Search Results (101)

Red tilapia (Oreochromis sp.) fry are routinely transported between hatcheries and grow out farms, yet the effects of transport duration on epidermal barrier-associated responses and goblet cells remain poorly defined. This study assessed the impact of simulated transport on epidermal morphology, immune-related gene expression and goblet cell density in red tilapia fry. Fish were assigned to four groups (0, 5, 12 and 20 h of transport). Skin samples were analyzed for relative mRNA expression of 10 genes associated with tight junction proteins, mucins, antimicrobial peptides and cytokines using RT-qPCR, and for epidermal goblet cell density by histology. Transport significantly modulated eight genes, forming three co-expression clusters associated with inflammatory, barrier-related, and mucus-related responses, with mainly non-linear time courses. MUC2, DB-4, IL-1β, and TGF-β1b showed transient increases at 5–12 h, whereas MUC5AC and claudin transcripts increased earlier and approached control levels at 20 h. Goblet cell density remained relatively stable up to 12 h but declined after 20 h, coinciding with changes in MUC2 and MUC5AC expression and suggesting altered mucosal responses during prolonged transport. Overall, transport durations ≤ 12 h were associated with relatively stable epidermal responses, whereas 20 h induced pronounced changes in goblet cell density and barrier-associated gene expression. These findings provide information that may assist future optimization of transport practices in tilapia aquaculture. Transport stress in red tilapia fry induces rapid defensive responses, significantly modulating gene expression and mucosal dynamics; this is characterized by increased mucus production, goblet cell density, and early upregulation of mucins (MUC2), followed by later increases in tight junction genes and anti-inflammatory cytokines, alongside a temporary downregulation of antimicrobial peptides. Full article

This study compared floating raft and media bed aquaponic systems, assessing fish growth, plant growth, and system performance between common system designs. The study consisted of two trials utilizing six replicated aquaponic systems. In each trial, three of the systems were floating rafts (1514 L/system) and three were media beds (1136 L/system). In Trial 1, basil (Ocimum basilicum, ‘Genovese’) and green salanova lettuce (Lactuca sativa, ‘Salanova Green’) plants were stocked, and, in Trial 2, green and red salanova lettuce (Lactuca sativa, ‘Salanova Red’) plants were stocked. Nile tilapia (Oreochromis niloticus) were used in both trials. In Trial 1, no differences (p > 0.05) in fish or basil growth between floating raft (0.28 ± 0.10% daily growth; 55.0 ± 21.2 g/plant fresh weight (FW); 1106 ± 72 g total biomass/system) and media bed systems (0.29 ± 0.20%; 42.1 ± 7.8 g/plant FW; 879 ± 160 g total biomass/system) were found. However, in Trial 1, floating raft systems produced a significant (p < 0.01) increase in green salanova lettuce (123 ± 21.9 g/plant FW; 3327 ± 256 g total biomass/system) as compared to plants grown in media beds (94.4 ± 35.3 g/plant FW; 2,356 ± 260 g total biomass/system). In Trial 2, no differences (p > 0.05) in fish growth between floating raft (0.50 ± 0.13% daily growth) and media bed systems (0.50 ± 0.01% daily growth) were found; however, floating raft systems produced a significant (p < 0.01) increase in both green and red salanova lettuce individual weight (176.0 ± 34.0 g/plant FW; 169.3 ± 43.6 g/plant FW) as compared to media bed systems (79.2 ± 25.3 g/plant FW; 96.4 ± 22.6 g/plant FW). Green lettuce had a significant (p < 0.01) increase in average total biomass within floating raft systems (3662 ± 350 g total biomass/system) as compared to media beds (1576 ± 474 g total biomass/system). This study highlights the need for further investigation into system design and effects on plant and fish growth to allow producers to make informed decisions when planning an operation. Full article

Unrinsed surimi production has emerged as a sustainable alternative to conventional rinsed surimi due to its substantial water savings, reduced nutrient loss, and lower environmental footprint. However, poor gel strength and water-holding capacity remain major bottlenecks limiting its industrial application. This study investigated the effects of κ-carrageenan (κ-CG) on the rheological properties, textural characteristics, water distribution, intermolecular interactions, and microstructure of unrinsed surimi gels. The results showed that κ-CG enhanced gel properties in a concentration-dependent manner. At 0.75% κ-CG, gel strength increased to 47.0 g·cm (a 2.2-fold increase vs. control), water holding capacity (WHC) reached 97.9%, and cooking loss decreased to 4.0%. In contrast, at 1.0% κ-CG, gel strength and hardness further increased, but WHC declined slightly. Low-field nuclear magnetic resonance analysis revealed that κ-CG promoted the conversion of free water to immobilized water, with the relative peak area of T₂₂ (immobilized water) increasing from 85.9% to 88.9% at 0.75% κ-CG. Protein solubility measurements indicated that hydrophobic interactions and disulfide bonds appeared to be the major contributors stabilizing the gel network. FTIR revealed enhanced hydrogen bonding via an O–H red shift and intensification with κ-CG, and amide I deconvolution showed that 0.75% κ-CG maximized β-sheet content while reducing α-helix, indicating ordered protein reorganization during heating. Quantitative SEM analysis further verified that 0.75% κ-CG produced the densest protein network with the maximum fractal dimension and minimum lacunarity, alongside reduced average pore area and porosity. These findings demonstrate that κ-CG at an appropriate level effectively improves the gel properties of unrinsed tilapia surimi by strengthening intermolecular interactions and optimizing water distribution, offering a practical approach for developing high-quality surimi products. Full article

Betanodavirus is a causative agent of viral nervous necrosis (VNN) and a major threat to marine and brackish-water aquaculture globally. This virus causes epizootic outbreaks with particularly high morbidity and mortality in larval and juvenile stages and causes significant economic losses in aquaculture. Here, we developed a rapid and highly sensitive single-tube Reverse Transcription–Loop-Mediated Isothermal Amplification (RT-LAMP) assay for the detection of red-spotted grouper nervous necrosis virus (RGNNV) genotype infection in fish tissue samples. Six primers targeting eight conserved regions of the RNA2 coat protein gene of RGNNV were designed with conservation regions across RGNNV genotypes. RT-LAMP assay was completed within 60 min at 65 °C using a single-tube format that combined reverse transcription and isothermal amplification, and results were directly visualized by the addition of SYBR Green I dye, producing a colour change from orange (negative) to green (positive), observable with the naked eye or under UV illumination. The developed RT-LAMP assay was able to detect five copies of RGNNV from infected samples, which was 20-fold more sensitive than conventional reverse transcription-PCR. The assay demonstrated diagnostic sensitivity and specificity in two fish hosts (Asian seabass and cobia) and showed no cross reactivity with other fish viruses such as tilapia lake virus and cyprinid herpesvirus-2. The developed assay is simple, cost-effective, specific, and enables rapid detection of RGNNV in fish tissues. This single-tube RT-LAMP assay can be applied to screening broodstock facilities, fingerlings, aquaculture farms, quarantine facilities, and juveniles before stocking in ponds or cages, helping prevent disease outbreaks and the transmission of RGNNV in aquaculture systems. Full article

This study proposed an artificial intelligence framework for red tilapia weight-range classification from UAV-based aerial imagery using two hybrid deep learning models, namely Hybrid CNN-XGBoost and Hybrid EfficientNet-B0-XGBoost. Two image sizes were evaluated: 5 × 5 m images, which preserved the spatial context of the cage culture system, and 2 × 2 m images, which focused on areas with high fish aggregation density. For the 5 × 5 m images, Hybrid CNN-XGBoost achieved the highest performance, with a mean accuracy of 0.988 ± 0.008 (98.8%) at 20 tuning units, whereas Hybrid EfficientNet-B0-XGBoost achieved 0.977 ± 0.021 (97.7%) at 40 tuning units. In addition, Hybrid CNN-XGBoost exhibited a substantially shorter average computational workflow time per image (0.038 ± 0.001 s) than Hybrid EfficientNet-B0-XGBoost (65.007 ± 6.141 s). In contrast, under the 2 × 2 m image condition with limited spatial context, Hybrid EfficientNet-B0-XGBoost outperformed Hybrid CNN-XGBoost, achieving the highest mean accuracy of 0.900 ± 0.010 (90.0%) at 30 tuning units, compared with 0.850 ± 0.022 (85.0%) at 50 tuning units. These findings indicate that larger images improve classification accuracy by preserving spatial context, whereas EfficientNet-B0 enhances deep feature extraction capability and improves classification accuracy when spatial context is limited. Full article

Diatoms are recognized as a valuable source of bioactive compounds that can stimulate the immune defense mechanisms of fish. This study aimed to assess the effects of Chaetoceros sp. in modulating the specific and non-specific immunity of red hybrid tilapia through in vitro functional assays, an in vivo feeding trial, and a bacterial challenge. The in vitro experiment (Phase One) examined the immune response of tilapia cells exposed to Chaetoceros sp. extract, while the in vivo experiment (Phase Two) evaluated the immune response following an 8-week dietary supplementation with Chaetoceros sp. powder. In Phase One, an 8 mg/mL concentration of Chaetoceros sp. extract demonstrated an overall enhancement in lysozyme activity and lymphocyte proliferation. In Phase Two, tilapia fed a diet containing 2% Chaetoceros sp. showed significantly improved lysozyme activity, while the 5% supplemented group exhibited a significant increase in lymphoproliferation activity (p < 0.05). Growth performance parameters were generally comparable among dietary groups, indicating that supplementation did not adversely affect growth. Notably, the 2% diet also enhanced fish survivability following a challenge with Streptococcus agalactiae. These findings highlight the immunomodulatory potential of the diatom Chaetoceros sp. as a functional feed additive for freshwater fish, particularly red hybrid tilapia, and suggest its positive impact on fish health management in aquaculture. Full article

With increasing global demand for fishery products, saline-alkaline aquaculture has emerged as a potential solution. However, limited information exists regarding the tolerance and adaptability of red tilapia (Oreochromis spp.) to alkaline environments. This study evaluated the acute semi-lethal toxicity of alkaline water and its physiological effects on juvenile red tilapia (44.80 ± 1.09 g; 12.84 ± 1.02 cm). Fish were exposed to NaHCO₃ for 96 h at five alkalinity levels (50, 55, 60, 65, and 70 mmol/L). Survival declined significantly with increasing alkalinity, and the 96 h LC₅₀ was 60.66 mmol/L, indicating relatively high alkaline tolerance. Gill tissue and serum samples were collected at 0, 12, 24, 48, and 96 h under 50 mmol/L NaHCO₃ and freshwater (control). Under prolonged alkaline exposure, gill structure exhibited marked alterations, with SLL and ILCMT progressively decreasing over time. Serum antioxidant responses were impaired, showing a sustained decline in SOD activity and a rise in MDA content, indicating the onset of oxidative stress. TAOC, CAT, and GSH-Px displayed a biphasic response, rising initially before declining with continued stress. TP and GLU levels remained largely stable throughout. Energy metabolism indices also shifted dynamically: TC showed a transient increase followed by a decrease, whereas TG and LDH initially declined before rising later in the exposure period. Stress-related markers, including cortisol, T3, ALP, and ACP, were notably elevated during the exposure. Additionally, serum ion concentrations (K⁺, Ca²⁺, Na⁺, Cl⁻) increased gradually over the 96 h period, reflecting progressive osmoregulatory disturbance under alkaline stress. Overall, this study shows that juvenile red tilapia (Oreochromis spp.) have high alkaline tolerance (96 h LC₅₀ = 60.66 mmol/L NaHCO₃), but exposure to alkaline water causes significant physiological stress, affecting gill structure, antioxidant defense, metabolism, and ion balance. These results offer valuable insights into their adaptability to saline-alkaline aquaculture. Full article

Genome editing using site-directed nucleases (SDNs), particularly with the CRISPR/Cas9 system, has emerged as a powerful platform for aquaculture innovation, enabling precise, heritable, and non-transgenic modifications that enhance productivity, sustainability, and animal welfare. This review synthesizes molecular, regulatory, ecological, and societal perspectives to highlight global advances in genome-edited fish and their transition from laboratory research to field applications. To date, over forty aquatic species have been successfully edited to improve traits such as growth, disease resistance, pigmentation, and reproductive control. Notably, market-approved SDN-1 fish lines, including mstn-knockout red seabream and Nile tilapia, and lepr-edited tiger puffer and olive flounder, have demonstrated improved productivity; however, publicly available welfare data remain limited. These examples illustrate how product-based SDN-1 regulatory frameworks in Japan, Argentina, and Brazil enable commercialization while ensuring biosafety. Nonetheless, limited field trials and regulatory heterogeneity continue to hinder global harmonization. Major challenges include the development of standardized welfare metrics, assessment of multigenerational stability, evaluation of ecological risks, and transparent data sharing. To address these gaps, a structured reporting checklist is proposed to guide consistent molecular validation, welfare assessment, biosafety containment, and data transparency. Genome editing through SDN-based precision, coupled with ethical governance, represents a crucial step toward sustainable, resilient, and publicly trusted aquaculture systems. Full article

Intensive aquaculture practices heighten oxidative stress and infectious disease risk, necessitating sustainable alternatives to antibiotics. This study evaluated the integrative probiotic and postbiotic potential of Bacillus velezensis AAHM-BV2302 in red tilapia (Oreochromis spp.), focusing on growth, antioxidant defense, immune modulation, and resistance to Streptococcus agalactiae. Whole-genome sequencing confirmed its classification as B. velezensis (4.16 Mb, GC 45.9%, ANI 99.4% with NRRL B-41580). Fish were fed diets supplemented with probiotic cells (Cell), cell-free supernatant (Cfs), or their combination (Cell + Cfs) for 30 days, followed by 30 days without probiotic supplementation. Growth performance significantly improved in Cell and Cell + Cfs groups at both Day 30 and Day 60 (p < 0.05). Antioxidant enzymes (SOD, CAT, GSH) increased significantly across tissues at Day 30, while malondialdehyde (MDA) declined (p < 0.05), indicating enhanced redox homeostasis. Humoral immunity was elevated, with higher lysozyme, bactericidal activity, and total IgM persisting post-supplementation (p < 0.05). Expression of il1b, il6, and il8 was upregulated in immune-related and mucosal tissues, reflecting robust immune activation (p < 0.05). After S. agalactiae challenge, survival rates were 55% in Cfs, 60% in Cell, and 70% in Cell + Cfs, corresponding to relative percent survivals (RPS) of 43.8%, 50.0%, and 62.5%, respectively (p < 0.05). These results demonstrate that B. velezensis AAHM-BV2302 enhances growth, antioxidant capacity, and immune resilience through complementary probiotic–postbiotic mechanisms, supporting its application as a safe, multifunctional biotic for antibiotic-free tilapia aquaculture. Full article

Recirculating aquaculture systems (RAS) address pollution, disease, and sustainability in commercial fish farming, but marine RAS are limited by biofilter maturation and nitrification. This study investigated the effects of air nanobubbles on water quality, fish growth, and bacterial communities in marine RAS stocked with juvenile Malabar red snapper, barramundi and saline-tolerant hybrid tilapia. Flow cytometry was evaluated as a rapid management tool for non-culturable microbes, finding viable bacterial counts 30–100 times higher than conventional total plate counts. There were no significant differences in fish growth, survival, or Feed Conversion Ratio between groups, likely due to low stocking densities (<20 kg/m³) and high water exchange rates (>100%/hour), indicating low system stress. Air nanobubbles did not significantly increase dissolved oxygen levels. While bacterial abundance in water was consistently higher in nanobubble-treated RAS (RAS-N), tank walls showed less biofilm. RAS-N also exhibited a higher abundance of nitrifying bacteria like Nitrospira and Marinobacter, leading to improved nitrogenous waste breakdown and lower nitrite levels. Future research should investigate nanobubbles’ benefits at higher stocking densities and longer durations to fully assess their impact on intensive aquaculture. Full article

The tilapia sector is advancing due to breakthroughs in aquaculture techniques and genetic enhancements. Comprehending sensory qualities is crucial for producers striving to meet market demands efficiently. As consumer preferences play a significant role in shaping the market, enhancing the sensory attributes of both farmed and wild red tilapia will be key to ensuring their success in the competitive aquaculture industry. One of Malaysia’s most prominent aquaculture projects is the Como River Aquaculture Project located in Kenyir Lake, where tilapia fish farming, trademarked as Red Kenyir™, is conducted. Thus, this study aimed to evaluate the nutrient analysis of raw and five sensory attributes (appearance, texture, smell, taste, overall quality) of filets from Red Kenyir™ and wild red tilapia (Oreochromis sp.). Red Kenyir™ were fed three different commercial diets (A, B, and C) from fingerling to adulthood, while wild tilapia (W) was sourced from the market. Proximate and nutritional analyses were conducted based on the standard food analysis protocol by AOAC/AOCS. To the best of our knowledge, this is the first study to comprehensively document the nutrient analysis of raw and consumer sensory perception of cooked Red Kenyir™ aquaculture tilapia in direct comparison with wild red tilapia. The sensory evaluation was conducted using a consumer preference test. Statistical analysis was performed using SPSS. Nutrient analysis showed that Red Kenyir™ tilapia had lower fat (0.25–1.37 g/100 g vs. 4.30 g/100 g) and lower energy (77.38–113.46 kcal/100 g vs. 132.79 kcal/100 g) levels. Protein levels varied across groups (19–26.54 g/100 g vs. 22.95 g/100 g). The tryptophan content of the Red Kenyir™ tilapia samples ranged between 0.13 and 0.23 g/100 g, while the wild tilapia contained 0.19 mg/100 g. Sensory evaluation with 36 panelists revealed no significant differences in appearance, texture, or smell (p > 0.05). However, wild tilapia scored slightly higher in taste (4.14) than Red Kenyir™ (3.54–3.71) for steamed preparation (p < 0.05). In conclusion, these findings suggest that variations in the nutritional composition of Red Kenyir™ do not affect the sensory experience for consumer acceptance, making it a sustainable alternative for customers. Full article

Background: This study aimed to investigate rapid oxidation in poultry and fish myoglobin compared to livestock myoglobin using protein structural differences and bioinformatics tools. Methods: Myoglobins from beef (Bos taurus), bison (Bos bison), sheep (Ovis aries), goat (Capra hircus), red deer (Cervus elaphus), pork (Sus scrofa), chicken (Gallus gallus), turkey (Meleagris gallopavo), yellowfin tuna (Thunnus albacares), and tilapia (Oreochromis niloticus) were analyzed to understand differences in structure and function that may influence oxidative behavior. Results: Fish and poultry had shorter or absent D-helix in their myoglobin structure than other species. Tilapia showed the largest heme cavity surface area, indicating significant internal void space, while yellowfin tuna had the largest heme cavity volume, which could affect ligand binding dynamics compared with poultry and other livestock species. However, the heme solvent-accessible area was greater in chicken and turkey than in fish and other livestock species. Tuna myoglobin contains a cysteine and fish myoglobins have fewer amino acids compared to other species. Limited knowledge is currently available on the effects of proteoform, especially post-translational modifications, on the oxidation of myoglobin from different species. Conclusions: The bioinformatics approach used in this study suggests that, in addition to physiological reasons, shorter D-helix, larger heme cavity in tilapia and yellowfin tuna, and greater solvent-accessible area in poultry contribute to increased oxidation in myoglobin from poultry and fish compared with myoglobin from livestock species. Full article

This study addresses the growing need for intelligent monitoring in aquaponic systems by developing a predictive system based on artificial intelligence and environmental sensing. The goal is to improve fish welfare through the early detection of adverse water conditions. The system integrates low-cost digital sensors to continuously measure key physicochemical variables—pH, dissolved oxygen, and temperature—using these as inputs for real-time classification of fish health status. Four supervised machine learning models were evaluated: linear discriminant analysis (LDA), support vector machines (SVMs), neural networks (NNs), and random forest (RF). A dataset of 1823 instances was collected over eight months from a red tilapia aquaponic setup. The random forest model yielded the highest classification accuracy (99%), followed by NN (98%) and SVM (97%). LDA achieved 82% accuracy. Performance was validated using 5-fold cross-validation and label permutation tests to confirm model robustness. These results demonstrate that sensor-based predictive models can reliably detect early signs of fish stress or mortality, supporting the implementation of intelligent environmental monitoring and automation strategies in sustainable aquaponic production. Full article

Aquaculture is an important food sector, which involves the commercial production of fish for consumption. Tilapias (Oreochromis sp.) are hardy and are one of the most commonly produced fishes in the aquaculture industry. Disease outbreaks caused by Streptococcus agalactiae, however, widely affect tilapia farms, resulting in high mortality. Consequently, this may lead to the misuse of antibiotics for the prevention of disease or overuse of antibiotics when used for the treatment of fishes, contributing to antibiotic resistance. In this study, date palm pits, a waste product from the date palm industry, were tested for potential antibacterial activity against S. agalactiae and for their ability to act as an immune enhancer in vitro through the use of the head kidney and serum from healthy adult tilapias. An in vivo study was performed by dividing tilapias into two groups, consisting of infected S. agalactiae and uninfected S. agalactiae. Each group consisted of extract-fed and distilled-water-fed tilapia. Then, the serum, spleen and head kidney were isolated from both groups and tested for their respiratory burst, lysozyme and myeloperoxidase activities. The results from this study indicate that the Raziz methanol extract at a concentration of 1 g/mL inhibited the growth of S. agalactiae, and concentrations of 10 mg/mL, 2 mg/mL and 0.016 mg/mL displayed the highest respiratory burst, lysozyme and myeloperoxidase activities, respectively, in vitro. In the infected group, extract-fed tilapias showed a significant effect on respiratory burst activity and lysozyme activity compared to the distilled-water-fed tilapias, while no significant activity was observed in the uninfected group. In conclusion, the Raziz methanol extract has promising potential to act as an antibacterial agent, and it enhanced the innate immune function during active infection of S. agalactiae. Full article

The utilization of saline–alkali water resources presents a promising approach for freshwater aquaculture. Red tilapia (Oreochromis spp.) exhibits moderate salinity tolerance, but its adaptation mechanism to alkaline conditions remains poorly understood. In the current study, five alkaline carbonate concentrations in a 60-day chronic stress experiment on red tilapia were evaluated. The experimental design included a control group (CA0, 0 mmol/L) and three treatment groups (CA10, 20 mmol/L; CA30, 30 mmol/L; and CA40 40 mmol/L). The results indicated that at alkaline carbonate concentrations exceeding 20 mmol/L, the gill filaments exhibited curling and deformation, the hepatocytes displayed migration, and tissue damage increased significantly. The gill’s antioxidant capacity initially decreased and then increased, with severe gill injury in the CA40 group, leading to significantly reduced levels of SOD, CAT, and GSH-PX compared to the CA40 group (p < 0.05). Conversely, the enzymatic activities related to energy metabolism showed an opposite trend under alkaline carbonate stress. The transcriptome analyses of gill tissues across five groups identified significant alterations in key pathways, including the metabolic process (endocytosis, focal adhesion, PI3K−Akt signaling pathway, MAPK signaling pathway, and Citrate cycle (TCA cycle)), and immune responses (mTOR signaling and NOD−like receptor signaling pathways). Additionally, we screened 13 differentially expressed genes (DEGs) as potential regulators of alkaline stress and validated their expression levels using quantitative real-time PCR (qPCR). This study preliminarily elucidated the molecular mechanism of red tilapia in the physiological regulation process under chronic alkaline stress, and offers a theoretical foundation for breeding programs aimed at developing alkali-tolerant strains for aquaculture in alkaline water environments. Full article