Managing the microbiological safety of tilapia from farm to consumer.

Tilapia stands out as one of the most extensively farmed and consumed fish species globally, valued for its ease of preparation and relative affordability. Although tilapia is a valuable protein source, it can also function as a vector for foodborne pathogens. This literature review reveals that tilapia could carry a variety of contamination with various foodborne pathogens, including Plesiomonas shigelloides, diarrheagenic Escherichia coli, Vibrio parahaemolyticus, Salmonella Weltevreden, Salmonella enterica, Shigella, Staphylococcus aureus, Campylobacter jejuni, Clostridium botulinum, and Listeria monocytogenes. Although guidelines from entities, such as the Global Seafood Alliance, Aquaculture Stewardship Council, and International Organization for Standardization, have been established to ensure the microbiological safety of tilapia, the unique challenges posed by pathogens in tilapia farming call for a more nuanced and targeted approach. Recognizing that contaminants could emerge at various stages of the tilapia supply chain, there is a crucial need for enhanced detection and monitoring of pathogens associated with this fish and its culturing environment. Additionally, it is essential to acknowledge the potential impact of climate change on the safety of tilapia, which may elevate the prevalence and contamination levels of pathogens in this fish. Proactive measures are essential to understand and mitigate the effects of climate change on tilapia production, ensuring the sustainability and safety of this seafood product for both present and future generations.

Computer-Simulated Virtual Image Datasets to Train Machine Learning Models for Non-Invasive Fish Detection in Recirculating Aquaculture.

Artificial Intelligence (AI) and Machine Learning (ML) can assist producers to better manage recirculating aquaculture systems (RASs). ML is a data-intensive process, and model performance primarily depends on the quality of training data. Relatively higher fish density and water turbidity in intensive RAS culture produce major challenges in acquiring high-quality underwater image data. Additionally, the manual image annotation involved in model training can be subjective, time-consuming, and labor-intensive. Therefore, the presented study aimed to simulate fish schooling behavior for RAS conditions and investigate the feasibility of using computer-simulated virtual images to train a robust fish detection model. Additionally, to expedite the model training and automate the virtual image annotation, a process flow was developed. The 'virtual model' performances were compared with models trained on real-world images and combinations of real and virtual images. The results of the study indicate that the virtual model trained solely with computer-simulated images could not perform satisfactorily (mAP = 62.8%, F1 score = 0.61) to detect fish in a real RAS environment; however, replacing a small number of the virtual images with real images in the training dataset significantly improved the model's performance. The M6 mixed model trained with 630 virtual and 70 real images (virtual-to-real image ratio: 90:10) achieved mAP and F1 scores of 91.8% and 0.87, respectively. Furthermore, the training time cost for the M6 model was seven times shorter than that for the 'real model'. Overall, the virtual simulation approach exhibited great promise in rapidly training a reliable fish detection model for RAS operations.

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.

Integration of down-flow hanging sponge reactor to oreochromis niloticus - Brassica oleracea aquaponics system.

Aquaponics is a promising solution for addressing food security concerns. Nonetheless, an effective water-purification system is necessary to achieve high and stable yields of fish and vegetables. This study aimed to evaluate the nitrification and oxygen transfer performance of a laboratory-scale down-flow hanging sponge (DHS) reactor with a Brassica oleracea aquaponics system to treat water in an Oreochromis niloticus closed-aquaculture system. The DHS reactor showed a higher oxygen transfer coefficient (KLa) than the conventional aerator and provided an adequate dissolved oxygen (DO) concentration of approximately 5.5 mg/L essential for O. niloticus growth throughout the experimental period. The evaluated DHS-based aquaponic system maintained high water quality in an aquaculture tank, with a survival rate of 97%. The O. niloticusgrew at a low feed conversion ratio of 1.5-2.1 and a low feeding rate of 0.5% at high stocking densities of 17.5-22.2 kg-fish-weight/m3. 16S rRNA gene sequencing indicated that the DHS sponge carrier effectively retained nitrifying bacteria such as Nitrosomonas and Nitrospira. This study demonstrated that the DHS reactor provided a high DO concentration and that a simultaneous DHS reactor with a hydroponic tank provided a low-cost aquaponic system that could be applied for food production in the aquaculture industry.

Upscaling and environmental impact assessment of an innovative integrated multi-trophic aquaponic system.

The increasing growth of the aquaculture sector has raised significant concerns regarding its environmental footprint, including nutrient discharge, substantial feed consumption, and high energy requirements. In response, innovative approaches such as aquaponics and integrated multi-trophic aquaculture (IMTA) are being developed as potentially more sustainable alternatives. This study aims to evaluate the environmental performance of an innovative Integrated Multi-Trophic Aquaponics system (IMTAcs) using the Life Cycle Assessment (LCA) approach. Given the experimental nature of the pilot plant, two distinct scaled-up scenarios were analysed: one utilizing an alternative feed (IMTAcs AF), and the other employing a commercial feed (IMTAcs CF). The functional unit was defined as 100 kcal and 1 kg of protein produced by the system, with a cradle-to-gate perspective defining system boundaries. Results revealed that IMTAcs AF has a higher global warming impact (0.234 kg CO2 eq./100 kcal) compared to IMTAcs CF (0.207 kg CO2 eq.). In both scenarios, electricity consumption was identified as the primary driver to environmental impact, exceeding 50%, in contrast to conventional systems where feed is the main hotspot. Moreover, while trends in impact categories such as net primary production use and eutrophication is opposite between the scenarios, the latter demonstrated substantial mitigation potential, attributable to the system's inherent nutrient recycling, in comparison with traditional aquaculture systems. While the findings are promising, certain limitations in the study (e.g. utilization of scaled-up data and inherent uncertainties analysed), with the scarcity of existing research, point to the opportunity for further exploration. This includes analysing real-scale implementations whenever feasible and conducting more detailed comparisons with traditional systems.

Globalization of wild capture and farmed aquatic foods.

Aquatic foods are highly traded, with nearly 60 million tonnes exported in 2020, representing 11% of global agriculture trade by value. Despite the vast scale, basic characteristics of aquatic food trade, including species, origin, and farmed vs wild sourcing, are largely unknown due to the reporting of trade data. Consequently, we have a coarse picture of aquatic food trade and consumption patterns. Here, we present results from a database on species trade that aligns production, conversion factors, and trade to compute apparent consumption for all farmed and wild aquatic foods from 1996 to 2020. Over this period, aquatic foods became increasingly globalized, with the share of production exported increasing by 40%. Importantly, trends differ across aquatic food sectors. Global consumption also increased by 19.4% despite declining marine capture consumption, and some regions became increasingly reliant on foreign-sourced aquatic foods. To identify sustainable diet opportunities among aquatic foods, our findings, and underlying database enable a greater understanding of the role of trade in rapidly evolving aquatic food systems.

Histopathology based study of Nile tilapia fish (Oreochromis niloticus) as a biomarker for water pollution evaluation in the southern gulf of Lake Tana, Ethiopia.

In the past decade, the increasing distribution of pollutants in the aquatic environment has been observed, causing integrative effects on fish. Likewise, due to anthropogenic activities, the southern gulf of Lake Tana is an impacted region, and the production of Nile tilapia fish is reduced. For this reason, the aim of this study was to conduct a histopathological-based study of 48 Nile tilapia fishes' health status at the southern gulf of Lake Tana and aquaculture using a cross-sectional study from February 2023 to May 2023. The study evaluated the histopathology of the gill, liver, gonads, and spleen organs using descriptive statistics accompanied by a 2 × 2 contingency table and t-test analysis. During the study, different histological alterations were detected, and the numbers of fish affected by a specific histological alteration were presented as percentage prevalence; hence, from the total fish examined, hyperplasia (54.15%), followed by pigment deposits (52%), hemorrhage (50%), and immune cell infiltration (50%), respectively, were the most frequently detected alterations. However, Nile tilapias from the southern gulf of Lake Tana were 1.4 (odds ratio) times more likely to show histopathological alterations than those from aquaculture, although statistically, was not significant (p > 0.05). In addition, the study found the mean value of the fish index (95.3) and regressive indices of the gill (13.6), liver (14.8), and gonad (12.3); moreover, the inflammatory indices of the spleen organ (11.3) and mean severity grade value of the gill (2.35) and gonad (1.7) organs, respectively, were obtained from the southern gulf of Lake Tana, and all those values were significantly higher (p < 0.05) from this site as compared to the aquaculture. In general, it has been found that tilapias from the southern gulf of Lake Tana showed higher pathological severity as compared with aquaculture. Among the four target organs evaluated, liver organs were observed to be the most damaged, while gonads were the least impacted organs. Therefore, it has been concluded that tilapia fish are living in abnormal conditions, so to ensure a sustainable fishery, water pollutant sources from Bahirdar city must receive proper attention, and future studies should consider age differences, seasonal variation, and the detection of specific pollutants.

Investigating dynamics, etiology, pathology, and therapeutic interventions of Caligus clemensi and Vibrio alginolyticus co-infection in farmed marine fish.

This study investigated a disease outbreak characterized by caligid copepod infestations and subsequent secondary bacterial infections in European seabass (Dicentrarchus labrax) and flathead grey mullet (Mugil cephalus) cultivated at a private facility in the Deeba Triangle region of Egypt. Moribund fish displayed brown spots on the skin, tongue, and gills, along with lethargy and excess mucus. The fish suffered severe infections, exhibiting external hemorrhages, ulcers, and ascites. The fish had pale, enlarged livers with hemorrhaging. Comprehensive parasitological, bacteriological, molecular, immunity and histopathological analyses were conducted to identify the etiological agents and pathological changes. Caligid copepod infestation was observed in wet mounts from the buccal and branchial cavities of all examined fish, and the caligids were identified as Caligus clemensi through COI gene sequencing and phylogenetic analysis. Vibrio alginolyticus was confirmed as a secondary bacterial infection through biochemical tests, recA gene sequencing, and phylogenetic analyses. Antibiotic susceptibility testing revealed resistance to ß-lactams, aminoglycosides, and trimethoprim-sulfamethoxazole in V. alginolyticus isolates. Upregulation of the inflammatory marker IL-1ß in gill and skin tissues indicated a robust cell-mediated immune response against the pathogens. Histopathological examination revealed severe tissue damage, hyperplasia, hemorrhage, and congestion in the gills, along with hepatocellular degeneration and steatosis in the liver, providing initial insights into this outbreak. A comprehensive therapeutic regimen was implemented, comprising prolonged hydrogen peroxide immersion baths, followed by the application of the nature-identical plant-based compound Lice-less and probiotic Sanolife Pro-W supplementation. This integrated approach effectively eliminated C. clemensi infestations, controlled secondary bacterial infections, and restored fish health, reducing morbidity and mortality rates to minimal levels.

The application of Global Burden of Animal Diseases methodology to aquatic animal production.

The Global Burden of Animal Diseases (GBADs) programme's key objective â€" to provide a systematic approach to determine the burden of animal disease â€" is as relevant to aquatic as to terrestrial animal production systems. However, to date GBADs methods have mainly been applied to terrestrial animal production systems. The challenges in applying GBADs methods, notably the Animal Health Loss Envelope (AHLE), vary considerably by production system. The authors demonstrate how the AHLE can be calculated for rainbow trout production in England and Wales and acknowledge that its application to other systems (e.g. hatchery production, polyculture and no-feed mollusc production) is more complex. For example, in small scale tropical fish production the impact of suboptimal nutrition on production would need to be addressed. Recirculating aquaculture systems have inherent high levels of biosecurity and disease control, and thus low levels of disease. Removing the capital and running costs associated with biosecurity fundamentally changes the system and invalidates the AHLE calculation. Lack of data from many systems, notably small-scale tropical finfish farming, means that expert opinion will be needed to support the application of GBADs methods. While calculation of the AHLE is the focus of this article, it should be noted that attribution to causes and value chain modelling are needed to generate data on the wider societal impact of aquatic animal diseases (and possible interventions), which governments require to support decision-making about resource allocation.

Les principaux objectifs du programme " Impact mondial des maladies animales " (GBADs) visent à fournir une méthode systématique pour déterminer l'impact des maladies animales et sont pertinents aussi bien pour les systèmes de production d'animaux terrestres que pour les systèmes aquacoles. Néanmoins, à ce jour, les méthodes du GBADs ont surtout été appliquées aux systèmes de production d'animaux terrestres. Les difficultés d'application des méthodes du GBADs, en particulier le calcul de l'enveloppe des pertes sanitaires animales varient considérablement d'un système de production à l'autre. Les auteurs décrivent la méthode appliquée pour calculer l'enveloppe des pertes sanitaires animales dans les élevages de truites arc-en-ciel en Angleterre et au pays de Galles, méthode dont ils reconnaissent que l'application à d'autres systèmes (par exemple la production en écloserie, la polyculture et la production de mollusques sans intrants de fourrage) est plus complexe. Par exemple, dans la production de poissons tropicaux à petite échelle, l'impact d'une nutrition sous-optimale sur la production devrait être pris en compte. Les systèmes de recirculation fermée en aquaculture garantissent intrinsèquement des niveaux élevés de biosécurité et de contrôle sanitaire qui se traduisent par un niveau faible de maladies. La suppression des coûts d'investissement et de fonctionnement associés à la biosécurité modifie fondamentalement le système et invalide le calcul de l'enveloppe des pertes sanitaires animales. Compte tenu de l'absence de données disponibles concernant un grand nombre de systèmes, notamment les petits élevages de poissons tropicaux, il faudra recourir aux avis d'experts pour étayer l'application des méthodes du GBADs. Si l'article aborde essentiellement le calcul de l'enveloppe des pertes sanitaires animales, les auteurs signalent l'importance de rechercher les causes et de modéliser les chaînes de valeur afin de générer des données représentatives de l'impact sociétal au sens large des maladies affectant les animaux aquatiques (ainsi que des interventions envisageables), outils indispensables pour étayer les décisions gouvernementales concernant les ressources à allouer.

El objetivo principal del programa sobre el Impacto Global de las Enfermedades Animales (GBADs), a saber, proporcionar un enfoque sistemático para determinar el impacto de dichas enfermedades, es tan pertinente para los sistemas de producción de animales acuáticos como terrestres. Sin embargo, hasta la fecha, los métodos del GBADs se han aplicado principalmente a los sistemas de producción de animales terrestres. Las dificultades que plantea la aplicación de los métodos del GBADs, en particular la cartera de pérdidas en sanidad animal, varían considerablemente según el sistema de producción. Los autores demuestran cómo puede calcularse la cartera de pérdidas en sanidad animal para la producción de trucha arco iris en Inglaterra y Gales y reconocen que su aplicación en otros sistemas (por ejemplo, la producción en viveros, el policultivo y la producción de moluscos sin insumos alimentarios) es más compleja. Por ejemplo, en la producción de peces tropicales a pequeña escala habría que abordar el impacto de una nutrición subóptima en la producción. Los sistemas de recirculación en acuicultura conllevan altos niveles de bioseguridad y control de enfermedades y, por lo tanto, bajos niveles de enfermedad. Si se eliminan los costos de capital y de explotación asociados a la bioseguridad, el sistema cambia radicalmente e invalida el cálculo de la cartera de pérdidas en sanidad animal. La falta de datos de muchos sistemas, especialmente de la cría de peces tropicales a pequeña escala, implica que se necesitará la opinión de expertos para apoyar la aplicación de los métodos del GBADs. Aunque el presente artículo se centra en el cálculo de la cartera de pérdidas en sanidad animal, cabe señalar que la determinación de las causas y la modelización de la cadena de valor son necesarias para generar datos sobre el impacto social más amplio de las enfermedades de los animales acuáticos (y las posibles intervenciones), que los gobiernos necesitan para respaldar la toma de decisiones sobre la asignación de recursos.

Molecular monitoring of Dinophysis species assemblage in mussel farms in the Northwestern Adriatic Sea.

Several Dinophysis species can produce potent lipophilic toxins that pose a risk to human health when contaminated seafood is consumed, especially filter-feeding bivalve mussels. In the mussel farms of the Northwestern Adriatic Sea, seawater and seafood are regularly monitored for the presence of Dinophysis species and their associated toxins, but the current methodological approaches, such as light microscopy determinations, require a long time to make results available to local authorities. A molecular qPCR-based assay can be used to quantify various toxic Dinophysis species in a shorter timeframe. However, this approach is not currently employed in official testing activities. In this study, field samples were collected monthly or bi-weekly over one year from various mussel farms along the Northwestern Adriatic coast. The abundance of Dinophysis species in the seawater was determined using both traditional microscopy and qPCR assays. In addition, the concentration of lipophilic toxins for DSP in mussel flesh was quantified using LC-MS/MS focusing on the okadaic acid group. Dinophysis spp. site-specific single cells were isolated and analysed by qPCR yielding a mean rDNA copy number per cell of 1.21 × 104 ± 1.81 × 103. The qPCR assay gave an efficiency of 98 % and detected up to 10 copies of the rDNA target gene. The qPCR and light microscopy determinations in environmental samples showed a significant positive correlation (Spearman rs = 0.57, p-value < 0.001) with a ratio of 2.24 between the two quantification methods, indicating that light microscopy estimates were generally 44.6 % lower than those obtained by the qPCR assay. The qPCR approach showed several advantages such as rapidity, sensitivity and efficiency over conventional microscopy analysis, showing its potential future role in phytoplankton monitoring under the Official Controls Regulations for shellfish.

Molecular identification of Mymarothecium viatorum and Anacanthorus penilabiatus in extensive native fish farming systems of the Peruvian Amazon.

Piaractus brachypomus (Pacú) is the main native fish species cultivated in Peru and holds great potential for growth in aquaculture from the Peruvian Amazon. Between October 2021 and January 2022 in two fish producing farms in the Amazon region of San Martín in Peru, P. brachypomus individuals were examined for parasite evaluation. A total of 6366 monogeneans were isolated from the gills of 30 fish, revealing a prevalence of 100%, with an abundance and mean intensity of 212 parasites per fish. Monogeneans were morphologically identified as Mymarothecium viatorum and Anacanthorus penilabiatus. The genetic divergence in the 28S rDNA gene found among A. penilabiatus sequences was 0.1% and among Anacanthorus spp. it ranged from 0.9% to 7.5%. The genetic divergence found among the M. viatorum sequences was 0.3%. These finding represents the first molecular data of M. viatorum and A. penilabiatus in Peru using the 28S rDNA gene of these monogeneans. The new sequences obtained will contribute to future studies on the phylogenetic relationships among dactylogyrids. However, further research with a broader range of host-parasite samples and additional genetic markers is needed to clarify these relationships and provide stronger support for the phylogenetic positions.

The draft genomes of Crassostrea gasar and Crassostrea rhizophorae: key resources for leveraging oyster cultivation in the Southwest Atlantic.

OBJECTIVES: The two oyster species studied hold considerable economic importance for artisanal harvest (Crassostrea rhizophorae) and aquaculture (Crassostrea gasar). Their draft genomes will play an important role in the application of genomic methods such as RNAseq, population-based genomic scans aiming at addressing expression responses to pollution stress, adaptation to salinity and temperature variation, and will also permit investigating the genetic bases and enable marker-assisted selection of economically important traits like shell and mantle coloration and resistance to temperature and disease. DATA DESCRIPTION: The draft assembly size of Crassostrea gasar is 506 Mbp, and of Crassostrea rhizophorae is 584 Mbp with scaffolds N50 of 11,3 Mbp and 4,9 Mbp, respectively. The general masked bases by RepeatMasker in both genomes were highly similar using different datasets. The masked bases varied from 9.41% in C. gasar to 10.05% in C. rhizophorae and 42.85% in C. gasar to 44.44% in C. rhizophorae using Dfam and RepeatModeler datasets, respectively. Functional annotation with eggNog resulted in 34,693 annotated proteins in C. rhizophorae and 26,328 in C. gasar. BUSCO analysis shows that almost 99% of genes (5,295) are complete in relation to the mollusk orthologous genes dataset (mollusca_odb10).

Development and application of an online tool to quantify nitrogen removal associated with harvest of cultivated eastern oysters.

Shellfish aquaculture can provide important ecosystem services to coastal communities, yet these benefits are not typically considered within the aquaculture permit review process. Resource managers have expressed interest in easy-to-use tools, based on robust science, that produce location and operation-appropriate values for beneficial services. These values need to be produced in a format that aligns with existing regulatory processes to facilitate seamless integration with permit review. The removal of excess nitrogen from coastal waters by shellfish farms is well documented in the literature and has been incorporated into nutrient management in the USA. Shellfish assimilate nitrogen into their tissue and shell as they grow, and this nitrogen is removed from the environment upon harvest. We have assembled a dataset of nitrogen concentration and morphometric measurements from farmed eastern oysters across the US Northeast, and adapted methodology used by existing nutrient management programs to quantify harvest-associated removal of nitrogen. Variability in oyster tissue and shell nutrient concentration was low within the dataset, and an assessment of farm location, ploidy, and three common cultivation practices (floating gear, bottom gear, no gear) suggested that a simple regression-based calculation could be applied across all farms within the region. We designed the new, publicly available online Aquaculture Nutrient Removal Calculator tool https://connect.fisheries.noaa.gov/ANRC/ based on this analysis, which uses inputs related to oyster size and harvest number to predict harvest-based nitrogen removal from an eastern oyster farm located within the geographic range of North Carolina to Maine, USA. The tool also produces a report that has been designed to integrate with the US Army Corps of Engineers public interest review process, and similar state-level permitting processes, and provides a succinct summary of the ecological services associated with nutrient removal in eutrophic locations, project-specific values, and citations supporting the calculation of those values.

Microalgae and phytase dietary supplementation improved growth and gut microbiota in juvenile European seabass (Dicentrarchus labrax).

Fishmeal and fish oil have been the main sources of protein and fatty acid for aquaculture fish. However, their increasing price and low sustainability have led the aquafeed industry to seek sustainable alternative feedstuffs to meet the nutritional requirements of fish and improve their health and performance. Plant proteins have been successfully used to replace fishery derivatives in aquafeeds, but the presence of anti-nutritional substances is a potential drawback of this approach. Thus, it has been reported that phytate breakdown can be caused by feed supplementation with exogenous phytase. The inclusion of microalgae has been proposed to improve gut functionality in fish fed diets with a high vegetable protein content. The aim of this study was to evaluate the effect on the growth and gut microbiota of European seabass (Dicentrarchus labrax) juveniles of a diet containing a blend of microalgae (Arthrospira platensis and Nannochloropsis gaditana) and different concentrations of phytase. An 83-day feeding trial was conducted, comprising four experimental diets with 2.5% microalgae and 500, 1,000, 2,000, or 10,000 phytase units (FTU)/kg feed and a microalgae- and phytase-free control diet. At the end of the trial, a significantly increased body weight was observed in fish fed the diet with the highest phytase concentration (10,000 FTU/kg) versus controls, although the gut bacterial composition did not differ from controls in alpha or beta diversity with either majority (Weighted UniFrac) or minority bacterial strains (Unweighted UniFrac). In comparison to the control group, the groups fed diets with 1,000 or 2,000 FTU/kg diets had a lower alpha diversity (Shannon's diversity index), while those fed diets with 500 FTU/kg or 1,000 FTU/kg showed distinct clusters in beta diversity (involving minority ASVs). According to these findings, the diet containing the 2.5% microalgae blend with 10,000 FTU/kg may be useful to increase the aquafeed quality and sustain the growth performance of juvenile European seabass.

Impact of transportation in freshwater and brackish water on Nile tilapia (Oreochromis niloticus) resistance.

BACKGROUND: Oreochromis niloticus has great economic value and potential for farming and development. Transportation of fish was done for breeding or trading purpose and it is a challenging aspect of aquaculture. This study aimed to investigate the effect of transportation in freshwater and brackish water on the resistance of O. niloticus as well as transportation stress mitigation effect of NaCl. Four equal groups were used; each of 50 fish, the 1st group served as the control (P 1), while the 2nd group (PT 2) was transported in water without salt, the 3rd (PT 3) and 4th (PT 4) groups were transported in water containing 5 gL- 1 and 10 gL- 1 salt respectively. PT 2, PT 3 and PT 4 were transported for 5 h without any rest or sedative drugs. RESULTS: The serum cortisol of O. niloticus significantly increased at 0 h and then decreased at 12 and 24 h post transportation in the PT 2 group and non-significantly increased at all point times in the PT 3 and PT 4 groups comparing to P 1 group. Mucin2 gene (MUC2) expression was non-significantly up regulated in the PT 2 group and down regulated in the PT 3 and PT 4 groups at 0 h comparing with P 1 group, but at 12 and 24 h it was significantly up regulated in the PT 2, PT 3 and PT 4 groups. The ß Defensin-1 (ß D1) and 2 (ß D2) genes expression was non-significantly down-regulated in the PT 2 group and significantly up regulated in the PT 3 and PT 4 groups at 0 h., while at 12 and 24 h was significantly down regulated in the PT 2 group and non-significantly down regulated in the PT 3 and PT 4 groups, it significantly down regulated in the PT 2 and PT 3 group and non-significantly down regulated in the PT 4 group at 24 h. Non-significant up regulation in interleukin - 1ß (IL-1ß) gene expression was reported in the PT 2 group and non-significant down regulation in the PT 3 and PT 4 groups at 0 h. However, significant up regulation was recorded in the PT 2, PT 3 and PT 4 groups at 12 and 24 h. The Tumor necrosis factor-alpha (TNF-α) gene expression was non-significantly up regulated in the PT 2 group and non-significantly down regulated in the PT 3 and PT 4 groups at 0 h. However, it was significantly up regulated in the PT 2, PT 3 and PT 4 groups at 12 and 24 h. CONCLUSION: The results of this study confirmed the stressful effect of transportation on O. niloticus as well as the transportation stress mitigation effect of NaCl.

Length-weight relationship and condition factor of Nile tilapia ( Oreochromis niloticus) fed diets supplemented with guava and star gooseberry leaf extract.

Background: Nile tilapia ( Oreochromis niloticus) is predominant cultured species in aquaculture. However, there is a scarcity of literature regarding relationship between guava and star gooseberry leaf extract and the condition factor. Thus, the present study aims to investigate the effect of guava and star gooseberry leaf extract-supplemented diets on the specific growth rate, length-weight relationship, and condition factor of Nile tilapia. Methods: Six hundred and thirty Nile tilapia (8.7±0.4 g) were randomly distributed among twenty-one tanks (30 fish per tank) within a recirculation system. Over a 60-day period, the fish were fed diets supplemented with 5g/Kg and 10g/Kg of guava leaf extract (GLE-5, GLE-10), star gooseberry leaf extract (SGLE-5, SGLE-10), and a mixture of both (MxLE-5, MXLE-10). Subsequently, specific growth rate, length-weight relationship, and condition factor were determined. Results: After 60 days, the specific growth rate was significantly higher in all the GLE, SGLE, and MxLE groups compared to the control group. The final lengths and weights differed significantly both in the control group and all the GLE, SGLE, and MxLE groups. The analysis of the regression equation indicated a positive correlation (r = 0.970, 0.977, 0.976, 0.974, 0.974, 0.974, and 0.969) between the length and weight of Nile tilapia in the control group and in all the GLE, SGLE, and MxLE groups. The regression exponent " b" values in all the GLE, SGLE, and MxLE groups were >3, indicating a positive allometric growth pattern in Nile tilapia compared to the control ( b=2.866), which exhibited a negative allometry. The final condition factor values did not differ significantly in either the control group or any of the plant extract groups. Conclusions: Nile tilapia exhibited positive allometric growth patterns and maintained good health when fed with GLE, SGLE, and MxLE groups. Therefore, these plant extracts demonstrate suitability for commercial Nile tilapia production.

Losses and destabilization of soil organic carbon stocks in coastal wetlands converted into aquaculture ponds.

Coastal-wetlands play a crucial role as carbon (C) reservoirs on Earth due to their C pool composition and functional sink, making them significant for mitigating global climate change. However, due to the development and utilization of wetland resources, many wetlands have been transformed into other land-use types. The current study focuses on the alterations in soil organic-C (SOC) in coastal-wetlands following reclamation into aquaculture ponds. We conducted sampling at 11 different coastal-wetlands along the tropical to temperate regions of the China coast. Each site included two community types, one with solely native species (Suaeda salsa, Phragmites australis and Mangroves) and the other with an adjacent reclaimed aquaculture pond. Across these 11 locations we compared SOC stock, active OC fractions, and soil physicochemical properties between coastal wetlands and aquaculture ponds. We observed that different soil uses, sampling sites, and their interaction had significant effects on SOC and its stock (p < .05). Reclamation significantly declined SOC concentration at depths of 0-15 cm and 15-30 cm by 35.5% and 30.3%, respectively, and also decreased SOC stock at 0-15 cm and 15-30 cm depths by 29.1% and 37.9%, respectively. Similar trends were evident for SOC stock, labile organic-C, dissolved organic-C and microbial biomass organic-C concentrations (p < .05), indicating soil C-destabilization and losses from soil following conversion. Soils in aquaculture ponds exhibited higher bulk density (BD; 11.3%) and lower levels of salinity (61.0%), soil water content (SWC; 11.7%), total nitrogen (TN) concentration (23.8%) and available-nitrogen concentration (37.7%; p < .05) than coastal-wetlands. Redundancy-analysis revealed that pH, BD and TN concentration were the key variables most linked with temporal variations in SOC fractions and stock between two land use types. This study provides a theoretical basis for the rational utilization and management of wetland resources, the achievement of an environment-friendly society, and the preservation of multiple service functions within wetland ecosystems.

A Collaborating Centre for animal health economics in the Americas.

Countries in the Americas play a vital role in global livestock and aquaculture production. With international trade of livestock and aquaculture products becoming an important source of income for countries, there has been an increased interest in using animal health economics for advocacy and allocation of resources. This article discusses the development of a new Collaborating Centre for the Economics of Animal Health and the applications of the Global Burden of Animal Diseases (GBADs) framework in the Americas region. Incentives for the increased use of economics in animal health decision-making and examples from the Americas region are examined. The article then discusses the newly formed World Organisation for Animal Health Collaborating Centre in the Americas region. Finally, it reviews two ongoing case studies that are implementing the GBADs framework in Peru and the United States of America.

Les pays des Amériques jouent un rôle crucial dans la production mondiale d'animaux d'élevage, qu'il s'agisse d'espèces terrestres ou aquatiques. Le commerce international des produits issus de l'élevage et de l'aquaculture étant désormais une source importante de revenus pour les pays, la possibilité d'utiliser les concepts de l'économie de la santé animale à des fins de plaidoyer et d'allocation des ressources suscite un intérêt croissant. Les auteurs abordent la désignation d'un nouveau Centre collaborateur pour l'économie de la santé animale ainsi que les applications du programme " Impact mondial des maladies animales " (GBADs) dans la région des Amériques. Ils examinent les avantages d'une meilleure prise en compte de l'économie dans les prises de décision en matière de santé animale, illustrés par quelques exemples concrets relevés dans la région. Ils décrivent ensuite la création du nouveau Centre collaborateur de l'Organisation mondiale de la santé animale dans la région des Amériques. Enfin, ils présentent deux études de cas menées actuellement concernant la mise en oeuvre du programme GBADs respectivement au Pérou et aux Etats-Unis d'Amérique.

Los países de las Américas desempeñan un papel fundamental en la producción ganadera y acuícola mundial. Dado que el comercio internacional de productos ganaderos y acuícolas se ha convertido en una importante fuente de ingresos para los países, el interés por utilizar la economía de la sanidad animal en favor de la promoción y la asignación de recursos ha ido en aumento. En este artículo se analiza la creación de un nuevo Centro colaborador para la economía de la sanidad animal y las aplicaciones del marco del impacto global de las enfermedades animales (GBADs) en la región de las Américas. Se examinan los incentivos para un mayor uso de la economía en la toma de decisiones sobre sanidad animal, así como ejemplos de la región. A continuación, en el artículo se presenta el recién creado Centro colaborador de la Organización Mundial de Sanidad Animal en la región de las Américas. Por último, se examinan dos estudios de casos en los que se está poniendo en práctica el marco del GBADs en Perú y los Estados Unidos de América.

Characteristics and pathogenicity of Vibrio alginolyticus SWS causing high mortality in mud crab (Scylla serrata) aquaculture in Hong Kong.

Introduction: Vibrio alginolyticus is a Gram-negative, rod-shaped bacterium belonging to the family of Vibrionaceae, a common pathogen in aquaculture animals, However, studies on its impact on Scylla serrata (mud crabs) are limited. In this study, we isolated V. alginolyticus SWS from dead mud crab during a disease outbreak in a Hong Kong aquaculture farm, which caused up to 70% mortality during summer. Methods: Experimental infection and histopathology were used to investigate the pathogenicity of V. alginolyticus SWS in S. serrata and validate Koch's postulates. Comprehensive whole-genome analysis and phylogenetic analysis antimicrobial susceptibility testing, and biochemical characterization were also performed. Results: Our findings showed that V. alginolyticus SWS caused high mortality (75%) in S. serrata with infected individuals exhibiting inactivity, loss of appetite, decolored and darkened hepatopancreas, gills, and opaque muscle in the claw. Histopathological analysis revealed tissue damage and degeneration in the hepatopancreas, gills, and claw muscle suggesting direct and indirect impacts of V. alginolyticus SWS infection. Conclusions: This study provides a comprehensive characterization of V. alginolyticus SWS as an emerging pathogen in S. serrata aquaculture. Our findings underscore the importance of ongoing surveillance, early detection, and the development of targeted disease management strategies to mitigate the economic impact of vibriosis outbreaks in mud crab aquaculture.

Using decapsulated local brine shrimp cysts on feeding common carp larvae in hatcheries.

The current study aims at using non-hatchable artemia eggs of local origin and making use of these eggs by decapsulating and presenting them as food for the larvae of the Cyprinus carpio as a source of animal protein with high nutritional value instead of throwing them away. The results showed that the second parameter (A2) was highly significant at the level (P≤0.05) in the growth rates of the larvae that were fed on decapsulated artemia eggs alone, and it was better than the two control parameters (A1), in which the larvae were fed with feed designated for Cyprinus carpio fish. It also outperformed the third parameter (A3), in which the feed was mixed with artemia eggs with 50% decapsulation, which also outperformed the control parameter with high significance at the same level (P≤0.05).