Search

Background: Interspecific hybrid combinations of Larimichthys crocea × Larimichthys polyactis exhibit heterosis in terms of growth traits; however, the molecular regulatory mechanism underlying this phenomenon remains unclear. DNA methylation plays a pivotal role in regulating gene expression and is involved in growth and development processes. In this study, we comprehensively investigated intricate regulatory processes by integrating transcriptome and methylome datasets from brain, liver, and muscle tissues. Results: We analyzed a total of 72 sequence datasets, including transcriptome and genome-wide DNA methylome data, from 36 tissue samples using LC, LP, LPC and LCP. We elucidated the distinct expression patterns of these four populations and examined their interactions with DNA methylation. Our findings revealed diverse DNA methylation profiles and demonstrated a greater number of hypo-DMRs in hybrid yellow croakers than in their parental lines. The majority (86 ~ 92%) of these DMRs were observed within the CG context. Moreover, we found that most DMRs were located within promoter regions as well as exons and introns. A total of 1288 DMEGs were identified through correlation analysis between DNA methylation and transcriptional activity. Functional enrichment analysis revealed that most of the DMEGs were significantly enriched in pathways related to the protein export pathway, proteasome, terpenoid backbone biosynthesis, ubiquitin-mediated proteolysis, autophagy-other pathway. Furthermore, we screened candidate growth-related genes, such as stat2, capn2, akt1, mTOR, and mef2aa. Among these, the expression levels of capn2, mTOR, and akt1 exhibited a positive correlation with DNA methylation levels, whereas the expression levels of stat2 and mef2aa showed a negative correlation. These findings suggest that alterations in DNA methylation patterns may promote growth advantages in hybrid yellow croaker by modulating the expression of these genes. Conclusions: Epigenetic changes exert distinct influences on genes related to growth heterosis. The presented data establish a foundation for comprehending the epigenetic and transcriptomic alterations underlying the growth of hybrid yellow croaker, thereby providing preliminary insights into the molecular mechanisms of growth heterosis. These findings have significant implications for breeding programs aimed at enhancing yellow croaker production. [ABSTRACT FROM AUTHOR]

Introduction: The large yellow croaker iridovirus (LYCIV) poses a significant threat to the aquaculture industry of Larimichthys crocea. Understanding the host defense response to LYCIV infection is crucial for developing effective strategies to mitigate its impact. Methods: In this study, an epigenetic approach was employed to investigate dynamic changes in chromatin accessibility using the assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq). Additionally, RNA sequencing (RNA-seq) was used to analyze the expression pattern of immune response genes upon LYCIV infection. Results: Substantial alterations in chromatin accessibility were observed, particularly in the regulatory regions of key immune-related genes. Significant changes in the expression of AP-1 transcription factors, including the Batf gene, were noted. CUT&Tag results revealed that AP-1 was significantly enriched in the open chromatin regions of cytokine genes, with Batf potentially regulating the cytokine genes LIF and CLCF1. Discussion: These findings suggest that AP-1 may play a crucial role in the defense response against viral infection by modulating inflammatory cytokines and contributing to cellular inflammatory responses. This study provides a comprehensive analysis of the epigenomic landscape and gene expression regulation during iridovirus infection in L. crocea , offering valuable insights for breeding programs aimed at combating iridovirus infections. [ABSTRACT FROM AUTHOR]

MicroRNA (miRNA), a conservatively evolved single-stranded non-coding RNA, exerts pivotal control over the appearance of target genes and several biological processes. This study conducted a comprehensive screening of candidate microRNAs (miRNAs) associated with Lipoprotein Lipase (LPL) in the large yellow croaker (Larimichthys crocea), utilizing sophisticated bioinformatics techniques across the species' muscular and hepatic tissues. The bioinformatics analysis facilitated the compilation and examination of miRNA datasets specific to these tissues. The investigation culminated in the identification of miR-84a and miR-1231-5p as key miRNAs that modulate fat hydrolysis, highlighting their potential roles in lipid metabolism. Subsequent in-depth analysis further implicated these miRNAs, along with miR-891a, as prospective targets of LPL, suggesting their integral involvement in the regulation of this critical enzyme. Validation of these bioinformatics predictions was conducted through the construction of double luciferase reporters concealing the LPL 3′ untranslated region (3′UTR), substantiating that miR-84a and miR-1231-5p can modulate LPL expression via the LPL 3′UTR. Conversely, miR-891a was not concerned with this regulatory mechanism. Site-directed mutagenesis experiments elucidated the specificity of the interaction sequences. Quantitative PCR assays suggested that miR-84a and miR-1231-5p might influence LPL expression during the starvation phase, intimating the regulatory role of miRNA in fatty acid metabolism within hepatic and muscular tissue under starvation. These findings offer a nuanced understanding of LPL's molecular functionality under stress conditions in fish, emphasizing the regulatory dynamics of miRNA during metabolic stress. [ABSTRACT FROM AUTHOR]

This study explores the effects of norfloxacin (NOR) on oxidative damage, iron (Fe) transport, energy metabolism, and immunotoxicity in the intestine of large yellow croaker under Fe stress. The fish were subjected to Fe (180 μg/L), low-dose NOR (1.8 μg/L, LNOR), high-dose NOR (180 μg/L, HNOR), Fe plus LNOR, and Fe plus HNOR for 60 days. These results demonstrated that Fe alone exposure increased malondialdehyde (MDA), protein carboxylation (PC), and mortality rate, and impaired intestinal tissue, which was related to the increment of Fe accumulation. Compared to Fe alone exposure, Fe plus LNOR exposure decreased MDA, PC, and mortality rate, and alleviated intestinal malformations by improving Fe transport, energy metabolism, anti-inflammatory response, and protein folding protective effect, and reducing pro-inflammatory response, indicating that LNOR had an antagonistic effect on Fe toxicity. Compared to Fe alone exposure, Fe plus HNOR exposure elevated MDA, PC, and mortality rate, and deteriorated intestinal malformations by inhibiting Fe excretion, energy metabolism, anti-inflammatory response, and protein folding protective effect, and enhancing pro-inflammatory response, indicating a synergetic effect between HNOR and Fe stress. These findings suggested that NOR had a dose-dependent effect on Fe-toxicity to large yellow croaker, which contributes to revealing the molecular mechanisms behind their interaction and its ecological implications. [ABSTRACT FROM AUTHOR]

To compare the impact of different post-harvest handling methods on volatile and non-volatile compounds, a total of 54 live large yellow croakers were subjected to commercial slaughter (CS), spinal cord cutting (SCC), or spinal cord cutting and bleeding (SCCB). The fish samples were ice-stored for 72 h, followed by the analysis of volatile compounds using gas chromatography–ion mobility spectrometry and non-volatile compounds using LC-MS-based untargeted metabolomics. The results revealed the detection of a total of 28 volatile organic compounds, with 23 being successfully identified, predominantly including alcohols, aldehydes, esters, ketones, and heterocyclic compounds. Substances such as (E)-2-nonenal and 2-butanone are highly sensitive to post-harvest handling methods during ice storage. Furthermore, 943 non-volatile metabolites were identified, showing significant differences in 180, 100, 117, and 186 metabolites across comparisons of SCC 0 h/CS 0 h, SCCB 0 h/CS 0 h, SCC 72 h/CS 72 h, and SCCB 72 h/CS 72 h, respectively. Notably, the altered metabolic pathways mainly involved fatty acid and amino acid metabolism, including pathways like glycerophospholipid metabolism and arginine biosynthesis. This study revealed the potential mechanisms underlying the enhancement of fish quality through spinal cord cutting and bleeding. [ABSTRACT FROM AUTHOR]

Despite the high cost of genotyping and the limited economic return per individual that restricts the use of genome selection technology in aquatic species breeding, integrating multiple traits in a selection index can reduce costs and present a promising direction for fish breeding. The aim of this study was to evaluate the feasibility and performance of breeding for dual resistance traits against C. irritans and V. alginolyticus in large yellow croaker, using a selection index approach. A candidate stock population from the C. irritans resistance strain (GS3) of the F2 generation (n = 560) was genotyped using a 55 K SNP array. A total of 50 broodstock with the highest genomic estimated breeding value (GEBV) ranking for the C. irritans resistance trait were selected to produce the F3 generation, while 50 broodstock with the highest selection index were selected to breed the double trait strain (GS9). In parallel, two populations without selective breeding population (C1and C2) were used as the control group to produce the offspring. The genetic improvement effect of all the breeding lines (GS3, GS9, C1, and C2) was assessed through artificial challenge experiments with C. irritans and V. alginolyticus , respectively. The GWAS result indicated that resistance to V. alginolyticus was a polygenic trait and the heritability of resistance to V. alginolyticus was estimated to be approximately 0.1. The survival rates of GS9 and GS3 were 43.74 and 86.81%, respectively, after 120 h of challenge with C. irritans infection, whereas those of C1 and C2 remained at 0%. Furthermore, the survival rates of GS9 and GS3 were 27.03 and 15.48%, respectively, after 48 h of V. alginolyticus infection, while the survival rates of C1 and C2 were 12.67 and 14.17%, respectively. These results indicate that genetic improvement of multiple traits in large yellow croaker using genomic selection technology is indeed feasible. Moreover, this study provides a valuable reference for advancing multi-trait breeding applications in aquatic species. [ABSTRACT FROM AUTHOR]

NLRP3 inflammasome activation is pivotal for cytokine secretion and pyroptosis in response to diverse stimuli, playing a crucial role in innate immunity. While extensively studied in mammals, the regulatory mechanisms governing NLRP3 activation in non-mammalian vertebrates remain largely unexplored. Teleosts, as basal vertebrates, represent an ideal model for exploring the evolutionary trajectory of inflammasome regulation. In this study, ABE assays, confocal microscopy, and biochemical analyses were applied to systematically characterize the mechanisms underlying NLRP3 inflammasome in teleosts, using large yellow croakers (Larimichthys crocea, Lc) and zebrafish (Danio rerio, Dr) as representative models. Our findings revealed a previously unrecognized palmitoylation-dependent regulatory mechanism essential for teleost NLRP3 activation. Specifically, zDHHC18- mediated palmitoylation at a teleost-specific cysteine residue (C946 in LcNLRP3, C1037 in DrNLRP3) was required for the translocation of NLRP3 to the dispersed trans-Golgi network, facilitating its subsequent recruitment to the microtubule-organizing center. This membrane trafficking was crucial for inflammasome assembly and downstream inflammatory responses. These findings provide new insights into the distinct regulatory mechanisms of NLRP3 activation in teleosts, highlighting an evolutionary divergence that contributes to innate immunity adaptation in early vertebrates. [ABSTRACT FROM AUTHOR]

Large yellow croaker (Larimichthys crocea) is a highly economically important marine fish species in China. However, substantial individual variations in growth performance have emerged as a limiting factor for the sustainable development of the large yellow croaker industry. Gut microbiota plays a crucial role in fish growth and development by regulating metabolic processes. To explore these dynamics, we employed metagenomics, transcriptomics, and untargeted metabolomics to comprehensively analyze the structure of the intestinal microbiome and its relationship with intestinal metabolism and host gene expression. We constructed association models for "gut microbiota–differentially expressed genes", "differentially expressed genes–metabolites," and "gut microbiota–metabolites." Sequencing data and LC–MS/MS raw data have been deposited in NCBI and MetaboLights databases for public access. Our findings offer critical insights into the molecular mechanisms underlying growth variations in L. crocea and provide valuable data for the selective breeding of improved strains. [ABSTRACT FROM AUTHOR]

The microbiota inhabiting the surface of fish mucosal tissue play important roles in the nutrition, metabolism and immune system of their host. However, most investigations on microbial symbionts have focused on the fish gut, but the microbiota associated with external mucosal tissues (such as the skin and gill) is poorly understood. This study characterised the traits and dynamic of microbial communities associated with the skin, gill and gut of large yellow croaker (Larimichthys crocea) culturing with net enclosures or pens at different sampling times (with seasonal transition). Results revealed the structure and function of microbial communities differed according to the mucosal tissues of large yellow croaker. The richness and diversity of microbiota in the skin were significantly higher than that in the gill and gut. Discriminative microbial taxa such as Psychrobacter in the skin, Enterobacterales in the gill, and Fusobacterium in the gut, and discriminative predictive functions were identified in the skin, gill and gut. Furthermore, different environmental-related factors (such as sampling time/season and culture method) had impacts on the fish microbiota differently. The diversity and composition of microbiota associated with the skin, gill and gut changed over time, and the difference in skin microbiota across sampling times was most significant among the three tissues. The culture method significantly impacted the diversity and composition of skin microbiota, but no significant difference was found in the gill and gut microbiota between net enclosure and net pen. These results indicated that the skin microbiota of large yellow croaker was more diverse and affected by environmental-related factors than other tissues. This study provides new insights into the structure, environmental response pattern, and relationship with host health of microbiota associated with the mucosal tissues of large yellow croaker. [ABSTRACT FROM AUTHOR]

Neutrophil extracellular traps (NETs) are crucial for the immune defense of many organisms, serving as a potent mechanism for neutrophils to capture and eliminate extracellular pathogens. While NETosis and its antimicrobial mechanisms have been well studied in mammals, research on NETs formation in teleost fish remains limited. In this study, we used the large yellow croaker (Larimichthys crocea) as the study model to investigate NETosis and its role in pathogen defense. Our results showed that infection with Pseudomonas plecoglossicida could induce NETosis. To further explore the underlying mechanism, we performed transcriptome analysis and western blotting, which revealed that P. plecoglossicida triggers NETosis through activation of the autophagy pathway. Inhibition of autophagy significantly reduced NET production, highlighting its critical role in this process. Furthermore, our studies demonstrated that NETs exert a bacteriostatic effect, significantly suppressing the growth of P. plecoglossicida. Taken together, our findings reveal that autophagy regulates NETosis in large yellow croaker and underscore the essential role of NETs in bacterial defense, providing new insights into immune responses in teleost fish. [ABSTRACT FROM AUTHOR]

Melatonin is a critical regulator of biological rhythms across organisms, transducing light signals into neuroendocrine signals that facilitate reproductive regulation in response to environmental cues. However, the precise mechanisms through which melatonin regulates reproduction in fish require further investigation. In this study, we employed molecular and organizational biological techniques to examine the expression patterns of melatonin and its five receptor subtypes (LcMTNR1A1, LcMTNR1A2, LcMTNR1B1, LcMTNR1B2, and LcMTNR1C) in various tissues of the large yellow croaker (Larimichthys crocea). Our results revealed significant expression of all receptors in the pituitary and testes, with distinct gender differences, including a lack of expression in the ovary. Moreover, our data indicate that melatonin and its receptors are primarily expressed during stage III, highlighting their role in sexual maturity. Enzyme- linked immunosorbent assay (ELISA) results further demonstrated that in vitro melatonin incubation in the brain of L. crocea influenced gonadotropin-releasing hormone (GnRH) and testosterone secretion in a dose-dependent manner, suggesting actions beyond the classical hypothalamic–pituitary–gonadal (HPG) axis. Overall, our findings provide new evidence supporting the role of the melatonin system in reproductive regulation in marine teleosts. [ABSTRACT FROM AUTHOR]

Sciaenidae is the family of marine fish that has the highest aquaculture growth and production in the world. In this study, the global production, historical characteristics, biological aspects, and aquaculture technologies used for the Sciaenid species with the highest aquaculture production were compiled and analyzed to determine the success factors and bottlenecks that favored these species aquaculture development. This study also presents the state of technological aquaculture development in Sciaenid species in Latin America. The principal Sciaenid aquaculture species are large yellow croaker (Larimichthys crocea), red drum (Sciaenops ocellatus) and meagre (Argyrosomus regius), which together contribute 99.9% of the global aquaculture production of Sciaenid species. The aquaculture success of these three species is attributed to their suitable biology for aquaculture, high consumer demand, good market prices, government support, and prior empirical and/or scientific knowledge with other species that was transferrable to Sciaenidae, however, the aquaculture development of these species has not been free of errors. Principal bottlenecks in development include poorly planned marine spatial planning, the introduction of exotic species, the excessive use of fresh seafood-based feeds (especially in China), and inadequate genetic selection programs. In Latin America, eleven Sciaenidae species with biological attributes similar to the three established aquaculture species are being investigated. The technologies for the totoaba (Totoaba macdonaldi) and the Chilean croaker (Cilus giberti) are the most advanced. The technology developed and the positive and negative experiences of the Sciaenid aquaculture industry identified in this review should be considered to assist government decision-making for research and development of aquaculture in the family Sciaenidae. [ABSTRACT FROM AUTHOR]

This study applied high-resolution satellite data to address the siting and evaluation challenges for potential cage aquaculture areas of large yellow croaker in Zhejiang Province. A typical template of water environmental factors for large yellow croaker cage aquaculture was developed, incorporating various environmental parameters and considerations that were not fully addressed in previous studies. This paper established the Site Selection Method for Large Yellow Croaker potential aquaculture (SSM-LYC) based on the template. Site selection and grading evaluation of potential cage aquaculture areas were performed using SSM-LYC. The findings include the following: (1) Potential aquaculture sites for large yellow croaker include 11 areas with water depths of 15–60 m along the coast of Zhejiang Province from 27° to 31° north latitude, of which 7 are in water depths of less than 40 m, and 4 are in water depths of 40–60 m. (2) Assessment and scoring for potential aquaculture sites were performed, pinpointing 4 central locations of first-level aquaculture areas offering scientific evidence for the feasibility of deep-sea aquaculture of large yellow croaker along the Zhejiang coast. (3) The conclusions drawn from this research provide significant guidance for future aquaculture strategies and regional planning. Moreover, SSM-LYC can be applied to other coastal waters in the world. [ABSTRACT FROM AUTHOR]

Ultrasound-assisted freezing (UAF) technology is commonly used in the freezing preservation of large yellow croaker (Larimichthys crocea). In order to improve the quality of frozen large yellow croaker, this study introduced orthogonal mode on the basis of UAF. A novel technique of Triple-frequency orthogonal ultrasound assisted freezing (TOUAF) was developed. In order to explore the effects of different power TOUAF on the quality of frozen large yellow croaker, the thawing loss, water retention, low field nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging (MRI), chromatic difference, texture properties, TBA, protein solubility and surface hydrophobicity were measured after TOUAF treatment with different powers (160 W, 175 W, 190 W, 205 W). The results showed that TOUAF-175 could significantly increase water retention (79.450%±1.571%), reduce thawing loss (2.343%±0.044%) and water migration. The low TBA value of TOUAF-175 [(0.108±0.014) mg MDA/kg] indicated that TOUAF-175 effectively inhibited lipid oxidation. At the same time, TOUAF-175 has better effects than other power groups in terms of color difference, texture properties, improving protein solubility and reducing surface hydrophobicity. However, the quality of the frozen samples in the treatment group with higher power decreased due to the release of latent heat and mechanical damage to the frozen samples. The study showed that proper power of TOUAF could effectively reduce the damage of frozen fish tissue and improve the quality of frozen large yellow croaker. TOUAF-175 is an effective method to promote the freezing process and improve the quality of frozen large yellow croaker. [ABSTRACT FROM AUTHOR]

Hypoxia is one of the major environmental stressors, frequently resulting in serious yield losses for maricultured large yellow croaker (Larimichthys crocea). We know that pyroptosis contributes to tissue damage under hypoxic conditions. However, whether GSDMEs-mediated pyroptosis is involved in hypoxia-induced tissue damage in fish remains unclear. In the present study, two Lcgsdme genes, Lcgsdmea/b, were cloned and characterized from the large yellow croaker. Both genes contain a conserved N-terminal pore-forming domain, a C-terminal autoinhibitory domain, and a flexible hinge region. After hypoxia stress, the expression of Lcgsdmea/b transcripts and proteins in the liver were significantly higher than in unstressed fish. The proteins of LcGSDMEa/b could be cleaved under hypoxic conditions. Compared to LcGSDMEb, the expression of LcGSDMEa was higher in both mRNA and protein levels, thus exhibiting a stronger response during hypoxia stress. Furthermore, after 48 h of hypoxia stress, approximately 65% liver cells exhibited abnormalities, with pyroptosis being detected using a transmission electron microscope. TUNEL/LcGSDMEa double staining assay revealed a high expression of LcGSDMEa in the dead cells. We observed a significant up-regulation of pyroptosis pathway genes (asc, caspase-3) and pro-inflammatory cytokine genes (il-1β, il-18). After simultaneous knockdown of Lcgsdmea/b in vivo, the liver exhibited better health compared to the control group, with less cell swelling and vacuolation. Taken together, these findings demonstrate that hypoxia stress could activate LcGSDMEa/b and induce pyroptosis in the liver of large yellow croakers, thereby contributing to tissue damage. Our study improves the understanding of hypoxiainduced tissue damage in fish, and provides new clues for protecting fish against hypoxia-induced damage. [ABSTRACT FROM AUTHOR]

In recent years, significant progress has been made in China in the field of deep-sea large yellow croaker (Larimichthys crocea) farming. Compared with the traditional inshore aquaculture model, deep-sea culture of large yellow croaker enjoys a wider growing space with better water quality, thus enhancing fish quality. However, deep-sea aquaculture also faces challenges such as typhoons and strong currents, which often lead to prolonged starvation in fish. Therefore, in order to further promote the technological advancement of large yellow croaker in the field of deep-sea aquaculture, this experiment aimed to investigate the effects of varying starvation durations on the feeding rhythm and physiological state of large yellow croaker. With an initial body mass of 122.62 ± 11.08 g and a body length of (17.9 ± 1.04) cm as the samples, the experiment was divided into five groups, which were starved for 0 d (S0), 2 d (S2), 4 d (S4), 8 d (S8), and 16 d (S16) before resumption of feeding. The results were as follows: under starvation stress for 8 consecutive days, the total duration of feeding gradually decreased in large yellow croaker, but increased at starvation up to 16 days. Each replicate group had 50 large yellow croakers as test subjects, for a total of 750 large yellow croakers. Analyzing the linear regression equations of S0 with S2, S4, S8, and S16 groups, it was found that the trend of rate of change in feeding duration was consistent with the total duration of feeding, i.e., it decreased during 8 days and increased at 16 days. It indicated that the rate of feeding of large yellow croaker was accelerated within 8 days of starvation, while the rate of feeding was slowed down at 16 days of starvation. Furthermore, the blood glucose concentration of large yellow croaker decreased significantly after 8 days of starvation, while it rebounded significantly in the S16 group. Meanwhile, large areas of fatty degeneration were observed in the liver on the 8th day of starvation, followed by extensive hepatocyte necrosis on the 16th day. After resumption of feeding, there was some recovery within 4 days, but hepatocytes were still extensively edematous in the S8 and S16 groups. Meanwhile, the expression of inflammatory factor genes such as IL-1β, IL-10 and TNF-α in the liver increased with the prolongation of starvation time, in which both S8 and S16 groups in the liver were significantly different from the S0 group, and after resumption of feeding, the IL-1β and TNF-α genes of the S8 and S16 groups were significantly different from those of the normal feeding group (p < 0.05), while there was no differentiation for the IL-10 gene. Therefore, based on the results of this study, it is recommended to limit the duration of starvation in the large yellow croaker to no more than 8 days. [ABSTRACT FROM AUTHOR]

To explore the effect of density on large yellow croaker (Larimichthys crocea) under intensive aquaculture conditions and determine the appropriate culturing density, this study investigate the effects of different stocking densities on the nutritional composition, stress, and immune levels of large yellow croaker. Through a long-term aquaculture experiment, conducted under flow-through conditions of intensive aquaculture, three initial density groups were set: a low density group [LD], 4.92 kg/m3; a medium density group [MD], 7.56 kg/m3; and a high density group [HD], 10.08 kg/m3, for a 150-day rearing trial. Large yellow croaker were fed to satiation twice daily (6:00, 17:00). At the end of this trial, the final densities were 10.38 ± 0.50, 14.41 ± 1.06, and 18.71 ± 0.99 kg/m3 in the LD, MD, and HD groups, respectively. The results showed that the growth performances were adversely influenced by a high stocking density. Levels of cortisol in serum, superoxide dismutase (SOD) and catalase (CAT) in liver, Na+-K+ ATPase and Na+-K+ ATPase gene in gills, and heat shock protein (HSP70/90) genes and glutathione S-transferase (GST) genes in the liver significantly increased under HD treatment. Results of immune response analyses showed that there was a clear decrease in immunoglobulin M (IgM), complement component 4 (C4), and lysozyme (LZM) in serum, lysozyme (LZM) genes, tumor necrosis factor-alpha (TNF-α) genes and interleukin-1β (IL-1β) genes in the head kidney of large yellow croakers reared in the HD group. An obvious increase in free amino acids and fatty acids in the muscle of large yellow croakers reared in HD group was also observed. Overall, this study showed that the optimal final culturing density of large yellow croaker under flow-through systems should be between 14.41 kg/m3 and 18.71 kg/m3 to improve aquaculture efficiency and product quality. [ABSTRACT FROM AUTHOR]

This study investigated the spatiotemporal distribution, feeding ecology, and trophic dynamics of the marine fish species brown croaker (Miichthys miiuy) in the southwestern sea of Korea. As a top predator, M. miiuy primarily consumes small fish, especially anchovies and Larimichthys polyactis, with peak catch rates occurring in autumn. Stomach content analysis confirmed that fish dominate its diet across all size groups. However, notable dietary shifts were observed during the spawning season (July to October), when caridean shrimp, cephalopods, and penaeid shrimp became more prominent, likely because of shifts in prey availability and increased reproductive energy demands. Ontogenetic changes were also apparent, with larger individuals selecting larger prey. The species' opportunistic feeding behavior, adjusting to seasonal and environmental variations, underscores its ecological adaptability. These findings highlight M. miiuy's significant role in controlling the abundance of lower trophic species and stress the importance of further research on its trophic interactions to support marine biodiversity conservation and sustainable fisheries management. [ABSTRACT FROM AUTHOR]

Large yellow croaker (Larimichthys crocea) has been demonstrated to be divided into three geographical stocks from south to north along the coast of China, including Nanhai, Mindong, and Daiqu. Although multiple versions of L. crocea have been published, no high-quality Nanhai and Daiqu genomes have been assembled, hampering the assessment of the fine-scale genetic structure and adversely affecting wild stock conservation, fishery management, and germplasm exploitation of large yellow croaker. To fill the gap, we sequenced the genomes of three L. crocea stocks using a combination of PacBio and Hi-C technologies. We assembled each genome (~712 Mb) into 24 chromosomes with a contig N50 of 19.46–29.71 Mb and an integration efficiency of 88.13–92.80%. Furthermore, 26,851–28,133 protein-coding genes were predicted. The reference genomes of three geographical stocks of L. crocea provide vital resources for future research on the conservation and utilization of genetic diversity. [ABSTRACT FROM AUTHOR]

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]

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.)

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. [ABSTRACT FROM AUTHOR]

The problem of marine noise pollution has a long history. Strong noise (>120 dB re 1 µPa) will affects the growth, development, physiological responses, and behaviors of fish, and also can induce the stress response, posing a mortal threat. Although many studies have reported that underwater noise may affect the survival of fish by disturbing their nervous system and endocrine system, the underlying causes of death due to noise stimulation remain unknown. Therefore, in this study, we used the underwater noise stress models to conduct underwater strong noise (50–125 dB re 1 µPa, 10–22,000 Hz) stress experiments on small yellow croaker for 10 min (short-term noise stress) and 6 days (long-term noise stress). A total of 150 fishes (body weight: 40–60 g; body length: 12–14 cm) were used in this study. Omics (metabolomics and transcriptomics) studies and quantitative analyses of important genes (HPA (hypothalamic–pituitary–adrenal)-axis functional genes) were performed to reveal genetic and metabolic changes in the important tissues associated with the HPA axis (brain, heart, and adrenal gland). Finally, we found that the strong noise pollution can significantly interfere with the expression of HPA-axis functional genes (including corticotropin releasing hormone (CRH), corticotropin releasing hormone receptor 2 (CRHR2), and arginine vasotocin (AVT)), and long-term stimulation can further induce metabolic disorders of the functional tissues (brain, heart, and adrenal gland), posing a lethal threat. Meanwhile, we also found that there were two kinds of death processes, direct death and chronic death, and both were closely related to the duration of stimulation and the regulation of the HPA axis. [ABSTRACT FROM AUTHOR]

Conventional methods for evaluating of fish freshness based on physiological and biochemical methods are often destructive, complicated, and costly. This study aimed to predict the freshness of large yellow croaker which was sampled every second day in 9 consecutive days at 4°C, using computer vision technology combined with pupil color parameters and different machine learning algorithms (back propagation neural network, BPNN; radial basis function neural network; support vector regression; and random forest regression, RFR). In the process of model building, the RFR model provided the most accurate prediction for the value of total volatile basic nitrogen (TVB‐N), with the R‐square of the test set (Rp2$R^{2}_p $) of 0.993. The BPNN model exhibited the best fit for predicting the value of thiobarbituric acid (TBA), with Rp2$R^{2}_p $ of 0.959. Additionally, the RFR model was the most effective in forecasting total viable count (TVC), with Rp2$R^{2}_p $ of 0.935. After validation, the root mean square error values of the RFR model for predicting TVB‐N value, TBA value, and TVC value were the lowest, which were 0.764, 0.067, and 0.219, respectively. It demonstrated the applicability and good predictive performance of the RFR model for predicting biochemical and microbiological indicators. These findings also demonstrated that monitoring the changes in pupil color could successfully predict the freshness of chilled fish. Practical Application: Quality inspectors detect changes in the freshness of large yellow croaker in real time from the beginning of distribution to the selling site. [ABSTRACT FROM AUTHOR]

Simple Summary: Due to unrestrained and excessive fishing, the migratory fishing season and spawning groups of the large yellow croaker (Larimichthys crocea) in the East China Sea have been hard to detect since the 1980s. Since the 1990s, the Chinese government has initiated large-scale stock enhancement programs to restore the endangered wild large yellow croaker population. However, after several decades, the stock enhancement has not achieved its desired effects. The reasons for this remain poorly understood. Our results provide evidence that in the early-growth stage of the large yellow croaker, when its body length and body mass are similar to those of the small yellow croaker (Larimichthys polyactis), it may have a life history strategy of cohabitation and forming a guild with the small yellow croaker. Since the fishery resources of the small yellow croaker are far higher than those of the large yellow croaker, fishing targeting the small yellow croaker will indirectly lead to the large-scale capture of the cohabitate large yellow croaker, dealing a heavy blow to the slightly recovering fishery resources of the large yellow croaker. Therefore, optimizations and adjustments are necessary in order for the fishing ban policy and stock enhancement strategy to effectively restore the resources of the large yellow croaker. In recent decades, China's large-scale stock enhancement programs to restore the collapsing large yellow croaker (Larimichthys crocea) fishery resources have not yielded the desired results, and a comprehensive analysis of the underlying reasons for this problem is required. Based on small yellow croaker (Larimichthys polyactis) catch survey data obtained from 15 fishing ports along the coast of the East China Sea, we examined the proportion of large yellow croakers mixed in the small yellow croaker catch and their biological parameters. In addition, we analyzed the differences in the intestinal microbiota and feeding ecology between these two species to explore the reason why the stock enhancement program failed to achieve the desired outcome. The results show that there is a high likelihood of the two species appearing in each other's ecological niches, and there is a significant overlap in their dietary ecology. They may cohabitate and form a guild. The fishing season targeting the small yellow croaker indirectly catches the large yellow croaker population, which puts huge fishing pressure on large yellow croaker resource and shows obvious overfishing. Therefore, it is necessary to optimize and adjust the fishing ban policy and stock enhancement strategies, appropriately reducing the fishing intensity after the fishing ban to facilitate the effective accumulation of resource replenishment effects during the fishing ban period, thus effectively restoring wild large yellow croaker resources. [ABSTRACT FROM AUTHOR]

The fact that aquatic product waste causes environmental pollution and is difficult to handle has become a major challenge globally. Hydrothermal liquefaction (HTL) has provided new ideas for addressing this challenge. In this study, small yellow croaker was used as the raw material for HTL. It was found that the transition temperature point R from P1 (liquefied but without biocrude production) to P2 (biocrude production) lies between 200 and 250 °C. The impact of the pyrolysis temperature on the physical properties and composition of the produced biocrude was examined. The results showed that as the temperature increased, the acidity and density of the biocrude decreased. Furthermore, gas chromatography–mass spectrometry (GC-MS) analysis identified the components, revealing that changes in the physical properties were closely related to changes in the chemical composition. Although the composition remained similar with increasing temperature, the content varied significantly: the content of fatty acids and their derivatives decreased markedly, whereas that of aromatic compounds increased significantly. At 300 °C, the carbon chain distribution of the compounds was notably lower, with most being light oils, resulting in a reduced viscosity and density of the biocrude. Additionally, GC-MS analysis explored the effect of residence time on biocrude quality and found that reaction conditions of 300 °C for 125 min yielded high-quality biocrude and showed great potential for quality improvement with the addition of catalysts. Moreover, by altering the temperature and residence time, the content of the products can be controlled to produce high-value-added products. [ABSTRACT FROM AUTHOR]

Copyright of Science & Technology of Food Industry is the property of Science & Technology of Food Industry Editorial Office 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.)

The noise analysis of a large-scale aquaculture vessel reveals that during its navigation, the primary equipment noise, particularly from the propeller, exerts a notable influence on the aquaculture environment for large yellow croaker. The free surface greatly impacts the noise performance of propellers, which is a significant factor affecting the fish's habitat. This study adopts the numerical simulation method to analyze the hydrodynamic and acoustic characteristics of the E1619 propeller operating near the free surface. The open-water performance and noise calculations of the propeller are verified through experiments, and the effects of different immersion depths and advance coefficients on the propeller are explored. The results demonstrate that the free surface significantly affects the thrust, torque, and noise of the propeller, especially at shallow immersion depths and low advance coefficients. Surface wave pattern causes the instability and breakup of tip vortices, causing increased thrust and torque fluctuations, reduced efficiency, and significant overall sound pressure levels in the entire flow field. As immersion depth and advance coefficients increase, the interaction between tip vortices and the free surface weakens, wake vortex instability decreases, and noise levels gradually reduce. These analyses and conclusions can guide the design of next-generation propellers for aquaculture vessels to optimize performance near the free surface. [ABSTRACT FROM AUTHOR]

Copyright of South China Fisheries Science is the property of South China Fisheries 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.)

Simple Summary: This study focuses on the molecular mechanisms behind sexual differentiation in the Nao-zhou stock of large yellow croaker (Larimichthys crocea), a key marine species in China's fisheries. By using high-throughput RNA sequencing to perform a comparative transcriptome analysis of male and female gonads, the research identifies critical genes and pathways involved in gonadal development. These findings advance our understanding of the genetic basis of sex differentiation, revealing specific molecular markers and regulatory networks that could guide breeding programs and improve understanding of reproductive biology in this commercially valuable species. The Nao-zhou stock large yellow croaker (Larimichthys crocea) is a unique economic seawater fish species in China and exhibits significant dimorphism in both male and female phenotypes. Cultivating all-female seedlings can significantly improve breeding efficiency. To accelerate the cultivation process of all female seedlings of this species, it is necessary to deeply understand the regulatory mechanisms of sexual differentiation and gonadal development. This study used Illumina high-throughput sequencing to sequence the transcriptome of the testes and ovaries of Nao-zhou stock large yellow croaker to identify genes and molecular functions related to sex determination. A total of 10,536 differentially expressed genes were identified between males and females, including 5682 upregulated and 4854 downregulated genes. Functional annotation screened out 70 important candidate genes related to sex, including 34 genes highly expressed in the testis (including dmrt1, foxm1, and amh) and 36 genes highly expressed in the ovary (including gdf9, hsd3b1, and sox19b). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis found that differentially expressed genes were significantly enriched in nine signaling pathways related to sex determination and gonadal development, including steroid hormone biosynthesis, MAPK signaling pathway, and the TGF-beta signaling pathway. By screening sex-related differentially expressed genes and mapping protein–protein interaction networks, hub genes such as dmrt1, amh, and cyp19a1a were found to be highly connected. The expression levels of 15 sex-related genes, including amh, dmrt1, dmrt2a, foxl1, and zp3b, were determined by qRT–PCR and RNA sequencing. This study screened for differentially expressed genes related to sex determination and differentiation of Nao-zhou stock large yellow croaker and revealed the signaling pathways involved in gonad development of male and female individuals. The results provide important data for future research on sex determination and differentiation mechanisms, thereby providing a scientific basis for the cultivation of all-female seedlings. [ABSTRACT FROM AUTHOR]

Seasonal spermatogenesis in fish is driven by spermatogonial stem cells (SSCs), which undergo a complex cellular process to differentiate into mature sperm. In this study, we characterized spermatogenesis in the large yellow croaker (Larimichthys crocea), a marine fish of significant commercial value, based on a highresolution single-cell RNA-sequencing atlas of testicular cells from three distinct developmental stages: juvenile, adult differentiating and regressed testes. We detailed a continuous developmental trajectory of spermatogenic cells, from spermatogonia to spermatids, elucidating the molecular events involved in spermatogenesis. We uncovered dynamic heterogeneity in cellular compositions throughout the annual reproductive cycle, accompanied by strongmolecular signatures within specific testicular cells. Notably, we identified a distinct population of SSCs and observed a critical metabolic transition from glycolysis to oxidative phosphorylation, enhancing our understanding of the biochemical and molecular characteristics of SSCs. Additionally, we elucidated the interactions between somatic cells and spermatogonia, illuminating the mechanisms that regulate SSC development. Overall, this work enhances our understanding of spermatogenesis in seasonal breeding teleosts and provides essential insights for the further conservation and culture of SSCs. [ABSTRACT FROM AUTHOR]

Pseudomonas plecoglossicida is a causative agent of visceral granulomas in large yellow croaker (Larimichthys crocea). Quorum sensing (QS) is widely involved in imparting virulence to pathogenic bacteria; however, it has not been studied in P. plecoglossicida. In this study, we annotated a LuxR family transcriptional regulator in P. plecoglossicida NB2011 and designated as PplR. We aligned the protein sequence by BlastP and Clustal X2, monitored the N-acyl-homoserine lactone (AHL) signal production through cross-feeding bioassay and HC-MS/MS; investigated exogenous AHL signal binding by recombinant expression and thin layer chromatography; constructed a deletion mutant of the target gene by method of double homologous recombination; sequenced the transcript RNA and analyzed the data; additionally, characterized phenotypes of wild type and mutant strain. The LuxR homolog PplR was found to share high similarity with PpoR—the LuxR solo of Pseudomonas putida —without a cognate LuxI. The wild-type strain did not produce any AHL signals and the recombinant LuxR protein was found to bind C6-L-homoserine lactone (C6-HSL), C8-HSL, 3-oxo-C10-HSL, and 3-oxo-C12-HSL. RNA-seq analysis indicated 84 differentially expressed genes—5 upregulated and 79 downregulated—mainly enriched in gene ontology terms, such as flagella-dependent motility, integral component of membrane, DNA binding and transcription, and metal ion binding, suggesting that PplR is a master transcription regulator. The mutant strain showed attenuated biofilm-forming ability and stress resistance, and the data support a role for PplR in the regulation of these traits in P. plecoglossicida NB2011 independent of the presence of AHL signals. This is the first study to provide QS-related information on P. plecoglossicida. [ABSTRACT FROM AUTHOR]

To cope with the increasing decline of offshore fishery resources and to provide essential information for spatial-based fishery management, in this study, the spatial distribution and influencing factors of Larimichthys polyactis in the southern waters of Jiangsu Province were examined using an ensemble species distribution model （ESDM） based on the survey conducted during spring and autumn in 2019-2022. Five biotic and abiotic factors were selected to analyze the distribution characteristics of L. polyactis and its relationship with influencing factors. Results showed that the ensemble species distribution model had higher AUC （spring: 0. 995±0. 002; autumn: 0. 985±0. 001） and TSS （spring: 0. 935±0. 038; autumn： 0. 903± 0. 029） values than those in single species distribution models. Sea bottom temperature（ 0. 40） and sea bottom salinity（ 0. 38） had the highest importance levels in spring, while chlorophyll a and prey had greater influences on the spatial distribution of L. polyactis in autumn with importance levels of 0. 53 and 0. 46. L. polyactis were mainly distributed in coastal areas in spring with a strip-like distribution; while in autumn, L. polyactis were mainly distributed in the offshore areas, with suitable habitat mostly distributed in the areas of 32. 5°N-33. 6° N, 122°E-122. 5°E with a block-like distribution, and the area of suitable area is larger than that in spring. Furthermore, the distribution of L. polyactis showed obvious interannual differences. For example, the range of suitable habitat for L. polyactis in 2021 was prominently smaller than that in other years and the range of distribution was also limited. The study showed that the ESDM had better performance and could better reflect the spatial distribution and influencing factors of L. polyactis; the suitable areas and influencing factors for L. polyactis varied from season to season. This study can provide a theoretical basis for revealing the spatiotemporal distribution and changing law of L. polyactis in this area, and provide basic information for the implementation of space-based fishery management and optimization of marine protected areas（ MPAs）. [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]

Flow velocity is a key environmental factor that affects the behavioral strategies and physiological homeostasis of fish. To study the effects of flow velocity on the behavioral changes and blood physiology of the yellow croaker, the behavioral patterns of yellow croakers in response to flow velocity stress were obtained by analyzing changes in tail wagging frequency and amplitude. Differences in blood glucose, lactate, and cortisol were compared to determine their appropriate flow rate ranges. The juvenile stage of the large yellow croaker is crucial, as environmental changes can affect the physiology of fish. Therefore, juvenile yellow croakers were selected as the experimental subjects for this study. Twenty-four healthy and uniformly sized large yellow croakers with body weights of (90.26 ± 9.91) g and body lengths of (19.91 ± 0.69) cm were randomly assigned to one control group and three experimental groups, with five fish in each group. The experimental group was set with three flow rates, namely 1 bl/s (20 cm/s), 2 bl/s (40 cm/s), and 3 bl/s (60 cm/s), with a flow rate stress duration of 1 h. The results showed that: (1) Under different flow velocities, the fish exhibited different tail wagging patterns. At low flow velocities, their tail fins exhibited a "C"-shaped swing, while at high flow velocities, their bodies exhibited an "S"-shaped swing. (2) Oscillation frequency and amplitude both increased with increasing flow velocity. At a flow velocity of 2 bl/s, the oscillation frequency significantly increased. When the flow velocity reached 3 bl/s, the oscillation amplitude significantly increased (p < 0.05). (3) Blood physiology showed significant changes with increased flow rate, and blood glucose content continuously decreased with increased flow rate, significantly decreasing at a flow rate of 2 bl/s (p < 0.05). Lactic acid and cortisol both increased with increasing flow rate, and significantly increased at a flow rate of 3 bl/s (p < 0.05). In summary, under high-flow velocity stress, significant changes occurred in the behavior and physiology of large yellow croakers, which were consistent with physiological changes in the blood. A flow rate higher than 2 bl/s can lead to intense swimming behavior, decreased blood sugar concentration, and increased lactate accumulation and stress levels. Therefore, the short-term tolerance of yellow croakers is 2 bl/s, and a flow rate of 1 bl/s is more suitable. [ABSTRACT FROM AUTHOR]

Soybean meal, renowned for its high yield, cost efficiency, and protein richness, serves as a pivotal plant-based alternative to fish meal. However, high soybean meal inclusion in Larimichthys crocea diets is linked to enteritis and oxidative damage, with unknown mechanisms. Our study aims to elucidate the molecular basis of soybean-meal-induced enteritis and its impact on intestinal microbiota in L. crocea. To this end, four isonitrogenous and isolipidic diets with varying soybean meal levels (0% FM, 15% SBM15, 30% SBM30, and 45% SBM45) were administered to L. crocea for 8 weeks. The results indicated that the SBM30 and SBM45 treatments significantly hindered fish growth, digestive efficiency, and protein utilization. Furthermore, high soybean meal levels (SBM30 and SBM45) activated intestinal Toll-like receptors (TLR2A, TLR2B, TLR5, and TLR22), stimulating C-Rel and mTOR protein expression and elevating ERK phosphorylation. This led to increased pro-inflammatory cytokine production (IL-1β, IL-6, and TNF-α) and decreased anti-inflammatory cytokine expression (IL-4/13A, IL-4/13B, and TGF-β), suggesting a potential signaling pathway for soybean-meal-induced enteritis. Furthermore, enteritis induced by high soybean meal levels led to oxidative damage, evident from increased MDA levels and decreased antioxidant enzyme activities (SOD and CAT). The SBM30 and SBM45 treatments increased Firmicutes and Bacteroidetes abundance in fish gut microbiota, while Proteobacteria abundance decreased. This microbiota shift may enhance soybean meal nutrient utilization, yet high soybean meal concentrations still impair growth. A soybean-meal-rich diet promotes harmful bacteria like Rhodococcus and depletes probiotics like Ralstonia, increasing disease risks. L. crocea has limited tolerance for soybean meal, necessitating advanced processing to mitigate anti-nutritional factors. Ultimately, exploring alternative protein sources beyond soybean meal for fish meal replacement is optimal for L. crocea. [ABSTRACT FROM AUTHOR]

The large yellow croaker (Larimichthys crocea) is an important economic fish in China. However, intensive farming practices, such as high stocking densities, suboptimal water quality, and imbalanced nutrition, have led to a decline in muscle quality. Muscle elasticity is a key texture property influencing muscle quality. Herein, transcriptomic and metabolomic analyses were performed on four groups: male high muscle elasticity (MEHM), female high muscle elasticity (MEHF), male low muscle elasticity (MELM), and female low muscle elasticity (MELF), to explore the molecular regulation underlying muscle elasticity in the large yellow croaker. Transcriptomics identified 2594 differentially expressed genes (DEGs) across the four groups, while metabolomics revealed 969 differentially expressed metabolites (DEMs). Association analysis indicated that the valine, leucine, and isoleucine biosynthesis pathways were significantly enriched between the MELF and MEHF groups; 2-Oxoisovalerate and L-Valine were DEMs; and the gene encoding L-threonine ammonia-lyase was a DEG. In the MELM and MEHM groups, pathways such as arginine biosynthesis; arginine and proline metabolism; and valine, leucine, and isoleucine degradation were significantly enriched. 4-guanidinobutanoate, L-aspartate, N-acetylornithine, and L-leucine were among the DEMs, while the DEGs included glul, gls, srm, hmgcs, and aacs. These findings provide insights into the molecular mechanisms controlling muscle elasticity, representing a theoretical foundation to breed high-quality large yellow croakers. [ABSTRACT FROM AUTHOR]

Disease outbreaks in aquaculture have recently intensified. In particular, visceral white-nodules disease, caused by Pseudomonas plecoglossicida, has severely hindered the small yellow croaker (Larimichthys polyactis) aquaculture industry. However, research on this disease is limited. To address this gap, the present study employed a 100K SNP chip to genotype individuals from an F1 full-sib family, identify single nucleotide polymorphisms (SNPs), and construct a genetic linkage map for this species. A high-density genetic linkage map spanning a total length of 1395.72 cM with an average interval of 0.08 cM distributed across 24 linkage groups was obtained. Employing post-infection survival time as an indicator of disease resistance, 13 disease resistance-related quantitative trait loci (QTLs) were detected, and these regions included 169 genes. Functional enrichment analyses pinpointed 11 candidate disease resistance-related genes. RT-qPCR analysis revealed that the genes of chmp1a and arg1 are significantly differentially expressed in response to P. plecoglossicida infection in spleen and liver tissues, indicating their pivotal functions in disease resistance. In summary, in addition to successfully constructing a high-density genetic linkage map, this study reports the first QTL mapping for visceral white-nodules disease resistance. These results provide insight into the intricate molecular mechanisms underlying disease resistance in the small yellow croaker. [ABSTRACT FROM AUTHOR]

In the present investigation, we have devised a hyperspectral imaging (HSI) apparatus to assess the chemical characteristics and freshness of the yellow croaker (Larimichthys polyactis) throughout its storage period. This system operates within the shortwave infrared spectrum, specifically ranging from 900 to 1700 nm. A variety of spectral pre-processing techniques, including standard normal variate (SNV), multiple scatter correction, and Savitzky–Golay (SG) derivatives, were employed to augment the predictive accuracy of total volatile basic nitrogen (TVB-N)—which serves as a critical freshness parameter. Among the assessed methodologies, SG-1 pre-processing demonstrated superior predictive accuracy (Rp2 = 0.8166). Furthermore, this investigation visualized freshness indicators as concentration images to elucidate the spatial distribution of TVB-N across the samples. These results indicate that HSI, in conjunction with chemometric analysis, constitutes an efficacious instrument for the surveillance of quality and safety in yellow croakers during its storage phase. Moreover, this methodology guarantees the freshness and safety of seafood products within the aquatic food sector. [ABSTRACT FROM AUTHOR]

The vasa gene, encoding an ATP-dependent RNA helicase, and the nanos-2 gene, an RNA-binding protein, are essential for germ cell origination, migration, maintenance, and development in vertebrates and invertebrates. The expression levels of the vasa and nanos-2 genes have not yet been investigated or reported in crappie species. These two genes were partially sequenced and characterized, and their expression patterns were analyzed using reverse-transcription quantitative polymerase chain reaction (RT-qPCR) according to age and sex. The vasa sequences of white crappie (WC) females and males showed significant similarity with the vasa homologs of largemouth bass (Micropterus salmoides; 93.1–93.98%) and smallmouth bass (M. dolomieu; 91.95–92.77%), indicating its conserved nature within the Family Centrarchidae. The vasa sequence of black crappie (BC) females showed significant similarity with the vasa homologs of white crappie (91.67%), largemouth bass (96.10%), smallmouth bass (96.10%), spotted scat (Scatophagus argus; 97.37%), mandarin fish (Siniperca chutasi; 96.15%), Japanese sea bass (Lateolabrax japonicus; 94.87%), lumpfish (Cyclopterus lumpus; 91.95%), southern bluefin tuna (Thunnus maccoyii; 94.74%), large yellow croaker (Larimichthys crocea; 92.21%), and Nile tilapia (Oreochromis niloticus; 92.21%). The nanos-2 sequences of WC females, WC males, and BC females showed significant similarity with the nanos-2 of largemouth bass (92.92–96.36%), smallmouth bass (92.92–96.36%), and mandarin fish (92.66–94.34%). The expression of vasa in BC females was significantly higher at age-2 than at age-1, while WC males and females presented no significant age-related differences. Neither species had a significant difference in nanos-2 gene expression with age. The expression levels of vasa and nanos-2 were significantly higher in WC males than females. [ABSTRACT FROM AUTHOR]

Small yellow croaker (Larimichthys polyactis) is a critical economic fish species in South Korea, where effective management is essential due to concerns over declining populations. This study aims to enhance fishery management strategies by applying machine learning techniques to classify the maturity stages and estimate the length at first maturity (L50 and L95), comparing these results with those obtained using traditional macroscopic methods. Five machine learning models, including Decision Tree (DT), Random Forest (RF), LightGBM (LGBM), EXtreme Gradient Boosting (XGB) and Support Vector Machine (SVM), were developed and evaluated for their effectiveness in predicting maturity stages. The XGB model demonstrated superior performance with the highest evaluation final score and low computation time. Using generalized linear models (GLM), this study estimated L50 and L95 for both machine learning predictions and macroscopic observations. The results showed that machine learning models, particularly XGB, provided more precise estimates with narrower confidence intervals and better model fit than the traditional macroscopic methods. These findings can support more sustainable fisheries management practices by offering reliable tools for setting appropriate regulatory measures, such as minimum landing sizes, which contribute to the conservation of marine resources. [ABSTRACT FROM AUTHOR]

Simple Summary: We identified a large number of core gut flora and key metabolites associated with muscle elasticity by integrating macrogenomic and metabolomic techniques, thus providing insights into the molecular mechanisms explaining the differences in muscle quality in the large yellow croaker (LYC, Larimichthys crocea). We further constructed an association model between gut flora and metabolites, which offers a new perspective on the potential mechanisms by which the LYC gut flora influences muscle quality via the regulation of the intestinal metabolism. Additionally, our study not only provides new insights into the gut microbiota–metabolism–muscle axis, but also strong support for future research on muscle quality trait improvement in LYC. The large yellow croaker (LYC, Larimichthys crocea) is highly regarded for its delicious taste and unique flavor. The gut microbiota has the ability to affect the host muscle performance and elasticity by regulating nutrient metabolism. The purpose of this study is to establish the relationship between muscle quality and intestinal flora in order to provide reference for the improvement of the muscle elasticity of LYC. In this study, the intestinal contents of high muscle elasticity males (IEHM), females (IEHF), and low muscle elasticity males (IELM) and females (IELF) were collected and subjected to metagenomic and metabolomic analyses. Metagenomic sequencing results showed that the intestinal flora structures of LYCs with different muscle elasticities were significantly different. The abundance of Streptophyta in the IELM (24.63%) and IELF (29.68%) groups was significantly higher than that in the IEHM and IEHF groups. The abundance of Vibrio scophthalmi (66.66%) in the IEHF group was the highest. Based on metabolomic analysis by liquid chromatograph-mass spectrometry, 107 differentially abundant metabolites were identified between the IEHM and IELM groups, and 100 differentially abundant metabolites were identified between the IEHF and IELF groups. Based on these metabolites, a large number of enriched metabolic pathways related to muscle elasticity were identified. Significant differences in the intestinal metabolism between groups with different muscle elasticities were identified. Moreover, the model of the relationship between the intestinal flora and metabolites was constructed, and the molecular mechanism of intestinal flora regulation of the nutrient metabolism was further revealed. The results help to understand the molecular mechanism of different muscle elasticities of LYC and provide an important reference for the study of the mechanism of the effects of LYC intestinal symbiotic bacteria on muscle development, and the development and application of probiotics in LYC. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the impacts of replacement of dietary fish oil by linseed oil on the growth performance, feed utilization, and muscle metabolic capacity of large yellow croaker (Larimichthys crocea). A total of 360 juvenile large yellow croaker with an initial weight of (3.89±0.01) g were randomly divided into two groups, with three replicates per group and 60 fish per replicate. Two isonitrogenous and isolipidic diets were formulated, namely the fish oil group (FO group, with a fish oil addition of 6%) and the linseed oil group (LO group, where linseed oil completely replaced fish oil). The experimental period was 10 weeks. The results showed that the final weight and weight gain rate of the large yellow croaker in the LO group were significantly lower than those in the FO group (P<0.05), and the feed conversion ratio was significantly higher than that in the FO group (P<0.05). Compared with the FO group, the concentrations of linoleic acid and α-linolenic acid in the muscle of the LO group were significantly increased (P<0.05), while the concentrations of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were significantly decreased (P<0.05). The substitution of fish oil with linseed oil significantly affected the expression of genes related to AMPK/SIRT1/PGC-1α pathway, and glucose and lipid metabolism in muscle (P<0.05). The activity of lactate dehydrogenase and the concentrations of glucose-6-phosphate and lactate in the muscle of the LO group were significantly higher than those in the FO group (P<0.05), while the activities of citrate synthase and cytochrome c oxidase were significantly lower than that in the FO group (P<0.05). The study indicates that the total replacement of dietary fish oil with linseedoil can inhibit growth performance and feed utilization, reduce the content of muscle EPA and DHA and induced the declines in the AMPK/SIRT1/PGC-1α pathway-related genes expression andmitochondrial aerobic metabolism in muscle of large yellow croaker. [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]

Copyright of Science & Technology of Food Industry is the property of Science & Technology of Food Industry Editorial Office 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.)

In fisheries' stock assessments, the concept of "growth plasticity"—the ability of organisms to modulate their growth rates in response to environmental conditions—has gained attention in recent years. Historically, the impacts of fishing activities and environmental fluctuations were considered separately, while their combined effects have recently come into focus. This study collected 834 adult small yellow croakers (Larimichthys polyactis) from the northern Yellow Sea, the central Yellow Sea, the southern Yellow Sea, and the northern East Sea by trawling during 2020–2021. Using otolith increments as a proxy for annual somatic growth, the study reconstructed otolith chronologies during 2015–2020 for these four stocks. The results of the mixed-effects modeling suggested that temperature during spawning and previous overwintering seasons had comparable importance for the annual growth of small yellow croakers, with higher temperature promoting growth. The growth of small yellow croakers was also found to be correlated with ENSO events, with a lag of 1 to 2 years. A further investigation into combined effects revealed that higher fishing pressure might inhibit the small yellow croaker's response to favorable environmental conditions. Furthermore, considering the potential differences in growth plasticity among stocks, an analysis was conducted on the spatial variations in growth response to these factors. The analysis revealed that, compared to the stocks in the Yellow Sea, the stock from the East China Sea could exhibit higher growth, superior adaptability to temperature, and a distinctive response to fishing pressure. In conclusion, the present study, while primarily focusing on temperature, preliminarily analyzed the combined effects of fishing and environment and underscored the differences in growth plasticity between stocks in the Yellow Sea and the East China Sea. Despite the limited factors analyzed in this study, it suggests a direction for future studies, highlighting the necessity to include more environmental factors, and even population factors (e.g., the biomass of preys), for a more comprehensive understanding of the combined effects. Based on the observed differences between the two potential subpopulations, this study also provides new insights for the management of the small yellow croaker based on metapopulation dynamics. [ABSTRACT FROM AUTHOR]

Nursery habitats play a significant role in completing fish life cycles, and they are now recognized as essential habitats. Monthly variations in nursery ground distributions of Larimichthys polyactis were investigated in the southern Yellow Sea in 2019. Bayesian hierarchical models with integrated nested Laplace approximation were utilized to model the preferential nursery habitats of L. polyactis larvae. The study analyzed the spatial and temporal distributions of the larvae and juveniles based on three environmental variables: sea surface temperature, sea surface salinity, and depth. Additionally, this study examined the utilization of habitats by different fish life stages and ontogenetic shifts. A total of 3240 individuals were collected from April to June, with the peak occurring in May (0.05 ind./m3), and the distribution areas varied between different months. The prediction of the model reveals the ecological adaptability of L. polyactis to temperature variations. The optimal temperature for L. polyactis density ranges from 12.5 °C to 16.5 °C in April and 16.5 °C to 17.5 °C in May, demonstrating a broad temperature tolerance for L. polyactis survival. In addition, there are variations in distribution patterns among different developmental stages. Larimichthys polyactis spawn in the inshore and nearshore waters, and after hatching, larvae in the pre-flexion stage tend to remain aggregated near the spawning beds. However, larvae in the advanced development stage (post-flexion) and juveniles move towards the sandy ridge habitats along the coast and start to migrate offshore in June. This study provides valuable insights for the effective management of fishery resources in the area and can be utilized to identify marine areas with specific habitat features that require conservation. [ABSTRACT FROM AUTHOR]

Simple Summary: This study examines the spatial distribution patterns of key fishery resources in the East China Sea across four seasons. Utilizing a habitat suitability index model, we identified the primary environmental factors influencing these patterns. Our results indicate that water temperature is a crucial factor for hairtail, while salinity and water depth are significant for small yellow croaker and Bombay duck, respectively. We also assessed the ecological niche overlap among different species and seasons, finding that predator-prey interactions primarily drive spatial habitat overlap. During summer and autumn, multiple species show increased overlap due to synchronized life cycles. An overlap index analysis demonstrated that species overlap rises from spring to winter, peaking in winter due to overwintering behavior and reduced food competition. These findings provide insights into species interactions and inform effective fishery resource management. The spatial niche has garnered significant attention in ecological research, particularly regarding species distribution patterns. The East China Sea, known for its favorable natural conditions and abundant fishery resources, exhibits diverse spatial distribution patterns among species, shaped by their seasonal physiological needs. This study utilized a habitat suitability index model to explore the spatial distribution patterns of key fishery resources in the East China Sea across four seasons and their interactions. Two methodologies were employed to identify key environmental factors and assess the ecological niche overlap among different species and seasons. Results indicated that the initial method identified water temperature as the critical factor for hairtail, while the subsequent method emphasized water temperature and salinity for hairtail, salinity for small yellow croaker, and water depth for Bombay duck. The main spatial habitat overlap was observed between paired species, likely driven by predator-prey interactions. During summer and autumn, increased overlap among multiple species was primarily influenced by synchronized life cycles. An overlap index formula quantified the seasonal species overlap, showing an increase from spring to winter, reflecting changes in convergent habitat preferences. The peak overlap occurred in winter, driven by overwintering, reduced food competition, and enhanced coexistence potential, while the lowest overlap was noted in spring as overwintering ended and predation and competition intensified. [ABSTRACT FROM AUTHOR]