Quanyou Guo

To explore the correlation between culture cycles and quality of offshore vessel-farmed Larimichthys crocea (initial weight: 505.32 ± 35.34 g), this study analyzed muscle quality changes at 0 (TK ₀ , control group), 1 (TK ₁ ), 2 (TK ₂ ), 3 (TK ₃ ) and 4 (TK ₄ ) months via metabolomics. Extended culture cycles significantly increased body length/depth, caudal peduncle length/depth, springiness and crude protein, but significantly decreased condition factors, adhesiveness and crude lipid, with these traits plateauing at TK ₃ ( P < 0.05). Although most parameters showed no significant difference between TK ₃ and TK ₄ , flavor-related indicators slightly decreased at TK ₄ . Culture cycles also significantly regulated muscle amino acid/fatty acid profiles, electronic tongue taste (umami, sweetness) and volatile flavors ( P < 0.05). KEGG analysis indicated that phenotypic variations were closely correlated with alterations in amino acid metabolism and antioxidant-related pathways, with optimal nutritional and flavor performance observed at the TK ₃ stage. In short, the 3-month culture stage corresponded to superior muscle nutritional quality and flavor characteristics, which coincided with comprehensive changes in amino acid metabolism and antioxidant-related pathways. This study provides a scientific basis for optimizing culture cycles and promoting the sustainable development of high-quality aquaculture.

Large yellow croaker (Larimichthys crocea) is an economically important marine fish, yet rapid and non-destructive discrimination between sea-caught and farmed collection-source groups remains challenging. This study developed a fish-level analytical workflow integrating YOLO11n-seg instance segmentation with visible–near-infrared hyperspectral imaging to extract relative reflectance ratios from six anatomical regions. The analytical cohort comprised 258 unique fish, including 171 sea-caught and 87 farmed individuals. Source categories were assigned according to the original capture or cage-culture collection channels. Fish identity was used as the grouping unit in five-fold internal cross-validation, and classification performance was evaluated based on out-of-fold fish-level predictions. Logistic-regression models achieved AUC values ranging from 0.985 to 1.000 across the six individual anatomical regions. The combined six-region model achieved an accuracy of 0.996 (95% CI, 0.988–1.000) and an AUC of 1.000 (95% CI, 1.000–1.000) within the present cohort. For anatomical-region segmentation, the 20-image validation set contained 140 annotated instances. Bounding-box precision, recall, mAP@0.5, and mAP@0.5–0.95 were 0.976, 0.983, 0.981, and 0.700, respectively, while the corresponding mask metrics were 0.969, 0.976, 0.972, and 0.669. These results indicate that region-specific hyperspectral information can support highly accurate internal discrimination between the two collection-source groups and provide an interpretable basis for characterizing source-associated spectral differences. However, the source labels were not independently verified, potentially influential covariates were incompletely recorded, and no independent external cohort was available. Therefore, the present findings should be interpreted as internally validated collection-source discrimination rather than verified provenance authentication or evidence of external generalizability.

Nanoplastics (NPs) pose growing threat to aquatic environments, but their sublethal impacts on ecologically critical behaviors like swimming, which directly determines migration success, and the underlying muscular mechanisms are still not well characterized. This study investigated the impact of NPs on skeletal muscle and swimming performance in the migratory large yellow croaker (Larimichthys crocea). Through a multi-concentration exposure experiment (0.01, 0.1, and 1 mg/L), and by integrating behavioral assays, ultrastructural histopathology, transcriptomics, and metabolomics, the results showed that 30 d of NPs exposure significantly inhibited growth and impaired both sustained (Ucrit) and burst (Ucat) swimming capacities in a concentration-dependent manner. Ultrastructural analysis revealed progressive muscle damage, from fiber disorganization to sarcomere disintegration. Integrated transcriptomic and metabolomic profiling identified a potentially conserved toxic effect pattern across fish species involving cellular barrier breakdown, a “metabolic decoupling” energy crisis, and specific perturbation of tryptophan metabolism which may amplify inflammatory responses. We also systematically revealed the progressive mechanisms of NPs induced muscle toxicity, as initial endocrine and metabolic disruption at low concentrations, shifting to oxidative stress and energy reallocation at moderate levels, and culminating in ferroptosis and excessive autophagy at high exposure. Our findings establish a direct link from NPs induced molecular and structural muscle damage to locomotor deficiency. This work demonstrates that sublethal NPs exposure can critically undermine swimming capabilities, thereby threatening migration and other vital life-history traits in fish. The results underscore the need to incorporate behavioral endpoints into environmental risk assessments of plastic pollution to safeguard aquatic ecosystem health.

Morphological differences between sea-caught and farmed fish reflect environmental conditions and long-term domestication. However, standardized and objective quantification of these differences remains limited for many commercially important species. The large yellow croaker (Larimichthys crocea) represents a typical marine fish with clear contrasts between natural and aquaculture production systems. In this study, an image-based phenotyping workflow was developed to quantify external morphological traits of sea-caught and farmed L. crocea. Visible-light images were acquired under standardized conditions. A YOLOv11-based instance segmentation model was applied to automatically delineate major anatomical regions, including the body, head, eyes, pectoral fins, and tail. Surface areas and proportional indices were calculated following geometric calibration to ensure measurement consistency. The segmentation model achieved high accuracy on the test dataset (mAP@50 > 98%). Morphometric analyses revealed clear differences between the two groups. Farmed individuals exhibited larger body-related surface areas, whereas the relative proportions of pectoral fins and tail regions were reduced. Sea-caught fish showed higher proportional investment in locomotor structures, consistent with the physical demands of natural marine environments. These results indicate a shift in morphological allocation associated with aquaculture, characterized by enhanced trunk growth and reduced relative development of propulsion-related structures. The proposed workflow provides a rapid, non-invasive, and reproducible approach for fish morphometric analysis. It offers practical potential for phenotypic monitoring and stock assessment, while contributing quantitative evidence for domestication-driven morphological divergence in marine fishes.

The large yellow croaker (Larimichthys crocea) is an economically significant aquaculture species in Asia, with skin coloration being a key quality attribute affecting consumer choice and commercial value. This study integrated morphological, biochemical, and proteomic approaches to investigate chromatophore characteristics, pigment composition, and diurnal body color variation in the large yellow croaker. Colorimetric analysis showed the highest yellowness, redness, and lightness values in ventral skin, followed by caudal skin, with dorsal skin showing the least yellowness. Three major chromatophores were identified: melanophores, xanthophores, and iridophores. Xanthophores were abundant in ventral and caudal skin, showing larger size and deeper pigmentation ventrally, while melanophores dominated dorsally and iridophores were mainly on scales. Skin and fins were key sites for carotenoid deposition, with lutein as the predominant carotenoid. Esters of lutein and zeaxanthin were the main contributors to yellow coloration in fish. A strong positive correlation was found between skin yellowness and total carotenoid content (R = 0.91, p < 0.05). The aggregation and dispersion of xanthosomes within xanthophores appeared to be the key driver behind the light-influenced diurnal body color variation. Proteomic analysis revealed motor proteins (such as KIF21, DYNC1L1, and MYO9) and pathways related to intracellular granule movement were probably related to the pigment transport in chromatophores of large yellow croaker. In addition, tubulin dynamics also appeared to participate in pigment translocation. This study is helpful to understand the pigmentary basis of this important farmed sea fish and provides a foundation for improving the golden color traits and further molecular research on diurnal color changes in large yellow croaker.

As a member of the order Perciformes, family Sciaenidae, and genus Larimichthys , the large yellow croaker ( Larimichthys crocea ) is characterized by tender, delicious, and nutritious flesh. This experiment was designed to investigate the differences in growth performance, serum biochemical indices, and muscle quality among different strains of large yellow croakers (initial average weight: 5.11 ± 0.11 g; final average weight: 383.50 ± 11.50 g). Individuals were randomly selected from each strain of large yellow croakers, including the Wenzhou common strain (LYC1), Dai‐qu population (LYC2), Fufa 1 (LYC3), and Ningde common strains 1 (LYC4) and 2 (LYC5), for the analysis of population genetic diversity. The results showed that the weight gain rate and specific growth rate exhibited no significant differences among the LYC1, LYC4, and LYC5 groups but were significantly lower than those of the remaining two groups ( p < 0.05). The muscle of the LYC3 group was found to have the highest crude protein content, coupled with the lowest crude lipid and moisture contents in muscle tissue. The relaxation time of noneasily flowable water in the muscle was the shortest in the LYC3 group. Serum levels of alanine aminotransferase, aspartate transaminase, and malondialdehyde were significantly lower in the LYC3 group than those in the other four groups ( p < 0.05). Serum activities of superoxide dismutase, catalase, alkaline phosphatases, and acid phosphatases were significantly higher in the LYC2 and LYC3 groups than those in the LYC1, LYC4, and LYC5 groups ( p < 0.05). Muscle contents of total volatile base nitrogen and thiobarbituric acid reactive substances were significantly lower in the LYC3 group than those in the LYC1 and LYC5 groups ( p < 0.05). The muscle cell diameter of the LYC3 group was significantly smaller than those of the other four groups, whereas the muscle cell density was significantly higher than those of the other four groups. The muscle of large yellow croakers in the LYC3 group presented optimal hardness, cohesiveness, springiness, gumminess, and chewiness. Muscle lipase and amylase activities were significantly higher in the LYC3 group than those in the other four groups, while muscle protease activity was remarkably lower in the LYC3 group than those in the LYC1, LYC2, LYC4, and LYC5 groups. Muscle levels of alanine aminotransferase and malondialdehyde were significantly lower in the LYC3 group than in the other experimental groups ( p < 0.05). Muscle activities of superoxide dismutase, catalase, and acid phosphatase were significantly higher in the LYC3 group than those in the other four groups ( p < 0.05). The mRNA expressions of muscle superoxide dismutase, catalase, and glutathione reductase were significantly upregulated in the LYC3 group compared with the other four groups ( p < 0.05). The mRNA expressions of muscle myogenic factor 4, myogenic factor 5, myoblast determination protein, and myogenin were significantly higher in the LYC2 and LYC3 groups than those in the LYC1, LYC4, and LYC5 groups, while the mRNA expression of myostatin was significantly lower in the LYC2 and LYC3 groups than those of the other three groups ( p < 0.05). In conclusion, the LYC3 group strain of large yellow croakers displays optimal growth performance and muscle quality. Meanwhile, this study provides a reference for exploring the molecular mechanisms underlying the differences in muscle quality among different strains of large yellow croakers in further research.

As a representative of traditional Chinese fermented fish, fermented large yellow croaker (Larimichthys crocea) is characterized by its rich aroma, appealing color, distinctive flavor, and long shelf life. In this study, Saccharomyces cerevisiae (S. cerevisiae) and Levilactobacillus brevis (L. brevis) were inoculated to enhance fermentation, and their effects on biogenic amine (BA) formation, volatile flavor compounds (VFCs), and microbial community composition were investigated. Combined inoculation significantly reduced most BAs and nitrite levels, thereby improving the safety of fermented large yellow croaker. The S. cerevisiae-inoculated group exhibited higher contents of ester compounds such as 3-methylbutyl acetate, 2-methylpropyl acetate, and ethyl 2-methylbutanoate. L. brevis effectively suppressed spoilage and amine-producing bacteria, including Aeromonas, Shewanella, and Morganella. Pearson’s correlation analysis revealed that Levilactobacillus was positively correlated with butyl 2-methylbutanoate, (Z)-4-heptenal, pentyl acetate, 2-ethyl-3-methylpyrazine, 3-methylbutyl acetate, 4-methyl-2-pentanone, 3-pentanone, and propanal, while Saccharomyces showed positive correlations with propionaldehyde, 1-penten-3-ol, 4-methyl-3-penten-2-one, (E)-2-pentenal, and 2-hexenal. In contrast, BAs were negatively correlated with Levilactobacillus and Saccharomycopsis, but positively correlated with Aeromonas, Shewanella, Photobacterium, Vagococcus, Vibrio, Morganella, Lactococcus, Apiotrichum, and Cutaneotrichosporon. Overall, these findings demonstrate that L. brevis and S. cerevisiae improve both the flavor and safety of fermented large yellow croaker. This study offers a theoretical basis for advancing industrial production of fermented fish products.