Sustainable Aquaculture Practices Research Articles

Crassocephalum crepidioides as a sustainable protein supplement in Chocolatemahseer (Neolissochilus hexagonolepis) diets: Implications for growth,health, and economic viability in sustainable aquaculture

This study investigated the potential of Crassocephalum crepidioides, an abundant weed as a protein supplement in chocolate mahseer (Neolissochilus hexagonolepis) diets. The plant replaced a combination of fish meal and mustard oil cake at 0%, 25%, 50%, 75%, and 100% in experimental diets. A 12-week feeding trial was conducted to assess growth performance, survival, biomass yield, digestive enzyme activity, blood parameters, and economic viability. Results indicated that C. crepidioides can effectively replace up to 61.3% of the combined fish meal and mustard oil cake protein without negatively impacting fish health or growth, while reducing feed costs. Fish fed diets with 25% replacement showed improved weight gain (15.5±0.7 g) and biomass yield (6.05±0.25 kg/m³) compared to the control (14.6±0.8 g and 5.75±0.28 kg/m³, respectively). Survival rates were high across all treatments (94.0- 97.3%). Digestive enzyme activities and blood parameters remained within normal ranges for inclusion levels up to 75%. Economic analysis revealed potential cost savings of up to 15.5% when incorporating C. crepidioides into mahseer diets. This finding presents an opportunity to develop low-cost fish feed for resource-poor farmers in Meghalaya, effectively converting a local weed into a valuable aquaculture input, with broader implications for sustainable aquaculture practices globally.

Impact of Water Quality and Phytoplankton on Juvenile Vannamei Shrimp Growth in Low-Salinity Ponds

The Vannamei shrimp (Litopenaeus vannamei) is a key species in global aquaculture, with its growth influenced by various environmental factors and nutritional quality. This study aimed to analyze water quality parameters and phytoplankton density, as well as assess the growth of juvenile Vannamei shrimp in circular ponds with low salinity (5-6 ppt). Shrimp were stocked at a density of 80 individuals per square meter in 5-ton capacity tanks and fed four times daily over a 30-day period. Water quality parameters, including temperature, dissolved oxygen, pH, and light intensity, were monitored bi-daily, revealing fluctuations that impacted shrimp health. Notably, plankton density assessments showed Cyclotella present on day 14 but absent on day 28, while Microcystis and Rhizosolenia were detected on day 28, indicating shifts in the phytoplankton community. The specific growth rate (SGR) of shrimp was measured at 18.69% per day, with initial and final weights recorded at 0.01 ± 0.00 g and 2.72 ± 0.23 g, respectively. This study highlights the importance of maintaining optimal water quality and understanding phytoplankton dynamics for enhancing shrimp growth. Additionally, it explores the potential benefits of alginate supplementation and the effects of low salinity on the growth of juvenile Vannamei shrimp, contributing valuable insights for sustainable aquaculture practices.

Strategies and Techniques for Enhancing Fish Health and Averting Disease Outbreaks in Aquaculture Settings through the Use of Vaccination: A Review

The fastest–growing animal food-producing agricultural sector in the world is aquaculture, which accounts for almost half of the world’s food fish production.However, the expansion of high-density fish populations also brings forth a challenge–the rapid transmission and spread of infectious agents including several viral, bacterial, and parasitic diseases. Expansion and successful development of sustainable aquaculture practice and increasing production largely depends upon the prevention and control of outbreaks of several emerging and re-emerging infectious diseases which can result in economic loss, food safety hazards, and environmental hazards. Vaccination strategies have become highly effective and economical in protecting the health of fish and other aquaculture organisms from various infectious diseases such as edwardsiellosis, motile aeromonas septicemia (MAS), Tilapia Lake Virus (TiLV) disease, infectious salmon anemia (ISA), vibriosis, and white spot disease etc. An ideal vaccine is expected to be safe, effective, economical, and easily administered. Most of the available fish vaccines are empirically designed vaccines based on inactivated or live attenuated bacterin vaccines. Novel advances in the fields of immunology, biotechnology, and molecular biology have led to the development in designing novel and effective fish vaccines and the improvement of the existing vaccines to provide sufficient immune protection against diseases. This review investigates the currently available fish vaccines for use in finfish aquaculture against different infectious diseases different mode of vaccine administration with addressing pros and cons in detail. The information was collected from different secondary sources, and then compiled systematically.

Interplay of natural and anthropogenic factors in sediment dynamics and trace element distribution in Güllük Gulf, western Türkiye: A comprehensive geochemical and hydrodynamic analysis

Güllük Gulf, located in the southeastern Aegean Sea, is significantly impacted by diverse human activities, including urban development, tourism, and intensive aquaculture. This study aims to assess the spatial distribution of trace metals in the Gulf's sediments, identify their sources, and evaluate their environmental impacts to inform effective management strategies. It also examines sediment transport patterns, which are crucial in influencing the distribution and concentration of pollutants. Establishing background concentration levels for various elements provides a baseline to assess pollution levels and identify deviations due to anthropogenic impact. Sediment samples were collected from 45 stations and analyzed for grain size, organic carbon, carbonate content, and concentrations of 26 elements. Contamination was assessed using indices such as Enrichment Factor (EF), Geoaccumulation Index (Igeo), Contamination Factor (Cf), Degree of Contamination (Cdeg), Pollution Load Index (PLI), Modified Pollution Index (MPI), and Toxic Risk Index (TRI). Statistical analyses, including Principal Component Analysis (PCA) and Cluster Analysis (CA), were used to identify pollution sources. Results indicated that Güllük Gulf's sediments are predominantly sandy, with significant silt and clay fractions in sheltered bays. Organic carbon content averaged 1.68%, with higher values near urban and aquaculture areas. Trace metal concentrations exhibited notable spatial variability, with elevated levels of Pb, Cu and Zn in specific areas, indicating both natural and anthropogenic sources. PCA identified five significant factors contributing to metal presence, linking them to lithogenic origins, aquaculture activities, and industrial inputs. TRI results showed moderate toxic risk in Asin Bay, primarily due to Ni, As and Cr. The sediment transport model of Güllük Gulf, crucial in understanding regional pollution dynamics, revealed a complex interplay of hydrodynamic forces. The study underscores the significant environmental impact of human activities on sediment quality in Güllük Gulf. Elevated trace metal levels near aquaculture sites emphasize the need for stringent environmental management practices. Effective strategies should include regular monitoring, sustainable aquaculture practices, and stakeholder engagement to mitigate environmental impacts and preserve the Gulf's ecological integrity. This comprehensive approach provides crucial insights for future research and environmental management policies aimed at addressing the complex challenges facing Güllük Gulf.

Modulatory effects of Enteromorpha prolifera powder and its enzymatic hydrolysate on growth performance, antioxidant capacity, and non-specific immunity of Trachinotus ovatus

The excessive proliferation of the genus Enteromorpha serves as the primary catalyst for the occurrence of red tides. Nonetheless, this genus is abundant in sulfated polysaccharides, phenolic compounds, peptides, and alkaloids, which exhibit remarkable efficacy in antioxidation, anti-inflammation, and immune response modulation. Consequently, Enteromorpha-derived products hold promising application prospects as aquatic feed additives. The primary objective of this study was to evaluate the impact of E. prolifera powder (EPM) and its enzymatic hydrolysate (EPH) on the growth, antioxidant capacity, intestinal morphology, and immunity of juvenile Trachinotus ovatus. Four isonitrogenous and isolipidic diets were formulated with varying levels of Enteromorpha products: 0 % (Control), 0.1 % EPH (EPH0.1), 0.3 % EPH (EPH0.3), and 3 % EPM, and were administered to juvenile T. ovatus for eight weeks. The findings revealed that growth performance in the EPH0.3 and EPM groups surpassed that of the control group, concomitant with increased feed intake and elongated intestinal villi. Notably, Enteromorpha-derived products supplementation significantly bolstered the antioxidant capacity of T. ovatus through activation of the Nrf2-Keap1 signaling pathway, leading to elevations in antioxidant enzymes such as SOD and CAT, as well as T-AOC. Conversely, MDA levels were conspicuously reduced in the Enteromorpha-treated groups. Moreover, Enteromorpha-derived products supplementation exhibited pronounced anti-inflammatory effects, marked by the downregulation of proinflammatory cytokine expression and upregulation of anti-inflammatory cytokines, along with decreased apoptotic gene expression. These observations highlight the potential anti-inflammatory properties of EPM and EPH, which may contribute to the preservation of hepatic tissue health and homeostasis. In summary, the optimal growth performance and antioxidant capacity were achieved with 0.3 % EPH supplementation, indicating the efficacy of this concentration in promoting the overall wellbeing of T. ovatus. Remarkably, the employment of processing methodologies, notably enzymatic hydrolysis, has not only facilitated the manifestation but also potentially augmented the inherent beneficial attributes traditionally ascribed to EPM. Furthermore, this refinement process has enabled a reduction in the inclusion rate of EPM within feed formulations, thereby enhancing cost-effectiveness. Consequently, Enteromorpha-derived products emerge as highly promising candidates for aquatic feed additives, with the potential to mitigate the economic burdens imposed by red tide management strategies. Their utilization represents a strategic approach towards sustainable aquaculture practices.

Developing a Microsatellite Polymerase Chain Reaction System for Small Yellow Croaker (Larimichthys polyactis) and Its Application in Parentage Assignment.

(1) Background: The small yellow croaker, an economically important fish in East Asia, has been subjected to population declines due to overfishing and environmental pressures. The development of effective breeding programs is considered crucial for the species, and accurate parentage assignment is deemed essential for such programs. (2) Methods: The assembled reference genome of the small yellow croaker was utilized to select highly polymorphic microsatellite markers. A multiplex PCR system was optimized for the simultaneous amplification of these markers. The system's accuracy was validated using controlled mating pairs and subsequently applied to a group mating scenario. (3) Results: The developed multiplex PCR system demonstrated high accuracy in assigning offspring to their parents in both the controlled and group mating scenarios. (4) Conclusions: The system is presented as a valuable tool for pedigree management, selective breeding, and conservation efforts for the small yellow croaker, facilitating sustainable aquaculture practices and genetic improvement.

Development of a haplotype reference panel and analysis of genetic structure in Golden Pompano (Trachinotus ovatus)

Trachinotus ovatus, a valuable marine fish, is primarily farmed in the South China Sea. Intensive aquaculture can lead to genetic uniformity and disease risks. Additionally, the high cost of genome sequencing restricts knowledge of genetic variation, hindering genetic analysis and breeding advancements. This study investigated the genetic diversity and structure of Trachinotus ovatus populations within the South China Sea aquaculture context, with the goal of strengthening sustainability. Additionally, the study also enhanced breeding strategies by developing a high-quality haplotype reference panel and an efficient imputation process. Through high-throughput sequencing (depth＞20X), 173 samples from three key breeding sites (SanYa, Hainan; Zhanjiang, Guangdong; and Beihai, Guangxi) were analyzed, revealing substantial genetic diversity and distinct population structures. Notably, the Beihai (BH) population exhibited significant stratification, suggesting regional genetic uniqueness. Low levels of genomic inbreeding coefficient and the identification of unique SNP loci across populations underscored the genetic richness within these Trachinotus ovatus communities. A major constructed of this work is the creation of the first high-quality haplotype reference panel for the species, demonstrating genotype imputation's viability as a cost-effective alternative for large-scale genetic studies in aquaculture. In particular, a Shapeit reference panel with 5476,550 SNPs was created, excelling in accuracy across various depths, notably achieving up to 95.8 % imputation accuracy at 1X sequencing depth. This high accuracy across populations shows the importance of genetic diversity in the panel. This research not only advances the understanding of Trachinotus ovatus genetic foundations but also provides crucial insights for conservation efforts and genetic analysis. By establishing a robust haplotype reference panel for Trachinotus ovatus helps lower the costs of future genetic research and variation studies, this study lays the foundation for sustainable aquaculture practices and breeding programs.

Aquaculture and climate change: a data-driven analysis

Abstract As climate change increasingly impacts the aquaculture industry, it poses challenges to production quality, management, and sustainability. This study provides a scientometric analysis of 47 years of research on aquaculture and climate change, analysing 4,785 articles and 224,895 references through CiteSpace software. The study highlights enduring themes such as “ocean acidification” and “global warming,” alongside emerging concerns like “deforestation” and “nutrient runoff,” reflecting new research directions. Notably, “seasonal variations” persist as a key focus due to their significant impact on aquaculture practices. Fourteen research clusters were identified, revealing a diverse array of topics from environmental performance to the effects of blue food systems and ocean acidification on marine life. Clusters related to “carbon sequestration,” “seaweed farming,” and “integrated multi-trophic aquaculture (IMTA)” emphasise the shift toward innovative practices aimed at mitigating climate impacts and enhancing sustainability. The analysis shows a need for more collaborative research, particularly from leading contributors such as the USA, Europe and Australia with underrepresented regions like Southeast Asia and Africa, to develop resilient aquaculture systems capable of adapting to climatic challenges. It advocates for the integration of new technologies and the exploration of sustainable aquaculture practices that minimise environmental impacts while enhancing global food security. This approach sets a direction for future research to promote adaptive strategies and technological innovations in aquaculture.

Sustainable aquaculture of West African freshwater prawns Macrobrachium vollenhovenii (Herklots, 1857) and M. macrobrachion (Herklots, 1851) (Decapoda: Caridea: Palaemonidae)

Abstract The river prawn Macrobrachium vollenhovenii (Herklots, 1857) and the brackish river prawn M. macrobrachion (Herklots, 1851) are economically and ecologically significant West African species. Recent molecular studies suggest they might be different ecotypes of the same species, complicating taxonomy and sustainable aquaculture practices. Both species face significant threats from human exploitation, leading to high exploitation rates and smaller average sizes within populations. Seasonal variations affect their abundance, with M. macrobrachion more prevalent during the rainy season and M. vollenhovenii thriving in the dry season. Their omnivorous detritivorous feeding habits involve consuming detritus, diatoms, phytoplankton, and insect larvae during juvenile stages. Aquaculture of M. vollenhovenii and M. macrobrachion encounters difficulties such as limited hatchery technology and low larval survival rates. Efforts to cultivate juveniles or adults in captivity face obstacles like high mortality rates due to moulting stress, handling, feeding, and cannibalism. Reintroducing captive-bred prawns into the wild offers dual benefits: controlling snail populations that host parasite causing schistosomiasis and restoring ecological balance while enhancing local fisheries and providing socio-economic benefits. To achieve sustainable aquaculture, it is crucial to address taxonomic complexities, implement management measures to mitigate overexploitation, improve hatchery technology, optimise feeding strategies, reduce stress during moulting and handling, and engage local communities through capacity building and awareness programs. This review aims to contribute to a better understanding of these prawns, promoting informed decision-making for sustainable management, conservation, and socio-economic benefits in West Africa.

Impact of Chaetomorpha aerea-enriched diet on growth, feed utilization, and haemato-immunological responses in Clarias batrachus challenged with Aeromonas hydrophila

The bacteria Aeromonas hydrophila, which causes motile Aeromonas septicemia (MAS), is dangerous to aquaculture because it affects the fish's well-being and production. As the aquaculture industry seeks sustainable and effective methods to enhance fish immunity and growth, natural supplements such as marine algae have gained attention. This study explored the potential benefits of incorporating the green marine algae Chaetomorpha aerea into the fish diet, focusing on disease resistance, growth, feed utilization, and hematological and immunological responses. Five diets were prepared, varying concentrations of C. aerea (0 control, T1: 1 g/kg; T2: 2 g/kg: T3: 5 g/kg: and T4: 10 g/kg) and administered to fish over 30 days. Following the feeding trial, the fish were exposed to A. hydrophila, and their survival rates were observed for the next 14 days. The findings demonstrated that the final weight, weight gain, relative growth rate, specific growth rate, and daily growth rate were all positively impacted by a diet containing 5 g/kg of C. aerea. Additionally, fish in the 5 g/kg C. aerea group demonstrated improved feed conversion efficiency compared to the control group. While there were no significant changes in red and white blood cell counts on the initial day, serum lysozyme activity and overall resistance to infection were enhanced in fish receiving C. aerea at 2 and 5 g/kg. These results imply that C. aerea supplementation with fish supplements may be a useful immunostimulant, boosting improved health and growth in sustainable aquaculture practices.

Palmatine as a potent immunomodulator: Enhancing resistance to Micropterus salmoides rhabdovirus in largemouth bass through innate immune activation and viral suppression

Micropterus salmoides rhabdovirus (MSRV) poses a significant threat to aquaculture, causing substantial economic losses. In this study, we evaluated the antiviral efficacy and immunomodulatory potential of palmatine, a plant-derived monomer, against MSRV infection in largemouth bass. Our results demonstrated that palmatine significantly inhibited MSRV replication, with a reduction in viral nucleoprotein expression by 85 % at a safe concentration. Additionally, palmatine pre-treatment of EPC cells enhanced their antiviral capacity, with a maximum inhibition rate of 82 % following 24 h pre-incubation. Palmatine also effectively reduced MSRV-induced cytopathic effects, protecting cellular integrity and maintaining mitochondrial membrane potential. In vivo studies revealed that palmatine immersion at 80 mg/L was non-toxic and significantly suppressed MSRV replication in largemouth bass, increasing survival rates by 53 % over 15 d. Furthermore, palmatine pre-treatment enhanced the fish's resistance to MSRV, with a 78 % inhibition rate of viral replication and a 46 % increase in survival rate. Mechanistically, palmatine activated key immune genes, including IRF3, IRF7, and IFN, indicating its role in boosting innate immune responses. The compound also reduced horizontal transmission of MSRV in a cohabitation model, decreasing viral spread by up to 78 % over nine days. These findings highlight palmatine's potential as a small-molecule immunomodulator in aquaculture, offering a sustainable approach to disease management and enhancing fish health and welfare. Integrating palmatine into fish diets as an immunostimulant could provide a continuous, proactive defense against viral outbreaks, promoting more resilient and sustainable aquaculture practices.

Pilot-scale investigation of an advanced biofloc technology for treating Pacific white shrimp effluent: Performance and insight mechanisms

Biofloc technology (BFT) is extensively used in the treatment of water quality in intensive shrimp aquaculture systems. However, the rapid accumulation of biofloc in middle-to-late culture stages poses challenges for system management, impacting the economic yield of aquaculture operations. To address this issue, an advanced biofloc system (A-BS) that integrates a moving bed biofilm reactor (MBBR) with BFT was constructed, and the biofloc system (BS) was used as a control group. During a 100-day pilot-scale operation, the A-BS group effectively regulated water quality and enhanced the growth rate of Pacific white shrimp (Litopenaeus vannamei). In the A-BS group, the average concentrations of ammonia, nitrite, chemical oxygen demand, and mixed liquor suspended solids were substantially reduced compared to those in the BS group, measuring 0.19, 0.55, 36.36, and 229 mg/L, respectively, across the middle-to-late culture stages. Notably, the final stocking density and survival rate of shrimp in the A-BS group, reached 7.04 kg/m3 and 81.22 %, surpassing those in the BFT group. Furthermore, microbial community and functional gene analyses revealed more in-depth insights into the related mechanisms. Bacterial abundance and diversity, as well as the presence of denitrification genes such as Unclassified_f_Rhodobacteraceae and Paracoccus, were markedly higher in the A-BS group than in the BS group. The integration of MBBR into A-BS significantly increased the abundance of amoA and nirK genes, which are crucial for water quality stability during later culture stages. This proof-of-concept investigation confirms that the MBBR–BFT coupling process in A-BS holds promise for advancing sustainable aquaculture practice and provides strategic guidance for the modernization of the industry.

CRISPR/Cas9 Technology for Enhancing Desirable Traits of Fish Species in Aquaculture.

Aquaculture, the world's fastest-growing food production sector, is critical for addressing food security concerns because of its potential to deliver high-quality, nutrient-rich supplies by 2050. This review assesses the effectiveness of CRISPR/Cas9 genome editing technology in enhancing desirable traits in fish species, including growth rates, muscle quality, disease resistance, pigmentation, and more. It also focuses on the potential effectiveness of the technology in allowing precise and targeted modifications of fish DNA to improve desirable characteristics. Many studies have reported successful applications of CRISPR/Cas9, such as knocking out reproductive genes to control reproduction and sex determination, enhancing feed conversion efficiency, and reducing off-target effects. Additionally, this technology has contributed to environmental sustainability by reducing nitrogen-rich waste and improving the nutritional composition of fish. However, the acceptance of CRISPR/Cas9 modified fish by the public and consumers is hindered by concerns regarding public perception, potential ecological impacts, and regulatory frameworks. To gain public approval and consumer confidence, clear communication about the editing process, as well as data on the safety and environmental considerations of genetically modified fish, are essential. This review paper discusses these challenges, provides possible solutions, and recommends future research on the integration of CRISPR/Cas9 into sustainable aquaculture practices, focusing on the responsible management of genetically modified fish to enable the creation of growth and disease-resistant strains. In conclusion, this review highlights the transformative potential of CRISPR/Cas9 technology in improving fish traits, while also considering the challenges and ethical considerations associated with sustainable and responsible practices in aquaculture.

Sustainable aquaculture practices in South Asia: a comparative analysis of feed formulation and utilization.

Sustainable aquaculture practices in South Asia: a comparative analysis of feed formulation and utilization.

Effects of disturbances on the spatiotemporal patterns and dynamics of coastal wetland vegetation

The coastal wetlands represented by mangroves are vulnerable to disturbances. To clarify the effects of disturbances quantitatively on mangroves, spatiotemporal changes in land use and land cover (LULC) were compared between the inside and outside of mangroves during 1988 and 2020 in Bangladesh by remote sensing. The mangrove region, which had diverse surface greenness due to natural and anthropogenic disturbances, were surveyed. Changes in greenness were estimated by five vegetation indices (VIs). To increase in the accuracy of land use classification, the five VIs were combined under a random forest (RF) classifier. The five VIs were: normalized difference vegetation index (NDVI), green NDVI (GNDVI), soil-adjusted VI (SAVI), green–red VI (GRVI) and enhanced VI (EVI), using data obtained from Landsat TM (30 m resolution) and Sentinel-2A (10 m) via Google Earth Engine. A Moran’s I analysis showed a random pattern of training samples of LULC classes for integrated RF classification. The classification accuracy was evaluated using the reference point data with multiple comparisons of VIs and κ coefficient. The area was classified into eight LULC classes. Although the respective VIs depicted unique characteristics, the accuracies of them were less than 89 %. The integrated classifier improved the accuracy of 96–97 % with κ of 0.96 in 1988 and 0.97 in 2020. The VI-integrated RF was the most effective classifier for LULC, particularly for separating mangroves from homestead vegetation. The changes for 32 years showed that the dense mangrove occupied 42 % of surveyed area in 1988 but declined ca 622 km2 in 2020, whereas sparse mangrove and aquaculture increased by 487 km2 and 464 km2, respectively, out of the total area of 8,360 km2. The changes in LULC classes were mostly from dense mangroves to sparse mangroves, sparse mangroves to dense mangroves and from cropland to bare land and aquaculture. Inaccessible mangrove degradation should result from natural disturbances, i.e., tropical cyclones, while areas near forest boundaries were distorted by anthropogenic disturbances such as aquaculture development. The restoration of habitat quality, mangrove afforestation and sustainable aquaculture practices were effective indicators for improving the mangrove ecosystems. Since natural and anthropogenic disturbances induce substantial loss of mangrove vegetation, the VI-integrated RF classifier should be applied for monitoring LULC and for developing the sustainable management strategies.

A Review Paper on Bioremediation, A Panacea to Aquaculture Productivity

Aquaculture production encompasses the cultivation of aquatic organisms, including fish, shellfish, and plants, within controlled environments, playing a pivotal role in meeting the escalating global demand for fish and seafood. Various techniques are employed, ranging from fish farming in ponds, cages, or tanks to the cultivation of seaweed and other aquatic flora. The overarching objective is to achieve sustainable production while minimizing adverse environmental impacts. The utilization of bioremediation techniques in aquaculture entails harnessing microorganisms to degrade pollutants and ameliorate water quality, thereby fostering a healthier environment conducive to the thriving of aquatic organisms. Strategic interventions, such as the introduction of specific bacteria or plants capable of absorbing excess nutrients, contribute to ecosystem equilibrium, thereby promoting sustainable aquaculture practices. Leveraging living organisms to detoxify or eliminate pollutants represents a promising strategy for addressing environmental challenges associated with intensive aquaculture. The review delves into elucidating the mechanisms underlying microbial communities and selected organisms' capacity to mitigate water quality issues, notably excess nutrients and organic matter accumulation. Common bioremediation approaches encompass the utilization of beneficial bacteria, denitrifying bacteria, Nano remediation, biological filters, bioaugmentation, and oxygenation. By integrating these bioremediation techniques, aquaculture enterprises can bolster water quality, mitigate disease risks, and foster a more sustainable and productive aquatic environment conducive to the flourishing of aquatic organisms.

Investigating the Impact of Senna alata Extract on Hematology and Histopathology of Juvenile of Clarias gariepinus

This paper sheds light on the mechanism of action, potential effects and implication of Senna alata on fish health and ecosystem. Senna alata is renowned for its medicinal properties and ornamental value but is also recognized for its potential toxicity, particularly to aquatic organisms Understanding the toxicity of Senna alata to Clarias gariepinus fingerlings is essential for sustainable aquaculture practices and environmental conservation efforts. 250 juveniles of C. gariepinus were procured from E. I farm Limited in Ikot Ekpene, Akwa Ibom State. Water quality tests were carried out to ensure that optimum water conditions were maintained and that the results obtained were solely due to the effects of the treatments (toxicants) on the fish samples. Chronic toxicity bioassay was done to determine the toxicity of the extract on the blood parameters and tissues of sensitive organs of the exposed fish. The bioassay was designed to be intermediate termed chronic test with 14 days exposure using sub-lethal concentrations of the treatment (0.0gm/, 0.18mg/L, 0.27mg/L. 0.4mg/L, 0.60mg/L, 0.90mg/L). Toxicology dose response (fish mortality) was subjected to detailed analysis using Statistical Package for Social Sciences (SPSS) 22.0. Data were analyzed using descriptive statistics. Senna alata exerted a toxic effect on the fish in the present study and toxicity increased with increased concentration. These findings underscore the potential adverse effects of prolonged exposure to Senna alata on the physiological and cellular integrity of the fish. Intriguingly, the absence of pathological changes in the control groups suggests a distinct response attributable to the treatment. This highlights the importance of continued monitoring and assessment of the impacts of Senna alata on aquatic organisms and ecosystem, emphasizing the need for further research to elucidate the underlying mechanisms and potential long-term consequences.

Sustainable aquaculture over the last 30 years: An analysis of the scientific literature by the Text Mining approach

AbstractA literature search approach (using Scopus®, Elsevier© database) was established to identify peer‐reviewed articles published in English between 1960 and 2023 dealing with ‘sustainable aquaculture’ and focusing on specific aquaculture practices (aquaponics, integrated multi‐trophic aquaculture, biofloc and recirculating aquaculture systems). Text Mining combined with Topic Analysis was utilized to extract information from the text data of the papers identified. After an appropriate screening procedure, 1111 articles were selected. The analysis showed a gradual increase in sustainable aquaculture publications over time, peaking at more than 200 publications in 2023. The first articles on biofloc, integrated multi‐trophic aquaculture and recirculating aquaculture systems as alternative aquaculture practices began to appear in 2010, while studies in aquaponics have only been published since 2015. Most publications (40%) came from Asia, in line with the leadership of this continent in aquaculture. European also showed considerable interest in sustainable aquaculture practices, with Italy (leader in publications), Portugal and Germany researchers contributing with 111 papers on the subject in the past 30 years. This study identified the main research topics on the subject and observed how these have evolved. The papers analysed dealt mainly with optimization of aquatic life, genetic in aquaculture and disease management. The topic of protein replacement in feed was also important, with the term ‘diet’ the most frequently utilized in papers. The subjects identified could serve as valuable primary data source, offering opportunities for deeper examination, such as systematic reviews on research topics or geographic regions.

Unveiling the Bacterial Community across the Stomach, Hepatopancreas, Anterior Intestine, and Posterior Intestine of Pacific Whiteleg Shrimp.

The gastrointestinal (GI) tract of shrimp, which is comprised of the stomach, hepatopancreas, and intestine, houses microbial communities that play crucial roles in immune defense, nutrient absorption, and overall health. While the intestine's microbiome has been well-studied, there has been limited research investigating the stomach and hepatopancreas. The present study addresses this gap by profiling the bacterial community in these interconnected GI segments of Pacific whiteleg shrimp. To this end, shrimp samples were collected from a local aquaculture farm in South Korea, and 16S rRNA gene amplicon sequencing was performed. The results revealed significant variations in bacterial diversity and composition among GI segments. The stomach and hepatopancreas exhibited higher Proteobacteria abundance, while the intestine showed a more diverse microbiome, including Cyanobacteria, Actinobacteria, Bacteroidetes, Firmicutes, Chloroflexi, and Verrucomicrobia. Genera such as Oceaniovalibus, Streptococcus, Actibacter, Ilumatobacter, and Litorilinea dominated the intestine, while Salinarimonas, Sphingomonas, and Oceaniovalibus prevailed in the stomach and hepatopancreas. It is particularly notable that Salinarimonas, which is associated with nitrate reduction and pollutant degradation, was prominent in the hepatopancreas. Overall, this study provides insights into the microbial ecology of the Pacific whiteleg shrimp's GI tract, thus enhancing our understanding of shrimp health with the aim of supporting sustainable aquaculture practices.

Replacement of fishmeal with a microbial single-cell protein induced enteropathy and poor growth outcomes in barramundi (Lates calcarifer) fry.

Fish meal (FM) replacement is essential for the sustainable expansion of aquaculture. This study focussed on the feasibility of replacing FM with a single-cell protein (SCP) derived from methanotrophic bacteria (Methylococcus capsulatus, Bath) in barramundi fry (Lates calcarifer). Three isonitrogenous and isoenergetic diets were formulated with 0%, 6.4% and 12.9% inclusion of the SCP, replacing FM by 0%, 25% and 50%. Barramundi fry (initial body weight 2.5 ± 0.1 g) were fed experimental diets for 21 days to assess growth performance, gut microbiome composition and gut histopathology. Our findings revealed that both levels of SCP inclusion induced detrimental effects in barramundi fry, including impaired growth and reduced survival compared with the control group (66.7% and 71.7% survival in diets replacing FM with SCP by 25% and 50%, respectively; p < .05). Both dietary treatments presented mild necrotizing enteritis with subepithelial oedema and accumulation of PAS positive, diastase resistant droplets within hepatocytes (ceroid hepatopathy) and pancreatic atrophy. Microbiome analysis revealed a marked shift in the gut microbial community with the expansion of potential opportunistic bacteria in the genus Aeromonas. Reduced overall performance in the highest inclusion level (50% SCP) was primarily associated with reduced feed intake, likely related to palatability issues, albeit pathological changes observed in gut and liver may also play a role. Our study highlights the importance of meticulous optimization of SCP inclusion levels in aquafeed formulations, and the need for species and life-stage specific assessments to ensure the health and welfare of fish in sustainable aquaculture practices.