Search Results (83)

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

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

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

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

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

The intestine is an important immune organ of aquatic animals and it plays an essential role in maintaining body health and anti-oxidative stress. To investigate the toxic effects of deltamethrin in intestinal tissue of Chinese mitten crabs (Eriocheir sinensis), 120 healthy crabs were randomly divided into two experimental groups (blank control group and deltamethrin-treated group), with three replicates in each group. After being treated with deltamethrin for 24 h, 48 h, 72 h, and 96 h, intestinal tissues were collected aseptically to assess the effects of deltamethrin on oxidative stress, immunity, apoptosis-related genes, and the structure of microflora in intestinal tissues. Additionally, correlations between gut microbiota composition and intestinal tissue damage-associated genes were analyzed. The results demonstrated that prolonged exposure to deltamethrin induced oxidative stress damage in intestinal tissue. Compared with the blank control group, the expression of autophagy-related genes B-cell lymphoma/Leukemia-2 (bcl-2), c-Jun N-terminal kinase (jnk), Microtuble-associated protein light chain 3 (lc3c), Cysteine-dependent Aspartate-specific Protease 8 (caspase 8), BECN1(beclin1), oxidative stress damage-related genes MAS1 proto-oncogene (mas), Glutathione Peroxidase (gpx), kelch-like ECH-associated protein 1 (keap1), Sequestosome 1 (p62), Interleukin-6 (il-6), and immune-related genes Lipopolysaccharide-induced TNF-alpha Factor (litaf), Heat shock protein 90 (hsp90) and prophenoloxidase (propo) in the deltamethrin treatment group were significantly up-regulated at 96 h (p < 0.05 or p < 0.01). Additionally, 16S rRNA sequencing showed that the diversity of intestinal flora in the deltamethrin-treated group was significantly higher compared with the blank control group (p < 0.01). Analysis of the differences in the composition of intestinal flora at the genus level showed that the relative abundance of Candidatus Bacilloplasma in the deltamethrin treatment group was significantly lower than that in the blank control group (p < 0.01). In contrast, the relative abundances of Flavobacterium, Lachnospiraceae_NK4A136_group, Acinetobacter, Chryseobacterium, Lacihabitans, Taibaiella, Hydrogenophaga, Acidovorax, and Undibacterium were significantly higher than those in the blank control group (p < 0.05 or p < 0.01). Pearson correlation analysis revealed that Malaciobacter, Shewanella, and Prevotella exhibited significant positive correlations with gene indicators (jnk, gpx, lc3c, litaf, hsp90), while Dysgonomonas, Vibrio, and Flavobacterium demonstrated significant negative correlations with multiple gene indicators (caspase 8, p62, il-16, keap1, jnk, etc). These results demonstrate that deltamethrin significantly impacts the gut microbiota, immune function, and antioxidant capacity of E. sinensis. The changes in gut microbiota have correlations with the biomarkers of intestinal tissue injury genes, indicating that gut microbiota plays a crucial role in deltamethrin-induced intestinal tissue damage. These insights contribute to a better understanding of the ecological risks associated with deltamethrin exposure in aquatic organisms. Full article

Housefly maggot larvae (HML) have been identified as a potential alternative animal diet for the fattening process of the Chinese mitten crab (Eriocheir sinensis). However, the feasibility and potential impacts of HML supplementation require further investigation. The present study evaluated the effects of dietary HML on the growth indices, nutrient compositions, antioxidant activity, and texture profiles of edible tissues of E. sinensis. The results showed that dietary HML supplementation effectively improved the hepatic steatosis index of both genders and sweet amino acid content of edible tissues (except for male gonad) (p < 0.05). Additionally, dietary HML significantly increased the total antioxidant capacity in the gonad and female muscle (p < 0.05). For the textural properties, HML feeding significantly improved the adhesiveness in the male muscle, and the cohesiveness, chewiness, and resilience in the female muscle (p < 0.05). Furthermore, HML feeding significantly decreased the levels of the equivalent umami concentration of the male gonad, male muscle, and hepatopancreas (p < 0.05). Conversely, HML feeding significantly increased the sweetness value in the muscle, hepatopancreas, and female gonad (p < 0.05). Our findings indicate that HML could serve as a viable alternative feed for fattening to improve the edible yield and change the flavor characteristics in E. sinensis. Full article

DNA methylation is a form of epigenetic regulation that plays an important role in regulating gene expression of organisms. However, the DNA methylation pattern of intersex crabs has not yet been clarified. In order to reveal the DNA methylation in intersex Eriocheir sinensis, this study investigated the genome-wide DNA methylation profiles of female, male, and intersex individuals. The similar results across samples showed that the levels of cytosine methylation in the CG context were significantly higher than that in the CHG and CHH contexts. The methylation levels in the promoter region were higher than those in other functional element regions. We screened 149 differentially methylated genes (DMGs) in the promoter region between female and intersex crabs and 110 DMGs between male and intersex crabs. Three core gene networks were found in a comparison group of female and intersex crabs that involved heat shock proteins, ribosomes, and metabolism pathways; two core gene networks were found in the comparison group of male and intersex crabs that involved ribosomes and metabolism pathways. The six confirmed genes of Hsc70, Hsp90, Rpl18, Acsl1, Yip2, and Rpl7 had lower methylation levels in the promoter region of intersex crabs than that of female and male crabs. However, six genes showed higher expression in intersex crabs than in female and male crabs. Our results reveal that DNA methylation is involved in the formation and maintenance of life activities of intersex crabs through the regulation of gene expression, enriching the DNA methylation library of the whole genome of E. sinensis and providing new insights for a better understanding of the epigenetic regulation of the formation of intersex E. sinensis. Full article

The carapace size of the Chinese mitten crab (Eriocheir sinensis) is a vital indicator for assessing the growth performance of crabs. However, measuring the carapace sizes of Chinese mitten crabs remains challenging due to environmental complexity, species-specific behavioral patterns, and the current limitations of data acquisition methods characterized by labor-intensive manual measurements and subjective empirical judgments. Our study proposes an automated carapace dimension-measuring method integrating enhanced computer vision techniques to address the above challenges. Specifically, we used the YOLOv8 algorithm combined with the pose keypoint detection algorithm to process Chinese mitten crab images to acquire carapace sizes. We redesigned the YOLOv8l-pose architecture by incorporating Swin Transformer as the backbone network to improve feature representation for multikeypoint detection on crab carapaces, significantly enhancing global contextual feature extraction capabilities. Furthermore, we refined the loss function to model spatial correlations between keypoint locations accurately and thus improve detection accuracy for dorsal carapace dimension key points in Chinese mitten crabs. Our system enabled noncontact size measurement to leverage the proportional relationship between precalibrated background markers and detected carapace keypoints. Experimental results demonstrated that our enhanced model achieved a mean average precision of 95.88%, representing a 2.61% improvement over the baseline. The overall object keypoint similarity reached 91.32%, with maximum and mean dimensional measurement errors of 4.8% and 2.34%, respectively, validating our method’s reliability for aquaculture applications. Full article

This research proposes using a neural network to detect and identify the landmark points of the carapace of the Chinese mitten crab, with the aim of improving efficiency in observation, measurement, and statistics in breeding and sales. A 37-point localization framework was developed for the carapace, with the dataset augmented through random distortions, rotations, and occlusions to enhance generalization capability. Three types of convolutional neural network models were used to compare detection accuracy, generalization ability, and model power consumption, with different loss functions compared. The results showed that the Convolutional Neural Network (CNN) model based on the Differentiable Spatial to Numerical Transform (DSNT) module had the highest R² value of 0.9906 on the test set, followed by the CNN model based on the Gaussian heatmap at 0.9846. The DSNT-based CNN model exhibited optimal computational efficiency, particularly in power consumption metrics. This research demonstrates that the CNN model based on the DSNT module has great potential in detecting landmark points for the Chinese mitten crab, reducing manual workload in breeding observation and quality inspection, and improving efficiency. Full article