Aquaculture International最新文献

The present study investigated the effects of different temperature on the larval development, survival, growth, and sex ratio of offspring in the swimming crab, Portunus trituberculatus. Three temperature treatments were set up in the experiment: (1) control group with 22 °C for ovigerous crabs (fertilized eggs at the late stage of embryonic development) incubation and larvae rearing (RG); (2) ovigerous crabs under high temperature of 32 °C and larvae rearing at 22 °C (FEH); (3) continuous high-temperature (32 °C) treatment for both ovigerous crabs and larvae (HG). During the rearing process from Z1 to C1, 30% of the water was exchanged daily, and stage-appropriate feed was provided. Crablets at the C1 stage were raised for 100 days at natural water temperature. Comparing with the RG group, elevated temperatures in FEH group significantly accelerated molting of larvae, promoting the growth performance of juvenile crabs (25.21% increase in body weight), but it also had negative impacts on the survival (decreased by 63.46%) and deformity (20% vs 0%). Continuous high temperature of 32 °C was detrimental to the development of larvae, with 100% deformities in the HG group at the C1 stage. Temperature treatment also altered sex ratios of offspring in the FEH group, with significantly higher (p < 0.05) female proportion at 100 days of age comparing to the RG group (increased by 27.78%); however, it did not induce sex reversal, and the survival rate of crabs was reduced significantly comparing to the RG group, indicating that males may have limited tolerance to temperature fluctuation. Results imply that incubating ovigerous crabs (at the late stage of embryonic development) at 32 °C and subsequently transferring them to 22 °C for larval rearing can significantly increase the female proportion and growth performance of the offspring; however, the negative effects of this treatment on survival should also be considered during the production of offspring with higher female composition in P. trituberculatus through temperature-mediated method.

The Chinese soft-shelled turtle (Pelodiscus sinensis) is a commercially important aquaculture species in China. The intestine serves as a primary organ for digestion and nutrient absorption, as well as a critical barrier against harmful external substances. Aeromonas hydrophila, a common pathogenic bacterium in aquaculture, causes various diseases in P. sinensis, leading to metabolic alterations and tissue damage in organs. In this study, we investigated the transcriptional responses of intestinal injury induced by A. hydrophila infection in P. sinensis. The results showed that infection led to severe morphological damage, including atrophy of intestinal villi and significant reductions in villus height, width, and crypt depth in the anterior intestine. TUNEL staining revealed a highly significant increase in late apoptotic cells in the infected group compared to the control group. Furthermore, A. hydrophila infection significantly up-regulated the expression of pro-apoptotic genes. Transcriptome analysis identified 345 significant DEGs (183 up-regulated, 162 down-regulated) in the intestine of P. sinensis following A. hydrophila infection. Among the most significantly altered genes, those related to immunity and apoptosis were strongly up-regulated, whereas genes involved in epithelial integrity and digestion were markedly down-regulated. GO enrichment revealed significant terms associated with response to biotic stimulus, cell adhesion, and cytoskeleton organization, while KEGG analysis highlighted tight junction, glycosaminoglycan degradation, metabolic pathways, and lysosome as the most significantly enriched core pathways. These results collectively indicated profound alterations in immune response, barrier function, and metabolic homeostasis during bacterial infection.

Excessive farming density–induced diseases and drug abuse have stimulated concern over the food-borne approaches in crayfish. Dietary andrographolide supplementation presents potential benefits for animal growth and hepatic health, yet its impact on host physiology and microbial metabolism remains poorly understood. This study aimed to explore the effects of dietary andrographolide on growth, hepatic antioxidant capacity, and immunity in crayfish, together with the underlying microbial mechanisms. A total of 450 individuals (4.00 g) were randomly allocated to experimental groups, receiving dietary regimens containing andrographolide at concentrations of 0, 0.05%, and 0.10% over 6 weeks. The results demonstrated that supplementation with andrographolide in the crayfish feed enhanced growth and hepatic health status, as evidenced by the well-developed hepatic tubules and more F cells, alongside decreased hemolymph glutamate oxaloacetate transaminase and malondialdehyde levels (P < 0.05). Crayfish supplemented with 0.05% andrographolide exhibited improved immunity, reflected by elevated lysozyme and acid phosphatase activities in the hemolymph, as well as decreased expression of nuclear factor kappa-B and Toll-like receptor (P < 0.05). Critically, dietary andrographolide profoundly reshaped the gut microbiota, characterized by a significant reduction in Citrobacter and an increase in Tyzzerella. Most notably, Exiguobacterium was identified as a key microbial biomarker whose abundance was strongly correlated with the improved host phenotypes. In summary, dietary andrographolide supplementation at the experimental level of 500 mg/kg was found to enhance immune and antioxidant functions in crayfish by reshaping microbial metabolic functions. Based on the dose–response models of growth and feed utilization, the optimal dietary andrographolide dosage was determined to be 510.01–542.88 mg/kg.

This study compared the effects of two culture systems, recirculating aquaculture system (RAS) and biofloc technology (BFT), and two stocking densities, D₀.₆ and D₁.₂ (0.65 and 1.29 kg m⁻³) on the performance, physiology, and intestinal health of juvenile Piaractus brachypomus over 60 days. RAS demonstrated increased fish growth performance with higher growth rates, feed conversion, and higher erythrocyte counts. BFT showed advantages in intestinal health parameters, including enhanced lamina propria integrity, increased goblet cell density, and higher total protein and globulin levels. Lower density (0.65 kg m⁻³) favored individual growth, while higher density (1.29 kg m⁻³) maximized total biomass production. These findings provide practical guidance for P. brachypomus farming, indicating that RAS systems are more suitable when growth performance is prioritized, whereas BFT systems offer advantages for fish health and welfare. Density selection should be based on specific production objectives.

Intensive aquaculture consumes high amounts of plant-based feed. Unfortunately, this practice increases the risk of aflatoxin B₁ (AFB₁) accumulation in fish tissues, impacting their physiological status. The ability of dietary silymarin to mitigate dietary AFB₁ (122.4 ppb) was investigated for 84 days in eight experimental groups: Sil-0 (control, uncontaminated feed), Sil-0.5 (0.5 g/kg), Sil-1 (1 g/kg), Sil-1.5 (1.5 mg/kg), AFB₁+Sil-0, AFB₁+Sil-0.5, AFB₁+Sil-1, and AFB₁+Sil-1.5. AFB₁ residue in the fish liver of AFB₁+Sil-0 was 0.86 ppb, while dietary silymarin decreased the residues in the hepatic tissues of AFB₁+Sil-0.5, AFB₁+Sil-1, and AFB₁+Sil-1.5 to 0.64, 0.37, and 0.22 ppb, respectively. Meanwhile, trace residues were found in muscle tissues regardless of AFB₁ levels. Results showed that dietary AFB₁ caused a decline in growth performance and blood indices (RBCs, WBCs, Hb, PCV, MCV, MCH, and MCHC) as well as a decline in lipid profile and serum proteins TP, ALB, and GLO, indicating malnutrition of Nile tilapia. The liver enzymes AST and ALT were up-regulated in response to dietary AFB₁. Regarding Streptococcus agalactiae infection, fish that received AFB₁ showed high mortality (MR%) and re-isolation (RI%) rates. It also resulted in a weak response to oxytetracycline (OTC) treatment, with high MR%. These effects partially subsided after receiving dietary silymarin, especially Sil-1 (1 g/kg). It is recommended that AFB₁ residues be monitored periodically before oxytetracycline treatment in case of bacterial infection.

Seaweed cultivation, particularly of Eucheuma and Kappaphycus species, plays a vital role in Indonesia’s coastal economy, supporting livelihoods and contributing to the global supply of carrageenan. Despite its economic significance, the sector faces challenges related to environmental sustainability, governance, technological access, and market integration. This study adopts a mixed-methods approach combining literature review, bibliometric analysis (Scopus-based using VOSviewer and Biblioshiny), field observations, and stakeholder interviews across three major cultivation sites (Southeast Sulawesi, Nusa Tenggara, and East Java). Findings show that while Indonesia maintains global leadership in seaweed production, productivity and resilience are increasingly limited by disease outbreaks, epiphytic infestations, climate variability, and declining seed quality, compounded by suboptimal farming protocols, post-harvest losses, and fragmented governance. Bibliometric analysis indicates a shift in research focus from cultivation biology toward sustainability, livelihoods, governance, and climate resilience, with remaining gaps in post-harvest innovation, domestic market development, and adaptive spatial planning. Based on these insights, the paper proposes evidence-based recommendations, including strengthening institutional governance, promoting sustainable and site-specific cultivation practices, enhancing capacity building and technology adoption, improving value chain integration, advancing applied research, and fostering participatory marine spatial planning. Implementing these strategies is essential for building a resilient, inclusive, and environmentally responsible seaweed industry that supports Indonesia’s blue economy objectives and enhances the well-being of coastal communities.

This study investigates the mechanisms underlying the rapid growth observed in hybrid triploid Carassius species. It focuses on blunt snout bream (Megalobrama amblycephala, MA), topmouth culter (Culter alburnus, CA), their diploid hybrid offspring (MC 2n), and the triploid hybrid (MC 3n) produced by crossing MA (female) with CA (male). Using anatomical measurements, histological examinations, gut content analysis, and muscle nutritional assessments, the research systematically compares differences in feeding adaptations, gonadal development, and muscle quality among these groups. The findings reveal that MC 3n has approximately 18 ± 2 gill rakers, with their length and spacing closely resembling those of the maternal MA. The pharyngeal tooth pattern (2.4.4—4.4.2) and the pharyngeal bone length-to-width ratio (2.8 ± 0.3) are also inherited from MA. The gut contents mainly consist of phytoplankton and plant material, indicating an herbivorous feeding adaptation. Gonadal development in MC 3n is notably impaired, with female ovaries arrested at stage I and male testes halted at stage IV without mature sperm. Levels of estradiol (E2) and testosterone (T) in female serum and gonads are significantly lower than those in MC 2n (P < 0.05). MC 3n exhibits significantly higher muscle crude protein and fat crude compared to both parent species and MC 2n (P < 0.05). Moreover, total umami amino acids are elevated, with an essential amino acid index of 0.92. Increased muscle fiber diameter (45.3 ± 2.1 μm) combined with intramuscular fat deposition contributes to enhanced meat tenderness. Overall, this study demonstrates that MC 3n improves muscle quality through maternal-influenced feeding adaptations and gonadal arrest, offering theoretical insights for breeding environmentally safe and high-quality aquatic species.

Carbohydrates are an important energy source for two omnivorous crustacean species, marine Antarctic krill (Euphausia superba) and freshwater redclaw crayfish (Cherax quadricarinatus), and α-glucosidase is an important enzyme of the amyloid metabolism pathway in crustaceans. However, the relationship between these enzymatic characteristics and the environment of crustaceans is still unclear. In this study, two GH13 family α-glucosidases from E. superba (EsAG) and C. quadricarinatus (CqAG) were heterologously expressed and characterized. They shared 60% amino acid sequence identity and were in the same evolutionary branch as other crustaceans according to the phylogenetic tree. Euphausia superba lives in a lower temperature, higher pH, and higher salinity environment compared to C. quadricarinatus, and the differences in the enzyme characterizations of each species were related to the differences in habitat. Firstly, the optimal temperature ranges of EsAG and CqAG were 25–35 °C and 50–55 °C, respectively. Secondly, the optimal pH of EsAG and CqAG were 6.5 and 5.0, respectively. Thirdly, EsAG exhibited extremely high salt tolerance, while CqAG lost most of its activity in high concentrations of salt. In addition, CqAG exhibited higher substrate affinity and catalytic efficiency compared to EsAG. The two α-glucosidases could hydrolyze several natural substrates such as maltose, sucrose and starch, and displayed transglycosylation activity to maltose. These results may enhance the understanding of carbohydrate metabolism in crustaceans and provide theoretical evidence for the nutritional and environmental status of aquatic animals.

Aquaculture underpins global food security; its digitalization is vital for resilience and high-quality growth, with smallholders’ digital adoption as the key foundation. This study examines the factors associated with adoption of smart aquaculture digital technologies (ASDT) among smallholder fish farmers within China’s freshwater fish sector. First, drawing on survey data, the ASDT and relevant characteristics of smallholder fish farmers were identified. Efficiency scores were calculated using a Slack-Based Measure Data Envelopment Analysis (SBM-DEA) model. By integrating efficiency levels with digital adoption intentions, farmers were segmented into eight distinct “efficiency–adoption” scenarios. Second, applying the Unified Theory of Acceptance and Use of Technology (UTAUT), survey data were analyzed using principal component analysis (PCA) and ordinary least squares (OLS) regression to examine the economic and behavioral factors associated with ASDT. Finally, interpretable machine learning methods were then employed to explain the each “efficiency–adoption” scenarios, incorporating transportation, climate, geographic, and economic–psychological factors. Findings indicate that: (1) The UTAUT exhibits strong explanatory relevance. performance expectancy, effort expectancy, social influence, and facilitating conditions are significantly associated with adoption intentions, while technology exposure, risk perception, and perceived resilience serve as important moderating variables. (2) For farmers with high technical but low scale efficiency, those who exposed to climatic risks are more likely to adopt digital technology. (3) For farmers with high scale but low technical efficiency, effective digital technology adoption requires high individual exposure to digital technologies and well-developed rural digital infrastructure. (4) Low-efficiency farmers with high technical exposure may attempt to improve performance through digital technology adoption, when perceived risks increase decline the likelihood of such attempts. (5) Reaching the production frontier is related to technology exposure, while variation in geography and climate shapes ASDT beyond that point. In conclusion, this study validates the applicability of UTAUT framework in aquaculture, clarifies the factors shaping ASDT across efficiency scenarios, and provides policy insights to guide efficiency-oriented digital transformation in the sector.

Flesh colour is a critical quality criterion for consumer purchasing of salmonid products. As fish cannot synthesize pigments endogenously, they must be provided in their diet, and in Atlantic salmon farming, synthetic astaxanthin is the most widely used dietary supplement. This study evaluated two astaxanthin products derived from the microalga Haematococcus lacustris against a commercial synthetic product. Seven dietary treatments were tested in duplicate tanks using Atlantic salmon reared in a commercial freshwater recirculation system. Diets included: a negative control with no astaxanthin (C); two synthetic astaxanthin positive control treatments at 40 and 80 mg Ax [kg diet]⁻¹, Low and High, respectively; and two natural astaxanthin products, oleoresin (O) and powder (P), each at the same two concentrations. Fish were assessed monthly for production parameters, and after six months, ten fish per tank were sampled for further analyses. Diet significantly influenced fillet pigmentation and tissue astaxanthin content, while most production parameters, biological indices, fillet proximate composition, structural parameters, and shelf life were not significantly affected. Initial fish size and stocking density significantly influenced several response variables. Oleoresin resulted in fillet pigmentation comparable to the synthetic product and superior to the powder product, indicating that it has strong potential as a natural alternative to synthetic astaxanthin in Atlantic salmon farming.