW 200–299 g) and Ctrl-3 (IBW 400–499 g) was much significantly lower than the corresponding GS7-1 and GS7-3 (P < 0.01). The BWG, WGR, and SGR of Ctrl-1 and Ctrl-4 were more significantly lower than those of the corresponding GS7-1 and GS7-4 (P < 0.01), while the BWG, WGR, and SGR of Ctrl-2 and Ctrl-3 were more significantly different from the corresponding GS7-2 and GS7-3 (P < 0.0001). Our results seem to point toward the same conclusion that the GS7 strain is better adapted to high plant protein diets than the unselected commercial large yellow croaker. These results will provide a reference for the low-fishmeal culture industry of large yellow croakers and the selection and breeding of strains tolerant to a high percentage of plant proteins in other marine fishes. [ABSTRACT FROM AUTHOR]

Suppressors of cytokine signaling (SOCS) proteins are important regulators of the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway. Within the SOCS family, SOCS3 is one of the most potent inhibitors of cytokine signaling. However, there is limited knowledge regarding the function of SOCS3 on regulating type I interferon (IFN) signaling in fish. In this study, the complete open reading frame (ORF) of SOCS3 from the large yellow croaker (Larimichthys crocea, LcSOCS3) was cloned and characterized. The ORF of LcSOCS3 was 618 nucleotides in length and encoded a protein containing 205 amino acids. LcSOCS3 had the typical domain architecture of the SOCS family, including an SRC homology 2 (SH2) domain, a SOCS box, an additional kinase inhibition region (KIR), and an extended SH2 subdomain (ESS). Phylogenetic analysis revealed that LcSOCS3 was clustered with other fish SOCS3s and most closely related to the SOCS3 of Collichthy lucidus. LcSOCS3 mRNA was detected in all organs or tissues examined, and its expression was significantly increased in both head kidney and spleen tissues, and primary head kidney leukocytes after poly(I:C) stimulation. Overexpression of LcSOCS3 significantly promoted Spring viremia of carp virus (SVCV) replication, resulting in a more severe cytopathic effect, increased viral titer, enhanced copy number of the SVCV-G gene, and decreased expression levels of IFN1, IRF7, ISG15, Viperin, PKR, and Mx in epithelioma papulosum cyprinid (EPC) cells. Silencing of LcSOCS3 correspondingly up-regulated the expression of IFNi, IFNh, PKR, Viperin, and Mx in large yellow croaker head kidney (LYCK) cells. Additionally, LcSOCS3 was shown to interact with Signal Transducer and Activator of Transcription 1 (STAT1) which may inhibit STAT1 translocating into the nucleus. This speculation was supported by the increased phosphorylation level of STAT1 in head kidney leukocytes after LcSOCS3 silencing. These results indicated that LcSOCS3 functioned as a potential negative regulator of type I IFN signaling in large yellow croaker through its interaction with STAT1. [ABSTRACT FROM AUTHOR]

Large yellow croaker (Larimichthys crocea), the most developing fish of China, suffering from both biotic and abiotic stressors. A genome-wide study was performed for the first time to investigate the roles of Toll-like receptor genes in large yellow croaker (LcTLRs) working in hypoxia response and Aeromonas hydrophila infection. 12 TLR genes were identified and annotated, and phylogenetic tree, analysis of structure and motifs demonstrated that TLRs were highly conserved. To further investigate the LcTLRs under environmental stress, expression pattern analysis of hypoxic response and Aeromonas hydrophila infection revealed that there were nine and six members of LcTLRs showing significant differential expression, indicating that they were concerned in hypoxia stress and disease responses. Meanwhile, their expression levels were validated utilizing qPCR. Taken together, a greater appreciation and understanding of TLRs function in the reaction to biotic and abiotic stress would ultimately lead to more efficiently environmental adaptation in large yellow croaker. [ABSTRACT FROM AUTHOR]

Emerging non-thermal technologies are widely applied in storage and processing of aquatic products, especially ultrasound-assisted technology. Frequency is an important component of ultrasound, and the effects of different ultrasound frequencies are obviously different. This research evaluated the effects of single-frequency (28 kHz, 40 kHz) and dual-frequency (28/40 kHz) ultrasound-assisted thawing (UAT) treatment on physicochemical quality, myofibril characteristics, and microstructure of large yellow croaker during frozen to refrigeration. The results revealed that UAT treatment retained a better performance, such as water-holding capacity (WHC), color, texture, and water distribution, and relieved disruption of microstructure, especially DUAT-28/40 treatment. The total volatile basic nitrogen (TVB-N) obtained the most desirable freshness property under the DUAT-28/40 treatment, as well as the free amino acids analysis. In addition, it reduced the myofibril denaturation during frozen to refrigeration, as shown in protein primary structure, infrared detection, and fluorescence intensity analysis. Therefore, DUAT-28/40 treatment could be a possible thawing method for relieving the quality deterioration of large yellow croaker during frozen to refrigeration. [ABSTRACT FROM AUTHOR]

How to reduce the quality loss of aquatic products during storage is a topic worth exploring. This study proposed a method combining orthogonal dual-frequency ultrasound-assisted treatment (20 kHz vertically, 40 kHz horizontally, 400 W) with bioactive coating (Melissa officinalis L. essential oil-carboxymethyl chitosan-locust bean gum) and discussed the effects of this combined treatment on the quality, lipid, and protein of large yellow croaker during cold storage (4 °C). The results showed that both ultrasound-assisted treatment (US) and bioactive coating (CMCS) significantly inhibited microbial growth and quality deterioration in the fish, with the combined treatment group (US+CMCS) showing the best effect. The shelf life of large yellow croaker in the control group (CK) was 6 d, while the shelf life for US, CMCS, and US+CMCS treatments was 12 d, 12 d, and 18 d, respectively. Additionally, the combined treatment inhibited lipid oxidation and effectively delayed the oxidative degradation of protein in the large yellow croaker during cold storage. Therefore, the method of orthogonal dual-frequency ultrasound-assisted treatment (20 kHz vertically, 40 kHz horizontally, 400 W) combined with bioactive coating (Melissa officinalis L. essential oil-carboxymethyl chitosan-locust bean gum) proposed in this study was a promising approach for the preservation of aquatic products during storage.

The large yellow croaker, an endemic migratory species in China’s coastal waters, holds considerable economic importance. It is very necessary and significant to study the spatio-temporal evolution of large yellow croaker fishery based on environmental factors. In this paper, the HY-1C/D Coastal Zone Imager was applied to reveal distributional details of suspended sediment concentration and chlorophyll-a concentration in large yellow croaker fishery. Furthermore, combined with multi-source data, the characteristics of other environmental parameters such as temperature, salinity, current, wind and fronts were analyzed to reveal the changing of large yellow croaker fishery location. The results show that: (1) The environmental factors of large yellow croaker fishery exhibit pronounced spatial and temporal characteristics. Generally, the temperature (9-28°C), salinity (20-34 ‰) and other water environmental factors of the fishing ground are conducive to the survival and growth of large yellow croaker. The formation and change of fishery are closely related to environmental factors in the water. (2) The change of environmental factors in the water may induce the change of large yellow croaker fishery location. Winter sea surface temperature has significantly risen over the past two decades (2004-2023). With the sea surface temperature rising by approximately 2°C west of 125°E, the overwintering ground has expanded westward, increasing by nearly 29%. In addition, the scale and number of offshore windmills increased by 836% and 456% respectively over the decade (2013-2023). In 2023, offshore wind farms cover an area of 145.47 km2 and have 200 windmills. Wind turbine piles resembling artificial reefs. It can not only promote the waters vertical exchange to enhance the nutrients in upper waters but also provide a protective base for fish spawning. Thus, effectively attracting fish species. The construction of offshore wind farms has extended spawning ground north-westward to the mouth of the Yangtze River Estuary, expanding by nearly 21%. This study improved the cognition level of resources, habitat environment and change trend of large yellow croaker. It also provided technical support for the construction and protection of the large yellow croaker fishery.

To investigate the effects of the interaction between water quality and gill function of large yellow croaker during transportation in packaging bags, a total of 186 large yellow croakers weighing 120.0 ± 28.0 g were randomly divided into two groups: a control group (tanks with a water treatment system to maintain normal water quality) and treatment groups subjected to simulated transport for 0, 6, 12, 18, and 24 hours at a temperature of 20°C. The results revealed that prolonging the transport duration (beyond 6 hours) caused significant changes in dissolved oxygen (DO), total ammonia nitrogen (TAN) and pH levels in the water. Beyond 6 hours of transport, gill tissue damage increased, and the histomorphological characteristics of the gills were altered. Regarding osmoregulation, the activities of Ca2+/Mg2+-ATPase and Na+/K+-ATPase were notably reduced in the treatment groups, indicating compromised osmoregulatory function of the gill tissue during transport. However, changes in lactic acid (LD) and lactate dehydrogenase (LDH) were not statistically significant, and fish did not experience hypoxia during packaging bag transport. In terms of antioxidant activity, the treatment groups exhibited significantly lower activities of catalase (CAT) and superoxide dismutase (SOD) after 24 hours, as well as increased malondialdehyde (MDA) content after 18 hours. This reduction in antioxidant capacity led to cellular membrane damage in the gill tissue. Furthermore, acid phosphatase (ACP) activity showed a notable decline from 12 hours onwards in immune indicators, while lysozyme (LZM) activity experienced a substantial decrease at 24 hours. Correlation analysis revealed a significant correlation between the osmoregulation, antioxidant capacity, and immune response of gill tissue with elevated TAN levels and reduced pH. In conclusion, the levels of TAN and pH experience notable alterations after 6 hours of transportation, which may lead to impairment of gill function in large yellow croakers. Hence, we advise limiting the transportation of large yellow croakers to less than 6 hours at 20°C.

This study investigated the impact of multi-frequency ultrasound-assisted (20/28/40 kHz) thawing (MUAT) at different power levels (195, 220, 245, and 270 W, respectively) on the flesh quality and protein stability of large yellow croakers. Compared with flowing water thawing (FWT) and the other MUAT sample, flesh quality results indicated that the MUAT-220 W significantly reduced (p

Zinc finger Asp-His-His-Cys motif-containing (zDHHC) proteins, known for their palmitoyltransferase (PAT) activity, play crucial roles in diverse cellular processes, including immune regulation. However, their non-palmitoyltransferase immunomodulatory functions and involvement in teleost immune responses remain underexplored. In this study, we systematically characterized the zDHHC family in the large yellow croaker (Larimichthys crocea), identifying 22 members. Phylogenetic analysis unveiled that each of the 22 LczDHHCs formed distinct clusters with their orthologues from other teleost species. Furthermore, all LczDHHCs exhibited a highly conserved DHHC domain, as confirmed by tertiary structure prediction. Notably, LczDHHC23 exhibited the most pronounced upregulation following Pseudomonas plecoglossicida (P. plecoglossicida) infection of macrophage/monocyte cells (MO/MΦ). Silencing LczDHHC23 led to heightened pro-inflammatory cytokine expression and diminished anti-inflammatory cytokine levels in MO/MΦ during infection, indicating its anti-inflammatory role. Functionally, LczDHHC23 facilitated M2- type macrophage polarization, as evidenced by a significant skewing of MO/MΦ towards the pro-inflammatory M1 phenotype upon LczDHHC23 knockdown, along with the inhibition of MO/MΦ necroptosis induced by P. plecoglossicida infection. These findings highlight the non-PAT immunomodulatory function of LczDHHC23 in teleost immune regulation, broadening our understanding of zDHHC proteins in host-pathogen interactions, suggesting LczDHHC23 as a potential therapeutic target for immune modulation in aquatic species. [ABSTRACT FROM AUTHOR]

This study assessed the impact of an acoustic stimulus on the behavioral responses and physiological states of the large yellow croaker (Larimichthys crocea). The test fish, with an average body weight of approximately 352.81 ± 70.99 g, were exposed to one hour of acoustic stimulation at seven different frequencies: 100 Hz, 125 Hz, 160 Hz, 200 Hz, 500 Hz, 630 Hz, and 800 Hz. The aim was to delineate the specific effects of acoustic stimulation on the behavior and physiological indices. The results show that acoustic stimulation significantly altered the behavioral patterns of the large yellow croaker, predominantly manifested as avoidance behavior towards the sound source. At a stimulus frequency of 630 Hz, the test fish exhibited continuous irregular motion and erratic swimming. Physiologically, one hour of exposure to acoustic stimulation notably affected the endocrine system. The levels of Epinephrine and thyroxine were significantly elevated at 200 Hz, while the cortisol levels did not show significant differences. Additionally, the lactic acid content significantly increased at 800 Hz, and the blood glucose content peaked at 630 Hz. This study discovered that sound frequencies of 200 Hz, 630 Hz, and 800 Hz led to a significant increase in the levels of Epinephrine, glucose, thyroid hormones, and lactate in large yellow croaker, consequently affecting their behavior. The changes in these physiological indicators reflect the stress response of the large yellow croaker in specific sonic environments, providing crucial insights into the physiological and behavioral responses of fish to acoustic stimuli. [ABSTRACT FROM AUTHOR]

Large yellow croaker (Larimichthys crocea) is a vital marine‐cultured species in China. Large yellow croaker iridovirus (LYCIV) can cause a high mortality rate in L. crocea. Rapid and convenient detection of LYCIV is an urgent demand for diagnosis. In this study, rapid and simple recombinase polymerase amplification (RPA), real‐time RPA and RPA combined with lateral flow dipstick (RPA‐LFD) methods were developed for the detection of LYCIV based on the conserved sequence of the LYCIV major capsid protein (MCP) gene. With these optimized RPA analyses, LYCIV detection could be completed within 20 min at 40°C. Both RPA and real‐time RPA could detect viral DNA as low as 102 copies/μL, while the detection limit of RPA‐LFD was 101 copies/μL, and there was no cross‐reaction with other aquatic pathogens (KHV, CyHV‐2, GCRV‐JX01, SVCV, LCDV and LMBV). In practical evaluation of RPA, real‐time RPA and RPA‐LFD methods, the results showed consistency with the general PCR detection. In short, the developed RPA, real‐time RPA and RPA‐LFD analyses could be simple, rapid, sensitive and reliable methods for field diagnosis of LYCIV infection and have significant potential in the protection of LYCIV infection. [ABSTRACT FROM AUTHOR]

To evaluate the putrefactive potential of dominant putrefactive bacteria in refrigerated large yellow croaker, seven putrefactive bacteria were isolated from fish meat at the end of storage, and analyzed the total bacterial count (TVC), total volatile base nitrogen value (TNB-N) and volatile component composition of fish meat samples inoculated with 7 types of spoilage bacteria. The results showed that there was a significant difference in the TVC values among the fish samples inoculated with different strains (P<0.05). Among them, Pseudomonas weihenstephanensis, Shewanella baltica strain and Carnobacterium maltaromaticum grew slowly at the end of storage; The TNB-N values increased rapidly after inoculation with Serratia liquefaciens, Aeromonas molluscorum and Shewanella baltica, with increases of 7.31%, 4.92%, and 7.03% compared to the initial stage, respectively, while the control group only increased by 0.98%; The yield factor results showed that Shewanella baltica was the dominant spoilage bacterium during the storage period of vacuum packaged large yellow croaker, with a final value of 46.58 X 10-8 mg TVB-N/CFU, followed by Serratia liquefaciens, Aeromonas molluscorum; A total of 81 volatile flavor compounds were identified by gas chromatography-ion migration spectrometry (GC-IMS), with the control group mainly producing ether, alcohol, ene, and thiazole compounds. Obviously different from the control group, The volatile components under the action of 7 types of spoilage bacteria were mainly esters, aldehydes and ketones, hydrocarbons, and nitrogen and sulfur compounds. After inoculation with different bacterial strains, the types of odor compounds in fish pieces showed significant differences and different inoculated fish pieces produced their unique flavor compounds. This study provides a reference for further exploring the spoilage mechanism of stored yellow croaker in the future. [ABSTRACT FROM AUTHOR]

The large yellow croaker (Pseudosciaena crocea), once a vital fishery resource in the East China Sea, has witnessed a substantial decline in its wild population towing to overfishing. The current resource circumstances mainly relies on artificial breeding, with limited contributions from wild populations. However, discriminating between wild and cultured populations of the large yellow croaker in market trade and parent fish selection remains largely dependent on experiential judgment, with precise and efficient discrimination methods lacking. In this study, the framework method was used to quantify the external morphological characteristics of wild and cultured populations. The differences in external morphology between the two populations were visualized using principal component analysis, and they were classified through stepwise discriminant analysis. Results revealed significant differences in the standardized morphological parameters among most large yellow croakers from these two populations. Additionally, their distributions on principal components 2 and 3 were dissimilar. Furthermore, significant sex-based differences were observed in the cultured population, whereas in the wild population, sex differences were comparatively minor. Cross-validation results revealed that the classification accuracy of distinguishing between different populations exceeded that for separating cultured or wild populations according to different sexes. These findings suggest that the framework method is effective for discriminating between cultured and wild populations of large yellow croaker, although it may not be as successful in distinguishing between individuals of different sexes in these populations. The outcomes of this research offer valuable support for large yellow croaker breeding initiatives. [ABSTRACT FROM AUTHOR]

The present study conducted a Life Cycle Assessment (LCA) to evaluate the carbon emissions associated with large yellow croaker farming on Aquaculture Vessel "Conson No. 1". The functional unit considered was 1 kg of fresh large yellow croakers delivered to a wholesaler. The life cycle of large yellow croaker farming on the aquaculture vessel was divided into five processes: feed production (FP), ship construction (SC), fingerling breeding (FB), adult fish farming (AF), and fish distribution (FD). Results showed that the carbon footprint (CF, kgCO2e/kg LW) for the complete life cycle amounted to 6.2170 kgCO2e/kg LW, while the CF per unit economic value of "Conson No. 1" large yellow croaker was estimated at 31 gCO2e/CNY. Among all processes, AF and FP had the highest CF contribution rates at 69.30% and 24.86%, respectively. Notably, energy consumption by aquaculture equipment on board emerged as the primary contributor across all sources of CF comparative analysis demonstrated that the CF of marine fish farming on the aquaculture vessel was lower than that of closed aquaculture systems' average level and it was a viable option for implementing low-carbon aquaculture in the deep sea. In order to reduce energy consumption and promote a low-carbon economy in aquaculture vessels, several suggestions were proposed, including adjusting energy structure, enhancing energy efficiency, improving feed ratio, and optimizing feeding methods. [ABSTRACT FROM AUTHOR]

This document provides a summary of a study on the sex differences in growth, gene expression, and intestinal microbiota of large yellow croaker fish during the overwintering period. The study found that females experienced a greater decrease in body weight compared to males, and there were differences in the expression of intestinal barrier-related genes and immune response genes between the sexes. The composition, structure, and function of the intestinal microbiota also varied between males and females. These findings have implications for managing large yellow croaker during the overwintering period and for aquaculture practices. The document also references scientific articles on the effects of cold stimulation on various biological processes, providing additional insights into the physiological responses to cold stimulation in different organisms. [Extracted from the article]

Using stable chlorine dioxide (ClO2) combined with slightly acidic electrolyzed water (SAEW), the quality variations of cold-stored large yellow croaker (Pseudosciaena crocea) were studied. The results of microbial indicators demonstrated that ClO2 and SAEW treatment inhibited microbial growth. Moreover, ClO2 + SAEW treatment had lower values of pH, malondialdehyde content, total volatile basic nitrogen, and higher water-holding capacity than those in other groups. From the results of free amino acids and trimethylamine, ClO2 + SAEW treatment could delay the breakdown of umami amino acids and the accumulation of bitter amino acids in large yellow croaker. According to the results of microbial indexes and K-value, compared with sterile distilled water treatment, the shelf life of large yellow croaker with ClO2 + SAEW treatment was extended for an additional 4 days. Therefore, ClO2 + SAEW treatment is a potential method to preserve the flavor and quality of large yellow croaker during cold storage. [ABSTRACT FROM AUTHOR]

Swimming is critical for fish survival, and little attention has been paid to the swimming performance of large yellow croaker, the largest farmed marine fish in China. To address this gap, we conducted a study to measure the critical swimming speed (Ucrit) of 1050 croaker in a designed swim test flume. Our findings shed light on the effects of group size, Ucrit test protocol, and recovery time on swimming performance. The water flow in the swim flume increased steadily and linearly. The linear fit equation was y = 2.89x + 1.79 with an R2 of 0.99. With the help of the swim flume, we found that group size, and the Ucrit test protocol had a significant effect on the Ucrit values, except for the recovery time: The Ucrit values obtained in the ramp-Ucrit test averaged 28.32 ± 6.11 cm.s−1, which was significantly lower than that obtained in the traditional Ucrit test of 32.75 ± 7.60 cm.s−1; The Ucrit value of a group size of 50 fish was 33.51 ± 5.96 cm.s−1, which was significantly higher than that of a group of 200 fish (28.49 ± 6.37 cm.s−1). These results provide insights into the swimming performance of large yellow croaker and can be used to standardize the swimming test protocols. [ABSTRACT FROM AUTHOR]

Larimichthys crocea is an important economic fish of East Asia, and numerous studies have been conducted on its breeding, aquaculture, preservation and processing; however, there is no systematic review of the literature on the research of Larimichthys crocea. Derwent Data Analyzer (DDA) was used to analyze 1192 Larimichthys crocea research papers indexed by SCI-E, CSCD and KCI from 2001 to 2023. The number of research publications on Larimichthys crocea has rapidly increased, and institutions and scholars from China, the United States, South Korea, Japan, and Norway have conducted the majority of Larimichthys crocea research. The immune response, Pseudomonas plecoglossicida, gene expression, lipid immune response, transcriptomics and other areas have attracted the most attention. To increase the immunity and disease resistance of Larimichthys crocea and improve its survival, growth, storage and transport, researchers have carried out a large amount of research, which has promoted not only the culture of Larimichthys crocea but also the restoration of wild Larimichthys crocea and the rehabilitation of the ecological environment.

In this study, large yellow croaker (Larimichthys crocea) was frozen using multi-frequency ultrasound-assisted freezing (MUIF) with different powers (160 W, 175 W, and 190 W, respectively) and stored at −18 °C for ten months. The effect of different ultrasound powers on the myofibrillar protein (MP) structures and lipid oxidation of large yellow croaker was investigated. The results showed that MUIF significantly slowed down the oxidation of MP by inhibiting carbonyl formation and maintaining high sulfhydryl contents. These treatments also held a high activity of Ca2+-ATPase in the MP. MUIF maintained a higher ratio of α-helix to β-sheet during frozen storage, thereby protecting the secondary structure of the tissue and stabilizing the tertiary structure. In addition, MUIF inhibited the production of thiobarbituric acid reactive substances value and the loss of unsaturated fatty acid content, indicating that MUIF could better inhibit lipid oxidation of large yellow croaker during long-time frozen storage.

Sterol regulatory element-binding protein 2 (SREBP2) is considered to be a major regulator to control cholesterol homoeostasis in mammals. However, the role of SREBP2 in teleost remains poorly understand. Here, we explored the molecular characterisation of SREBP2 and identified SREBP2 as a key modulator for 3-hydroxy-3-methylglutaryl-coenzyme A reductase and 7-dehydrocholesterol reductase, which were rate-limiting enzymes of cholesterol biosynthesis. Moreover, dietary palm oil in vivo or palmitic acid (PA) treatment in vitro elevated cholesterol content through triggering SREBP2-mediated cholesterol biosynthesis in large yellow croaker. Furthermore, our results also found that PA-induced activation of SREBP2 was dependent on the stimulating of endoplasmic reticulum stress (ERS) in croaker myocytes and inhibition of ERS by 4-Phenylbutyric acid alleviated PA-induced SREBP2 activation and cholesterol biosynthesis. In summary, our findings reveal a novel insight for understanding the role of SREBP2 in the regulation of cholesterol metabolism in fish and may deepen the link between dietary fatty acid and cholesterol biosynthesis. [ABSTRACT FROM AUTHOR]

Summary: Fish is susceptible to spoilage for enzymatic and microbial activities during storage, proteolysis of MPs by endogenous proteases played a crucial influence in the early postmortem decomposition of myosin. This study aimed to investigate the impact of stable chlorine dioxide (ClO2) combined with slightly acidic electrolyzed water (SAEW) on myofibrillar proteins (MPs) and endogenous proteases alterations in large yellow croaker (Pseudosciaena crocea) during cold storage. The results of Fourier‐transform infrared spectroscopy (FT‐IR) and intrinsic fluorescence intensity (IFI) showed that the ClO2 + SAEW treatment kept the structural stability of protein in fillets during cold storage. Moreover, ClO2 + SAEW treatment dramatically inhibited protein degradation and oxidation. The results of light microscopy further confirmed the results. Meanwhile, there was a tendency to first increase and then decrease on the activities of calpain and cathepsin B, L. According to the correlation analysis and principal component analysis, the activities of endogenous proteases (cathepsin B, D, L, and calpain) were significant (P < 0.01) positively correlated to myofibrillar fragmentation index and trichloroacetic acid‐soluble peptide, and were significant (P < 0.01) negative correlated with the contents of total sulfhydryl and Ca2+‐ATPase. The endogenous proteases activities and protein deterioration were strongly associated. Therefore, endogenous protease was affected by ClO2 and SAEW, which delayed protein degradation in large yellow croaker, especially ClO2 combined with SAEW treatment. [ABSTRACT FROM AUTHOR]

The effect of gum tragacanth (GT) and sodium alginate (SA) active coatings incorporated with epigallocatechin gallate (EGCG; 0.16%, 0.32%, and 0.64%, respectively) on the quality of large yellow croaker fillets was evaluated during superchilling storage at –3 ˚C for 42 d. The results revealed that the GT-SA-EGCG active coatings delayed microbial spoilage by reducing the total viable counts of Pseudomonas spp. and psychrophile bacteria and retarded the degradation of the physical properties of water-holding capacity, cooking loss, color, odor and texture. GT-SA-EGCG coatings could also maintain fillet freshness by maintaining lower total volatile basic nitrogen, K value, and histidine content, inhibiting myofibrillar protein degradation during superchilling storage. These results suggested that the active coatings embedded with GT-SA-EGCG could be used as a preservative to enhance the quality of large yellow croaker and prolong the shelf life by 7–14 d during superchilling storage at –3 ˚C. [ABSTRACT FROM AUTHOR]

Intensive aquaculture combatting the decline of large yellow croaker populations can trigger bacterial outbreaks, resulting in extensive antibiotic use. In this study, we screened 5 aquaculture sites in the coastal areas of Zhejiang and identified 17 antibiotics in large yellow croakers using UPLC-MS/MS. The distribution and occurrence of antibiotic pollutants were different in the different tissues of large yellow croakers, being primarily dominated by quinolones. Relatively higher average residue levels of enrofloxacin and ciprofloxacin were detected in the inedible parts, specifically the gills (37.29 μg/kg). Meanwhile, relatively high average residue levels of enrofloxacin and ciprofloxacin were also found in the edible parts, particularly in the muscle (23.18 μg/kg). We observed that the residue levels detected in the swim bladder exceeded the prescribed limit for fish muscle, but there is currently no specific regulatory limit established for this particular tissue. Despite the HI values of enrofloxacin and ciprofloxacin being below 0.01, the health risks should not be disregarded. The findings of this research provide significant practical implications for assessing antibiotic contamination and enhancing the risk management of coastal regions. [ABSTRACT FROM AUTHOR]

Pseudomonas plecoglossicida is a major pathogen that causes visceral white nodules disease (VWND), a highly devastating disease, in cultured large yellow croaker (Larimichthys crocea), leading to severe economic losses. Peptide chain release factor methyltransferase hemK in bacteria plays a role in pathogenicity, but its exact function in P. plecoglossicida remains unclear. In this study, a P. plecoglossicida mutant strain (ΔhemK) was constructed by deleting hemK, and the roles of hemK in regulating P. plecoglossicida virulence were thereafter investigated. Compared to the wildtype strain, cell motility and biofilm formation of ΔhemK were weaken, and extracellular protein profile was altered. In vitro study showed that the hemK deletion significantly decreased the survival rate of P. plecoglossicida in large yellow croaker macrophage cell line (LYC-FM) by impairing oxidative stress tolerance. Furthermore, large yellow croakers infected with ΔhemK showed a significant reduction in mortality rate, bacterial load, and noticeable nodules within the spleen, when compared to the wild-type strain. These findings indicated that hemK plays an essential role in the pathogenicity of P. plecoglossicida, thus providing a valuable insight into the pathogenic mechanisms of P. plecoglossicida and offering a potential target for its attenuated-vaccine development.

A 60-day feeding trial was conducted to investigate the effects of dietary a Chinese herbal compound (CHC) including Pulsatillae Radix, Coptidis Rhizoma, Cortex Phellodendri Amurensis and Fraxini Cortex on the growth performance, intestinal and liver histology, antioxidative capacity and immunity of juvenile large yellow croaker (Larimichthys crocea) with the initial body weight of 17.00 ± 0.03 g. Four experimental diets were formulated to contain 0 mg/kg (CHC0), 250 mg/kg (CHC250), 500 mg/kg (CHC500), and 750 mg/kg (CHC750) of CHC, respectively. Results showed that dietary CHC did not significantly affect the survival of large yellow croaker (P > 0.05). Compared with the control, the CHC500 group showed higher weight gain and protein efficiency ratio, along with a lower feed conversion ratio (P < 0.05). Furthermore, increasing levels of dietary CHC linearly decreased the activities of aspartate aminotransferase and alanine aminotransferase, and malondialdehyde content in serum. Moreover, dietary CHC significantly increased the total antioxidative capacity and complement levels in serum (P < 0.05). The relative expressions of sod1, nrf2, il-10 and tnf-α in liver and intestine were upregulated in the CHC500 group (P < 0.05). Additionally, the activities of digestive and absorptive enzymes in intestine were significantly increased in the CHC500 group (P < 0.05). The length of intestinal villus height, villus width and perimeter ratio were higher in the CHC supplemented diets. In conclusion, CHC supplementation in diet could improve growth performance, anti-oxidative capacity and immunity of large yellow croaker.

The present study aims to investigate the effects of dietary Chinese herbs mixture (CHM) including Artemisia capillaris, Gardenia jasminoides, Scutellaria baicalensis, Reynoutria japonica and Uncaria rhynchophylla on the growth performance, anti-oxidative and immune responses, and intestine and liver histology of juvenile large yellow croaker Larimichthys crocea (initial body weight: 17.03 ± 0.03 g), which were fed graded levels of CHM (0 (control group), 250, 500 and 750 mg/kg, respectively) for 60 days. The results indicated that supplementing 250 and 500 mg/kg CHM in diet significantly increased the weight gain rate and decreased the feed conversion ratio of juvenile large yellow croaker (P < 0.05). The activities of lipase, chymotrypsin, γ-glutamyl transferase and Na+, K+-ATPase were significantly increased in CHM250 and/or CHM500 groups (P < 0.05). Besides, the levels of total anti-oxidative capacity, immunoglobulin M, complement 3 and complement 4 were significantly increased in the CHM250 and/or CHM500 groups (P < 0.05). The expressions of anti-oxidation gene (nuclear factor erythroid 2-related factor 2, nrf2), anti-inflammatory cytokines (interleukin-10, il-10 and transforming growth factor-β, tgf-β) and anti-apoptotic gene (B-cell lymphoma-2, bcl-2) in liver were significantly up-regulated, while the malondialdehyde content and the expressions of kelch like ECH associated protein 1 (keap1) and nuclear factor κB p65 (nf-κb p65) were significantly down-regulated after supplementing 250 and/or 500 mg/kg CHM in diet (P < 0.05). The histological analysis of liver and intestine showed the better morphology in CHM250 and CHM500 groups than the control group. In conclusion, above results indicated that dietary CHM (250 – 500 mg/kg) significantly improved the growth performance, anti-oxidative capacity, immunity and histology of liver and intestine of juvenile large yellow croaker.

The present study aimed to comparatively evaluate the protein requirements of large yellow croaker (initial body weight: 17.03 ± 0.11 g) fed with five dietary protein sources including fish meal (FM), cottonseed protein concentrate (CPC), Clostridium autoethanogenum protein (CAP), Tenebrio molitor meal (TM) and Chlorella meal (CM). The basal diet contained 30% of FM. Based on it, each of the five dietary protein sources was used to formulate graded levels of dietary protein (35%, 40%, 45%, 50%, 55% and 60%, respectively). After a 56-day feeding trial, it was indicated that the protein requirement of large yellow croaker was 50.91%, 44.95%, 39.92%, 40.34% and 52.19%, when FM, CPC, CAP, TM and CM were used as the dietary protein source, respectively. Overall, the TM and CM groups showed lower weight gain rat, feed intake, feed efficiency, protein efficiency ratio, protein retention and in vitro digestibility of dietary protein compared to the FM, CPC and CAP groups at the same dietary protein level. Meanwhile, the FM groups showed the highest amylase, lipase and trypsin activities followed by CPC, CAP, CM, and TM. At the same dietary protein level, the FM groups showed the highest muscularis thickness, villus height and perimeter ratio of intestine, followed by the CPC, CAP, CM and TM groups. The fish fed with dietary TM showed severe liver damage compared to those in the FM, CPC, CAP and CM groups. In summary, the present study demonstrated that the dietary protein requirement of large yellow croaker could be different because of different protein source included into diets. The CPC and CAP were more suitable as the alternative dietary protein sources for large yellow croaker than TM and CM according to the growth, feed utilization, digestive and absorptive enzyme activities, intestinal and liver histology analysis.

In this study, our purpose was to investigate the effect of mild salting on the flavor of large yellow croaker. The volatile flavor compounds of raw (unsalted) and low-salted large yellow croaker were determined by solid phase microextraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS) and evaluated by gas chromatography-olfactometry (GC-O) and odor activity values (OAV) analysis. The GC-MS analysis showed that the contents of hexanal, nonanal, heptanal, 1-octene-3-ol, anethole and hexanol in both samples were higher than those of other volatile compounds identified. GC-O and OAV analysis showed that the flavor of raw large yellow croaker was significantly affected by 1-octene-3-ol, octanal, nonanal, hexanal, heptanal, (E,Z)-2,6-nonadienal, trans-2-octenal and anethole (OAV > 1); the flavor of low-salted large yellow croaker was significantly affected by linalool, nonanal, hexanal, octanal, 1-octene-3-ol, anethole, (E,Z)-2,6-nonadienal and heptanal (OAV > 1). The changes in flavor after salting treatment was attributed to a significant increase in the OAV of linalool and anethole, and a significant decrease in the OAV of 1-octene-3-ol, hexanal, nonanal, trans-2-octenal, (E,Z)-2,6-nonadienal, heptanal and octanal. The changes of some flavor components might be related to reactions such as the oxidative degradation of unsaturated fatty acids, the biosynthesis of terpenoids, the isomerization of aromatic alcohols, the oxidation and reduction of aliphatic aldehyde and esterification.

Objective: The effects of freezing method and storage temperature on the quality of large yellow croaker during storage were investigated. Methods: Fresh large yellow croaker fillets were frozen with dry ice and air freezing (-40 ℃) to the central temperature of -18 ℃, and then stored at -40 ℃ and -18 ℃, respectively. Physical and chemical indexes such as freezing curve, ice crystal morphology, pH value, volatile base nitrogen, K value, Ca2+-ATPase activity, total sulfhydryl group, carbonyl group, protein degradation and texture characteristics of large yellow croaks were determined after freezing and during freezing storage. Results: The time of dry ice freezing through the maximum ice crystal formation zone was 40 min, which is 1/6 of that of air freezing at -40 ℃. The initial ice crystal cross-section area and equivalent diameter of dry ice frozen fish samples were (96.12±1.61) μm2 and (11.06±1.43) μm, respectively, which is significantly lower than that of air frozen fish samples. Conclusion: The effect of freezing temperature on fish myofibrillator protein was greater than that of freezing temperature, and a lower freezing temperature can result in a lower degradation degree of fish myofibrillator protein. Storage at -40 ℃ after dry ice freezing is beneficial to maintain freshness and quality stability of large yellow croaker.

Seafood is highly perishable after being caught, making effective preservation technology essential. A few studies have explored the mechanisms of near-freezing storage combined with high-voltage electric fields for seafood preservation. This study uses near-freezing storage at −1 °C in conjunction with three high-voltage electric fields (5 kV/m, 8 kV/m, and 16 kV/m) to store large yellow croakers for 21 days and assesses their quality through sensory evaluation, pH values, malondialdehyde, total volatile basic nitrogen, and total viable counts. The results indicate that high-voltage electric fields effectively inhibit endogenous enzyme activity and microbial growth while reducing lipid oxidation in large yellow croakers. The preservation effect is optimal at an electric field strength of 16 kV/m, extending their shelf life by 9 days. These findings offer valuable theoretical and data-driven insights for applying near-freezing storage and electric field preservation technology in cross-regional fish transportation.

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: Improper stunning methods before slaughter could cause fish to deteriorate more quickly during cold storage. However, it is unclear how stunning methods affect the mitochondrial structure and the role of mitochondria in oxidation in muscle‐based food. RESULTS: This study explored the potential mechanism of oxidation induced by different stunning methods (hit on the head, T1; gill cut, T2; immersion in ice/water slurry, T3; CO2 asphyxiated, T4; 40% CO2 + 30% N2 + 30% O2, T5) in large yellow croaker during cold storage. The results showed that T4 samples had the minimum stress response and the mitochondrial membrane potential and permeability were less damaged. Besides, the mitochondrial functional structure and peroxisome of T4 samples were less damaged compared with other samples, which was reflected in higher total superoxide dismutase, catalase and glutathione peroxidase activities. In terms of oxidation indices, the T4 samples showed higher pH values and iron myoglobin contents and lower total volatile basic nitrogen and thiobarbituric acid reactive substances after 168 h cold storage, indicating that the T4 samples significantly maintained oxidative stability of large yellow croaker. CONCLUSION: The CO2 asphyxiation had the least oxidative damage to large yellow croaker during cold storage, possibly because it had the least effect on mitochondrial structure, reactive oxygen species and antioxidant enzyme activity. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effects of different slaughter methods (immersion in ice/water slurry, T1; gill cut, T2; CO2 asphyxia, T3; percussion (hit on the head with a stick), T4; Melissa officinalis L. essential oil + CO2, T5) on physiological stress, oxidative stress, and muscle quality in large yellow croaker. In terms of physiological stress, the levels of glucose (GLU), lactate dehydrogenase (LDH), and catalase (CAT) in CO2 asphyxia samples were significantly lower than those in other samples (p < 0.05). The level of cortisol (COR) in T1 sample was 1.25–1.84 times higher than that of other samples. The GLU level of T1 group was 3.2 times higher than that of T3 sample, and significantly higher than that of other samples. The creatine phosphokinase (CPK) and CAT levels of T2 samples were the highest (2.03 ng/mL and 8.34 U/mL, respectively). Furthermore, the superoxide dismutase (SOD) and glutathione peroxidase (GPx) analysis revealed that T3 and T4 samples could maintain good antioxidant enzyme activity during cold storage. The T3 samples maintained the stability of the protein (the lowest carbonyls and surface hydrophobicity) and reduced lipid oxidation (lower TBARS). In addition, the analysis of pH and water-holding capacity (WHC) revealed that T3 samples had better muscle quality. The muscle of T2 samples kept better color due to bloodletting treatment. The samples obtained after addition of Melissa officinalis L. essential oil had poorer indexes in all aspects compared to the T3 samples, which might be caused by the long anesthesia time of the essential oil. [ABSTRACT FROM AUTHOR]

Wild large yellow croakers are generally considered superior to farmed large yellow croakers in quality and taste. The metabolites of large yellow croakers vary because of different growth environments and dietary conditions, allowing easy differentiation of wild large yellow croakers from farmed large yellow croakers. The adulteration of wild large yellow croakers using farmed large yellow croakers in the market, which is driven by economic interests, disturbs market balance and negatively affects the trade in large yellow croakers. Therefore, the quality control (QC) of wild large yellow croakers is important for the maintenance of the market and the trade development of aquatic products. Non-targeted metabolomics based on liquid chromatography–mass spectrometry was employed in this study to clarify the differences in metabolic composition between muscle tissues of wild and farmed large yellow croakers. Results showed that the partial least squares discriminant analysis model could effectively distinguish the wild and farmed large yellow croakers without overfitting. KEGG enrichment analysis showed that the main metabolism pathways were closely associated with lipid, amino acid, carbohydrate, and vitamin-related metabolism. Overall, non-targeted metabolomics can identify and differentiate wild and farmed large yellow croakers, supporting new insights to improve the QC level of aquatic products. [ABSTRACT FROM AUTHOR]

Hypoxia has become an unfavorable factor affecting the sustainable development of the large yellow croaker Larimichthys crocea, an economically important mariculture fish in China. Apoptosis is a consequence of hypoxia on fish. However, the effects of hypoxia stress on apoptosis in L. crocea remain largely unknown. We investigated the effect of environmental hypoxia on apoptosis in L. crocea. Results show that hypoxia induced apoptosis in L. crocea both in vivo and in vitro. The mitochondrial membrane potential was significantly reduced in large yellow croaker fry (LYCF) cells. The expression levels of B-cell lymphoma/leukemia-2 (Bcl-2) mRNA and protein were also significantly decreased in the liver and LYCF cells during 96 h and 48 h of hypoxia stress, respectively, whereas the expression level of Bcl-2 associated X (Bax) mRNA, Casp3 mRNA, and activity of caspase-3/7/9 were significantly increased, indicating that hypoxia induced caspase-dependent intrinsic apoptosis in L. crocea. The expression level of the apoptosis-inducing factor (AIF) protein was significantly increased in the liver and LYCF cells. The level of AIF protein was significantly decreased in the cytoplasm but increased in the nuclei of L. crocea, demonstrating that hypoxia induced the AIF-mediated caspase-independent intrinsic apoptosis. In addition, the activity of caspase-8 was significantly increased, indicating that hypoxia stress induced extrinsic apoptosis in L. crocea. Therefore, hypoxia induced apoptosis in L. crocea through both the intrinsic and extrinsic pathways. The present study accumulated basic biological information to help elucidate the mechanism of hypoxia response in marine fish. [ABSTRACT FROM AUTHOR]

This study mainly evaluated the effect of different energies of pulsed light (PL) treatment (100, 200, 300, 400, and 500 J/pulse) on myofibrillar protein (MP) of large yellow croaker during refrigerated storage. The results showed that PL treatment would cause a certain degree of oxidation to the MP of large yellow croaker at the initial stage, which showed that the total sulfhydryl content of the protein decreased, the carbonyl content and the average particle size increased, and the β‐sheet to β‐turn transformation, the tertiary structure of the protein unfolds, and the hydrophobic groups were exposed, causing the reduction of intrinsic fluorescence intensity. However, subsequent storage studies found that PL treatment could slow down the oxidation rate of MP. The decrease rate of total sulfhydryl content and the increase rate of carbonyl content in the 300 J/pulse group were both reduced by about 1.7 times compared with the control group. At the same time, the PL treatment with this intensity could also better protect the secondary structure, tertiary structure, and microstructure of MP. This study provided theoretical basis and reference for analyzing the quality change rule and mechanism of large yellow croaker during refrigerated storage after PL treatment. Studies have shown that PL treatment can reduce the adverse changes of MP in large yellow croaker during cold storage. [ABSTRACT FROM AUTHOR]

Large yellow croaker (Larimichthys crocea) is one of economic important mariculture fish species with abundant nutritional value, and usually stored at refrigerated temperature. Our study investigated the effects of temperature fluctuation and abuse on the quality of the large yellow croaker and further analyzed the volatile compounds as temperature abuse sensitivity or indicators during temperature fluctuations. We simulated a cold chain model that mapped the temperature of chilled large yellow croaker during land-sea freight. Temperature fluctuation caused a non-negligible effect on the quality of the large yellow croaker. Samples exposed to greater temperature fluctuation had a higher rise in total viable count (TVC), total volatile basic nitrogen content, K value, and thiobarbituric acid reactive substances value. Among them, TVC is the sensitive index to temperature fluctuation. A total of 81 typical target compounds were identified by using headspace-gas chromatography-ion mobility spectrometry. During temperature fluctuations, the concentration of volatile aldehydes, including pentanal, heptanal, nonanal, and octanal decreased, while the concentration of ketones and nitrogenous and heterocyclic compounds increased. Principal component analysis and orthogonal partial least squares discriminant analysis showed that 2-pentanone and ethyl acetate were significantly correlated with the quality changes during temperature fluctuations, which could be the potential indicators for observing quality changes in large yellow croaker during temperature fluctuation.

This study assessed the impact of an acoustic stimulus on the behavioral responses and physiological states of the large yellow croaker (Larimichthys crocea). The test fish, with an average body weight of approximately 352.81 ± 70.99 g, were exposed to one hour of acoustic stimulation at seven different frequencies: 100 Hz, 125 Hz, 160 Hz, 200 Hz, 500 Hz, 630 Hz, and 800 Hz. The aim was to delineate the specific effects of acoustic stimulation on the behavior and physiological indices. The results show that acoustic stimulation significantly altered the behavioral patterns of the large yellow croaker, predominantly manifested as avoidance behavior towards the sound source. At a stimulus frequency of 630 Hz, the test fish exhibited continuous irregular motion and erratic swimming. Physiologically, one hour of exposure to acoustic stimulation notably affected the endocrine system. The levels of Epinephrine and thyroxine were significantly elevated at 200 Hz, while the cortisol levels did not show significant differences. Additionally, the lactic acid content significantly increased at 800 Hz, and the blood glucose content peaked at 630 Hz. This study discovered that sound frequencies of 200 Hz, 630 Hz, and 800 Hz led to a significant increase in the levels of Epinephrine, glucose, thyroid hormones, and lactate in large yellow croaker, consequently affecting their behavior. The changes in these physiological indicators reflect the stress response of the large yellow croaker in specific sonic environments, providing crucial insights into the physiological and behavioral responses of fish to acoustic stimuli.

The present study conducted a Life Cycle Assessment (LCA) to evaluate the carbon emissions associated with large yellow croaker farming on Aquaculture Vessel “Conson No. 1”. The functional unit considered was 1 kg of fresh large yellow croakers delivered to a wholesaler. The life cycle of large yellow croaker farming on the aquaculture vessel was divided into five processes: feed production (FP), ship construction (SC), fingerling breeding (FB), adult fish farming (AF), and fish distribution (FD). Results showed that the carbon footprint (CF, kgCO2e/kg LW) for the complete life cycle amounted to 6.2170 kgCO2e/kg LW, while the CF per unit economic value of “Conson No. 1” large yellow croaker was estimated at 31 gCO2e/CNY. Among all processes, AF and FP had the highest CF contribution rates at 69.30% and 24.86%, respectively. Notably, energy consumption by aquaculture equipment on board emerged as the primary contributor across all sources of CF comparative analysis demonstrated that the CF of marine fish farming on the aquaculture vessel was lower than that of closed aquaculture systems’ average level and it was a viable option for implementing low-carbon aquaculture in the deep sea. In order to reduce energy consumption and promote a low-carbon economy in aquaculture vessels, several suggestions were proposed, including adjusting energy structure, enhancing energy efficiency, improving feed ratio, and optimizing feeding methods.

BACKGROUND: Large yellow croaker (Larimichthys crocea) is an economical marine fish consumed in China. Theaflavins have antibacterial and antioxidant properties. However, there is a lack of research into their application in large yellow croakers during refrigerated storage. This study investigated the effect of theaflavins on the quality of large yellow croaker (Larimichthys crocea) during 12 days of storage at 4 °C. RESULTS: The results showed that theaflavin treatment was able to inhibit microbial growth and reduce the production of total volatile basic nitrogen (TVB‐N). Meanwhile, theaflavins were beneficial in reducing the unfolding of myofibrillar proteins, decreasing the degree of protein aggregation, and improving the stability of protein structure. The degree of protein oxidation was lower in a theaflavin‐treated group compared with an untreated group. Theaflavin treatment effectively inhibited increases in acid value (AV), peroxide value (PV), and malonaldehyde (MDA) content. The effect of theaflavin was positively correlated with an increase in concentration under refrigeration conditions. This study therefore suggests that the use of theaflavins is a viable method for extending the period for which refrigerated large yellow croaker can be preserved. CONCLUSIONS: Adding theaflavins to large yellow croaker can be an effective method for preserving quality during refrigerated storage. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Large yellow croaker fish fillets were sous vide processed and stored at 2°C for 4 weeks. Rosemary extract and chlorogenic acid were used to inhibit the lipid and protein oxidation. Rosemary extract and chlorogenic acid could significantly reduce levels of peroxide value (45% and 60%) and thiobarbituric acid reactive substances (39% and 47%) at the end of storage. Rosemary extract and chlorogenic acid reduced the carbonyl content by 40% and 51%, respectively, during storage but not the sulfhydryl loss during the sous vide processing step. Phenol–protein interaction needed to be studied further for quality improvement/evaluation in the future. [ABSTRACT FROM AUTHOR]

Large yellow croaker (Larimichthys crocea) is an important aquaculture species in China. This study analysed whole-genome methylation differences in liver tissues of young fish under different hypoxic and acidification conditions. Differentially methylated regions (DMRs) and differentially methylated genes (DMGs) were identified. Gene ontology (GO) and Kyoto encyclopaedia of genes and genomes (KEGG) enrichment analyses of DMGs were conducted to explore the mechanism of coping with hypoxic acidification. The main methylation type was CG, accounting for > 70% of total methylation, significantly higher than CHG and CHH methylation types. GO enrichment analysis of DMGs revealed strong enrichment of nervous system development, cell periphery, plasma membrane, cell junction organisation, cell junction, signalling receptor activity, molecular sensor activity, cell-linked tissue junction organisation, cell–cell adhesion and nervous system development. KEGG enrichment analysis of DMR-related genes identified cell adhesion molecules, cortisol synthesis and secretion and aldosterone synthesis and secretion as the three key pathways regulating the physiological responses to hypoxia and acidification. Long-term hypoxic and acidification stress affected the immune system, nervous system and stress responses of large yellow croaker. Whole-genome sequencing analysis of exposed tissues was used to investigate changes that occur in L. crocea in response to hypoxic and acidic conditions at the DNA methylation level. The findings contribute to our comprehensive understanding of functional methylation in large yellow croaker and will support future research on the response mechanisms of this species under different environmental pressures. [ABSTRACT FROM AUTHOR]

Genome selection is mainly used in disease-resistant traits of aquatic species; however, its implementation is hindered by a high cost of genotype and phenotype data collection. Single-step genomic best linear unbiased prediction (SSGBLUP) can integrate phenotypes, genetic markers, and pedigree records into simultaneous prediction without increasing genotyping costs. The objective of this study is to investigate the performance of SSGBLUP in large yellow croaker and to evaluate the effects of the number of phenotypic records and genotyping per family on the predictive ability of SSGBLUP. A large yellow croaker population consists of 6898 individuals from 14 families with survival time resistant against Cryptocaryon irritans (C. irritans), body weight (BW), and body length (BL) traits were collected, of which 669 individuals were genotyped. Results showed that the mean predictive ability of all traits in the individuals randomly sampling for SSGBLUP, GBLUP, and BLUP was 0.738, 0.738, and 0.736, respectively. Moreover, the predictive ability of SSGBLUP and BLUP models did not increase with the extra phenotypic records per family, in which the predictive ability of SSGBLUP and BLUP in survival time was 0.853 and 0.851 for only genotyped data (N = 0) used, and 0.852, 0.845 for all phenotypic records (N = 600) used, respectively. However, with the increase in the genotype number of training set, the prediction ability of SSGBLUP and GBLUP model was increased and the highest predictive ability was gained when the genotype number per family was 40 or 45. In addition, the prediction ability of SSGBLUP model was higher than that of GBLUP. Our study showed that the SSGBLUP model still has great potential and advantages in genomic breeding of large yellow croakers. It is recommended that each family provide 100 phenotypic individuals, of which 40 individuals with genotyping data for SSGBLUP model prediction and family resistance evaluation. [ABSTRACT FROM AUTHOR]