Aquaculture International最新文献

This study was conducted to investigate the effects of dietary N-methyl-D-aspartate (NMDA) on growth performance, protein deposition, muscle quality, and physiological responses in triploid crucian carp (Carassius auratus). Six isonitrogenous (32.00%) and isolipidic (8.00%) diets were prepared containing NMDA levels of 0, 0.25, 0.50, 1.00, 2.00, and 4.00 g/kg diet. At the conclusion of an 8-week feeding trial, results demonstrated that 0.25 g/kg NMDA significantly enhanced growth performance metrics. The growth performance parameters measured included final body weight (FBW), weight gain rate (WGR), specific growth rate (SGR), feed efficiency (FE), and nitrogen retention efficiency (NRE). Additionally, it was observed that the crude protein content in the body and dorsal muscle increased, and the diameter of muscle fibers significantly enlarged in the 0.25 g/kg NMDA group. Gene expression analysis revealed that 0.25 g/kg NMDA upregulated the expression of intestinal nutrient absorption-related genes (pept1, cdx2, sp1) and muscle development-related genes (tor, igf-1, myod, myog, mrf4, myf5, myhc, col1a1, col1a2). Higher levels of NMDA supplementation (1.00 to 4.00 g/kg) significantly increased the content of flavor compounds, specifically inosine monophosphate (IMP) and free glutamic acid (GlU), while also causing some alterations in muscle texture parameters. Physiological analysis revealed that NMDA supplementation improved the antioxidant defense system, as indicated by increased plasma superoxide dismutase (SOD) activity, heightened total antioxidant capacity (T-AOC), and decreased activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). In conclusion, dietary supplementation with 0.25 g/kg of NMDA significantly enhances growth, improves muscle quality, and increases antioxidant capacity in triploid crucian carp, thereby positioning it as a promising feed additive for aquaculture practices.

Pronounced individual growth variation in Apostichopus japonicus, a key mariculture Holothuroidea, challenges efficient cultivation. To better understand this variability, this study investigated relationships between personality, physiology, and growth divergence. Sixty full-sib juveniles (initial body weight 13–18 g), individually reared for 30 days under ad libitum feeding, showed widening growth divergence, with the coefficient of variation in body weight increasing from 8.053 to 16.218%. Highly variable specific growth rate, with a max-to-min ratio of 6.424, strongly correlated with food intake (P < 0.01). Notably, final body weight was not significantly correlated with initial body weight (P > 0.05), and specific growth rate negatively correlated with initial body weight (r =  − 0.274, P < 0.05), indicating that higher initial body weight did not guarantee superior growth. Individual behavioral traits were assessed twice, before and after the rearing period, and results indicated that A. japonicus exhibited personality. Specifically, feeding duration and movement distance were repeatable indicators of boldness and activity, respectively. However, these traits showed no significant correlations with specific growth rate (P > 0.05), suggesting their limited direct influence on growth variation. Further physiological assessments revealed that resting metabolic rate and cortisol concentration in coelomic fluid, measured post-rearing, were both significantly correlated with specific growth rate (P < 0.05). Individual specific growth rate was positively correlated with resting metabolic rate (r = 0.299) and negatively with cortisol concentration (r =  − 0.334), suggesting that faster growth in A. japonicus may be associated with a higher basal metabolic capacity and lower physiological stress levels. By excluding group interferences and food limitation, this study provides new insights into A. japonicus growth variation. These findings can inform development of more efficient aquaculture practices for this species.

This study investigated the effects of varying carbon-to-nitrogen (C/N) ratios in biofloc systems, incorporating sugar beet raffinate as a carbon source, to reduce reliance on Dunaliella salina algae while assessing growth, reproductive performance, biomass production, proximate composition, fatty acid profiles, and digestive enzyme activities. Eight experimental diets were formulated and tested over a 21-day period: T1 (control: 25% algae + 75% yeast; C/N 3.5), T2 (2.5% algae + 0.625% raffinate; C/N 11), T3 (2.5% algae + 1.25% raffinate; C/N 11), T4 (5% algae + 0.625% raffinate; C/N 10.5), T5 (5% algae + 1.25% raffinate; C/N 10.5), T6 (10% algae + 0.625% raffinate; C/N 9.5), T7 (10% algae + 1.25% raffinate; C/N 9.5), and T8 (25% algae + 75% probiotic bacteria; C/N 3.5). Results demonstrated that the T7 diet yielded higher values than the control in multiple parameters. Artemia fed T7 exhibited 88.8 ± 2.3% survival (vs. 75.3 ± 2.0% in T1), 12.03 ± 0.41 mm total length (vs. 9.67 ± 0.32 mm in T1), 1600 ± 87 total offspring (vs. 1067 ± 54 in T1), and higher activities of alkaline protease (1.92 ± 0.08 U mg⁻¹ protein; twofold increase vs. T1), amylase (46.89 ± 1.9 U mg⁻¹ protein), and lipase (0.48 ± 0.02 U mg⁻¹ protein). Additionally, this diet yielded 2518 ± 98 g biomass (vs. 1690 ± 75 g in T1) and 0.16 ± 0.01 feed conversion ratio (FCR; vs. 0.28 ± 0.02 in T1), alongside 58.45 ± 2.3% body protein (vs. 63.72 ± 2.1% in T1). Diets incorporating reduced algae levels combined with raffinate yielded 20–30% higher growth, biomass, and reproductive output at C/N ratios of 9.5–10.5. Comparative cost analysis revealed a 73% reduction in feed costs for T7 (0.42 USD/kg biomass) versus T1 (1.53 USD/kg), driven by 60–80% microalgae substitution with raffinate, enhancing economic viability for large-scale production. Sensitivity modeling of C/N deviations (± 10%) confirmed robust biomass stability (< 0.1% loss) and TOC within safe limits (< 150 mg/L), supporting process tolerance in industrial biofloc systems. These findings highlight the potential of sugar beet raffinate as a sustainable, cost-effective carbon source in biofloc systems, offering a viable strategy to optimize Artemia culture while reducing dependence on costly algal feeds. This study provides novel insights into the nutritional dynamics of biofloc-based Artemia culture, with implications for sustainable aquaculture practices.

The tiger dwarf goby, Mugilogobius tigrinus, is a high-potential brackish water ornamental species, yet protocols for its captive production remain undocumented. The research investigates the impact of sex ratio (low male bias: 1:2, 1:3, 1:4; balanced: 1:1, 2:2, 3:3; high male bias: 2:1, 3:1), salinity (0, 10, 20, 30 ppt) on spawning success, hatching rates, fertilization rate and fecundity of M. tigrinus as well as the influence of tank background colour (black, grey, white) on spawning and hatching success. Balanced sex ratios (2:2 and 3:3) significantly (p < 0.05) increased spawning frequency, hatching success and fertilization rates. Salinity strongly influenced reproductive performance, with optimal spawning and hatching at 30 ppt, whereas no spawning occurred at 0 ppt. Tank colour also affected reproduction, with black tanks yielding the highest spawning frequency and hatching rates. Larval development followed a positive exponential growth trajectory (R² = 0.947), with metamorphosis to the benthic juvenile stage completed by 51 days post-hatch (DPH). The larval rearing protocol yielded a final survival rate of 26 ± 5%. A separate 35-day larval rearing trial revealed that highest survival was achieved with rotifer (Brachionus plicatilis), copepod nauplii (Apocyclops royi) and ciliates (Euplotes sp.), while growth was maximized with copepods, particularly in combination with rotifer. The findings contribute valuable insights for its aquaculture potential in the ornamental fish industry and contribute to the conservation of the species.

Shrimp aquaculture is a key industry in global aquaculture, contributing to high-quality nutrition, food security, and economic development. However, environmental changes driven by climate change and pathogenic infections are among the challenges that negatively affect shrimp supply and economic growth. Transcriptomic approaches, particularly RNA sequencing (RNA-seq), have been widely applied to investigate molecular features of shrimp stress responses to abiotic and biotic stressors by identifying differentially expressed genes (DEGs). However, these technologies impose a limit on the molecular interactions among the identified DEGs. Molecular interaction information is essential, as most biological processes function through groups of interacting genes rather than a single gene. Thus, this review aims to explore the potential of network analysis approaches for available transcriptomic datasets to understand the mechanisms of shrimp stress responses. This review provides an overview of current progress in shrimp transcriptomics and highlights available network approaches, i.e., protein–protein interaction (PPI), gene co-expression, and gene regulatory networks, that can be integrated with the transcriptomic data. Relevant databases and tools are outlined to provide available sources for network construction and analysis. A framework for network analysis of a transcriptomic dataset was presented to illustrate how network approaches can be used to identify genes and associated biological functions involved in shrimp stress responses. The future directions and challenges of integrating network analysis into shrimp research are also discussed for the way forward. This review demonstrates that network-integrated transcriptomics can provide a systems-level understanding of shrimp responses to stress, assisting in improving shrimp aquaculture production.

Fish nutrition is one of the major challenges of aquaculture, accounting for over 60% of the cost of fish production. This study investigates the effects of varying inclusion levels of ethanolic Moringa oleifera leaf extract (EMOLE) on the plasma biochemistry and histopathology of Heterobranchus bidorsalis broodstock. M. oleifera leaf was processed by air drying method at 26 ± 0.5 °C and 85% temperature and relative humidity respectively. Sample was pulverized and cold extracted using 98% absolute ethanol. Filtrates were concentrated at 40 °C under reduced pressure and dried in hot-air oven at 45 °C. Yield of bio-active compounds was determined using UV spectrophotometry following standard procedures. Fish were fed diets supplemented with 1.0, 2.0, and 3.0 g/100 g of EMOLE at a daily rate of 5% body weight, twice a day (09:00 and 16:00 h) for 16 weeks. Subsequently, plasma glucose (GLU), cholesterol (CHOL), albumin (ALB), total protein, liver enzymes (aspartate aminotransferase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP)), and globulin concentrations were analyzed. GLU ranged from 20.47 (control) to 45.23 mg/dl (3.0 g/100 g), showing a significant increase at higher EMOLE levels. CHOL varied from 94.80 (control) to 219.58 mg/dl (2.0 g/100 g) while ALB levels from 1.44 (control) to 1.80 g/L. Total protein values ranged from 5.52 to 5.79 g/L, with no significant changes across treatment groups. Liver enzyme activities showed slight increases at higher inclusion levels, with ALT ranging from 20.60 (control) to 37.33 IU/L (3.0 g/100 g), AST from 23.12 (control) to 28.48 IU/L (3.0 g/100 g), and ALP, 47.17 (control) to 77.47 IU/L (3.0 g/100 g). Histopathological analysis revealed no lesions in the liver and intestine of fish fed the control or 1.0 g/100 g diets. However, mild hepatic and intestinal lesions were observed at 2.0 and 3.0 g/100 g, including hepatocyte vacuolation and mucosal erosion. These findings indicate that while low to moderate EMOLE inclusion may have minimal adverse effects, higher inclusion levels could lead to physiological stress and organ dysfunction in H. bidorsalis.

Graphical Abstract

This study assessed the effects of dietary shrimp head meal (SHM) on growth performance, metabolism, antioxidant status, and health of Nile tilapia (Oreochromis niloticus) fingerlings. Five isonitrogenous and isoenergetic diets were precisely formulated on a digestible nutrient basis, containing graded SHM levels (0, 5, 10, 15, and 20%), and fed for 45 days to fish (3.24 ± 0.07 g) reared in 50 L tanks (10 fish tank⁻¹; four replicates diet⁻¹) within a recirculating aquaculture system. Growth performance increased significantly with SHM inclusion, and quadratic regression analyses suggested an estimated inclusion level near 16% associated with maximal weight gain and feed conversion efficiency. Improved eviscerated weight and whole-body protein, together with reduced hepatosomatic and viscerosomatic indexes and lipid content, indicated a shift toward lean growth and efficient nutrient utilization. Enhanced villus height and elevated digestive enzyme activities (amylase, proteases, and lipases) confirmed superior nutrient assimilation. Antioxidant defenses were strengthened by higher catalase and glutathione activities in liver and muscle, while feed malondialdehyde content decreased with increasing SHM levels during storage. Hematological and biochemical improvements, including higher erythrocyte, leukocyte, and platelet counts, elevated serum protein fractions, and lower glucose, cholesterol, alanine aminotransferase, and aspartate aminotransferase levels, reflected enhanced metabolic regulation, immune competence, and hepatoprotection. Collectively, these results demonstrate that SHM functions not only as a sustainable protein source but also as a functional feed ingredient that enhances physiological resilience. The valorization of shrimp-processing residues through SHM inclusion supports circular bioeconomic development and sustainable intensification in aquaculture.

Vibriosis is the most devastating bacterial disease affecting shrimp hatcheries and grow-out farms, posing a major constraint to sustainable aquaculture. As shrimp lack adaptive immunity, disease resistance relies entirely on an innate immune system of cellular defenses such as phagocytosis, encapsulation, nodule formation, coagulation, and apoptosis, along with humoral effectors including prophenoloxidase enzymes, agglutinins, antioxidant enzymes, melanin, and antimicrobial peptides (AMPs), primarily mediated by hemocytes. Among these effectors, AMPs are regulated mainly by the IMD and JAK/STAT signaling pathways that play a central role due to their broad antimicrobial activity against Vibrio spp. This review highlights the classification, structure, and functional roles of various AMPs, with particular emphasis on shrimp immune responses to vibriosis. The emerging evidence underscores the promise of AMPs as immunoprophylactic agents for vibriosis management, while also highlighting existing knowledge gaps that must be addressed to facilitate their effective therapeutic application in shrimp aquaculture.

Accurate assessment of fish feeding behavior is essential for efficient feed management and stable operation of aquaculture systems. Aquaculture feeding mainly relies on manual and machine-based approaches. Manual feeding depends on operator experience, often resulting in uneven feed distribution and increased water pollution. Machine-based feeding typically uses preset quantities based on stocking density, yet this fixed strategy cannot adjust to environmental fluctuations that influence fish appetite, leading to substantial feed waste. To address the problem of uneven feed distribution, we introduce a Lightweight Dynamic Cross-Modal Fusion Network (LDMF). The system synchronously acquires visual and acoustic information related to fish feeding behavior and evaluates the feeding state with high precision. By obtaining reliable real-time assessments, the network enables accurate feed delivery and effectively supports intelligent feeding management. First, the network extracts feeding-related features through dual audio–video branches, allowing the two modalities to complement each other and address the problem of uneven feed distribution more effectively. In addition, the proposed dynamic interaction fusion module adjusts fusion weights according to the characteristics of the input features. This mechanism enables the model to adapt to real feeding fluctuations and supports timely adjustments to feeding strategies, thereby reducing the risk of feed waste and environmental pollution. Finally, experimental results show that LDMF achieves an accuracy of 98.22% on the AV-FFIA dataset, outperforming existing unimodal models and other mainstream multimodal approaches. The network maintains strong robustness under highly dynamic recirculating aquaculture conditions and offers a practical solution for intelligent feeding applications.