Aquaculture International最新文献

Intensive aquaculture commonly exposes fish to environmental and handling stressors that elevate oxidative stress, suppress immunity, and reduce growth and productivity. Therefore, safe dietary nutraceuticals such as polyphenols are being explored as functional feed additives to strengthen antioxidant defenses and immune performance in cultured fish. This study investigated the pharmacokinetic properties and molecular interactions of nutraceuticals (quercetin, resveratrol, and curcumin) with key antioxidant and immune proteins of Labeo rohita (L. rohita) through an integrated in-silico and wet-lab approach. Pharmacokinetic properties and molecular interactions of these nutraceuticals with key antioxidant and immune-related proteins were evaluated using an integrated in silico approach. Pharmacokinetic predictions confirmed compliance with drug-likeness criteria, with resveratrol showing superior bioavailability, while quercetin exhibited higher polarity which may limit absorption. Docking analysis revealed quercetin as the strongest binder to CAT, resveratrol as most effective with SOD1 and GPx1, and curcumin showing moderate but consistent activity. Wet-lab validations showed that treated groups had higher antioxidant enzyme activities, less lipid peroxidation, a better balance of glutathione, stronger immune responses, and better growth performance, especially when they were on diets high in resveratrol and quercetin. Compared with the control, resveratrol increased SOD to 78.93 ± 1.63 U/mg and GPx to 19.35 ± 1.95 U/mg (control 52.90 ± 4.32 and 12.21 ± 0.97), quercetin increased CAT to 29.30 ± 3.36 U/mg (control 18.28 ± 1.35), and lipid peroxidation (MDA) decreased from 6.34 ± 0.52 to 3.69–4.67 nmol/mg. Overall, findings highlight complementary and complementary roles of these nutraceuticals in strengthening antioxidant defense, immunity, and aquaculture performance of L. rohita. These findings support polyphenolic supplementation (especially resveratrol and quercetin) as a practical approach for aquaculture to improve stock robustness, enhance growth and feed efficiency, and potentially reduce reliance on synthetic additives/antibiotics.

Green synthesis of silver nanoparticles (AgNPs) offers a sustainable approach to control bacterial infections in aquaculture systems. In this study, AgNPs were synthesized using Catunaregam spinosa leaf extract and optimized for concentration, pH, temperature, and incubation time. The optimized conditions (1 mM AgNO₃, 10% plant extract, pH 7, 37 °C, 24 h) produced well-dispersed, stable nanoparticles with a total yield of 568.4 mg (14.2%). The biosynthesized AgNPs were characterized using UV–Vis spectroscopy, XRD, FTIR, DLS, Zeta potential, and SEM–EDX analyses. Their antibacterial activity was evaluated against five bacterial strains isolated from injured freshwater crabs Barytelphusa cunicularis: Citrobacter braakii (PP832928), Aeromonas caviae (PP832929, PP832943), Citrobacter portucalensis (PP832930), and Citrobacter freundii (PP832944). The AgNPs exhibited significant antibacterial effects, with minimum inhibitory concentrations ranging from 50 to 100 μg.mL⁻¹ and the highest zones of inhibition against C. portucalensis (13 mm) and A. caviae (12 mm). Additionally, the nanoparticles demonstrated antioxidant potential, with dose-dependent DPPH radical scavenging activity up to 47% at 100 μg.mL⁻¹. These results indicate that green-synthesized AgNPs are stable, eco-friendly, and effective antibacterial and antioxidant agents, with promising applications in aquaculture for disease management and improving the health of freshwater crustaceans.

Enterocytozoon hepatopenaei (EHP) is an obligate intracellular microsporidian parasite that has become a major constraint to shrimp aquaculture, particularly in Penaeus vannamei. Unlike pathogens associated with acute mortality, EHP causes hepatopancreatic microsporidiosis (HPM), leading to substantial production losses worldwide. This review synthesizes current understanding of EHP biology and infection strategies, emphasizing its highly specialized intracellular lifestyle and strong dependence on host cellular resources. Accumulating evidence indicates that EHP disrupts host metabolic homeostasis and physiological regulation, thereby impairing growth performance. We further summarize current approaches for EHP detection and discuss key environmental and biological factors that influence disease emergence and persistence in farming systems. Although effective treatments are not yet available, emerging concepts for disease mitigation and future research priorities are highlighted. Overall, this review integrates recent biological insights to clarify EHP pathogenesis and provides a conceptual basis for improved risk assessment and management of EHP in shrimp aquaculture.

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The sustainable management of hydroelectric power consumption in intensive aquaculture operations represents a critical challenge for modern fish farming, where energy costs can constitute up to 40% of operational expenses. This study introduces a novel bio-inspired metaheuristic algorithm, the seahorse optimization algorithm with adaptive Lévy-Dunkl mutations (SOA-ALDM), specifically designed to optimize power consumption patterns in recirculating aquaculture systems (RAS). The proposed algorithm mimics the unique locomotion patterns, feeding behaviors, and territorial dynamics of seahorses (Hippocampus spp.), incorporating five key modifications: (1) adaptive spiral swimming mechanism for exploration–exploitation balance, (2) camouflage-based population diversity enhancement, (3) brood pouch-inspired solution storage strategy, (4) tail-grasping local intensification operator, and (5) current-riding momentum transfer mechanism. The integration of adaptive Lévy-Dunkl mutations provides superior escape capabilities from local optima through heavy-tailed statistical distributions with orthogonal polynomial foundations. The optimization framework addresses multi-objective power scheduling for aeration systems, water circulation pumps, temperature control units, and automated feeding mechanisms across 24-h operational cycles. Experimental validation was conducted on three commercial salmon farms (capacity, 150–500 tons/year) over 180-day operational periods, with performance evaluation using novel statistical metrics including the Generalized Hypervolume Indicator (GHI), Polynomial Chaos Expansion-based Sensitivity Index (PCE-SI), and Cramér-von Mises divergence measure. Comparative analysis against 12 state-of-the-art algorithms (PSO, GWO, WOA, HHO, MPA, SSA, AO, GTO, DBO, AVOA, RUN, and NGO) demonstrates that SOA-ALDM achieves superior performance with 23.7% average energy reduction, 15.3% improvement in power factor, and 89.4% Pareto front coverage and maintains optimal dissolved oxygen levels (> 6.5 mg/L) while reducing peak demand charges by 31.2%. Statistical validation through Friedman ranking test (p < 0.001) and post-hoc Wilcoxon signed-rank tests confirms significant superiority across all benchmark instances. The proposed method achieved cost savings of $47,300–$89,600 annually per facility while improving fish growth rates by 8.2% and reducing mortality by 2.3 percentage points, establishing a new paradigm for energy-efficient aquaculture operations.

The effects of live microalgal diets on survival, growth, proximate, fatty acid and amino acid composition were investigated in the edible oyster Crassostrea belcheri under laboratory conditions for five weeks. In this study, four different feeding regimes were tested for C. belcheri spat: unfed (Control), two monospecific diets Chaetoceros gracilis (T1) and Tetraselmis chuii, (T2), and one mixed diet composed of C. gracilis and T. chuii (T3). It is hypothesized that mixed microalgal diets enhance oyster growth, and biochemical quality compared to monospecific or unfed treatments, owing to a broader and complementary nutritional profile. The oyster group fed the mixed algal diet (T3) showed a significantly greater survival rate in comparison with the other groups (p < 0.05). Additionally, the T1 diet resulted in the highest protein, (41.7 ± 0.38) in oysters whereas, the highest lipid (20.7 ± 0.33) and carbohydrate (34.2 ± 0.33) contents were found with the T3 diet. In addition, the T3 diet substantially enhanced the energy content (23.4 ± 0.24 MJ kg⁻¹) in oyster meat compared to the other diets. The fatty acid content of oysters was increased significantly when mixed algae was fed (p < 0.05). In contrast, the amino acid content of oysters was highest with the T1 diet. In this study, the mixed algal diet resulted in improved survival, growth, proximate, essential fatty acid and essential amino acid accumulation in oysters. The findings demonstrated that indoor cultivation system with mixed microalgal diet might be a potential farming technology for the production of nutritionally enriched edible oysters.

The study presents one-year monitoring data on the meat yield index, morphometric parameters, and sex structure of the mussel Mytilus galloprovincialis. Mussels were collected from seven locations in the Black Sea and the Sea of Azov that differ in anthropogenic pressure and hydrochemical characteristics. Differences were observed between cultivated and wild mussels for the studied parameters. The meat yield index was slightly higher in cultivated mussels from the shellfish farm (21.8 ± 4.1%) than in wild populations (20.9 ± 6.1%). Statistical analysis revealed that both season and sampling location significantly influenced meat yield, with month-to-month variations differing among locations. Anthropogenic pressure did not have a decisive effect on mussel meat yield. Morphometric indices indicated that environmental conditions influenced shell shape variability in M. galloprovincialis. In wild populations, the shell height-to-length ratio (H/L) was 0.57 ± 0.05 and the width-to-length ratio (D/L) was 0.38 ± 0.10, whereas in cultivated mussels, these ratios were 0.54 ± 0.03 and 0.37 ± 0.03, respectively. The shells of cultivated mussels were more elongated and less convex, suggesting more favorable growth conditions in the mussel farm environment. Variations in these morphometric parameters can be used to assess mussel well-being and to distinguish between different populations of the same species. Across all studied water bodies, the sex ratio of M. galloprovincialis was skewed toward males. In cultivated mussels, the female-to-male ratio was 0.57 ± 0.35, whereas in natural populations it was 0.49 ± 0.31.

This study assessed the effect of dietary oil sources on tambaqui (Colossoma macropomum) exposed to acute cold stress. Three different oil sources were incorporated individually at 7% into the diets: fish oil (FO), a blend of linseed and palm oils (LO), or corn oil (CO). These diets differed in their n-6/n-3 polyunsaturated fatty acid (PUFA) ratios, with n-3 PUFA derived from EPA + DHA (FO) or linolenic acid (LO) and n-6 PUFA from linoleic acid (CO). Fish (initial weight, 43 g) were fed ad libitum at 28°C for 49 days before the water temperature was reduced to 21°C within 40 min. Sampling occurred before (0h) and at 3h and 24h after cold stress. The dietary oil source had no significant effect on growth performance. Plasma cortisol and glucose levels were lowest at 3h post-stress, with FO-fed fish showing consistently reduced cortisol levels regardless of time. Plasma glucose was unaffected by diet composition. At 0h, fish fed the LO diet showed the lowest hepatic lipid peroxidation (LPO) levels, while at 3h and 24h, fish fed the FO and CO diets and the FO and LO diets showed lower LPO levels, respectively. Enzymatic activities of SOD, GPX, and GR exhibited a decline at 3 h and 24 h relative to the initial time point (0 h) across all dietary treatments. LPO levels also decreased post-stress, except in CO-fed fish at 24h. In conclusion, dietary n-3 PUFA improves oxidative stress resilience in tambaqui during acute cold exposure.

This study assessed the comparative performance of candidate marine macroalgae species under integrated multi-trophic aquaculture (IMTA) culture conditions in a system culturing yellowtail snapper (Ocyurus chrysurus) at a commercial-scale biomass density. The nutrient-rich effluent water from the marine finfish culture tank supplied replicated macroalgae raceways containing four candidate species of macroalgae (Agardhiella subulata, Caulerpa racemosa, Gracilaria caudata, and Ulva lactuca) native to the Southeast U.S. and Caribbean regions. Water temperature, dissolved oxygen (DO), salinity, alkalinity, pH, phosphate, and total ammonia nitrogen (TAN) readings were sampled daily, and dissolved CO₂ was calculated over the course of the trials. Each species of macroalgae was analyzed for protein, fat, fiber, ash, minerals, and metals. Additionally, the carbon and nitrogen content and stable isotope ratios of the nutritionally enriched (i.e., “fortified”) macroalgae (“seaweed”) species were analyzed. Results provide novel insights on macroalgae biomass levels under specific hydraulic retention times (HRT) that allow for the reduction of TAN levels in fish effluent water below detectable levels. Specifically, Agardhiella subulata at a density of 6.73 kg m⁻³, lowered TAN levels in fish effluent water below detectable limits under a hydraulic residence time (HRT) of 54 min from average starting concentrations of 0.04 mg/L TAN. Compositional analyses indicated Caulerpa racemosa had the highest protein content (25.49%) and Ulva lactuca had the highest carbohydrate content (61.48%) of the macroalgae species tested. Calculated dissolved CO₂ concentrations of effluent water before and after the macroalgae culture tanks and the carbon-to-nitrogen ratio of macroalgae samples indicated that Ulva lactuca up took and incorporated carbon most efficiently. The results of this project provide novel information that will help improve economic and environmental sustainability for existing and prospective marine finfish aquaculture operations throughout the focal regions and allow producers to make well-informed decisions on candidate species of macroalgae for marine IMTA applications.

Hypnea is a cosmopolitan genus of red seaweeds and an important source of carrageenan worldwide. However, Hypnea species remain largely unutilized in seaweed aquaculture in the Philippines. This study aimed to evaluate the growth performance and carrageenan properties of an indigenous, unexploited Hypnea sp. collected from Panay Island and to compare them with those of the commercially cultivated Kappaphycus striatus. In a field cultivation experiment, Hypnea sp. showed significantly higher biomass (145.1 ± 53.7 g) than K. striatus (92.9 ± 10.3 g) up to day 28 (p < 0.001), while no significant difference was observed at days 36 and 43. The final yields were 181.0 ± 68.4 g for Hypnea sp. and 191.1 ± 33.0 g for K. striatus (p > 0.05). Semi-refined carrageenan extracted from the cultured Hypnea sp. exhibited gel-forming capacity, suggesting the presence of κ-carrageenan. However, both the viscosity and gel strength of Hypnea sp. (9.52 ± 3.53 cP; 148 ± 41.6 g cm⁻²) were significantly lower in K. striatus (70.9 ± 49.4 cP; 456 ± 201 g cm⁻²) (p < 0.001), indicating that Hypnea sp. possesses distinct carrageenan properties from conventional commercial seaweed. Although further development of carrageenan-based products tailored to its unique properties will be required for commercial utilization, these findings highlight the potential of Hypnea sp. as a candidate seaweed for aquaculture in the Philippines.

High-carbohydrate aquafeeds can induce metabolic disorders and growth inhibition in fish. This study aimed to investigate the beneficial effects of sodium acetate supplementation to a high-carbohydrate diet on grass carp (Ctenopharyngodon idella) and the related molecular mechanisms. Three isonitrogenous and isolipidic diets, including MC (27.5% carbohydrate), HC (42.5% carbohydrate), and HCA (42.5% carbohydrate + 1800 mg/kg sodium acetate), were fed to grass carp until apparent satiation for 7 weeks. The chemical composition, plasma parameters, the expression of genes related to appetite and glucose/lipid metabolism, and the AMPK signaling pathway were evaluated. The results showed that the HC diet upregulated appetite-suppression genes (pomc, pro-opiomelanocortin; cart, cocaine–amphetamine-regulated transcript) and reduced feed intake compared to the MC group. Indicators of glucose and lipid metabolic disorder increased significantly, suggesting the development of fatty liver. These alterations might contribute to poor growth. Sodium acetate supplementation in the HC diet restored feed intake and weight gain, along with downregulation of pomc. Furthermore, the HCA group showed reduced systemic and hepatic lipid deposition compared to the HC group. Mechanistically, sodium acetate enhanced AMP-activated protein kinase (AMPK) phosphorylation and downregulated key lipogenic genes (srebp1, sterol regulatory element-binding protein 1; acc1, acetyl-CoA carboxylase 1; fas, fatty acid synthase). In conclusion, dietary sodium acetate attenuated the adverse effects of the high-carbohydrate diet, potentially by modulating the AMPK/SREBP1 pathway to suppress lipid synthesis and by improving appetite regulation.