Search Results (119)

Numerous studies have demonstrated the positive effects of formulated feeds on gonadal and hepatopancreatic development of Eriocheir sinensis. However, there are limited studies on the effects of formulated feeds on the immune homeostasis and metabolism of muscle tissue in E. sinensis during the fattening period. Therefore, this study used metabolomic and lipidomic to systematically analyze the effects of formulated diets on muscle metabolism in female E. sinensis. The results indicate that the formulated feeds improved immune performance by inhibiting inflammatory responses, apoptosis and autophagy. In addition, the feed promoted amino acid metabolism and protein synthesis while decreasing muscle fatty acid metabolism. Metabolomic analysis reveal that pyrimidine metabolism is involved in the regulation of muscle physiological health in fattening female crabs. Lipidomic analysis revealed that the formulated feeds play a role in muscle immune homeostasis, amino acid and fatty acid metabolism by regulating the level of ceramide (Cer (d18:1/22:0)) in sphingolipid metabolism. Through subnetwork analysis, the functional interactions of sphingolipid metabolism with the pathways of sphingolipid signaling, apoptosis regulation, inflammatory response and lipid dynamic homeostasis were identified, which further defined the important role of sphingolipid metabolism in the regulation of muscle physiological health and metabolic homeostasis was further identified. In summary, the formulated feeds effectively promote immune homeostasis and metabolism in the muscle of female E. sinensis during the fattening period. These findings provide a solid theoretical foundation for feed formulation optimization and application in fattening practices. Full article

Oxidative stress is a key mediator of physiological dysfunction in aquatic organisms under environmental challenges, yet its comprehensive impacts on gill physiology require further clarification. This study investigated the molecular and cellular responses of Eriocheir sinensis gills to hydrogen peroxide (H₂O₂)-induced oxidative stress, integrating antioxidant defense, ion transport regulation, and stress-induced cell apoptosis and autophagy. Morphological alterations in the gill filaments were observed, characterized by septum degeneration, accumulation of haemolymph cells, and pronounced swelling. For antioxidant enzymes like catalase (CAT) and glutathione peroxidase (GPx), activities were enhanced, while superoxide dismutase (SOD) activity was reduced following 48 h of exposure. Overall, the total antioxidant capacity (T-AOC) showed a significant increase. The elevated concentrations of malondialdehyde (MDA) and H₂O₂ indicated oxidative stress. Ion transport genes displayed distinct transcription patterns: Na⁺-K⁺-2Cl⁻ co-transporter-1 (NKCC1), Na⁺/H⁺ exchanger 3 (NHE3), aquaporin 7 (AQP7), and chloride channel protein 2 (CLC2) were significantly upregulated; the α-subunit of Na⁺/K⁺-ATPase (NKAα) and carbonic anhydrase (CA) displayed an initial increase followed by decline; whereas vacuolar-type ATPase (VATP) consistently decreased, suggesting compensatory mechanisms to maintain osmotic balance. Concurrently, H₂O₂ triggered apoptosis (Bcl2, Caspase-3/8) and autophagy (beclin-1, ATG7), likely mediated by MAPK and AMPK signaling pathways. These findings reveal a coordinated yet adaptive response of crab gills to oxidative stress, providing new insights into the mechanistic basis of environmental stress tolerance in crustaceans. Full article

Temperature is one of the critical factors influencing the survival, growth, and reproduction of organisms. The molting and developmental mechanisms of crustaceans are highly sensitive to temperature, yet the regulatory mechanisms underlying their thermal adaptation remain unclear. In this work, transcriptome sequencing was performed to analyze the gene expression profiles of Eriocheir sinensis under normal temperature (22 °C) and high-temperature (27 °C and 32 °C) conditions. A total of 377 differentially expressed genes (DEGs) were identified, including 149 up-regulated and 227 down-regulated genes. Through Gene Ontology (GO) enrichment analysis of these DEGs, 11 significantly temperature-regulated signaling pathways were identified, including the estrogen and androgen receptor signaling pathways, and two neurotransmission signaling pathways. These findings suggest that temperature may influence sex regulation in E. sinensis, while the dopamine receptor and neuropeptide signaling pathways may play a role in its thermal adaptation. Further validation via RT-qPCR of DEGs involved in neurotransmission signaling pathways revealed that crustacean hyperglycemic hormone (CHH) and excitatory amino acid transporter 3 (EAA3) genes are likely involved in the thermal adaptation of E. sinensis. In addition, the hemolymph glucose levels associated with the elevated temperatures were detected and consistent variations between glucose levels and CHH expressions were found. This indicates that the eyestalk CHH is strongly correlated with the hemolymph glucose levels and likely mediates the response to temperature changes by regulating blood glucose in E. sinensis. The results of this study not only provide key molecular targets for elucidating the mechanisms by which temperature affects molting and development in E. sinensis, but also establish a theoretical foundation for further research into thermal adaptation strategies in crustaceans. Full article

The “milky disease” in Chinese mitten crabs (Eriocheir sinensis), caused by Metschnikowia bicuspidata, poses significant threats to aquaculture, though its pathogenic mechanisms remain poorly understood. This study employs transcriptomic sequencing to analyze gene expression changes in Metschnikowia bicuspidata under hemocyte challenge, iron overload (1 mmol/mL), and combined stress, with functional validation through Common in Fungal Extracellular Membrane (CFEMgene) overexpression strains. Key findings reveal that (1) hemocyte challenge activated base excision repair (−log₁₀[P] = 7.58) and ribosome biogenesis pathways, indicating fungal adaptation through DNA repair and enhanced protein synthesis to counter host immune attacks (e.g., ROS-mediated damage). (2) Iron overload induced glutathione metabolism and pentose phosphate pathway enrichment, demonstrating mitigation of ferroptosis through NADPH/GSH antioxidant systems and autophagy/proteasome coordination. (3) Under combined stress, ribosome biogenesis (−log₁₀[P] = 1.3) and non-homologous end-joining pathways coordinated DNA repair with stress protein synthesis, complemented by vacuolar V-ATPase-mediated iron compartmentalization. (4) CFEM genes showed significant upregulation under hemocyte stress, with overexpression strains exhibiting enhanced biofilm formation (35% increased MTT cytotoxicity) and infectivity (40% higher infection rate), confirming CFEM domains mediate pathogenesis through iron homeostasis and virulence factor production. This work elucidates how M. bicuspidata employs metabolic reprogramming, oxidative stress responses, and CFEM-mediated iron regulation to establish infection, providing critical insights for developing targeted control strategies against milky disease. Full article

The Chinese mitten crab (Eriocheir sinensis) industry is currently facing the challenges of origin fraud, as well as a lack of precision and interpretability of existing traceability methods. Here, we propose a high-precision origin traceability method based on a combination of stable isotope analysis and interpretable machine learning. We sampled Chinese mitten crabs from six origins representing diverse aquatic environments and farming practices, and analyzed their δ¹³C, δ¹⁵N, δ²H, and δ¹⁸O stable isotope compositions in different sexes and tissues (hepatopancreas, muscle, and gonad). By comparing the classification performance of Random Forest, XGBoost, and Logistic Regression models, we found that the Random Forest model outperformed the others, achieving high accuracy (91.3%) in distinguishing samples from different origins. Interpretation of the optimal Random Forest model, using SHAP (SHapley Additive exPlanations) analysis, identified δ²H in male muscle, δ¹⁵N in female hepatopancreas, and δ¹³C in female hepatopancreas as the most influential features for discriminating geographic origin. This analysis highlighted the crucial role of environmental factors, such as water source, diet, and trophic level, in origin discrimination and demonstrated that isotopic characteristics of different tissues provide unique discriminatory information. This study offers a novel paradigm for stable isotope traceability based on explainable machine learning, significantly enhancing the identification capability and reliability of Chinese mitten crab origin traceability, and holds significant implications for food safety assurance. Full article

The cultured habitat of Eriocheir sinensis is a crucial factor influencing its nutritional quality. Therefore, it is essential to clarify the differences in the nutritional quality of Eriocheir sinensis reared in different habitats. This study investigated and compared the nutritional value of three edible parts (the hepatopancreas, gonads, and muscles) of female Eriocheir sinensis from three different habitats in the lower reach of the Yangtze River, with a special emphasis on lipid compounds. In addition to tissue indices, proximate composition, energy content, lipid classes, and fatty acid profile, eight lipid quality indices were proposed to evaluate the lipid nutritional quality. The results indicated that the Eriocheir sinensis from the three different habitats were all in good developmental condition. No significant differences were observed for the hepatopancreas index (HIS), gonadosomatic index (GSI), and total edible yield (TEY) among the three habitats, except for muscle index (MI), which was significantly higher in the L-crabs and E-crabs compared to the P-crabs. The highest protein content was found in the gonads, while the hepatopancreas had the highest crude lipid content. Regarding lipid classes, triglycerides dominated the hepatopancreas, and phospholipids were predominant in muscles, whereas phospholipids and triglycerides were predominant in approximately equal amounts in the gonads. Taking eight lipid quality indices into account together, the three major edible tissues of Eriocheir sinensis from the estuarine habitat had the highest nutritional value, followed by the hepatopancreas from the pond habitat. The current research will provide basic nutritional data for consumers to purchase Eriocheir sinensis and establish the theoretical groundwork for paving new paths for improving the nutritional quality combined with habitat conditions in future studies. Full article

During the cultivation and circulation of Chinese mitten crab (Eriocheir sinensis), the difficulty in tracing geographic origin leads to quality uncertainty and market disorder. To address this challenge, this study proposes a two-stage origin traceability framework that integrates a lightweight object detector and a high-precision classifier. In the first stage, an improved YOLOv10n-based model is designed by incorporating omni-dimensional dynamic convolution, a SlimNeck structure, and a Lightweight Shared Convolutional Detection head, which effectively enhances the detection accuracy of crab targets under complex multi-scale environments while reducing computational cost. In the second stage, an Improved GoogleNet’s Inception Net for Crab is developed based on the Inception module, with further integration of Asymmetric Convolution Blocks and Squeeze and Excitation modules to improve the feature extraction and classification ability for regional origin. A comprehensive crab dataset is constructed, containing images from diverse farming sites, including variations in species, color, size, angle, and background conditions. Experimental results show that the proposed detector achieves an mAP50 of 99.5% and an mAP50-95 of 88.5%, while maintaining 309 FPS and reducing GFLOPs by 35.3%. Meanwhile, the classification model achieves high accuracy with only 17.4% and 40% of the parameters of VGG16 and AlexNet, respectively. In conclusion, the proposed method achieves an optimal accuracy-speed-complexity trade-off, enabling robust real-time traceability for aquaculture systems. Full article

During intensive aquaculture of Eriocheir sinensis (E. sinensis), wastewater containing feed additives, heavy metals, and antibiotics can cause water eutrophication and lead to the accumulation of complex pollutants in sediments. In this study, heavy metals and antibiotic resistance genes (ARGs) were analyzed for their distribution and accumulation patterns via ICP-OES and qPCR, and their correlations with bacterial communities in sediments from E. sinensis ponds were evaluated using co-occurrence network and redundancy analysis. Our results demonstrated that aquaculture activities significantly elevated the concentrations of heavy metals such as Cadmium (Cd) and Manganese (Mn) in the sediments, and Cd was identified as the dominant factor contributing to the increase in the potential ecological risk index (RI). The abundance of ARGs significantly increased, with sulfonamide resistance genes (sul1, sul2), β-lactam resistance genes (blaTEM), and integron-associated genes (intl1) showing the highest levels. Correlation and redundancy analyses showed that most ARGs were positively correlated with and linked to Proteobacteria, Bacteroidetes, and Dechloromonas as potential hosts. Positive correlations were generally observed among heavy metals, suggesting a common source, namely aquaculture wastewater, and some showed positive associations with Acidobacteria. This study provides a theoretical basis for further understanding the distribution, accumulation patterns, and coupling relationships of heavy metals and ARGs, as well as their relation and effects on bacterial communities in the sediment of E. sinensis ponds. Full article

The inclusion of suitable quantities of plant protein hydrolysates in feed enhances the growth performance of aquatic animals, a benefit closely linked to the bioactive peptides generated during plant protein hydrolysis. In our previous study, we developed a recombinant Bacillus subtilis expressing the P4’ peptide of cottonseed meal (P4’ peptide-bearing B. subtilis). We observed that the addition of this recombinant B. subtilis at a dose of 10⁹ CFU/kg to the diet of E. sinensis produced a significant growth-promoting effect. The mechanism underlying this growth-promoting effect remains unclear. This experiment aimed to investigate the effects of feed supplementation with P4’ peptide-bearing B. subtilis on the growth performance, digestive enzyme activities, serum protein content, antioxidant-related enzyme activities, and genes associated with the PI3K/AKT/TOR pathway in the Chinese mitten crab (Eriocheir sinensis). A total of 240 crabs (mean body weight: 0.85 ± 0.01) were randomly assigned to three groups and provided with three distinct diets: one without B. subtilis (CON), one containing 10⁹ CFU/kg of unmodified B. subtilis (BS9), and one with P4’ peptide-bearing B. subtilis (RBS9) at 10⁹ CFU/kg. After 8 weeks of feeding, the BS9 and RBS9 groups had significantly increased specific growth rate, average body weight, muscle crude protein content, hemolymph total protein/albumin/globulin levels, hepatopancreatic digestive enzyme (protease and amylase) activities, and tor expression in crabs compared to the CON group. Conversely, muscle water content, hepatopancreatic ROS levels, and 4ebp-1 expression were significantly reduced. Furthermore, mean body weight, protein retention, muscle crude fat content, total hemolymphatic protein, and globulin content, as well as the hepatopancreatic expression of pi3k, tor, and s6k1, were significantly higher in the RBS9 group compared to the BS9 group. In contrast, the hepatopancreatic ROS level exhibited a declining trend. The result demonstrated that compared to unmodified B. subtilis, incorporating 10⁹ CFU/kg P4’ peptide-bearing B. subtilis into the feed significantly enhanced the growth performance and protein deposition in E. sinensis. This enhanced effect coincided with the upregulation of key PI3K/AKT/TOR pathway genes (pi3k, tor, s6k1) and the downregulation of 4ebp-1 in the hepatopancreatic cells, indicating a potential role of this pathway in mediating the observed growth promotion. Full article

The Chinese mitten crab (Eriocheir sinensis) is a high-value seafood. Efficient quality-grading methods are needed to meet rapid increases in demand. The current grading system for crabs primarily relies on manual observations and weights; it is thus inefficient, requires large amounts of labor, is costly, and no longer meets the requirements for the market. Here, we employed computer vision techniques combined with deep learning modeling to efficiently quantify key physiological traits, such as sex identification, carapace dimensions (length and width), and fatness assessment for quality classification. To this end, a YOLOv5-seg integrated with an SE attention model was developed using 2282 RGB images and manual measurements of the physiological traits of 300 crabs. The RGB dataset was further augmented by rotating and resizing. The results revealed that the accuracy of sex recognition was 100%, and the mAP for carapace segmentation was 0.995, which was superior to YOLOv8-seg and other variants. In addition, we proposed an improved conditional factor K to evaluate the fatness of crabs and classify their quality based on fatness. The consistency between the grading method proposed in this article and manual grading was 100%. This study could aid in developing precise and non-destructive grading systems for the aquaculture and food industries. Full article

Hedgehog (HH) signaling plays important roles in the development of the nervous system (Sonic hedgehog), bone, cartilage (Indian Hedgehog) and testis (Desert Hedgehog). Research on HH and testes has mostly been conducted in HH-knockout mice and rats, etc. The relationship between HH and cellular junctions has mostly been found in the nervous system and intestine. However, few research studies concerning the link between HH signaling and cell junctions in testis function have been reported. We identified the members of HH signaling that are involved in Eriocheir sinensis testes: HH, Smoothen, Patched, Kif27 and Ci. HH has only one homolog in E. sinensis and is expressed in several types of germ cells in the testes. We found that Kif27 colocalized with Ci in the testes. The knockdown of HH induced enlarged interstitial spaces of the seminiferous tubules. A biotin–streptavidin immunofluorescence experiment indicated that the hemolymph–testis barrier (HTB) was disrupted. Western blot results showed that pinin, HH signaling and cell proliferation- and apoptosis-related protein levels were downregulated. Further immunofluorescent results showed the dislocation of several junction proteins, the abnormality of F-actin and the slowdown of germ cell proliferation and apoptosis. While β-catenin entered the spermatocyte nucleus, it did not activate Wnt-β-catenin signaling, which indicated that the disturbance of the cell cycle in germ cells was not caused by Wnt-β-catenin signaling. In summary, HH signaling plays some roles beyond our understanding in the regulation of the HTB and the germ cell cycle in E. sinensis testes. Full article

Fishery bycatch is a significant threat to biodiversity, with birds being frequent casualties. Current research mainly focuses on seabird bycatch in large-scale marine fisheries, while bird bycatch in inland freshwater areas remains poorly understood. Crayfish traps are extensively used in China’s freshwater environments, but their ecological impacts on birds are overlooked due to monitoring difficulties. Through iEcology approaches, we collected and analyzed 146 bird bycatch incidents in crayfish traps from Chinese social media platforms between September 2010 and December 2023. The results revealed 420 identified birds from 62 species (11 orders, 24 families), predominantly omnivorous and carnivorous, while 106 individuals could not be identified. Cases were concentrated in the middle and lower reaches of the Yangtze River, showing significant positive correlations with water area ratio and aquaculture production (p < 0.001). During fishing seasons, the number of cases, species, and individuals were significantly higher (p < 0.001), though mortality rates increased in off seasons. The middle and lower reaches of the Yangtze River are main production areas of red swamp crayfish (Procambarus clarkii) and Chinese mitten crab (Eriocheir sinensis), where intensive use of crayfish traps may increase bird bycatch risk. Despite existing regulations, systematic supervision is needed to minimize ecosystem impacts. Full article

Cu is a chemical contaminant that is toxic to aquatic animals at certain concentrations. The present study describes the gill transcriptome, proteome, and histology of the Chinese mitten crab (Eriocheir sinensis) subjected to copper stress. Female 14-month-old E. sinensis (n = 60) crabs (79.6 ± 4.8 g, body weight) were randomly divided into two groups and subjected to copper stress at concentrations of 0 μg/L (Blank group, GBL) and 50 μg/L (Copper group, GCP) for 96 h. In total, 278 upregulated and 189 downregulated differentially expressed genes (DEGs) were identified in the GBL and GCP groups. In addition, upregulated and downregulated differentially expressed proteins (DEPs) in the GBL and GCP groups were 260 and 308, respectively. An integrated analysis demonstrated that the three DEGs overlapped between the two omics approaches. Comparative omics analysis indicated that seven GO terms were significantly (p < 0.05) enriched by overlapping DEGs in the transcriptome and proteome. Further analysis revealed that only one overlapping DEG (stumps) was enriched in two common KEGG pathways, the PI3K-Akt and B cell receptor signaling pathways. Histological analyses showed that copper-stressed gills had collapsed lamellae with enlarged marginal vessels and shortened interlamellar spaces due to the disruption of the pillar cells and cuticles. These results demonstrate the variations in copper-stressed gills and will be helpful for better understanding the mechanisms of copper toxicity in E. sinensis. Full article

The Chinese mitten crab, Eriocheir sinensis, is a water-dwelling crustacean that is widely distributed in northern hemisphere water systems. Body size is one of the crucial indicators determining the economic value of E. sinensis. However, research on the genetic basis and regulatory mechanisms of body size in this species is limited, with only a few relevant genes reported. Therefore, it is imperative to investigate the regulatory pathways associated with its growth. This study first utilized transcriptomic profiling and metabolomic sequencing to construct gene expression profiles and metabolite profiles of E. sinensis of different body sizes. Subsequently, through integrated omics analysis, the key genes and regulatory pathways involved in controlling the growth and size of crabs were preliminarily identified. This study found that larger female crabs exhibited significantly enhanced digestive functions, primarily reflected in the upregulation of trypsin-1 expression, suggesting its potentially pivotal role in regulating the growth and development of crabs. Interestingly, a variety of tissue-specific proteins such as APOLPP, RICK A, AGMO, and NEPHRIN, as well as REXO1L1P and ZCCHC24, indirectly influence the growth and development of crabs through their respective functional pathways. In addition, the key KEGG pathways, such as ECM–receptor interaction, cell adhesion, and the PI3K-Akt signaling pathway, were revealed to play central roles in the growth regulation of E. sinensis. These findings expand our understanding of the growth regulation mechanisms in crustaceans and offer potential molecular targets for body-size improvement in aquaculture. Full article

This study used geometric morphometrics to investigate the carapace features of Chinese mitten crabs (Eriocheir sinensis) from non-traditional/emerging origins (Zhenlai County and Bosten Lake) and identify differences in features relative to crabs from traditional origins (Yangcheng Lake). Thirty-five landmark data points on the crab carapace were extracted based on the geometric morphometrics landmark point approach and standardized to obtain the mean shape of the crabs from the three origins. The carapace morphologies of crabs from the three different origins varied. Compared to the average morphology, the first lateral tooth of the carapace of the Zhenlai crab was shorter, and the M pattern was enlarged in males, whereas the first and second lateral teeth of the crabs from the other two origins were longer, and the M pattern was reduced. In female crabs, distinct morphological variations were observed across regions. In Zhenlai crabs, the lateral teeth were shorter, and the M pattern was enlarged. In Bosten crabs, the frontal tooth was shorter, the first and second lateral teeth were longer, and the posterior carapace margin was narrowed. In Yangcheng Lake crabs, the frontal and third lateral teeth were elongated, and the M pattern was narrowed. The discrimination accuracy of individual female and male crabs from different origins reached 100%. The results confirm that the carapace geometric morphometric method represents a convenient and non-lethal method of tracing E. sinensis origins in fine-scale production areas. Thus, this study provides guidance on developing a characteristic industrial chain for aquatic products of emerging origins, which may help to promote the sustainable development of the aquaculture industry in associated areas. Full article