Search Results (120)

Crayfish with cyan soft-carapace and red hard-carapace differ considerably in market value. To investigate the causes underlying this difference in shell color, we selected 120 healthy Procambarus clarkii of similar size (9–10 cm), equally divided by shell color and sex. Muscle quality, pigment deposition, and DGAT2 mRNA expression were compared between the two shell-color types. The results showed that: (1) Muscle hardness was significantly higher in red hard-carapace crayfish than in cyan soft-carapace crayfish (p < 0.05), whereas no significant difference in muscle elasticity was observed among groups (p > 0.05). (2) A significant interaction between shell color and sex influenced crude fat and ash content (p < 0.05). Crude fat content was higher in red hard-carapace crayfish, and ash content was highest in male red hard-carapace crayfish, significantly exceeding that in male cyan soft-carapace crayfish (p < 0.05). (3) Moisture and crude protein content were not significantly affected by the interaction between shell color and sex (p > 0.05), with no notable differences across groups. (4) The contents of astaxanthin, lutein, and β-carotene in the shell were significantly influenced by the interaction between sex and shell color (p < 0.05). Astaxanthin was lowest in female cyan soft-carapace crayfish, and lutein was highest in male red hard-carapace crayfish, and β-carotene showed no significant differences. (5) DGAT2 mRNA expression was highest in hepatic tissue across all groups (p < 0.05). In gonads, expression was higher in ovaries of cyan soft-carapace crayfish and in testes of red hard-carapace crayfish (p < 0.05). (6) DGAT2 mRNA expression in the inner membrane, muscle, and intestine was significantly affected by the interaction between shell color and sex (p < 0.05), with specific expression patterns varying among tissues and groups. These findings indicate that shell color and sex interact to influence nutritional composition, carotenoid profile, and gene expression, providing insights into the mechanisms of body color formation and its physiological correlates. Full article

Water temperature fluctuations directly affect the feeding, reproduction, and survival of aquatic animals. Understanding the molecular networks that regulate temperature responses is therefore critical for selective breeding of thermotolerant strains. In this study, we first assessed the thermotolerant performances of two Procambarus clarkii populations (selected and normal cultured populations) with contrasting thermal endurance capacities. Temperature stress challenges showed that the selected population exhibited great endurance capacities to both heat and cold stresses. Further comparative transcriptomic analysis showed that cold stress mainly upregulated energy metabolism genes, whereas heat stress affected oxidative stress and membrane-related genes in both populations. However, we found that immune-related pathway genes were significantly downregulated in the selected population in response to heat challenge. Furthermore, heat shock proteins (HSPs), E3 ubiquitination, and autophagy-related genes showed contrasting expression patterns between the thermotolerant and normal cultured populations, suggesting that transcriptional regulations of these signaling pathways may contribute to thermal tolerance. Collectively, these results provide a reference for breeding thermotolerant P. clarkii strains and supporting the sustainable development of the aquaculture industry. Full article

Emerging contaminants constitute a growing pressure on river ecosystems due to their persistence, chemical diversity, and ecotoxicological effects. The objective of this study was to analyze the presence of these compounds in muscle tissue across a range of aquatic species, including benthic fish (Gobio lozanoi, Cobitis sp.), nektonic species (Salmo trutta, Lepomis gibbosus), diadromous species (Anguilla anguilla, Petromyzon marinus, in the larval stage), generalist species (Pseudochondrostoma duriense), and crustaceans (Procambarus clarkii). Concentrations were determined using LC-MS/MS, grouping the compounds into different chemical families (e.g., pharmaceuticals, personal care products, industrial compounds, and other emerging contaminants). The results showed significant differences both among species and among compound families. At the interspecific level, Petromyzon marinus (larvae) exhibited the highest total concentrations, followed by Salmo trutta and benthic species such as Gobio lozanoi and Cobitis sp. Intermediate values were observed in Pseudochondrostoma duriense and Lepomis gibbosus, while Anguilla anguilla showed moderate levels. Procambarus clarkii displayed notable accumulation, especially of sediment-associated compounds. Analysis by compound families revealed distinct patterns: pharmaceutical and personal care compounds showed a relatively homogeneous distribution among species, whereas more hydrophobic and industrial compounds tended to accumulate in species with higher lipid content or greater benthic exposure. In particular, benthic species (lamprey larvae, gudgeon, spined loach, and crayfish) showed higher accumulation of sediment-associated compounds, confirming their role as contaminant reservoirs. Lamprey larvae, which exhibit filter-feeding behavior and remain buried in fine sediments for several years, showed high accumulation of multiple contaminant families, highlighting the importance of this life stage as an indicator of environmental contamination. The results demonstrate the coexistence of different accumulation mechanisms: (i) direct exposure to sediment, (ii) trophic biomagnification, and (iii) accumulation linked to the physicochemical properties of the compounds. This combined approach by species and contaminant families allows for a more comprehensive assessment of the ecological status of the system. Finally, the relevance of including multiple taxonomic groups and life cycle stages in monitoring programs is emphasized, especially in vulnerable species such as Petromyzon marinus. Full article

Copper (Cu) contamination in aquatic environments induces oxidative stress and structural damage to crustaceans. This study investigated the protective effects and associated mechanisms of exogenous melatonin (MT) against Cu-induced toxicity in Procambarus clarkii using integrated physiological, histopathological, proteomic, and molecular analyses. MT supplementation enhanced antioxidant defense by elevating SOD, CAT, and T-AOC activities, while reducing MDA accumulation, with peak effects observed at 24 h. MT also restored endogenous melatonin levels and regulated phosphatase activity, thereby maintaining immune and metabolic homeostasis. Histopathology showed reduced hepatopancreatic damage, characterized by reduced epithelial vacuolization and preserved basement membrane integrity. Proteomics suggested that MT modulates a multilayered network associated with detoxification, redox balance, and cellular homeostasis. Pathway enrichment showed that Cu exposure dysregulated proteins involved in mitochondrial biogenesis, ABC transporters, membrane trafficking, and apoptosis. MT administration partially counteracted these alterations and was associated with the regulation of glutathione metabolism, as well as reduced enrichment of lysosome- and apoptosis-related pathways. Quantitative RT-PCR results were consistent with the proteomic data. Overall, MT partially alleviated Cu-induced toxicity and was associated with enhanced antioxidant defense, improved cellular homeostasis, and metabolic regulation. Our study provides new molecular insights and suggests its potential application for mitigating metal toxicity in aquaculture. Full article

Procambarus clarkii, a prominent aquaculture species, are mainly cultured through conventional modes: pond culture and rice–crayfish co-culture. In the present study, we proposed a novel industrial recirculating aquaculture system (RAS) for the culture of Procambarus clarkii. The nutritional quality of Procambarus clarkii under different culture modes was evaluated. The results indicated that industrial culture achieved optimal amino acid profiles and a higher level of flavor amino acids. Crayfish cultured in RAS also showed more balanced textures with moderate hardness and good springiness. Moreover, distinct crayfish metabolites were identified across different culture modes. The main differential metabolites include amino acids, peptides (and their analogs), organic acids and acyl carnitines. Industrial culture prioritized metabolites linked to flavor and rapid growth, while other culture modes enriched metabolites associated with ecological resilience and nutritional diversity. Overall, industrial culture displays great potential in improving the nutritional quality and regulating metabolic characteristics of red swamp crayfish. Full article

This study investigated the diurnal dynamics of the gut microbiota and core clock gene expression in the red swamp crayfish, Procambarus clarkii. Samples were collected at four time points (06:00, 12:00, 18:00, and 24:00) over a 24 h period. Gut microbiota characteristics were analyzed using 16S rRNA gene sequencing, while quantitative real-time polymerase chain reaction (qPCR) was used to examine the expression patterns of core clock genes, including Cycle (Cyc), Clock (Clk), and cryptochrome type 1 (Cry1), in the hepatopancreas and eyestalk. The results showed that Kruskal–Wallis tests for α-diversity indices (Shannon, Simpson, ACE, Chao1) and PERMANOVA for β-diversity (Bray–Curtis) of the gut microbiota revealed no significant diurnal variation across the four time points (all p > 0.05). Firmicutes, Proteobacteria, and Bacteroidota were the dominant phyla, with norank_o_RsaHf231, ZOR0006, and Bacteroides as the predominant genera. Although the overall microbial structure remained stable, several taxa, including unclassified_c_Bacilli, unclassified_f_Caulobacteraceae, Gemmobacter, unclassified_f_Rhodobacteraceae, Allorhizobium–Neorhizobium–Pararhizobium–Rhizobium, Lactobacillus, and unclassified_f_Vibrionaceae exhibited time-dependent fluctuations. In addition, the relative mRNA expression levels of Cyc, Clk, and Cry1 in the hepatopancreas and eyestalk showed significant diurnal variation. This study reveals the diurnal dynamic characteristics of the gut microbiota and core clock gene expression in P. clarkii, providing a foundation for further investigation of diurnal regulatory mechanisms and physiological adaptations. Full article

The purpose of this study was to investigate the effects of different feeding-promoting substances added to high plant protein diets on the growth, antioxidant, serum biochemical parameters, immune, and feeding-related genes of Procambarus clarkii. A total of 450 crayfish (3.94 ± 0.03 g) were selected and randomly divided into six groups, with each group consisting of three replicates and 25 crayfish per replicate. The crayfish were fed a basal diet without attractant (control group) and five experimental diets supplemented with 0.4% betaine (BET), 0.4% trimetlylamine oxide (TMAO), 0.4% squid paste (SQU), 0.4% dimethyl-β-propiothetin (DMPT), and 0.4% taurine (TAU). The feeding trial lasted for 6 weeks. The results showed that compared with the control group, the BET, SQU, DMPT, and TAU groups significantly improved in growth performance, weight gain rate, and specific growth rate of crayfish. Compared with the control group, the BET, MTAO, and SQU groups significantly increased hepatopancreas SOD, CAT, and T-AOC. Histological results showed that compared with the control group, all feeding attractant groups could alleviate hepatopancreas tissue damage. Compared with the control group, the TMAO and SQU groups significantly reduced serum GLU content as well as ACP and AKP activities. The results of gene quantitative analysis showed that, compared with the control, TMAO significantly upregulated the expression of tlr, nf-kb, propo, hsp70, and tgf-β, while TAU significantly increased the expression of hsp70, hsp90 and nf-kb genes. Compared with the control group, the expression levels of tor, 4ebp1, and s6k1 in the TMAO group were significantly increased. Compared with the control group, the expression levels of leptin and npy genes in the DMPT group were significantly increased. In summary, the addition of attractants to high plant protein feed has the effects of promoting growth, enhancing antioxidant capacity, improving digestive enzyme activity, alleviating hepatopancreas injury, improving immunity, and promoting feeding. Full article

This study investigated whether these contrasting environments are associated with the development of coherent, organism-wide phenotypic–physiological syndromes reflecting a fundamental life-history trade-off. A controlled 60-day trial was conducted comparing crayfish from a high-input pond system (fed to satiation) and a low-input rice paddy system (primarily natural diet). Pond crayfish were fed a commercial formulated feed twice daily to satiation (approximately 3% of biomass per day). Rice paddy crayfish primarily consumed natural food webs and received a once-daily supplement of 30% of the pond feed amount (approximately 0.9% of biomass per day). Results revealed two distinct syndromes. Pond-cultured crayfish exhibited a growth-oriented syndrome: they were 33% heavier with a compact, volumetrically enhanced body shape, coupled with elevated lipid-anabolic enzyme activities (lipase and ACC), higher hemolymph protein and cholesterol concentrations, but also significantly increased levels of a stress-related endocrine factor (cortisol-like immunoreactivity) and oxidative damage (MDA). Conversely, rice paddy-cultured crayfish displayed a stress-resistance-oriented syndrome: a streamlined, deeper-abdomen morphology, fortified antioxidant (SOD, CAT, and GST) and immune (lysozyme and phenoloxidase) capacities, enhanced carbohydrate digestion (amylase), and lower systemic stress. Transcriptomic analysis showed that the hepatopancreas of paddy-cultured crayfish was enriched in pathways related to lipid metabolism, detoxification, and endocrine regulation, notably with upregulation of the SULT1E1 gene. Our findings demonstrate that the distinct environmental and nutritional conditions of each aquaculture system are linked to specific multi-level adaptation syndromes, presenting a clear trade-off between rapid biomass production and systemic stress resistance (within the 60-day trial period), providing a mechanistic basis for optimizing sustainable practices: integrated systems enhance stock robustness, while intensive systems require strategies to mitigate physiological load. Full article

Acute heat stress frequently causes mass mortality in farmed red swamp crayfish (Procambarus clarkii), yet the mechanisms underlying immune collapse remain poorly understood. We established an acute heat stress model (37 °C, 6 h) and performed an integrative analysis combining hemocyte profiling, redox and immune assays, RNA-seq, and qRT-PCR. Heat stress significantly increased mortality and disrupted the hemocyte system, with a ~25% reduction in total hemocyte count and a selective decline in granular cells. This was associated with severe redox imbalance, evidenced by ROS/H₂O₂ accumulation, suppressed SOD and CAT activities, and lipid peroxidation damage. Transcriptomic analysis revealed 1446 differentially expressed genes, indicating concurrent activation of ER stress and autophagy alongside suppression of energy metabolism. Key gene validation confirmed upregulation of pro-apoptotic factors (CASP3, P53) and ER stress markers (GRP78, XBP1), consistent with hemocyte depletion. These findings provide multi-level evidence that acute heat stress triggers a redox crisis (“oxidative burst–defense suppression”), which in turn activates ER stress and apoptosis, leading to selective loss of granular cells and systemic immune compromise. This study establishes a mechanistic framework for understanding heat-induced mortality in crustaceans and offers a theoretical basis for developing targeted interventions to enhance thermal resilience in crayfish aquaculture. Full article

Background/Objectives: Low-fishmeal diets are widely adopted to improve sustainability in shrimp aquaculture, yet reduced palatability and metabolic stress frequently suppress feed intake and growth. We evaluated whether a crayfish (Procambarus clarkii) by-product protein hydrolysate (CBPH) could mitigate low-fishmeal-induced performance losses by modulating feeding-related metabolic signaling and gut microbiota features in Pacific white shrimp (Litopenaeus vannamei). Methods: In an 8-week feeding trial, 360 juveniles (initial body weight 0.46 g) were assigned to three diets (four replicates per diet): a commercial control (CON), a low-fishmeal diet (LFM), and LFM supplemented with 2% CBPH (CBPH). Growth, feed utilization, whole-body composition, hemolymph biochemical indices (TP, TG, GLU, AST, ALT), intestinal appetite-related gene expression (5-HTR, CART, CCK1R, D2-like, NPY), and intestinal microbiota profiles (full-length 16S rRNA sequencing, V1–V9, PacBio) were assessed. Results: Compared with the LFM group, CBPH supplementation increased feed intake and improved feed conversion, restoring final body weight and growth rates to levels comparable to CON. CBPH also alleviated low-fishmeal-associated metabolic stress, including reduced AST and ALT activities and lower glucose levels. The LFM diet induced upregulation of anorexigenic genes (5-HTR, CART, D2-like) and downregulation of NPY in the shrimp intestine, whereas CBPH supplementation reversed these transcriptional changes. In addition, microbiota richness indices (ACE and Chao1) were elevated by CBPH relative to LFM, accompanied by compositional shifts at the phylum and genus levels. Conclusions: CBPH effectively alleviated low-fishmeal-induced reductions in feeding and growth, accompanied by coordinated changes in feeding-related gene expression, systemic biochemical markers, and gut microbiota composition, supporting its potential as a functional ingredient to stabilize metabolic responses in low-fishmeal shrimp feeds. Full article

Soil degradation poses a serious threat to the sustainability of global agricultural development, endangering the foundation and environment of human survival. Therefore, elucidating the effects of different agricultural production patterns on the quality and health of paddy soils is of great significance. To investigate the impact of the integrated rice-red swamp crayfish farming on paddy soil health, this paper systematically analyzed the differences in 19 soil physicochemical indicators and bacterial and eukaryotic microbial communities between the traditional rice monoculture (TRM) and integrated rice-red swamp crayfish (Procambarus clarkii) farming (IRPF), and it features a comprehensive quantitative assessment of paddy soil health status through Principal Component Analysis based on a minimum dataset. The experimental results showed that IRPF significantly increased the soil aggregate mean weight diameter, total phosphorus, available potassium, cation exchange capacity, pH, available zinc, and available silicon contents. Meanwhile, IRPF exerted marked effects on the beta diversity and composition of both bacterial and eukaryotic microbial communities, markedly enhancing the relative abundances of Bacillariophyta and Chlorophyta in the paddy soil. The integrated analysis of 19 soil physicochemical indicators along with bacterial and eukaryotic microbial community parameters revealed that the Soil Health Index under IRPF was obviously higher than that under the rice monoculture. In conclusion, the integrated rice-red swamp crayfish farming system markedly impacted the soil fertility, effectively improved soil aggregate structure and enhanced the overall paddy soil health status, representing a promising and sustainable agricultural production pattern within a single production cycle. Full article

This study aimed to investigate the effects of dietary tryptophan (Trp) on growth performance and muscle quality of Procambarus clarkii. Six experimental diets with graded Trp concentrations (0.05%, 0.13%, 0.29%, 0.43%, 0.56%, 0.69%; designated Trp0.05 to Trp0.69) were fed to crayfish for 8 weeks. Growth parameters, muscle proximate composition, texture, histology, related gene expression, and intestinal microbiota were measured. Compared with the Trp0.05 group, the Trp0.43 group significantly increased FW, WGR, SGR, and muscle crude protein content, while decreasing FCR. It also improved muscle texture (hardness, springiness, cohesiveness, gumminess, chewiness), increased muscle fiber diameter, and reduced fiber density and the proportion of fibers < 30 μm. Additionally, the Trp0.43 group upregulated mRNA expression of MEF2A, MEF2B, MLC1, MyHC, mTOR, S6K1, AKT, LARP6, Col1α1, Col1α2, TGF-β1, and Smad, and downregulated MSTN, 4EBP1, FOXO, and LC3. It reduced Proteobacteria and Shewanella abundance, and increased Bacteroidota and Firmicutes. In conclusion, appropriate dietary Trp improves P. clarkii growth, muscle quality, and intestinal microbiota. Based on quadratic regression analysis of WGR and SGR, the dietary Trp requirement of P. clarkii was estimated to be 0.39%, corresponding to 1.22% of feed protein. Full article

The molting of crustaceans is accompanied by exoskeleton reconstruction. To reveal the molecular regulation mechanism of exoskeleton remodeling, the transcriptomic profiles of the exoskeleton across the entire molting process in the red swamp crayfish Procambarus clarkii were investigated by RNA sequencing, yielding a total of 7671 differentially expressed genes (DEGs) across five different molting stages. Notably, the key DEGs were those related to cuticular exoskeleton synthesis (cuticular proteins), degradation (chitinase 2, chitinase 10) and hardening (chitin deacetylase 1), and their expression abundance varied by 10-fold or greater across the molting cycle. Analysis of Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) showed that significantly enriched pathways included the structural constituents of the cuticle, structural molecule activity, chitin binding of chitin metabolism, and hormone biosynthesis. The expression profiles of nine selected molting-related DEGs were further validated via real-time RT-PCR assays. The acquired unique temporal expression patterns involved in exoskeleton remodeling provide a preliminary insight into the regulation of gene expression during the molting cycle in the red swamp crayfish. Full article

Molting determines survival and growth in cultured crustaceans, yet its specific regulatory mechanisms remain complex. This study integrated transcriptomics and microbiome analyses to elucidate molting regulation in crayfish (Procambarus clarkii). Crayfish were injected with 20-hydroxyecdysone (20E) at 20 and 250 ng/g to simulate early premolt and middle premolt, respectively. The comprehensive upregulation of nuclear receptor family genes confirmed the reliability of the in vivo 20E injection simulation. The results showed that 20 ng/g 20E stimulation induced 13,253 unique DEGs in the epidermis, mainly enriched in protein catabolism (promoting proteolysis to degrade the old exoskeleton), and induced 137 unique DEGs in hemocytes, mainly linked to ribosomal biosynthesis, while the 250 ng/g group showed 2395 unique DEGs in the epidermis, enriched in metabolic processes and biosynthetic processes (supporting the biosynthesis of the new stratum corneum), and 99 unique DEGs in hemocytes enriched in mitochondrial pathways, concomitantly enhancing energy metabolism and antioxidant defense capabilities. Notably, 20E upregulation potentially leads to the dysbiosis of pathogens, specifically Escherichia-Shigella and Vibrio. This study elucidates key biological events in the early and middle premolt of crayfish, clarifies tissue-specific regulatory mechanisms during premolt, and provides molecular-level insights into the growth regulatory network of crustaceans. Full article

The Pantanos de Villa wetland, a protected Ramsar site in Lima, Peru, faces significant pressure from invasive species and urban pollution. This study provides a comprehensive evaluation of microhabitat use and trace-element bioaccumulation in the invasive crayfish Procambarus clarkii (Girard, 1852). We analyzed the physicochemical parameters of the microhabitat and measured the concentrations of macroelements (Na, Mg, P), trace metals (Cu, Zn, Al, Ni, Ti, Pb), and a metalloid (B) in water, sediment, and crayfish tissues (gill, hepatopancreas, and muscle) using ICP-OES. Additionally, we examined the growth pattern of P. clarkii through its length–weight relationships. A total of 171 individuals were recorded: 99 males and 72 females. Males were longer (13–15 cm), while females were heavier (18–21 g). Additionally, a positive correlation was observed in females between the size and weight of the hepatopancreas and abdominal muscle, whereas no significant link was found in males. Sediments had higher levels of the evaluated chemical elements, with Cu (28.26 mg kg⁻¹) and Zn (66.88 mg kg⁻¹) exceeding international quality guidelines, indicating a possible ecotoxicological risk. The significant negative correlation between dissolved oxygen and the abundance of P. clarkii suggests that higher D.O. is associated with less bioturbation and more predators, making the microhabitat less suitable for juveniles. We conclude that P. clarkii serves as an essential bioindicator and potential vector for the relocation of the trace in an urban wetland, highlighting the need for integrated management strategies to reduce the ecological impacts of this invasive species. Full article