Aquaculture International最新文献

In aquaculture, real-time and rapid detection of dead fish is important for early risk warning and improving aquaculture efficiency. However, the complex actual environment and uncontrollable fish movement have brought great challenges to the detection of dead fish. Therefore, this paper proposes a high-precision and lightweight dead fish-detection transformer (DF-DETR) based on machine vision and original RT-DETR (real-time detection transformer). The specific implementation is as follows: Firstly, the backbone of the original RT-DETR was replaced by the RepNCSPELAN module which extracts multi-scale features. This not only improves the model’s ability to detect targets of different sizes but also reduces the amount of model parameters. Secondly, the AIFI in the RT-DETR was improved to CascadedGroupAttention (CGA). By changing the original feature fusion method, different levels of features are grouped and attention mechanism is added, so as to capture more target features. Finally, the CCFM_CSP module was constructed to fuse important features using parallel dilated convolution with different expansion rates, which improves the detection accuracy. The experimental results show that the mAP@.5 of the proposed dead fish detection model DF-DETR can reach 96.6%, and the parameter amount is reduced by 27% compared with the original RT-DETR. In summary, the proposed DF-DETR model realizes real-time and high-precision dead fish detection, which can provide effective technical support for the development of intelligent inspection robots.

This study examined the protective effects of Spirulina platensis (SP) on African catfish (Clarias gariepinus) against ultraviolet radiation-A (UV-A) induced oxidative stress, immunotoxicity, and histological damage. Recognized for its nutritional value and environmental benefits, SP was evaluated as a potential bioremediation agent. The experiment involved four groups: a control group, a UV-A-exposed group, a UV-A + 100 mg/L SP group, and a UV-A + 200 mg/L SP group, with UV-A exposure for 1 h daily over 3 days. Serum markers of oxidative stress (superoxide dismutase (SOD), total antioxidant capacity (TAC), and malondialdehyde (MDA)) and immune responses (lysozyme (LYZ) and phagocytic activity (PhA)) were measured. UV-A exposure significantly decreased SOD and TAC levels and increased MDA levels. However, SP treatment countered these effects, raising SOD and TAC levels while lowering MDA levels in both SP-treated groups. Similarly, the UV-A-induced reduction in LYZ and PhA activities was reversed by SP treatment, returning to near control levels. Histological analysis showed substantial tissue damage in UV-A-exposed fish, which was mitigated in SP-treated groups, with higher SP concentrations offering greater protection. These results suggest that SP effectively reduces oxidative stress, boosts immune responses, and preserves tissue integrity in UV-A-exposed African catfish. Overall, this study highlights the potential of SP as a valuable bioremediation agent in aquaculture, promoting fish health and resilience to environmental stressors. SP emerges as a promising candidate for enhancing sustainable aquaculture practices through its protective and ameliorative properties.

Aquaponics is an activity that has been growing worldwide as a sustainable alternative for food production and practical implementation throughout society. The objective of this study was to develop micro-scale aquaponics with a native Brazilian species, the tambaqui (Colossoma macropomum), associated with the cultivation of microgreens, an agro-food trend, using arugula (Eruca sativa), with the aim of evaluating the economic viability of family production. For 70 days, the growth performance of 80 tambaqui juveniles (average initial weight = 61.88 g ± 8.31 g) was monitored. Two treatments with two hydroponics structures, Nutrient Film Technique (NFT) and Floating Raft Technology (FRT), each with four replications, were compared. Tambaqui survival was 100% in both treatments. The final weight of juveniles was 136.38 g (± 35.67 g) in NFT systems and 116.5 g (± 24.63 g) in FRT systems. In the four production cycles carried out, the arugula microgreens performed better in the NFT systems (157.38 g ± 21.74 g; 6.68 cm ± 0.17 cm) compared to FRT (41 g ± 6.18 g; 4.46 cm ± 0.58 cm), identifying the best hydroponic unit for the cultivation of E. sativa microgreens. Finally, the economic viability study was conducted considering the average wage in Brazil of US$ 285.66 for the implementation of a homemade aquaponic system. The possible scenarios considered a family income of two or more minimum wages for the implementation of at least one aquaponic system.

During the cultivation and transportation process, fish are often exposed to many types of stressors such as heat or cold shock, vibration, etc. Stress may cause diverse stress-related health problems such as endocrine disruption, slow growth, immune dysfunction and even produce high mortality. Various anti-stress agents have been developed to alleviate stress. However, the deficiency of stress related animal models limited the development of anti-stress agents. Therefore, it is very necessary to establish an animal model for monitoring of stress in fish species. In this study, we generated a transgenic Nile tilapia (Oreochromis niloticus) line Tg(Hspa8b: GFP) with a Hspa8b promoter-driven Green Fluorescence Protein (GFP) expression. Next, we validated the efficiency and sensitivity of Tg(Hspa8b: GFP) model by monitoring the effects of stresses including heat shock, cold shock and vibration on GFP expression. The results showed the ubiquitous GFP expression was inducible in all examined tissues, including gill, brain, eye, heart, caudal fin, intestine and muscle of Tg(Hspa8b: GFP) transgenic fish under stressful conditions. The elevated green fluorescent signals were even found in the gill of Tg(Hspa8b: GFP) transgenic fish as early as 0.5 h after exposure to stress, and the strong green fluorescence can be continuously observed from 0.5 to 12 h after stress. There was a strong positive correlation between the GFP expression and the endogenous Hspa8b mRNA expression, which indicates that the Tg(Hspa8b: GFP) transgenic Nile tilapia can be used as an effective model to monitor stress in vivo. Furthermore, we evaluated anti-stress protective effects of anti-stress agents using Tg(Hspa8b: GFP) transgenic fish and identified the optimum anti-stress agent under different stressful conditions. We found that vitamin C and eugenol were the two preferred anti-stress agents to alleviate heat stress. MS-222 and tea polyphenols possesses the most significant anti-stress activity under cold stress. MS-222 and vitamin C were the two preferred anti-stress agents to alleviate vibration stress. This report would suggest new avenues for monitoring of fish stress responses in vivo and evaluating the anti-stress effects of related agents.

The emergence of diseases is one of the main obstacles to the shrimp industry when it comes to intensive aquaculture practices. Ecytocnucleospora hepatopenaei (EHP) is one of the shrimp microsporidia known to cause growth retardation and white discoloration associated with musculature, thereby decreasing shrimp production yield. Prolonged use of chemotherapeutic agents in bulk quantities may result in drug-resistant pathogenic microbes, toxic, and residual sedimentation in aquatic ecosystems. In this present study, Melaleuca cajuputi leaf extract (MCLE) was extracted, and an acute toxicity test was carried out to determine a 96-h median lethality concentration (LC₅₀). The behavior of shrimp was also observed after exposure to MCLE to determine their responses. The microsporidian-infected Litopenaeus vannamei was obtained from the shrimp farm in Terengganu, Malaysia, and the isolation and identification of EHP were performed using the Percoll-gradient method and polymerase chain reaction (PCR), respectively. Subsequently, the MCLE at 10, 20, and 30% of 96-h LC₅₀ were exposed to the isolated EHP to determine their antimicrosporidian potential and the morphological changes were viewed under scanning electron microscopy (SEM). Results showed that the 96-h LC₅₀ of MCLE to L. vannamei was recorded to be 162.14 mg L⁻¹. Behavior responses were observed in L. vannamei after exposure to MCLE including agitation, swimming erratically, gasping at the water surface constantly, lethargy, and color changes in abdominal segments and carapace, and the severity was proportional with the MCLE concentrations. All MCLE concentrations cause inhibition to EHP, with 48.6 mg L⁻¹ causing severe impairment on the EHP cell membrane. The finding could be useful to find natural antimicrosporidian therapeutics as an alternative to combat EHP in shrimp farms.

This study evaluated the effects of adding Sophora flavescens ethanol extract to high soybean meal feed (soybean meal replaced 50% fish meal protein) on growth, antioxidant status, and immune response in pearl gentian grouper. The fish (72.5 ± 0.5 g) were randomly divided into three groups: the fish meal group (the FM group), the soybean meal group (the SBM group), and the SBM + 0.2% S. flavescens ethanol extract group (the SBMSF group). Three groups of iso-nitrogenous (50% protein) and iso-lipidic (10% lipid) diets were prepared and fed to fish for 8 weeks. The weight gain rate of the SBM group was 47.53 ± 13.07%, which was significantly decreased compared with the FM group (P < 0.05). After adding ethanol extract of S. flavescens, the average weight gain rate of the SBMSF group recovered to 89.75 ± 30.16%. Compared to the FM group, the SBM group showed decreased contents of immunoglobulin M (IgM) and complement 3 (C3) in serum and increased activity of trypsin in the intestinal tract, and the above phenomenon was effectively reversed in the SBMSF group. Intestinal antioxidant enzymes activity, including catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-PX), were significantly higher in the SBMSF group and FM group, than the SBM group (P < 0.05). The SBMSF group also had lower levels of malondialdehyde (MDA) than the SBM group. The SBM group showed increased intestinal inflammatory cytokine (tnf-α, il-8, il1-β) mRNA expression and decreased anti-inflammatory il-10 expression compared to the FM group, but the SBMSF group showed a reversal of these expression changes. Histological analysis revealed shortened intestinal villus folds, wider lamina propria, more goblet cells, and higher inflammatory cell infiltration in the SBM group versus the FM group, with the SBMSF group significantly improving these intestinal health parameters. In summary, S. flavescens ethanol extract supplementation in high-SBM feed enhanced antioxidant status, immunity, and growth in pearl gentian grouper, and exerted anti-inflammatory and antioxidant benefits. This highlights implications for developing soybean meal aquafeeds and therapies.

In recirculating aquaculture system, precise estimation of perch size from images is essential for developing intelligent management system. However, variations in fish postures and visual field lead to different fish sizes in RGB images, posing challenges for accurate fish detection and localization. To address the above issues, this paper proposes a nondestructive target detection and size measurement method for perch, based on depth information and RGB-D images. The details are as follows: firstly, the capture ability of perch key point features is augmented by a bi-level routing attention (BRA) mechanism. Secondly, the enhanced CSPDarknet53 to 2-Stage FPN(C2f) module and new detection layer are introduced into the model’s backbone and neck, further improving the learning ability of perch features and the recognition accuracy of small-size targets. Finally, based on the detected key point coordinates, the perch size is calculated by combining the three-dimensional transformation from depth camera and measurement model. The experimental results show that the mAP@.5:.95 for key point detection reaches 86.4%, which is 3.6% higher than the baseline model, and the average relative error of perch size measurement is ± 5%. The proposed model provides an important basis for developing scientific feeding strategies and harvest plans.

The farming of Marsupenaeus japonicas in recirculating aquaculture system (RAS) is relatively recent; consequently, knowledge of their dietary protein requirements is still insufficient. Due to the specific ecological conditions of RAS, these systems may affect the nutritional requirements of shrimp. Therefore, this study aimed at assessing the optimal protein requirement of M. japonicas in RAS. Six experimental diets were devised to contain 35%, 40%, 45%, 50%, 55%, and 60% crude protein (P35, P40, P45, P50, P55, and P60, respectively) and were fed in triplicate groups of 20 shrimp (initial body weight 1.86 ± 0.01 g) at a feeding rate of 3.0% body weight per day for 56 days. At the end of the feeding period, the optimal protein requirement was estimated at 46.13% for weight gain rate, and specific growth rate with all groups exhibited high survival rates. The P45 diet increased the digestive enzyme activities, antioxidant indices, and improved intestinal morphology, while the P50 diet showed the highest intestinal microbiome diversity. The experimental results showed that diets containing higher protein seemed to have compromised the antioxidant status of shrimp and did not necessarily result in better growth. Hence, results from this study suggested that the optimal protein requirement of M. japonicas fed in RAS was determined to be 46.13%, but protein levels up to 50% can be beneficial to the intestinal microbiome diversity.

The burgeoning field of the aquaculture industry has experienced a paradigm shift over the last three decades with the introduction of triploid animals. This review paper aims to dissect the comparative investigations on the performance of triploid and diploid animals within aquacultural practices, focusing on salmonids and oysters. The core of this article lies in the application of omics platforms, encompassing genomics, transcriptomics, proteomics, and metabolomics, to a comprehensive understanding of the intricacies of triploid biology in contrast to their diploid counterparts. Omics technologies have developed as crucial tools in studying triploid fish and bivalves, offering unprecedented visions into their genomic, transcriptomic, proteomic, and metabolic makeups. These visions are vital for enhancing our understanding of triploid performance, often marked by increased growth rates and partial or complete reproductive sterility, making them highly valuable for aquaculture. The paper highlights the importance of omics in identifying the molecular determinants of these desirable traits, thereby providing a molecular lens through which the efficacy of triploid aquaculture species is assessable. The review synthesizes the main findings from various omics platforms, revealing that triploids display distinct molecular profiles that confer them with superior aquacultural qualities. These comprise alterations in gene expression patterns related to growth and stress response, gonadal development, nutritional requirements, and unique metabolic adaptations. Providing a comprehensive omics-based comparison illuminates the path forward for optimizing triploid production, ensuring food security, and advancing the aquaculture industry toward a more sustainable future.

Aquaculture plays a vital role in global food production, and maintaining optimal water quality is essential for the health and growth of aquatic species. This research addresses the need for an efficient, adaptive solution by introducing an innovative water quality monitoring and maintenance system for aquaculture ponds. Unlike conventional systems, our approach uniquely integrates fuzzy logic with IoT technologies to optimise the precision and adaptability of pond management. The system stands out with its continuous monitoring of critical parameters such as temperature, pH, dissolved oxygen (DO), weather conditions and salinity and its ability to autonomously adjust operational controls, such as aerators and water pumps, based on dynamic environmental changes. This ensures ideal water conditions without manual intervention, providing a reliable and effective solution for aquaculture pond management. This work’s novelty lies in applying fuzzy Logic to handle the complexity and variability of aquaculture environments, allowing for nuanced control decisions that improve water quality management. The system’s efficiency was demonstrated through a 72-h operational test, where it maintained optimal DO and salinity levels, showcasing its reliability and effectiveness in real-world conditions. The fuzzy logic model has demonstrated a commendable accuracy rate of 98%. These results validate the system’s performance and underscore its practical benefits, meeting the demands of aquaculture production and significantly enhancing operational efficiency by enabling remote monitoring and rapid issue identification. This research contributes a robust technological solution for aquafarmers, offering a promising advancement in aquaculture management by improving productivity and ensuring the health and growth of aquatic species.