Search Results (168)

Temperature is a critical abiotic factor regulating the physiology, growth, and reproduction of ectothermic aquatic animals. In China, the rapid expansion of the red swamp crayfish Procambarus clarkii) industry faces significant challenges due to seasonal temperature fluctuations (optimal growth at 20–25 °C and reproduction favored at 18–22 °C). This review focuses specifically on TRP channels, particularly TRPA1 as a key thermosensor in crayfish, and on downstream signaling pathways involving heat shock proteins (HSPs) and antioxidant defenses. We further link these biological mechanisms to aquaculture applications by evaluating best management practices for mitigating thermal stress, including integrated rice–crayfish co-culture, recirculating aquaculture systems (RAS), molecular marker-assisted breeding for thermal tolerance, and nutritional modulation (e.g., probiotics and immunostimulants). By maintaining thermal stability within the optimal range and directly enhancing physiological resilience through genetic and nutritional interventions, these practices provide a foundation for more sustainable and climate-resilient crayfish aquaculture. Full article

Aquaculture faces environmental challenges from sediment contamination by potentially toxic elements. This study investigated how aquaculture patterns and seasons jointly affect the distribution and ecological risks of these potentially toxic elements in sediments. By analyzing and comparing sediment samples from different aquaculture systems across seasons, we found that Mn (mean = 435.42 mg/kg) was the most abundant, followed by Zn (mean = 172.69 mg/kg), Cr (mean = 106.79 mg/kg), and Cu (mean = 63.44 mg/kg). Aquaculture patterns were the primary factor determining the composition of potentially toxic elements, followed by season. Fish farming tended to promote their accumulation in sediments, whereas the rice–crayfish co-culture model effectively reduced the enrichment of potentially toxic elements and their associated ecological risks. Therefore, optimizing aquaculture practices proves more effective in controlling these risks than managing seasonal variations. Moreover, total phosphorus was identified as a key driver of potentially toxic element accumulation in sediments. The results from the rice–crayfish co-culture system indicate that enhanced phosphorus management is crucial for mitigating such risks. Accordingly, it is necessary to develop systematic monitoring and integrated remediation strategies focused on priority metals and their main drivers. Full article

Smallholder rice farmers in sub-Saharan Africa face persistent livelihood challenges due to declining returns from monocropping, limited diversification opportunities, and vulnerability to climate and market shocks. This study integrated the Drivers–Pressures–State–Impact–Response (DPSIR) framework with the sustainable livelihood approach to evaluate how the transition from rice monocropping to integrated rice–fish farming influences productivity, profitability, and household welfare in Nigeria’s leading rice-producing region. Using a mixed-methods, three-year panel (2021–2023) of 228 households across three communities in Kebbi State, descriptive statistics, regression models, and thematic analyses were combined to assess changes in livelihood capitals, system pressures, and response mechanisms. Adoption of rice–fish systems was associated with substantial improvements: 96.1% of farmers reported increased income, 56.3% improved food security, and 30.6% greater dietary diversity. Regression analyses confirmed that access to more land (p < 0.001 for healthcare and education; p = 0.011 for social status), labor affordability (p < 0.001), and farm size (p < 0.05) were consistent predictors of gains in healthcare, education, and social status, while pesticide and herbicide use negatively affected food access and wellbeing (p < 0.05). The DPSIR assessment revealed that rice–fish integration altered the state of rice production systems through reductions in input-related pressures and generated positive livelihood impacts. The results align with Sustainable Development Goals (SDGs) related to poverty reduction, food and nutrition security, sustainable production, and biodiversity conservation, and provide the first large-scale, longitudinal evidence from West Africa that integrated rice–fish systems support food security, income diversification, and sustainable resource management. Full article

Aquaculture is the fastest-growing food production sector globally. As its largest producer, China plays a pivotal role in ensuring aquatic food supply and supporting the blue economy. Despite its massive scale, a systematic understanding of the geographic distribution, structural composition, and drivers of China’s aquaculture value chain remains limited. We comprehensively characterized the sector’s composition, spatiotemporal evolution, and structural dynamics. We compiled and analyzed over 2.85 million enterprise registration records from the TianYanCha database, applying rigorous industry classification, spatial mapping, correlation analysis, and bottleneck assessment with natural and socioeconomic variables. Results show that policy reforms, notably the 2013 Company Law amendment and 2016 aquaculture certification measures, drove sharp increases in enterprise registrations, particularly in retail and farming. Enterprises are highly clustered in the Yangtze River Basin, Pearl River Delta, and southeastern coast, with inland expansion along major river systems. Strong interdependencies exist among sectors, while wholesale remains numerically scarce, forming a structural bottleneck. Standardization levels are low. Foreign investment, though under 5%, concentrated in processing and distribution, contributed to advanced technologies in the 1990s–2000s. These findings highlight rapid formalization, regional clustering, and structural imbalances, suggesting that enhancing formalization and addressing intermediary bottlenecks could improve sector resilience and efficiency. Full article

This study evaluates regional differences in ecosystem service values (ESVs) between the integrated rice–crayfish systems of Huoqiu County (HQ) and Chongming District (CM) in China. The assessment was based on the Common International Classification of Ecosystem Services (CICES) V5.1, which categorizes ecosystem services into provisioning, regulation and maintenance, and cultural services. In this framework, each service category was quantified using region-specific biophysical indicators combined with monetary valuation methods. The results showed that the ESVs in HQ and CM were 346,113.59 CNY/ha and 467,334.89 CNY/ha, respectively, with greenhouse gas (GHG) emissions accounted for as a negative value. Regulation and maintenance services dominated both regions (59% in HQ and 52% in CM), followed by provisioning services (22%) in HQ and cultural services (19%) in CM. Among these, temperature regulation, water storage and flood control, soil nutrient retention, social security functions, and greenhouse gas emissions were higher in HQ than in CM, with the key difference lying in social security value in HQ and greater tourism development value in CM. A SWOT-AHP analysis recommends a pioneering strategy leveraging strengths and opportunities for sustainable development. These findings inform region-specific policies to balance economic growth and environmental sustainability, contributing to global discourse on integrated agriculture–aquaculture (IAA) systems. Future research incorporating primary data and refining model parameters would further enhance the precision and practical application of these assessments. Full article

This study investigates factors that encourage and discourage farmers to adopt rice–fish (RF) farming in the Hau Giang province in the Mekong Delta, Vietnam. A mixed-method approach was employed to collect data, comprising focus group discussions, face-to-face interviews with rice (R) and rice–fish (RF) farmers, as well as in-depth interviews with agricultural officers and selected R and RF farmers. Economic benefits are the main motivation for adopting RF farming, but suitable agro-ecological conditions, farm size and access to social networks, technical training, and support from extension officers also positively influence the adoption of RF farming. Environmental and health factors have less impact on farmers’ choice of farming. The study also identifies several barriers to the adoption of RF farming, including spatial, operational, and market barriers. To enhance the adoption of RF farming, policymakers should prioritize promoting RF farming in areas with suitable agro-ecological conditions and implement supportive measures, particularly financial assistance and technical training. Additionally, raising farmers’ awareness of both the economic advantages and long-term ecological benefits of RF farming is essential. Full article

This study addressed the optimal magnesium (Mg) requirement for juvenile largemouth bass (Micropterus salmoides) and assessed the effects of dietary Mg supplementation on growth performance, nutrient metabolism, and alleviation of heat stress in it. In this study, six diets with varying Mg levels (1.01, 1.26, 1.78, 2.24, 2.35, and 2.51 g/kg), designated as MG1, MG2, MG3, MG4, MG5, and MG6, respectively, were formulated using MgSO₄·7H₂O as the Mg source. These diets were fed to juvenile M. salmoides (initial body weight 2.27 ± 0.02 g) for 8 weeks. The growth performance of the MG4 group was significantly improved. In addition, Plasma GLU, LDL-C, and TG levels were significantly reduced in the MG4 group, while plasma HDL-C levels were increased. In terms of gene expression, glut2, g6pdh, ppar-γ, fas, elovl2, acc, and igf-1 were significantly upregulated in the MG4 and MG5 groups, while g6pase and ppar-α were significantly downregulated in the MG5 group. In the heat stress test, MG4 group exhibited enhanced antioxidant capacity, as evidenced by decreased plasma MDA levels and increased CAT activity, coupled with enhanced gill Na⁺/K⁺-ATPase activity. Gene expression results also showed that il-10 and bcl-2 were significantly upregulated in the MG4 group, while nf-κb, ifn-γ, il-8, tnf-α, casp3, casp8, bax, jnk2 and ask1 were significantly downregulated. Furthermore, the results of TUNEL immunofluorescence labeling analysis showed that the apoptotic index was significantly decreased in the MG2-MG6 groups. Overall, appropriate dietary Mg levels promoted growth performance, improved glucose metabolism, and induced lipid deposition in juvenile M. salmoides. Notably, Mg reduced oxidative damage by enhancing antioxidant enzyme activity, thereby modulating heat stress-induced Antioxidant–Inflammatory–Apoptotic of juvenile M. salmoides. Based on quadratic regression analysis of SGR and FCR, the optimal Mg requirement for juvenile M. salmoides was 2.04, and 2.15 g/kg, respectively. Full article

In this 8-week feeding trial, we systematically investigated the effects of replacing fishmeal with enzymatically hydrolyzed pork bone meal (EHPBM) at graded inclusion levels (EHPBM0, EHPBM20, EHPBM50, and EHPBM100) in largemouth bass (Micropterus salmoides). The results showed that the EHPBM50 group maintained growth performance comparable to the fishmeal-based control, whereas higher replacement levels led to significant metabolic disturbances. Specifically, the EHPBM100 group exhibited marked reductions in final body weight (FBW), weight gain rate (WGR), and specific growth rate (SGR), along with an elevated feed conversion ratio (FCR). Serum biochemical markers—alanine aminotransferase (ALT) and aspartate aminotransferase (AST)—were significantly decreased in a dose-dependent manner under EHPBM50 and EHPBM100 substitution. Regarding whole-body composition, ash content was significantly lower in the EHPBM50 group, while no significant differences were observed in other metrics compared to the control. Furthermore, dietary EHPBM inclusion enhanced systemic antioxidant capacity. All EHPBM substitution groups showed significantly increased superoxide dismutase (SOD) and catalase (CAT) activities, along with significantly reduced malondialdehyde (MDA) levels. In key metabolic pathways, compared with the EHPBM0 group, the expression of mtor and rps6k genes was significantly up-regulated in the EHPBM50 group, while that of g6pase, fbp1, and cpt1 genes was significantly down-regulated. Intestinal integrity markers (occludin, zo-1) and nutrient transporters (pept1, lat1) remained largely unaffected except in the EHPBM100 group, indicating the species’ tolerance to partial fishmeal replacement. In summary, these findings demonstrate that EHPBM can effectively replace up to 50% of fishmeal in largemouth bass feed without compromising growth performance or nutrient utilization, while significantly enhancing antioxidant capacity. Full article

The freshwater drum (Aplodinotus grunniens) is a promising aquaculture species due to its strong environmental adaptability, tolerance to low temperatures, rapid growth rate, high nutritional value, high-quality texture (garlic-clove-shaped flesh), and absence of intermuscular bones. Nevertheless, processing technologies related to freshwater drum remain largely unexplored. Salting pretreatment serves as a viable strategy for enhancing the quality attributes of frozen fish products. This study investigated the effects of different sodium chloride (NaCl) pickling concentrations (0.25, 1, and 3 mol/L) on the physicochemical properties and quality attributes of frozen–thawed freshwater drum (Aplodinotus grunniens). Results indicated that elevated NaCl concentrations (1–3 mol/L) significantly (p < 0.05) shortened the transit time through the maximum ice crystal formation zone during freezing, effectively mitigating structural damage to myofibrillar networks. As the NaCl concentration increased from 0 to 3 mol/L, the water content decreased from 71.26 ± 0.22% to 68.64 ± 0.50%, while the salt content increased from 0.31 ± 0.01% to 8.46 ± 0.12%. Pickling pretreatment markedly enhanced water-holding capacity and improved texture profiles, including hardness, springiness, gumminess, and chewiness. Histological analysis revealed preserved myofibril integrity in high-salt-treated samples, supported by reduced fluorescence intensity of myofibrillar proteins, indicating mitigated freeze-induced denaturation. Low-field NMR confirmed salt-induced redistribution of water states, with decreased free water proportion. Our results identify that pretreatment with NaCl at concentrations ≥ 1 mol/L is an effective strategy to preserve the post-thaw quality. Due to 3 mol/L NaCl resulting in a relatively high salt content, 1 mol/L NaCl pretreatment is more suitable for maintaining the quality of freeze–thawed freshwater drums. Full article

Salinity is a pivotal environmental factor that significantly influences the survival, growth, development, and reproduction of aquatic organisms. However, the characteristics of serum metabolites and their mechanistic roles in mediating the response of grass carp (Ctenopharyngodon idellus) to long-term salinity stress remain incompletely understood. Therefore, the present study exposed grass carp to different salinity levels (0, 4, and 8 g/L) for 60 days to evaluate the associated physiological alterations and metabolic responses. The results revealed that high salinity (8 g/L) significantly suppressed growth performance (p < 0.05), whereas low salinity (4 g/L) caused no significant reduction in growth or survival. Physiological analyses indicated that fish in the 8 g/L group exhibited markedly reduced levels of lactic acid and total protein, along with elevated concentrations of total cholesterol, triglycerides, glucose, and glutamic-oxaloacetic transaminase (p < 0.05). Serum ion homeostasis was also disrupted under high salinity, characterized by increased Ca²⁺, Na⁺, and Cl⁻ levels and decreased Mg²⁺ (p < 0.05). Furthermore, oxidative stress was evident in the high-salinity group through heightened activities of antioxidant enzymes (SOD, CAT, GPx), accumulation of oxidative damage markers (protein carbonyl, 8-OHdG) (p < 0.05). Metabolomic profiling identified 367 and 403 significantly altered metabolites in the 4 g/L and 8 g/L groups, respectively, primarily belonging to lipids and lipid-like molecules along with organic acids and derivatives. KEGG enrichment analysis revealed that these differential metabolites were chiefly involved in amino acid biosynthesis, glycerophospholipid metabolism, biosynthesis of unsaturated fatty acids, and glycine, serine, and threonine metabolism. Trend analysis further uncovered eight distinct expression patterns of metabolites across salinity gradients. These results provide novel insights into the metabolic adaptations of grass carp to salinity stress, demonstrating that high salinity induces oxidative stress, disrupts ion regulation, and drives extensive metabolic reprogramming. The study offers valuable theoretical support for improving salinity tolerance management in aquaculture and informs the selective breeding of salt-tolerant fish strains. Full article

The propagation of antibiotic resistance genes (ARGs) in aquatic environments poses a significant threat to global health. This study compared sediment resistome profiles in river crab (Eriocheir sinensis) polyculture systems with and without stone moroko (Pseudorasbora parva). The results showed that, compared to the control group (MC group), the sediment from the polyculture system containing stone moroko (PC group) exhibited significant reductions in the total abundances of ARGs, metal resistance genes (MRGs), biocide resistance genes (BRGs), and mobile genetic elements (MGEs). Crucially, the total abundance and composition of MGEs in pond sediment were substantially correlated with ARGs, MRGs, and BRGs, respectively. Co-occurrence network analysis revealed that there was only one edge between ARGs and MGEs in the PC group, whereas the MC group had eight edges. Additionally, the proportion of mobile ARGs in the PC group was significantly lower than that in the MC group. Alterations in resistome profiles were markedly associated with decreased levels of total carbon (TC) and phosphate in the sediment. All of the findings demonstrated that the introduction of stone moroko in the river crab polyculture system effectively mitigated the sediment resistome primarily by altering environmental factors and suppressing MGEs, thereby disrupting the horizontal transfer network of resistance genes. This study highlights the potential of leveraging aquatic biota as a novel biological strategy for the in situ management of environmental antimicrobial resistance. Full article

The inhibition mechanism and binding properties of four phenolic acids (ferulic acid (FA), p-coumaric acid (CA), gallic acid (GA), and protocatechuic acid (PA)) on xanthine oxidase (XOD) were investigated. All four phenolic acids acted via a mixed inhibition pattern, mainly influencing the hydrophobic regions and secondary conformation of XOD through hydrophobic bonding and hydrophobic association. Molecular dynamics simulations exhibited that the complexes of XOD with FA and CA revealed smaller radii of gyration (Rg) and solvent-accessible surface areas (SASA), along with lower variability in root-mean-square deviation (RMSD) and root-mean-square fluctuation (RMSF), collectively indicating greater structural stability. FA, CA, and PA significantly reduced uric acid (UA) concentration in the 25–100 μM range. Although GA only reduced UA levels in cell models at 25 μM, this effect was likely due to its larger polar surface area, which limits cellular uptake. Absorption, distribution, metabolism, excretion, and toxicity (ADMET) evaluation suggested that these phenolic acids have potential for development. Full article

Six dietary groups were supplemented with graded vitamin C (VC) levels: VC1 (control, 0.39 g/kg), VC2 (0.51 g/kg), VC3 (0.66 g/kg), VC4 (0.81 g/kg), VC5 (0.97 g/kg), and VC6 (1.11 g/kg). Largemouth bass (Micropterus salmoides) with an initial weight of 2.21 ± 0.00 g were fed these diets for 8 weeks to evaluate the effects of different VC levels on growth performance, immune response, and heat stress resistance. Heat stress was induced at a constant temperature of 33.00 ± 0.16 °C for one week. The VC3 and VC4 groups showed significantly improved growth performance (FBW, WGR, SGR) compared to VC1 (p < 0.05). VC4 exhibited lower ALT and AST levels before and after heat stress. Antioxidant capacity (T-AOC, GSH-Px, CAT) was significantly enhanced in VC3–VC5, with VC5 showing the highest after stress activity (except CAT). Expression of pro-inflammatory genes (nf-κb, il-8) was downregulated in VC4 and VC5, while anti-inflammatory il-10 was upregulated in VC4 after stress. Apoptosis-related genes (bcl-2, caspase, bax) and TUNEL assays indicated the strongest anti-apoptotic effects in VC3 and VC4 under heat stress (p < 0.05). These findings suggest that VC supplementation in low-fishmeal diets enhances growth, immune response, apoptosis resistance, and acute heat stress tolerance in fish. Full article