Improving denitrification estimation by joint inclusion of suspended particles and chlorophyll a in aquaculture ponds.

The denitrification process in aquaculture systems plays a crucial role in nitrogen (N) cycle and N budget estimation. Reliable models are needed to rapidly quantify denitrification rates and assess nitrogen losses. This study conducted a comparative analysis of denitrification rates in fish, crabs, and natural ponds in the Taihu region from March to November 2021, covering a complete aquaculture cycle. The results revealed that aquaculture ponds exhibited higher denitrification rates compared to natural ponds. Key variables influencing denitrification rates were Nitrate nitrogen (NO3--N), Suspended particles (SPS), and chlorophyll a (Chla). There was a significant positive correlation between SPS concentration and denitrification rates. However, we observed that the denitrification rate initially rose with increasing Chla concentration, followed by a subsequent decline. To develop parsimonious models for denitrification rates in aquaculture ponds, we constructed five different statistical models to predict denitrification rates, among which the improved quadratic polynomial regression model (SQPR) that incorporated the three key parameters accounted for 80.7% of the variability in denitrification rates. Additionally, a remote sensing model (RSM) utilizing SPS and Chla explained 43.8% of the variability. The RSM model is particularly valuable for rapid estimation in large regions where remote sensing data are the only available source. This study enhances the understanding of denitrification processes in aquaculture systems, introduces a new model for estimating denitrification in aquaculture ponds, and offers valuable insights for environmental management.

Effects of two fillers and process conditions on the water treatment efficiency of a continuous packed bed biofilm reactor.

This study evaluated the treatment efficiency of two selected fillers and their combination for improving the water quality of aquaculture wastewater using a packed bed biofilm reactor (PBBR) under various process conditions. The fillers used were nanosheet (NS), activated carbon (AC), and a combination of both. The results indicated that the use of combined fillers and the hydraulic retention time (HRT) of 4 h significantly enhanced water quality in the PBBR. The removal rates of chemical oxygen demand, NO2-─N, total suspended solids（TSS）, and chlorophyll a were 63.55%, 74.25%, 62.75%, and 92.85%, respectively. The microbiota analysis revealed that the presence of NS increased the abundance of microbial phyla associated with nitrogen removal, such as Nitrospirae and Proteobacteria. The difference between the M1 and M2 communities was minimal. Additionally, the microbiota in different PBBR samples displayed similar preferences for carbon sources, and carbohydrates and amino acids were the most commonly utilized carbon sources by microbiota. These results indicated that the combination of NS and AC fillers in a PBBR effectively enhanced the treatment efficiency of aquaculture wastewater when operated at an HRT of 4 h. The findings provide valuable insights into optimizing the design of aquaculture wastewater treatment systems.

Evolution of parasites in the Anthropocene: new pressures, new adaptive directions.

The Anthropocene is seeing the human footprint rapidly spreading to all of Earth's ecosystems. The fast-changing biotic and abiotic conditions experienced by all organisms are exerting new and strong selective pressures, and there is a growing list of examples of human-induced evolution in response to anthropogenic impacts. No organism is exempt from these novel selective pressures. Here, we synthesise current knowledge on human-induced evolution in eukaryotic parasites of animals, and present a multidisciplinary framework for its study and monitoring. Parasites generally have short generation times and huge fecundity, features that predispose them for rapid evolution. We begin by reviewing evidence that parasites often have substantial standing genetic variation, and examples of their rapid evolution both under conditions of livestock production and in serial passage experiments. We then present a two-step conceptual overview of the causal chain linking anthropogenic impacts to parasite evolution. First, we review the major anthropogenic factors impacting parasites, and identify the selective pressures they exert on parasites through increased mortality of either infective stages or adult parasites, or through changes in host density, quality or immunity. Second, we discuss what new phenotypic traits are likely to be favoured by the new selective pressures resulting from altered parasite mortality or host changes; we focus mostly on parasite virulence and basic life-history traits, as these most directly influence the transmission success of parasites and the pathology they induce. To illustrate the kinds of evolutionary changes in parasites anticipated in the Anthropocene, we present a few scenarios, either already documented or hypothetical but plausible, involving parasite taxa in livestock, aquaculture and natural systems. Finally, we offer several approaches for investigations and real-time monitoring of rapid, human-induced evolution in parasites, ranging from controlled experiments to the use of state-of-the-art genomic tools. The implications of fast-evolving parasites in the Anthropocene for disease emergence and the dynamics of infections in domestic animals and wildlife are concerning. Broader recognition that it is not only the conditions for parasite transmission that are changing, but the parasites themselves, is needed to meet better the challenges ahead.

Antimicrobial use, residues and resistance in fish production in Africa: systematic review and meta-analysis.

In low- and middle-income countries, data on antimicrobial use (AMU) and antimicrobial resistance (AMR) in aquaculture are scarce. Therefore, summarizing documented data on AMU, antimicrobial residue (AR), and AMR in aquaculture in Africa is key to understanding the risk to public health. Google Scholar, PubMed, African Journals online, and Medline were searched for articles published in English and French following the PRISMA guidelines. A structured search string was used with strict inclusion and exclusion criteria to retrieve and screen the articles. The pooled prevalence and 95% confidence intervals were calculated for each pathogen-antimicrobial pair using random effects models. Among the 113 full-text articles reviewed, 41 met the eligibility criteria. The majority of the articles reported AMR (35; 85.4%), while a few were on AMU (3; 7.3%) and AR (3; 7.3%) in fish. The articles originated from West Africa (23; 56.1%), North Africa (8; 19.7%), and East Africa (7; 17.1%). Concerning the antimicrobial agents used in fish farming, tetracycline was the most common antimicrobial class used, which justified the high prevalence of residues (up to 56.7%) observed in fish. For AMR, a total of 69 antimicrobial agents were tested against 24 types of bacteria isolated. Bacteria were resistant to all classes of antimicrobial agents and exhibited high levels of multidrug resistance. Escherichia coli, Salmonella spp., and Staphylococcus spp. were reported in 16, 10, and 8 studies, respectively, with multidrug resistance rates of 43.1% [95% CI (32.0-55.0)], 40.3% [95% CI (24.1-58.1)] and 31.3% [95% CI (17.5-49.4)], respectively. This review highlights the high multidrug resistance rate of bacteria from aquaculture to commonly used antimicrobial agents, such as tetracycline, ampicillin, cotrimoxazole, gentamicin, and amoxicillin, in Africa. These findings also highlighted the lack of data on AMU and residue in the aquaculture sector, and additional efforts should be made to fill these gaps and mitigate the burden of AMR on public health in Africa.

Farmed fish welfare research status in Latin America: A review.

Latin America (LATAM) plays an important role in the world's production of aquatic animals and is the second most productive region in the world. Chile, Ecuador, Brazil, Mexico, Colombia, and Perú contribute 87% of LATAM aquaculture production. The fish welfare in aquaculture is of increasing public concern globally, and LATAM is no exception, growing in importance for fish farmers, authorities, and scientists. Although the topic is somewhat controversial, the welfare status of farmed fish has direct implications for their production and the sustainability of the industry. Therefore, this study analyses scientific papers on animal welfare in farmed fish, from the six countries in LATAM with the highest aquaculture production. The main objectives were to quantify the number of papers published between 2000 and 2023 on fish welfare by using scientific databases. A total of 285 papers were found for the period analysed. The country with the largest number of publications was Brazil (75.79%), followed by Chile (13.33%), Mexico (7.02%), Peru (1.75%), Ecuador, and Colombia (1.05%). Nile tilapia was the most studied species, appearing in 30.18% of the publications, with most of the studies mainly dealing with nutrition (32.28%). The growth of aquaculture is leading to joint efforts to generate knowledge on welfare issues, especially in poorly studied species with high production, to create policies that help minimize welfare risks. Given this, the insights generated by this review could be a useful addition to approaches investigating the trends and concepts of fish welfare in LATAM.

Modelling and mapping carbon capture potential of farmed blue mussels in the Baltic Sea region.

This study applies a regional Dynamic Energy Budget (DEB) model, enhanced to include biocalcification processes, to evaluate the carbon capture potential of farmed blue mussels (Mytilus edulis/trossulus) in the Baltic Sea. The research emphasises the long-term capture of carbon associated with shell formation, crucial for mitigating global warming effects. The model was built using a comprehensive pan-Baltic dataset that includes information on mussel growth, filtration and biodeposition rates, and nutrient content. The study also examined salinity, temperature, and chlorophyll a as key environmental factors influencing carbon capture in farmed mussels. Our findings revealed significant spatial and temporal variability in carbon dynamics under current and future environmental conditions. The tested future predictions are grounded in current scientific understanding and projections of climate change effects on the Baltic Sea. Notably, the outer Baltic Sea subbasins exhibited the highest carbon capture capacity with an average of 55 t (in the present scenario) and 65 t (under future environmental conditions) of carbon sequestrated per farm (0.25 ha) over a cultivation cycle - 17 months. Salinity was the main driver of predicted regional changes in carbon capture, while temperature and chlorophyll a had more pronounced local effects. This research advances our understanding of the role low trophic aquaculture plays in mitigating climate change. It highlights the importance of developing location-specific strategies for mussel farming that consider both local and regional environmental conditions. The results contribute to the wider discourse on sustainable aquaculture development and environmental conservation.

First Feeding of Cuttlefish Hatchlings: Pioneering Attempts in Captive Breeding.

In the last few decades, the cuttlefish market has grown to approximately 14% of the world's fisheries, and operators have begun to express concerns about the decline of this resource. In this context, the production of cuttlefish through aquaculture could offer a diversifying and valuable response to the increasing market demand and help alleviate the environmental pressure on this species. Therefore, the aim of this study is to identify a dry, cost-effective, and easy-to-administer diet that can successfully support the initial phases of cuttlefish growth and provide a similar performance to a krill-based diet, which closely mimics their natural diet. To achieve this objective, cuttlefish hatchlings were distributed among different experimental tanks, each receiving one of the five different diets (namely Diets A to E). Mortality and morphological parameters were monitored until day 10 post hatching, and the two most effective diets (Diets A and B) were chosen for further trials. The results indicated that Diet B had similar survival and growth rates to Diet A, which was based on frozen krill. Histological analysis revealed a comparable degree of gut maturity between the organisms fed the two diets. Likewise, levels of amylase and trypsin enzymes and hsp70, cat, and sod mRNA did not exhibit significant differences between the two groups. In conclusion, our findings provide preliminary evidence supporting the possibility of cultivating cuttlefish in captivity using a pelleted diet, representing a promising starting point for larger-scale breeding efforts.

Effects of Hypoxia on the Antibacterial Activity of Epidermal Mucus from Chilean Meagre (Cilus gilberti).

Comprehending the immune defense mechanisms of new aquaculture species, such as the Chilean meagre (Cilus gilberti), is essential for sustaining large-scale production. Two bioassays were conducted to assess the impact of acute and intermittent hypoxia on the antibacterial activity of juvenile Chilean meagre epidermal mucus against the potential pathogens Vibrio anguillarum and Vibrio ordalii. Lysozyme and peroxidase activities were also measured. In general, fish exposed to hypoxia showed a 9-30% reduction in mucus antibacterial activity at the end of hypoxic periods and after stimulation with lipopolysaccharide. However, following water reoxygenation, the activity of non-stimulated fish was comparable to that of fish in normoxic conditions, inhibiting bacterial growth by 35-52%. In the case of fish exposed to chronic hypoxia, the response against V. anguillarum increased by an additional 19.8% after 6 days of control inoculation. Lysozyme exhibited a similar pattern, while no modulation of peroxidase activity was detected post-hypoxia. These results highlight the resilience of C. gilberti to dissolved oxygen fluctuations and contribute to understanding the potential of mucus in maintaining the health of cultured fish and the development of future control strategies.

Addressing ocean planning challenges in a highly crowded sea space: a case study for the regional sea of Catalonia (Western Mediterranean).

Background: This study performs an exploratory analysis of current-future sustainability challenges for ocean planning for the regional seas of Catalonia located in the Western Mediterranean (Spain). Methods: To address the challenges we develop an Maritime Spatial Planning (MSP)-oriented geodatabase of maritime activities and deploy three spatial models: 1) an analysis of regional contribution to the 30% protection commitment with Biodiversity Strategy 2030; 2) a spatial Maritime Use Conflict (MUC) analysis to address current and future maritime activities interactions and 3) the StressorGenerator QGIS application to locate current and anticipate future sea areas of highest anthropogenic stress. Results & Conclusions: Results show that the i) study area is one of the most protected sea areas in the Mediterranean (44-51% of sea space protected); ii) anthropogenic stressors are highest in 1-4 nautical miles coastal areas, where maritime activities agglomerate, in the Gulf of Roses and Gulf of Saint Jordi. iii) According to the available datasets commercial fishery is causing highest conflict score inside protected areas. Potential new aquaculture sites are causing highest conflict in Internal Waters and the high potential areas for energy cause comparably low to negligible spatial conflicts with other uses. We discuss the added value of performing regional MSP exercises and define five challenges for regional ocean sustainability, namely: Marine protection beyond percentage, offshore wind energy: a new space demand, crowded coastal areas, multi-level governance of the regional sea and MSP knowledge gaps.

Probiotic Bacillus amyloliquefaciens B-1895 Improved Growth of Juvenile Trout.

The aim of this study was to evaluate a new Bacillus amyloliquefaciens B-1895 probiotic as a feed additive for farmed trout. Final weight, absolute and average daily gain of fish, and average daily growth rate were higher in the group that received the probiotic than in the control group (p<0.05). Moreover, the probiotic-fed trout had more intense growth rates than the control group (higher by 15.7%; p<0.05). A decrease in feed ratio was also observed in the group that received probiotic (25% decrease; p<0.05), indicating more efficient digestion and assimilation of feed. In general, the introduction of probiotic in the feed did not adversely affect the functional status of the fish. In young trout of the control group, when assessing the general chemical composition of the organism in the muscle tissue revealed significantly (p≤0.001) higher level of moisture content by 5.1% and lower by 11.0% dry matter content. In muscle, the protein content was higher by 1.33% (p≤0.001) and fat content by 2.1% (p≤0.001) in experimental fish. Generally, Lactobacilli, Enterococcus, Vibrio, Bacillus, and coliform bacteria were found in the intestinal samples of rainbow trout. Significant reliable difference (p≤0.05) between the samples of experimental and control groups was noted in the content of Bacillus bacteria. In the control group, 5.0±0.4×103 CFU/g was detected, while in the experimental group 8.4±0.8×104 CFU/g. Overall, the data indicate that probiotic bacteria B. amyloliquefaciens B-1895 has no adverse effect on selected microorganisms in the study fish.

Biogenic silica in sediment core indicates the historical development of off-bottom oyster farming.

Sediment cores are commonly used for reconstructing historical events by determining the biogenic elements in sediment vertical profiles. The vertical flux of biogenic silica (BSi) can be enhanced by bivalve mollusks through biodeposition and can be subsequently recorded in the sediment core. However, whether BSi in sediment core can indicate the interactions between aquaculture farms and the ecosystem is unclear. In this study, sediment cores were collected from a typical off-bottom oyster farm in Sanggou Bay, China. Based on 210Pb chronology analysis of the sediment vertical profile, BSi content was determined to reflect the BSi burial flux during the farming history. The BSi biodeposition fluxes were estimated based on the biodeposition model, to identify the correspondence among BSi burial flux, BSi biodeposition flux, and annual oyster production during the historical development of the farm. The results show that the BSi density in the sediment increased obviously after 1980 when intensive oyster farming began, and reduced after 2000 when farming began to decline. Moreover, BSi burial flux had a corresponding relationship with oyster production and the simulated biodeposition rate, except for 1997-2001 when oyster production peaked. Our finding supported that the variation of BSi from biodeposition can be preserved and then recorded in the sediment, suggesting that BSi could be considered as an indicator to reconstruct the historical development of the oyster farm.

Multi-omics reveals the molecular mechanism of muscle quality changes in common carp (Cyprinus carpio) under two aquaculture systems.

Preliminary experiments in our laboratory have demonstrated that common carp (Cyprinus carpio) cultivated for two months in land-based container recirculating aquaculture systems (C-RAS) exhibit superior muscle quality compared to those raised in traditional pond systems (TP). To elucidate the molecular mechanisms underlying muscle quality variations in common carp cultured under two aquaculture systems, transcriptomic and metabolomic analyses were performed on muscle tissues of specimens aged 11 to 23 months. Comparison of muscle histological sections between the two groups indicated a significantly lower long diameter of muscle fibers in the C-RAS group compared to the TP group (P < 0.01). Conversely, the muscle fiber density was significantly higher in the C-RAS group than in the TP group (P < 0.05). Transcriptomic and metabolomic analyses identified 3390 differentially expressed genes (DEGs)-1558 upregulated and 1832 downregulated-and 181 differentially expressed metabolites (DEMs)-124 upregulated and 57 downregulated-between the groups. Based on integrated transcriptomic and metabolomic analyses, the significant differences focus on metabolic pathways involving glycolysis/gluconeogenesis, arginine and proline metabolism, arginine biosynthesis, and purine metabolism. The study revealed that the muscle quality of common carp in two aquaculture systems is primarily regulated through improvements in energy metabolism, amino acid metabolism, fatty acid metabolism, and purine metabolism. These metabolic processes play significant roles in promoting muscle fiber hyperplasia and hypertrophy, enhancing muscle flavor, and increasing muscle antioxidant capacity. This study provides new insights into the molecular and metabolic pathways that control muscle quality in common carp under different environmental factors.

A seasonal study on the microbiomes of Diploid vs. Triploid eastern oysters and their denitrification potential.

Oyster reefs are hotspots of denitrification mediated removal of dissolved nitrogen (N), however, information on their denitrifier microbiota is scarce. Furthermore, in oyster aquaculture, triploids are often preferred over diploids, yet again, microbiome differences between oyster ploidies are unknown. To address these knowledge gaps, farmed diploid and triploid oysters were collected over an annual growth cycle and analyzed using shotgun metagenomics and quantitative microbial elemental cycling (QMEC) techniques. Regardless of ploidy, Psychrobacter genus was abundant, with positive correlations found for genes of central metabolism, DNA metabolism, and carbohydrate metabolism. MAGs (metagenome-assembled genomes) yielded multiple Psychrobacter genomes harboring norB, narH, narI, and nirK denitrification genes, indicating their functional relevance within the eastern oysters. QMEC analysis indicated the predominance of carbon (C) and nitrogen (N) cycling genes, with no discernable patterns between ploidies. Among the N-cycling genes, the nosZII clade was overrepresented, suggesting its role in the eastern oyster's N removal processes.

Horizontal gene transfer plays a crucial role in the development of antibiotic resistance in an antibiotic-free shrimp farming system.

Antibiotic selective pressure in aquaculture systems often results in the antibiotic resistance genes (ARGs) proliferation. Nonetheless, a paucity of data exists concerning the mechanisms of ARGs development in aquaculture systems without the influences of antibiotics. This study utilized metagenomic approaches to elucidate the dynamics and transfer mechanisms of ARGs throughout the aquaculture of Pacific white shrimp. A marked change in the resistome was observed throughout the aquaculture without antibiotics. The total ARGs relative abundance increased from 0.05 to 0.33 by day 90 of cultivation, with even higher in mixed wastewater (0.44). Both bacterial communities and mobile genetic elements play pivotal roles in the development of ARGs. Metagenome-assembled genomes showed enrichment of environmentally intrinsic ARGs on chromosomes including macB and mdtK. The plasmid-mediated horizontal transfer was recognized as a principal factor contributing to the rise of ARGs, particularly for tetG and floR, and this led to an escalation of resistance risk, peaking at a risks core of 35.43 on day 90. This study demonstrates that horizontal gene transfer plays a crucial role in ARGs development without antibiotic pressure, which can provide a theoretical foundation for controlling ARGs proliferation in aquaculture systems.

Salinity-Induced Variations in Bacterial Composition and Co-occurrence Patterns within Salicornia-Based Constructed Wetlands in Mariculture.

Constructed wetlands use vegetation and microorganisms to remove contaminants like nitrogen and phosphorus from water. For mariculture, the impact of salinity on the efficiency of wastewater treatment of wetlands is unneglectable. However, little is known about their impact on the microbiome in constructed wetlands. Here, we set four salinity levels (15, 22, 29, and 36) in Salicornia constructed wetlands, and the experiment was conducted for a period of 72 days. The 15 group exhibited the highest removal rates of nitrogen compounds and phosphate, compared to the other salinity groups, the nosZ gene exhibited significantly higher expression in the 22 group (p < 0.05), indicated that microorganisms in 22 salinity have higher denitrification abilities. The three dominant phyla identified within the microbiomes were Proteobacteria, known for their diverse metabolic capabilities; Cyanobacteria, important for photosynthesis and nitrogen fixation; and Firmicutes, which include many fermenters. The ecological network analysis revealed a 'small world' model, characterized by high interconnectivity and short path lengths between microbial species, and had higher co-occurrence (45.13%) observed in this study comparing to the Erdös-Réyni random one (32.35%). The genus Microbulbifer emerged as the sole connector taxon, pivotal for integrating different microbial communities involved in nitrogen removal. A negative correlation was observed between salinity levels and network complexity, as assessed by the number of connections and diversity of interactions within the microbial community. Collectively, these findings underscore the critical role of microbial community interactions in optimizing nitrogen removal in constructed wetlands, with potential applications in the design and management of such systems for improved wastewater treatment in mariculture.

The AutoSpawner system - Automated ex situ spawning and fertilisation of corals for reef restoration.

The restoration of reefs damaged by global and local pressures remains constrained by the scale of intervention currently feasible. Traditional methods for ex situ sexual propagation of corals produce limited materials, typically of limited genetic diversity and only sufficient for small field trials. The development and validation of new technologies to upscale and automate coral propagation is required to achieve logistically and financially feasible reef restoration at ecologically relevant scales. To address the need for upscaled production of genetically diverse material for use in reef restoration we designed an automated system (the AutoSpawner) for harvesting, fertilising and washing gametes from tropical broadcast-spawning corals. The system includes a novel high density dynamic fertilisation process, which enables the production of large numbers of fertilised coral eggs (>7 million per night for highly fecund species) without any downstream negative effects on larval quality. The functionality of the system and the quality of the produced larvae was assessed using multiple species from two coral families (Acroporidae and Merulinidae) across a range of spawning and gamete characteristics. We present the schematics and protocols required for automated sexual propagation of high-quality coral larvae using this novel system; and demonstrate that the time demands, and labour costs, associated with traditional manual-based sexual propagation of corals can be reduced by up to 113-fold using the AutoSpawner.

Exposure of female lobsters to sediments spiked with emamectin benzoate: Effects on eggs and larvae early development.

The salmon aquaculture industry is an important economic activity established on both the west and east coast of Canada. To control sea lice infestations, in-feed products like emamectin benzoate (EMB) are widely used. Due to its low solubility and persistence EMB can accumulate in marine sediments and be potentially bioavailable to non-target organisms from months to years. The American lobster (Homarus americanus) is a key species in the Northwest Atlantic with high economic and ecological value. It may be exposed to therapeutants considering lobster habitats overlap with aquaculture locations requiring a better understanding of the potential impact of these therapeutants through varied pathways of exposure. In this study, we investigated the exposure of gravid female lobsters to EMB spiked sediment to mimic the likely presence of these females at aquaculture sites for a 10-day period. We completed testing by assessing EMB effects on adult molting and quality, embryo hatching rates, and larval offspring quality and larval molting. Our results show that a single, 10-day exposure of ovigerous females to EMB concentrations higher than environmentally relevant values did not affect females or their offspring.

Effect of diets containing probiotic yeast Cystobasidium benthicum and fruit Cyrtocarpa edulis on growth and immune parameters of Nile tilapia (Oreochromis niloticus).

This study investigates Cystobasidium benthicum (Cb) probiotic yeast and Cyrtocarpa edulis (Ce) fruit dietary effects, single (0.5%) or combined (Cb:Ce, 0.25:0.25%), on growth performance, humoral immunity in serum and skin mucus, and intestinal morphology of Nile tilapia (Oreochromis niloticus) after 14 and 28 days. The Cb group presented the highest (P < 0.05) specific growth rate, weight gain, and absolute growth rate with respect to the control group. Immunological assays indicated that Cb, Ce and Cb:Ce groups increased serum nitric oxide concentration compared to the control group (P < 0.05). Cb and Cb:Ce groups showed the highest serum myeloperoxidase enzyme activity at day 14 and 28, respectively (P < 0.05); whereas, Cb:Ce group had the highest (P < 0.05) myeloperoxidase activity in skin mucus. The superoxide dismutase enzyme activity was unaffected. On day 28, Cb, Ce, and Cb:Ce groups showed higher and lower (P <0.05) catalase enzyme activity in serum and skin mucus, respectively, compared with the control group. Only the Cb group had higher (P <0.05) total protein concentration in serum (day 14) and skin mucus (day 14 and 28) with respect to the control group. The lysozyme activity in serum (day 28) and skin mucus (day 14) was higher (P <0.05) in the Cb group compared to the control group. Only the skin mucus of Ce group showed bactericidal activity against Aeromonas dhakensis (P <0.05). Histological studies indicated that Cb and Cb:Ce groups increased microvilli height, and Cb, Ce and Cb:Ce augmented goblet cell area at day 14 compared to the control group (P <0.05). At day 28, microvilli height was higher in all groups and the number of intraepithelial leukocytes increased in Cb and Ce groups with respect to the control group (P <0.05). The ex vivo assay revealed that A. dhakensis in leukocytes decreased cell viability similar to the control group (P <0.05). A principal component analysis (PCA) confirmed the results. In conclusion, C. benthicum in the diet was the best supplement to improve the growth and immunity of Nile tilapia.

Investigating the impact of nanoemulsion of curcumin-loaded olive oil on growth performance, feed utilization, immunological responses, and redox status of Litopenaeus vannamei shrimp with emphasis on economic efficiency of supplementation.

The trail aimed to explore the effect of dietary supplementation of curcumin loaded olive oil nanoemulsion (CUR-OLNE) on growth performance, feed utilization, blood biochemical, redox status, and immune response of Litopenaeus vannamei shrimp, considering the economic efficiency of supplementation. A total of 280 healthy shrimps (3.42 ± 0.02 g) were randomly distributed into five equal groups and were fed diets containing 0 (CUR-OLNE0), 5(CUR-OLNE5), 10(CUR-OLNE10), 15(CUR-OLNE15) and 20 (CUR-OLNE20) mg CUR-OLNE/kg diet, respectively for 16 weeks. Among CUR-OLNE treated groups, CUR-OLNE20 showed the highest growth performance and feed utilization traits, including final body weight, specific growth rate, feed conversion ratio, and protein efficiency ratio. Notably, the photomicrographs provided further compelling evidence regarding the potential effect of CUR-OLNE supplementation on muscle structure and integrity. Compared to the control, the levels of blood protein significantly induced in CUR-OLNE15 and CUR-OLNE20 treated groups (p < 0.05). All CUR-OLNE -supplemented groups possessed lower activities of liver enzymes as well as the levels of urea and creatinine compared to the control (p < 0.05). The addition of 20 mg CUR-OLNE/kg diet decreased the concentrations of cortisol, glucose and triglycerides. The dietary treatment significantly improved the secretion of digestive enzymes, including amylase, lipase, and protease. The lowest levels of Malondialdehyde and the highest levels of total antioxidant capacity, super oxide dismutase, catalase, lysozyme and immunoglobulin M were detected in both of CUR-OLNE15, and CUR-OLNE20 treated groups compared to the control (p < 0.05). There were considerable significant effects of dietary supplementation of CUR-OLNE on economic efficiency. In conclusion, the application of nanocarriers for the delivery of dietary immune stimulants such as CUR-OLNE to Litopenaeus vannamei shrimp is a promising strategy for improving shrimp nutrition. The addition of 20 mg CUR-OLNE/kg to the diets of can be recommended as an affective intervention to improve growth performance, feed utilization, and health status of shrimp. Implementing this intervention can maximize the economic efficiency of shrimp farming while promoting sustainable practices in the industry.

Identifying potential drug targets in the kinomes of two monogenean species.

Protein kinases are enzymes involved in essential biological processes such as signal transduction, transcription, metabolism, and the cell cycle. Human kinases are targets for several drugs approved by the US Food and Drug Administration. Therefore, the identification and classification of kinases in other organisms, including pathogenic parasites, is an interesting subject of study. Monogeneans are platyhelminths, mainly ectoparasites, capable of causing health problems in farmed fish. Although some genomes and transcriptomes are available for monogenean species, their full repertoire of kinases is unknown. The aim of this study was to identify and classify the putative kinases in the transcriptomes of two monogeneans, Rhabdosynochus viridisi and Scutogyrus longicornis, and then to predict potential monogenean drug targets (MDTs) and selective inhibitor drugs using computational approaches. Monogenean kinases having orthologs in the lethal phenotype of C. elegans but not in fish or humans were considered MDTs. A total of 160 and 193 kinases were identified in R. viridisi and S. longicornis, respectively. Of these, 22 kinases, belonging mainly to the major groups CAMK, AGC, and TK, were classified as MDTs, five of which were evaluated further. Molecular docking analysis indicated that dihydroergotamine, ergotamine, and lomitapide have the highest affinity for the kinases BRSK and MEKK1. These well-known drugs could be evaluated in future studies for potential repurposing as anti-monogenean agents. The present study contributes valuable data for the development of new antiparasitic candidates for finfish aquaculture.