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This study involved two series of independent trials that investigated the storage temperature and time of raw fish to eliminate Opisthorchis viverrini metacercarial infection in Thai pickled fish. A total of 330 healthy silver barb fishes (30‐day posthatch) were infected with O. viverrini cercariae at an inoculation ratio of 50 cercariae/fish. After infection, the fish was reared for 3 months. The first trial was to evaluate the effect of fish storage temperature in the recovery from O. viverrini metacercariae. The infected fishes were randomly divided into five groups and stored at −20°C, 2°C, 4°C, and 8°C or room temperature (as a control) for 24 h. The results showed that at a storage temperature of −20°C, the fish initially had a reduced recovery rate from O. viverrini metacercariae. The second trial investigated the storage time for the recovery of infected fish stored at −20°C for 18, 24, 36, 48, or 60 h and used room temperature as a control group. The results revealed that storing infected fish at −20°C for 48 and 60 h had the lowest recovery rate from O. viverrini metacercariae at 0.00%. In conclusion, storing infected fish at a temperature of −20°C for a period of 48 h or longer could restrict the O. viverrini metacercaria recovery rate. These results were recommended as suitable conditions for the preparation of Pla‐som to avoid O. viverrini metacercaria contamination. [ABSTRACT FROM AUTHOR]

Biofloc technology offers a viable choice for the rearing of fish seed by offering a safe and protected habitat for young fish. Nevertheless, it is crucial to establish a standardised stocking density and implement effective ameliorative steps in order to successfully utilise this technology. In this study, a 90‐day investigation was conducted to assess the effect of stocking density and dietary vitamin C (Vit C) levels on the growth and immunity of Labeo gonius fry (1.03 ± 0.01 g) reared in a biofloc system. Three stocking density groups (5, 10 and 15 fish per 50 L) were established, and each experimental group was supplemented with three levels of Vit C (0, 500 and 1000 mg kg−1). The highest survival rate was observed in the lowest density group (five fish per 50 L) fed with 1000 mg kg−1 Vit C. A better feed conversion ratio and significantly higher protein efficiency ratio were found in the moderate stocking density group (10 fish per 50 L) fed with 500 mg kg−1 Vit C. Total leukocyte count (TLC), haemoglobin, and packed cell volume improved in Vit C‐fed groups. The total erythrocyte count (TEC) increased in groups fed Vit C and stocked at lower densities (5 and 10 fish per 50 L). Total serum protein (TPP) content increased when Vit C was added at a rate of 500 mg kg−1. Serum glucose and cortisol levels were significantly reduced in Vit C‐supplemented groups. Supplementation of Vit C at 500 mg kg−1 resulted in a significantly lower value of malondialdehyde (MDA). Thus, the findings confirm that the incorporation of Vit C in the basal diet promotes the growth and health status of L. gonius fry reared in the biofloc system at high‐density rearing. [ABSTRACT FROM AUTHOR]

The use of antimicrobials is essential for the aquaculture sector; however, their misuse is cause for concern because it could adversely affect the environment and human health. Irresponsible use of antimicrobials can lead to antimicrobial resistance and result in the presence of unwanted residues in aquaculture products. The establishment of maximum residue limits (MRLs) for antimicrobials is of great importance for monitoring their correct use, but the lack of harmonized standards as well as the regulatory gaps for the aquatic products create a challenging situation, as it is reflected in import notifications related to food safety. This paper collects information about current MRLs for antimicrobials in aquatic commodities in the main importing and exporting countries of aquatic products and compares them with each other and with MRLs set by Codex Alimentarius. This analysis highlighted the need for Codex Alimentarius guidance regarding MRLs for nine antimicrobials in aquaculture products (chlortetracycline, doxycycline, enrofloxacin, erythromycin, florfenicol, sulfadimethoxine + ormetoprim, sulfamerazine, tetracycline, and trimethoprim). This paper shows that there is still work to do to implement exhaustive science‐based international standards for residues permitted in aquatic commodities and promote harmonization. [ABSTRACT FROM AUTHOR]

This review paper provides an in‐depth analysis of the current status, challenges, and strategies for improvement within the fish feed industry in East Africa, focusing on Kenya, Uganda, Tanzania, and Rwanda. Aquaculture production in these countries is experiencing steady growth, driven by increasing demand for fish and fish products for both nutritional and economic purposes. Despite the market facilitating the transition from extensive to semi‐intensive and moderately intensive farming systems across the four countries, the sector's progress is hampered by a lack of sustainable, locally produced, high‐quality, and cost‐effective fish feeds tailored to different developmental stages of fish. Despite the evident need, there is a notable scarcity of comprehensive reviews addressing the regional perspective of fish feed due to heightened cross‐border trade driven by the soaring demand and increased installation of cages in Lake Victoria, as well as in inland dams and reservoirs. This paper addresses critical challenges, such as regional scarcity and limited access to quality feed ingredients, regulatory obstacles, insufficient quality control measures, infrastructure constraints, and a lack of awareness and understanding of feed management and formulation. To overcome these challenges, the paper recommends fostering collaboration to establish a robust regional fish feed supply chain, investing in research and development initiatives, advocating for policy reforms and regulatory support, and compliance with East African Community quality standards for fish feed. Moreover, there is an urgent need to enhance human resource capacity through training and extension services, promote public investment support, strengthen sector institutions and industry associations, conduct training and awareness programs for feed providers, and improve storage facilities to maintain feed quality. The paper provides policymakers with valuable insights to inform targeted interventions that will catalyze positive transformation within the fish feed industry in East Africa. [ABSTRACT FROM AUTHOR]

The widespread use of commercial feeds with high‐fat content in aquaculture may lead to oxidative stress and inflammation in fish during culture, which may cause changes in fish muscle texture. Therefore, mitigating oxidative stress and inflammation during fish farming holds paramount importance in improving fish muscle quality. In this study, we investigated the effect of different dietary levels of chlorogenic acid (CGA; 0, 100, 200, 400, 800, 1600 mg/kg diet, P1–P6) in commercial diets on the muscle of blackspotted croaker (Protonibea diacanthus) through an 8‐week feeding trial in open sea cages. The results showed that high dietary CGA levels (P5–P6) could significantly reduce muscle oxidative stress and inflammation (P < 0.05). Muscle toughness (hardness, chewiness, shear force, and gumminess) improved significantly as CGA levels increased (P < 0.05). It was also observed that the gap of muscle fiber was significantly reduced, while the muscle fiber density was significantly increased with the increase of CGA level (P < 0.05). Notably, dietary CGA also had a significant effect on collagen content in the muscle (P < 0.05), which may also be a crucial factor affecting muscle texture. Furthermore, it was found that the reduction of inflammation and increase of collagen deposition in muscle by dietary CGA may be related to the upregulation of transforming growth factor beta (TGF‐β) signaling pathway. Finally, it can be concluded that a dietary CGA supplementation of 1173.11 mg/kg is suggested for the aquaculture of P. diacanthus, based on the muscle texture quality. [ABSTRACT FROM AUTHOR]

Tilapia, a widely farmed aquaculture fish, produces substantial waste, including viscera that contain extracellular matrix (ECM) utilized as a biomaterial for tissue regeneration applications. Extracting ECM from viscera requires a specific decellularization method, as no standardized protocol exists. This study performed three decellularization methods: sonication, orbital shaking at room temperature, and agitation at 4°C, using SDS and TX100 at concentrations of 0.1% and 0.3%. The effectiveness of each method was assessed through H&E staining, dsDNA quantification, and SEM imaging to verify cellular content removal and ECM structure preservation. Additional analyses, including ATR‐FTIR, SDS‐PAGE, protein quantification, HPLC, and detergent residue tests, were performed to examine functional groups, collagen composition, protein content, amino acid profiles, and detergent residues in the decellularized samples. The results of H&E staining showed a significant reduction in cellular components in all samples, which was confirmed through DNA quantification. Sonication with 0.3% SDS achieved the highest DNA removal rate (96.5 ± 1.1%), while SEM images revealed that agitation at 4°C with 0.3% TX100 better preserved ECM structure. Collagen was present in all samples, as confirmed by ATR‐FTIR analysis, which revealed pronounced spectral peaks in the amide I, II, III, A, and B regions. Samples treated with agitation at 4°C using 0.1% SDS exhibited the highest protein content (875 ± 15 µg/mg), whereas those treated with TX100 had lower detergent residue. Overall, the decellularization methods effectively reduced DNA content while preserving ECM structure and components, highlighting the potential of tilapia viscera as bioscaffolds and offering insights into utilizing fish waste for high‐value products. [ABSTRACT FROM AUTHOR]

Background. The Babon River is one of the drainage channels in Semarang, Indonesia, that is used for drinking water, irrigated agriculture of paddy fields and gardens, fish farming media, and the disposal of industrial wastewater. This study aimed to assess the spatial distribution of metals in the sediment of the Babon River through the utilization of different pollution indices. These indices included concentration factor (Cf), contamination factor (CF), enrichment factor (EF), geoaccumulation index (Igeo), sediment pollution index (SPI), threshold effect level (TEL), and probable effect level (PEL). Methods. Seven sampling locations were sampled for water and sediment in April, June, and September of 2021. The measurement of the metal was conducted using an atomic absorption spectrophotometer. Results. The findings of the study demonstrated that sediments with a predominant sand texture exhibited higher levels of Cd and Pb, while the sediments characterized by a predominant clay texture had a higher concentration of Cr. Upon analyzing the Cf, CF, EF, Igeo, and SPI data, it has been confirmed that the sediment in the Babon River has substantial levels of Cd, Cr, and Pb. According to the TEL and PEL values, it can be observed that the presence of Cd and Pb has detrimental effects on the biological health of the benthic biota. Conclusions. The aquatic biota and the benthic environment may be subject to adverse effects in the event where the concentration of metals in the sediment is higher than the natural concentration of metals. [ABSTRACT FROM AUTHOR]

The interplay between environmental, biological, and physical factors often leads to the deterioration of dead fish in marine cages prior to their removal. Depending on the weight of the dead fish and the frequency of their removal, deterioration can progress to a stage where visual identification by divers becomes challenging, thereby disrupting accurate counting of dead fish. This study presents a practical precision tool for monitoring the number of dead fish during the pregrowth and growth phases of caged European sea bass (Dicentrarchus labrax). To improve the assessment of collected mortality, experiments were conducted in farming cages with various fish weights. Identifiable fish rates (I, %) were calculated every 24 hr and classified into four weight classes: WC1 (4–15 g), WC2 (15–30 g), WC3 (30–80 g), and WC4 (>80 g). The corrected number of dead fish (M) was calculated by dividing the collected number (C) by a correction factor (McR), which was determined based on the adopted removal frequency. The possible mortality removal frequencies per week (Fn) included operations such as F7 (daily), F3 (3 times), F2 (2 times), and F1 (once). The smallest correction denominator was 22% for WC1 at a frequency of once per week, whereas the maximum was 100% for WC3 and WC4 daily. The results revealed a high negative significant correlation between Fn and uncollected degraded fish rate (UR) (r = –0.841, p < 0.05). Applying corrections to mortality collected in three finished batches (B2, B3, and B7) led to an increase in the mortality rate by 3.9% ± 1.5%, 5.5% ± 0.7%, and 5.0% ± 0.5%, respectively. This explained 16.8% ± 4.7%, 65.5% ± 26.7%, and 30.3% ± 3.7% of fish disappearances in B2, B3, and B7, respectively. The significance of this study lies in its practical applicability to fish farms as a precise tool for monitoring fish raised in marine cages. [ABSTRACT FROM AUTHOR]

The starry flounder Platichthys stellatus, an economically important benthic fish species widely distributed throughout the North Pacific Ocean, exhibits poor heat tolerance, resulting in frequent adult mass mortality in aquaculture settings. Heat stress disrupts the energy metabolism of P. stellatus, elevating blood glucose and implying its sensitivity to rising water temperatures. In particular, the survival of adult fish in aquaculture settings during the summer season is less than that of larvae or juveniles. This study aimed to understand the heat stress‐associated survival of adults by focusing on the molecular pathways of glycolysis/gluconeogenesis using comparative transcriptome analysis. Transcriptomes were obtained by RNA sequencing of P. stellatus livers of adults exposed to 16 and 28°C, together with juveniles at the same conditions. A total of 16,121,503–18,774,222 raw paired‐end reads were obtained after trimming. The assembled unigenes (39,489 out of 127,460) were annotated in the nr, Clusters of Orthologous Groups (COG), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Swiss‐Prot databases. A total of 6,858 differentially expressed genes were found in juveniles and adults at control (16°C) and high (28°C) water temperatures. Juveniles and adults had 1,856 genes downregulated and 1,548 genes upregulated at the 16°C control water temperature and 1,055 genes downregulated and 1,231 genes upregulated at 28°C, overall involving at least 47 KEGG pathways. When raising the water temperature and comparing the DEGs of juveniles and adults, respectively, we found that both groups showed similar upregulation patterns for the major heat shock protein (HSP) genes under temperature‐increasing conditions, indicating a conserved response mechanism. Additionally, both juvenile and adult fish showed similar upregulation of ER stress‐related genes, including endoplasmic reticulum chaperone BiP (BiP) and homocysteine‐responsive endoplasmic reticulum‐resident ubiquitin‐like domain member 1 (HERP), suggesting consistent transcriptional changes associated with ER stress under heat stress conditions. However, notable differences were observed in the expression of inflammation and immune response‐related genes, and juvenile P. stellatus showed upregulation of immune costimulatory protein B7‐H3 (B7H3) and immunoglobulin superfamily member 9 (IGSF9), while adults showed upregulation of high‐affinity immunoglobulin epsilon receptor subunit gamma (FCER1G), V‐type immunoglobulin domain‐containing suppressor of T‐cell activation (VSIR), and immunoglobulin superfamily DCC subclass member 3 (IGDCC3). Especially, phosphoglucomutase (PGM), glucose‐6‐phosphatase catalytic subunit (G6PC), phosphofructokinase (PFK), and bisphosphoglycerate mutase (BPGM), the enzymes involved in the glycolysis/gluconeogenesis pathway, showed significantly higher FPKM in adult P. stellatus than in juveniles. Overall, this study provides valuable insights into the transcriptional responses of P. stellatus to heat stress, which differ with age and may inform the development of strategies to improve the survival and productivity of this economically important fish species in aquaculture. [ABSTRACT FROM AUTHOR]

Aquaculture allows sustainable fish farming to meet global demand; however, fish feed can contain mycotoxins and contaminate animals and humans. Bentonites are clayey materials composed mainly of montmorillonite and are used to reduce or diminish the toxicity of aflatoxins to animals and humans. In this sense, new cheap technologies from natural resources are necessary for controlling fungi and mycotoxins in food. However, information on the potential adverse effects on fish health and performance caused by adding bentonite clays to reduce mycotoxin exposure is scarce. Thus, this systematic review aims to analyze recent studies focusing on the use of bentonite clays as adsorbent materials for mycotoxins in fish feed. In this systematic evaluation of the literature on the subject, which was conducted in Cochrane, Science Direct, PubMed, and Scopus, 1,878 publications from the last 10 years were found, but 1,871 of them were excluded, leading to the selection of only seven for this study. The articles were classified according to the main theme of fish detoxification, the use of natural or chemically modified bentonite clays through adsorbents to remove mycotoxins. The results of the risk of bias analysis of the included studies (seven) were carried out according to the Down and Black criteria. The studies showed that hematological parameters such as total serum protein, albumin, alanine aminotransferase, aspartate aminotransferase, N-urea, and creatinine were altered in some fish species due to contamination by aflatoxin B1 in the diet. On the other hand, the use of bentonite reveals that it has the potential to reduce the effects of aflatoxicosis in fish, causing an increase in body weight, changes in serum enzymes related to humoral immunity, and changes in gill morphology and liver tissue. Contamination of fish diets (especially tilapia) by aflatoxins B1 produces severe changes in all investigated parameters and is extremely dangerous for fish productivity and public health. It was observed that adding clays to tilapia diets reduces the effects of aflatoxicosis while improving economic output and lowering health hazards by adsorbing aflatoxins B1. Thus, the use of bentonite clays is one of the most promising decontamination techniques that can be used by pisciculture. [ABSTRACT FROM AUTHOR]

The aim of the current study was to assess the impacts of tank color on the growth, stress, biochemical, hematological, and immunological responses, and expression of growth-related genes in juvenile Oscar (Astronotus ocellatus). Therefore, a total of 120 fish (9.14 ± 0.34 g) were distributed into 12 aquariums (60 × 50 × 35 cm) and divided into four treatments (aquariums with blue, white, yellow, and red colors) in three replicates (10 fish per aquarium). The fish were daily hand-fed ad libitum in three meals at 7:00, 12:00, and 17:00 hr for 56 days. Results showed that Oscar fish cultured in the red aquariums had higher final weight and weight gain and lower feed conversion ratio. Plasma cortisol, glucose, and lactate values of fish were significantly higher, and the amount of white blood cells was lower in the blue aquariums compared to other tank colors. Plasma triglyceride values were significantly higher in the white and yellow groups than the blue aquariums. Moreover, fish cultured in yellow and red aquariums had significantly higher melatonin levels than the blue aquariums. Plasma cholesterol, total protein, albumin, complement 3, and total immunoglobulin values were highest in Oscar fish cultured in the red aquariums. Also, lysozyme and alternative complement (ACH50) activities and complement 4 values of fish cultured in yellow and red aquariums were meaningfully higher compared to blue and white groups. Growth hormone relative gene expression levels were meaningfully higher in Oscar fish cultured in white, yellow, and red aquariums than the blue aquariums. Furthermore, insulin-like growth factor-1 (IGF-1) relative gene expression levels were significantly higher in fish cultured in yellow and red aquariums compared to those cultured in blue and white tank colors. Thus, the most suitable tank color for rearing juvenile A. ocellatus is red, while blue tank color is unsuitable. [ABSTRACT FROM AUTHOR]

Cyprinus carpio is a widely distributed and commercially important fish species in Ethiopia. Effective management is essential to sustain fisheries and provide benefits to local communities. This study aims to estimate the growth, mortality, and exploitation rate of C. carpio using length-frequency data. A total of 194 C. carpio specimens (117 females and 77 males) were collected between June 2022 and May 2023. The population parameters were determined using FISAT (ELEFAN I) software. The Von Bertalanffy growth function estimations were L ∞ = 51.45 cm total length, K = 1.1 year−1; t 0 = −0.124 year, and growth performance index (Φ′) = 3.464. The total mortality rate (Z), natural mortality rate (M), and fishing mortality rate (F) were 2.55 year−1, 1.58 year−1, and 0.97 year−1, respectively. The estimated potential longevity (tmax) and average age at which C. carpio attains length at the optimum cohort biomass or yield per recruit (Lopt = 34.79) in Lake Arekit were calculated as 2.60 years and 1.29 years, respectively. The Z/K ratio (2.32), exploitation rate (E = F/Z = 0.38), and highest permissible yield per recruit for C. carpio (Emax = 0.421) suggest enhancing fishery production by increasing the exploitation rate of the underexploited C. carpio in Lake Arekit. The results of this study provide information on the stock of C. carpio, which can be used to guide management efforts. The fish catch in Lake Arkeit is currently far lower than it could be. Therefore, the fish harvest should be boosted through the use of permitted nets, the establishment of groups of fishermen who can catch fish effectively, and the linking of the benefits of fish farming's supply chain to the potential of fisheries. [ABSTRACT FROM AUTHOR]

The development of deformities in farmed fish is largely the result of abiotic, biotic, and xenobiotic factors, information deficiencies in optimizing nutrition, and the genetic background to which the fish are exposed in their early life stages. In general, skeletal anomalies are considered to have significant adverse effects on animal welfare, biological performance of farmed fish, product quality, and production costs. In the data obtained by the meta-analysis method, the presence of negative effects on the formal structures of fish was found, regardless of the region, duration, stage, factor, stock density, and method used to detect deformation. In this regard, in the studies considered within the deformation region/type, 46% of deformities were found in the spine, 37% in the head, and 16% in the total skeleton. In turn, the results of the meta-analysis showed that the percentages of the apparent value were 35.82% in the spine, 33.12% in the skeleton, and 31.06% in the head. The deformation rate had an overall negative effect on the functional characteristics of the fish, regardless of the variables considered. In addition, all statistically significant individual response variables had a negative effect size. In the future, advanced statistical tools such as Bayesian meta-analysis, network meta-analysis, and meta-regression analysis can be used to explore more complex data structures. The rapid development of artificial intelligence techniques will increase the efficiency of data collection and the robustness of results for meta-analysis studies in aquaculture and other fields. [ABSTRACT FROM AUTHOR]

This study analyzed the quality of large yellow croaker (Larimichthys crocea) of different sizes cultured in farmed floating sea-cage (common cage, CC) or deep-water cage (DWC) models. The quality was assessed based on several factors: condition factors, ventral color, texture, protein and lipid content, and fatty acid composition. In addition, we analyzed and identified taste characteristics and volatile substances. The results showed that large yellow croaker cultured in DWC had a better body shape than CC with lower condition factors and higher body length-to-height ratio. The DWC cultured fish were yellower with lower lipid content than the CC cultured fish. The springiness of the flesh from fishes cultured in DWC was significantly higher than those cultured in CC. The level of immobilized water and n-3 polyunsaturated fatty acid was higher in DWC. The DWC culture model contributed to the sweetness, saltiness, and umami of the flesh. The flesh from DWC had a higher content of aldehydes, such as pentanal, heptanal, and hexanal. The results demonstrated that the DWC culture model is a better choice to improve the quality of large yellow croaker in terms of organoleptic properties, nutritional value, and taste. [ABSTRACT FROM AUTHOR]

Olive flounders are susceptible to annual outbreaks of streptococcosis, which accounts for approximately 10% of all fish farm diseases and is associated with high mortality rates. The development of an antibiotic therapy against streptococcosis is thus necessary. This study determined the therapeutic effects of varying cephalexin concentrations in Streptococcus parauberis-infected olive flounders and evaluated its histopathological toxicity and residual concentration in the fish. Compared with the control group, the 200 and 800 mg/kg cephalexin groups showed significant mean survival rates of approximately 10% and 30%, respectively, and the 400 mg/kg group showed the highest survival rate of approximately 40%. The average residual cephalexin concentration in muscle samples on day 1 post-cephalexin administration was 13.21 µg/kg, showing a rapid decrease. At the optimum water temperature (25°C), cephalexin was rapidly metabolized within 24 hr of its administration being terminated, and most of it was excreted from the bodies of the fish. A histopathological analysis showed that the oral administration of cephalexin did not lead to specific inflammatory lesions, and there were no significant differences between the treatment and control groups. Our novel findings suggest that cephalexin is a promising candidate for treating streptococcosis outbreaks in fish farms. [ABSTRACT FROM AUTHOR]

Conservation aquaculture aids in restoring and rebuilding populations of endangered species through artificial breeding. The Ussuri cisco (Coregonus ussuriensis Berg) is a valuable fish species in China, known for its high nutritional value. However, its current yield heavily relies on fishing, leading to a rapid decline in wild populations. This study documents the successful artificial breeding of C. ussuriensis and provides a comprehensive description of its life cycle. We performed in situ gamete stripping followed by manual fertilization. Fertilized eggs were incubated at the Bohai cold-water fish experimental station in Mudanjiang, China, where seed breeding and parental fish farming were conducted. Under controlled conditions, we obtained around 110,000 fertilized eggs. After a 2-month incubation period, we obtained around 50,000 oviparous eggs with an eyed rate of 45.5%. Additionally, we observed over 30,000 larvae with a hatching rate of 60%. We produced 20,000 juvenile fish weighing 30 g after 1 year. This procedure facilitates the successful completion of the C. ussuriensis life cycle in aquaculture, aiding in the species' recovery. [ABSTRACT FROM AUTHOR]

Viral haemorrhagic septicaemia virus (VHSV) is a fish disease notifiable to the World Organisation for Animal Health. The United Kingdom is currently free from VHSV, and the introduction and onward spread of this disease could cause major economic losses in aquaculture facilities. Legislation in Great Britain requires that imports of live fish for aquaculture purposes into declared disease-free areas are of equivalent disease-free status. However, conditions on fish products are less stringent, whereby eviscerated fish or fillets can be transported from areas with disease to areas declared disease-free. Market-size rainbow trout were experimentally infected with VHSV to investigate two important factors relevant for pathogen introduction and transmission: (1) VHSV shedding, quantified by daily assessment of viral titres in tank water samples, and (2) VHSV concentrations in liquid and solid processing waste. Evisceration and filleting preclinical fish, maceration, and wastewater separation processes within a facility were mimicked, and VHSV was quantified in each fraction of the wastewater. Shedding was detected 25 hr post-challenge. Levels increased daily to peak on day 5 post-challenge, with a calculated average titre of 1.35 × 103 TCID50 mL−1 kg−1 fish, 1 day before clinical signs of disease. Preclinical fish contained virus levels in their kidney, skin, and muscle >107 TCID50 g−1. The fish had significantly higher levels in the kidney, and evisceration led to higher VHSV concentrations in the waste compared to filleting. However, there was no significant difference in levels in wastewater released from the two processes after the removal of solids, even when macerated; average titres were >104 TCID50 mL−1. The quantities of VHSV from shedding and processing can be utilised when modelling transmission and undertaking more accurate risk assessments for imports and processing of commodities, with the ultimate aim of reducing the global risk of disease from international trade and processing. [ABSTRACT FROM AUTHOR]

As the increase of demand for seafood supplies, a large amount of high-protein feed has been added to mariculture aeras, which causes hazards for the cultured organisms and environment. Here, we used 16S rRNA gene high-throughput sequencing to evaluate the bacterial communities in the sediments of two aquaculture systems (fish and oyster culture) in Xiangshan Bay, China for four seasons. Analysis of variance results showed that the abundance and biodiversity differed significantly between the culture areas and control areas, and different seasons as well. Proteobacteria, Planctomycetes, and Bacteroidetes were the three most abundant phyla. Gammaproteobacteria, Deltaproteobacteria, and Bacteroidia were the three most abundant classes. Principal co-ordinates analysis showed that sediment bacterial community composition in the fish and oyster culture areas significantly differed from that in the control areas. Analysis of the function prediction of pathways related to the nitrogen cycle in sediments revealed a higher proportion of genes involved in denitrification in aquaculture farms. Nitrate respiration particularly occurred in fish areas, whereas nitrate reduction occurred both in fish and oyster areas, and the proportions in winter were significantly higher than that in other seasons. It also provides insights into the indirect effects of human aquaculture activities on coastal algal blooms. [ABSTRACT FROM AUTHOR]

Aquaculture in Bangladesh has expanded, diversified, and intensified over the last decades. Control of infectious diseases is critical for a successful and sustainable aquaculture. In this study, we examined the extent of use of probiotics in aquaculture of Bangladesh, using a questionnaire. Data were collected from 200 individual respondents from commercial fish farms located at Mymensingh, Rajshahi, Jashore, and Cumilla (50 from each) regions. A total of 88 different probiotics products from 36 companies, mostly imported, are used in the aquaculture in Bangladesh. Although in most cases the purpose of the use of probiotics is not clear for the farm owners, several representatives of different companies suggested the use of their different probiotic products, for different situations. Most of the farm owners responded that they used probiotics to get higher production by promoting the growth of fish. A considerable number of farm owners responded that probiotics reduced mortality as well as reduced gas emissions from the aquaculture ponds. Although the use of commercial probiotics varies from region to region, Pondcare and Safegut, the product of SK + F, are mostly used in aquaculture based on the responses (32% and 21% of respondents, respectively). To safeguard and clarify the value and effectiveness of these goods, the fish feed manufacturers and regulatory authorities should monitor their production, collection, and marketing. [ABSTRACT FROM AUTHOR]

Understanding the spawning and rearing habitats of fishes is critical to effective fisheries management and conservation. Longfin smelt Spirinchus thaleichthys is an imperiled migratory fish that is believed to spawn and rear in habitats of varying salinities; however, optimal conditions for each stage remain unknown. Here, we examined the effects of variation in salinity on egg fertilization, hatch success, and larval growth and survival. Eggs that were fertilized in freshwater (0.4 ppt) exhibited a significantly higher fertilization rate (81%) than those fertilized in brackish water (62% at 5 ppt), with no detectible effects of fish origin or female size. In contrast to fertilization rates, once the eggs were fertilized, their hatching rates were not affected by the fertilization salinity, incubation salinity, nor their interaction; however, hatching success and larval survival both increased with increasing maternal body mass. Larval growth rate appeared to be independent of salinity and maternal size. Taken together, the results indicate that fertilization is possible at a range of salinities, but optimal at lower salinities for longfin smelt; however, embryos and larvae can perform well across a range of salinities. Furthermore, results indicated that larger mothers produced high-quality offspring, a finding that supports the "bigger is better" paradigm in fisheries science and management. These results likely explain, in part, the spawning and rearing behaviors of wild longfin smelt and suggest that the conservation culture program would likely be optimized by utilizing freshwater fertilization and larger females as broodstock. [ABSTRACT FROM AUTHOR]

The presence of antinutritional substances, such as phytate, in fish feed affects the digestibility and absorption of minerals and nutrients by fish, while reduced availability of phosphorus (P) in wheat-based feeds used in fish farming can increase pollution in the aquatic environment. Phosphorus digestibility can be effectively increased in aquaculture through the addition of both phytase and citric acid. The aim of our study was to investigate the effects of phytase enzyme and citric acid addition on P digestibility, production parameters and blood parameters in farmed common carp (Cyprinus carpio L.). Two trials were undertaken using the following experimental diets: control with no additives (C), low enzyme content (500 FTU/kg; L), high enzyme content (1,000 FTU/kg; H), low enzyme contents with 3% citric acid (LA), high enzyme contents with 3% citric acid (HA). Initial results showed that LA increased P digestibility by 27% and HA by 26%, with no increase detected using L and H. In the second trial, in which production and blood parameters were examined, use of LA and HA resulted in a 20% decreased feed conversion ratio and 11% higher specific growth rate. Furthermore, acidified diets resulted in an increased blood plasma calcium and inorganic P, without negative effects on any parameter. Addition of phytase and citric acid to C. carpio granulated feeds also has a positive influence on the environment by reducing excreted P. [ABSTRACT FROM AUTHOR]

Growing microalgae on vegetable waste (rotten potatoes) media is not only a plausible technique to replace expensive commercial media but also a way of reducing feed costs for rearing zooplankton and fish larvae in aquaculture. As a way of starting an inevitable step up, Monoraphidium littorale was grown in 25% (T1), 50% (T2), and 75% (T3) of digested rotten potato supernatant (DRPS) and at the same time in Bold Basal Medium (BBM) as a control (T4) for 16 days. The highest cell density of M. littorale was recorded in T1, followed by T4, T2, and T3. A similar increasing trend of chlorophyll-a and optical density was also observed during the experimental period. The study also ascertained T1 as a potential growth medium where M. littorale showed superior biomass production which was significantly higher (P < 0.05) than other treatments. It was also worth mentioning that the highest (P < 0.05) protein content was determined in T1 at the end of the cultivation time. Similarly, a highly significant difference (P < 0.05) was also found in the lipid content of the microalgae grown in T1 and T4. Furthermore, the morphology of the cells of M. littorale was found to be strongly affected by the DRPS concentrations and BBM. Thus, the lower concentration of the DRPS served as the best medium for enhancing the growth and biomass of M. littorale. Consequently, to expedite the sustainable progression of microalgal production, cost-effective culture techniques by using different wastes may be adopted. [ABSTRACT FROM AUTHOR]

In Ghana, aquaculture offers acceptable opportunities for generating income. Cage aquaculture has a lot of potential for growth in Lake Volta. In this region, cage aquaculture farmers perform aquaculture in a variety of ways that fall into three major groups: commercial, medium scale, and small scale. In this study, the profitability and production economics of small-scale aquaculture operations in Lake Volta were examined. The average total revenue accrued and the average total costs of production were Gh₵395231.25 and Gh₵267970.15, respectively. The overall gross margin and net return for all the farms were Gh₵130294.02 and Gh₵127,261.10 per cycle, respectively. The overall assessment of the profitability performance indicators such as the benefit-cost ratio (BCR), the return on investment (ROI), the net present value (NPV), the operating expense ratio (OE), the operating profit margin (OPM), and the gross margin ratio (GMR) were 1.47, 47.49%, Gh₵407625.47, 0.77%, 32.20%, and 33.00%, respectively. These indicators showed that small-scale cage fish farming in the study area is profitable. The sensitivity analysis further demonstrated that small-scale cage fish production was robustly profitable. In light of this, the study suggests that stakeholders educate small-scale cage aquaculture farmers on the profitability of the business and make a concerted effort to teach and equip farmers with best management practises (BMPs), water quality management, feeds, and feeding management. [ABSTRACT FROM AUTHOR]

In the recent past, fish farming has gained great prominence in Kenya as the country straggles to meet food security. Nile tilapia (Oreochromis niloticus L.) farming has attracted the most demand, with the use of manure to enhance primary productivity in fish ponds being encouraged as a form of increasing productivity and returns on investment. The objective of this study was to understand the role of Nile tilapia farming in greenhouse emissions (GHGEs) in the region. Generally, there is paucity of such information originating from sub-Saharan Africa. Here, we report the levels of methane (CH4), carbon dioxide (CO2), and nitrous oxide (N2O) emissions from Nile tilapia fish ponds fertilized with organic and inorganic fertilizers. We also try to establish if there exists any relationship between GHGEs and physicochemical parameters (PCPs). The methane fluxes ranged from 0.001 to 0.043°mg·m−2h−1 in UF ponds, 0.005 to 0.068°mg·m−2h−1 in IF ponds, and 0.001 to 0.375°mg·m−2h−1 in OF ponds. The findings show that the fluxes were significantly different (P < 0.05). Mean fluxes of CO2 did not show significant difference among the treatments (P > 0.05), ranging from −0.180 to 1.40°mg·m−2h−1 in UF ponds, −0.020 to 1.101°mg·m−2h−1 in IF ponds, and −0.049 to 1.746°mg m−2h−1 in OF ponds. N2O mean fluxes were not significantly different (P > 0.05), ranging from −0.628 to 0.326°µgm−2h−1 in UF ponds, −0.049 to 0.187°µgm−2h−1 in IF ponds, and −0.022 to 1.384°µgm−2h−1 in OF ponds. UF had a mean flux of −0.003 ± 0.175°µgm−2h−1, IF had a mean flux of 0.032 ± 0.056°µgm−2h−1 and OF had a mean flux of 0.093 ± 0.324°µgm−2h−1. There was significant difference in the carbon to nitrogen (CN) ratio among the fertilization treatments (P < 0.05), whereas temperature, pH, dissolved oxygen, and conductivity showed no significant difference among the fertilization treatments (P > 0.05). The study observed that fertilization of Nile tilapia ponds significantly increases the release of CH4 emission and the CN ratio. Temperature, conductivity, and CN positively correlated with CH4, CO2, and N2O emissions. Dissolved oxygen showed a negative correlation with CH4 and CO2 emissions while negatively correlated with N2O emissions. The study identified the use of OF as a potential form of fish farming that promotes the emission of GHGEs and calls for adoption of sustainable technologies for the management of organic and inorganic fertilizers before their use in pond fertilization. [ABSTRACT FROM AUTHOR]

Body colors are an important trait for the survival and reproduction of animals. In this study, transcriptomes and related single nucleotide polymorphisms (SNPs) of black- and red-colored Plectropomus leopardus (Lacépède) were identified to investigate important molecules and SNP markers associated with body color formation. In the comparison of red- and black-colored groups, 489 differential expressed genes (DEGs) were detected and among them, 236 up- and 253 down-regulated genes were found in the red-colored group. Gene ontology (GO) analysis of DEGs showed that pigmentation associated terms including pigment granule, pigmentation, melanin metabolic process, tyrosine metabolic process, pigment metabolic process, and pigmentation cell differentiation were enriched. Kyoto encyclopedia of genes and genomes (KEGG) analysis of DEGs presented that melanin related pathways (tyrosine metabolism and melanogenesis) were enriched. Furthermore, lipid metabolism and immune-related metabolism were also enriched. A total of 1,048,575 SNPs were detected from the transcriptome, and among them, 627,172 SNPs were located in the gene region. A total of 1323 SNPs were identified as differential SNPs in the comparison of black- and red-colored groups and were located in 1127 genes. Among the 1127 genes, 20 genes were identified as DEGs and were comprised of 9 SNPs with a potential role in body color selective breeding in fish farming. [ABSTRACT FROM AUTHOR]

Biosecurity practice limits the occurrence of diseases and economic losses in fish farms. The objective of this study was to characterize fish farming in the Administrative Division of Wouri, Cameroon (3°97′04″–3°58′13″N; 9°76′78″–9°46′4.3″E) and assess the biosecurity practices. A cross-sectional biosecurity audit was then conducted in 33 fish farms from March to May 2022. The "snow ball" technique, on-farm observations, and face-to-face interviews of farm managers using a semistructured questionnaire were used for data collection. The results showed that most of the fish farmers were between 18 and 40 years of age (63.64%) and not trained in fish farming (60.61%). The lack of finance (57.57%) was the main constraint to the biosecurity practice. The high fish mortality rate (>15%) was recorded in 66% of the farms. Overall, the compliance rate (CR = 40.52 ± 14.70%) and adoption rate (AR = 40.40 ± 30.10%) of biosecurity measures were intermediate. No type C farm or at the minor risk level of contamination was recorded. Farmers of 18 to 40 years of age (45.24 ± 14.75%) who attended higher school (43.83 ± 14.44%) and received training in fish farming (47.44 ± 14.39%) recorded a significant higher CR. The CR and AR were significantly higher for the isolation component (CR = 60.17 ± 19.81%; AR = 60.17 ± 25.68%) followed by traffic control (CR = 53.53 ± 25.87%; AR = 53.53% ± 34.86) and sanitation (CR = 27.70 ± 19.70%; AR = 29.84 ± 26.00%). A strong (R2 = 0.725), positive, and significant (p = 0.019) linear relationship was found between the level of education of fish farmers and the biosecurity compliance rate while the health status of fish was weakly (R2 = 0.207), positively, and significantly (p = 0.017) influenced by the compliance rate. Fish farming is an income-generating activity that still requires socioeconomic, technical, and institutional efforts for optimal productivity. The Cameroonian government should emphasize on the education, training, and capacity building of farmers on biosecurity practices to minimise the introduction, establishment, and spread of diseases. [ABSTRACT FROM AUTHOR]

The present study aims at investigating the antibiofilm activity of two various ginger (Zingiber officinale) extracts in comparison to peracetic acid in broth culture and food model against pathogenic bacteria. The GC-MS analysis proved that the major components in the subcritical water extract of ginger were Zingerone (28.99%) and cis-6-shogaol (22.1%), while in the aqueous-ethanolic extract was Gingerol (28.404%) and Zingiberene (11.954%). According to the results, ginger subcritical water extract in a concentration of 50% (V/V) had the highest antibiofilm activity, and no significant difference was observed with peracetic acid (0.5%). However, similar results were obtained regarding the antibiofilm activity of the ginger extracts in both environments (broth culture and fish extract as a food model). The gram-positive B.subtilis bacterium was more susceptible to ginger extracts than the gram-negative P.aeruginosabacterium. In conclusion, ginger subcritical water extract could be recommended as a natural and safe antimicrobial compound with antibiofilm potential in the food industry. [ABSTRACT FROM AUTHOR]

Snakeskin gourami (Trichogaster pectoralis) is a freshwater fish species that is being increasingly cultivated in Southeast Asia. The expansion of farms and intensive farming practices has led to the unexplained mortality of snakeskin gourami and tremendous economic losses in many farms. We investigated the unusual mortality of snakeskin gourami at 22 farms in Central Thailand. The moribund fish showed darkened skin, erratic swimming, exophthalmos, and haemorrhaging around the eyeballs, with cumulative mortality between 20% and 45%. Our necropsy findings revealed an enlarged liver and anterior kidney, splenomegaly, haemorrhage in most internal organs, pericarditis, and brain congestion. Histopathology revealed haemorrhaging and congestion of the blood vessels in the liver with infiltration of lymphocytes, enlarged blood vessels with mononuclear and lymphocyte infiltration in the meninges, and cerebral parenchyma were observed. Severe necrotising and suppurative pericarditis with myocardial infarction were found. Epidemiological studies and laboratory diagnosis revealed that Streptococcus agalactiae was predominantly isolated from the moribund fish. Laboratory investigations of the representative 33 isolates of S. agalactiae using mass spectrometry, multiplex polymerase chain reaction assay, pulse-gel electrophoresis, and serotyping suggested that all the isolates were S. agalactiae serotype VII, which is different from the serotype III isolated from diseased tilapia in Thailand. An experimental challenge using three representative isolates of S. agalactiae on snakeskin gourami caused clinical signs, gross lesions, and pathological changes, with high mortality exceeding 60%, which is similar to the mortality in most natural infections. Moreover, S. agalactiae was recovered from the spleen, kidneys, and liver of all the challenged fish. Taken together, this study provides important information that S. agalactiae serotype VII is virulent in snakeskin gourami and can potentially spread among these fish in fish farms. Appropriate preventive measures and the control of animal movements should thus be implemented. [ABSTRACT FROM AUTHOR]

The current study aimed to explore the intestinal fungal community characteristics of grass carp and black carp and their correlation with cultured water fungi. Grass carp, black carp, and their cultured water samples were collected from the same reservoir. Based on the Illumina HiSeq 2500 high-throughput sequencing platform, the fungal internal transcribed spacer (ITS) region sequences of each sample were determined and analyzed. The results showed that a total of 1,193,261 valid sequences with an average length of 235–251 bp were detected in the three groups of samples, which included 9 phyla, 27 classes, 65 orders, and 288 genera. Ascomycota, Basidiomycota, Mortierellomycota, and Chytridiomycota were the dominant phyla. Mortierella, Thermoascus, and Thermomyces were the main genera. Compared with cultured water samples, the abundance of major phyla and genera was significantly different from grass carp and black carp samples, but there was no significant difference between grass carp and black carp samples. Surprisingly, Ascomycota was enriched in CY and QY samples. In conclusion, the dominant fungi in grass carp, black carp, and cultured water samples were similar, but the relative abundance was significantly different compared with cultured water samples. The results will provide a basis for the tolerance of fish with different feeding habits to colonize water and provide a theoretical basis for the regulation and improvement of aquaculture water quality and the realization of healthy and green aquaculture of fish. [ABSTRACT FROM AUTHOR]

While copepods are important prey for many wild marine fish larvae and are preferred as a live feed for culturing larval fish, their low productivity and the costs associated with culturing them typically limit their use as a live food source in all but experimental situations. In a series of experiments with four readily and commercially available microalgae (Thalassiosira weissflogii Grunow, Rhodomonas salina Wislouch, Tetraselmis suecica Kylin Butch, and Isochrysis galbana Parke), we determine which of them, when exclusively fed to a commonly occurring copepod, Oithona oculata, over a 15-day period, results in the greatest copepod survival and egg production rates. We posit that species of Oithona might be an ideal candidate for copepod taxa for commercial-scale copepod culture and that the microalga Rhodomonas salina is an ideal food source to culture them. [ABSTRACT FROM AUTHOR]

Tuna (genus Thunnus), particularly Pacific bluefin tuna (T. orientalis; PBT), are commercially important fish in the aquaculture industry worldwide. The objective of this study was to investigate sexual dimorphism in the growth performance of aquaculture-produced PBT and develop techniques for its sex manipulation, for the first time in tuna. A comparison of the body size between sexes revealed that male-cultured PBTs were larger than females at harvest. We also confirmed that cyp19a1a (encoding a gonadal aromatase) expression increased specifically in the genotypic female PBT gonads during sex differentiation. This suggested that aromatase plays an important role in ovarian differentiation and that the suppression of aromatase activity may effectively induce masculinization in genotypic females. Therefore, we administered letrozole—an aromatase inhibitor (AI)—into sexually undifferentiated PBT through the oral route. AI administration resulted in a 100% sex reversal of genotypic females into phenotypic males at the molecular level. Our results provide the basis for future studies on the establishment of mono-sex male production technology in PBT, which would help improve the productivity of closed-cycle PBT aquaculture. Furthermore, this study offers important insights into the understanding of the sex-wise growth of tuna species in aquacultural settings, and developing sex manipulation techniques. [ABSTRACT FROM AUTHOR]

The growth of the fish is influenced by a variety of scientific factors. So, profit can be easily achieved by using some clever techniques, for example, maintaining the correct pH level along with the dissolved oxygen (DO) level and temperature, as well as turbidity for good growth of fish. Fully grown fish are generally sold at a good price because price of fish in the market is governed by weight as well as size of nurtured fish. Artificial intelligence (AI)-based systems may be created to regulate key water quality factors including salinity, dissolved oxygen, pH, and temperature. The software programme operates on an application server and is connected to multiparameter water quality meters in this system. This study examines smart fish farming methods that show how complicated science and technology may be simplified for use in seafood production. This research focuses on the use of artificial intelligence in fish culture in this setting. The technical specifics of DL approaches used in smart fish farming which includes data and algorithms as well as performance was also examined. In a nutshell, our goal is to provide academics and practitioners with a better understanding of the current state of the art in DL implementation in aquaculture, which will help them deploy smart fish farming applications as well their benefits. [ABSTRACT FROM AUTHOR]

Why seawater‐reared Japanese sea bass (Lateolabrax japonicus) tastes better than that reared in freshwater has not been well determined. Given that flavour nucleotides have great impact on meat flavour, we compared the contents of AMP, GMP and IMP in the back muscle of Japanese sea bass cultured in marine cage and freshwater pond. The results showed that IMP was the main kind of flavour nucleotide and that the content of IMP in the back muscle of fish reared in seawater was significantly higher than that of fish reared in freshwater (p < 0.05). Quantitative real‐time PCR analysis revealed that the transcript level of adenylosuccinate lyase (ADSL), a key player involved in IMP synthesis, was also significantly higher in marine cage cultured sea bass than that reared in freshwater pond (p < 0.05). These results suggest that marine cage culture may improve the content of IMP in the muscle of Japanese sea bass by enhancing the expression of ADSL gene, which makes sea bass taste better in turn. In addition, shear force test revealed that the tenderness of fish back muscle was significantly different between the two culture models. Since many environmental factors differ between marine cage culture and freshwater pond culture, more study is needed to elucidate the key factor and mechanism making this huge difference in IMP content. [ABSTRACT FROM AUTHOR]

Comparative impact of two phyto‐piscicides viz. mahua (Bassia latifolia) oil cake (MOC) and castor (Ricinus communis L.) bean cake (CBC) upon the mineralizing heterotrophs was tested in outdoor experimental tanks. Following a sharp decline, aerobic heterotrophs and cellulose decomposing bacterial population recovered and the population density remained significantly higher than the pre‐treatment level, indicating strong heterotrophic potential of both the phyto‐piscicides in the culture system. Among the nutrient mineralizers, the sustained negative effect of both the piscicides was observed in denitrifying and ammonifying bacteria, whereas population of nitrifying and phosphate solubilizing bacteria was not affected. Because of narrower C: N ratio, CBC underwent faster decomposition thereby expressed it is manurial value quicker than MOC after exerting toxicity at the beginning. However, with distinctly higher N:P ratio CBC treatment might result in P limitation and toxicity when acting as manure in the culture system. [ABSTRACT FROM AUTHOR]

Animal welfare is an issue of increasing importance in global aquaculture. However, the incorporation of this issue into routine aquaculture operations is a challenge. A possible path to change this is the recognition, identification and addressing of the ecological, physiological, nutritional, behavioural and psychological needs of fish. The present study uses grass carp (Ctenopharyngodon idella), the world's most widely produced fish species, and earth ponds, the world's most widely used production system in fish farming worldwide, as the basis for developing indices to assess and monitor the welfare of farmed fish. The proposed indices were structured based on specific welfare indicators, reference values, individual weights and associated scores to address the Animal Welfare Five Freedoms and a Life Worth living concepts. Two types of indices were proposed: (1) partial welfare indices (PWIx), specific to each of the four observed/analysed freedoms; (2) general welfare index (GWI), which simultaneously summarizes the addressees' freedoms in a single variable. Both indices range from 0 (critical welfare impairment) to 1.0 (minimal risk of welfare impairment). The study was based on a comprehensive systematic review of the literature using the PRISMA method. The proposed indices were based on 10 environmental indicators, nine indicators for health, five for nutrition and four for behaviour. The PWIx can be used to determine how each category of indicators contributes to the GWI, which defines the level of fish farm welfare at a given point in time and which needs are affected or met during a production cycle. [ABSTRACT FROM AUTHOR]

Assessing fish haemato‐biochemical profile and growth performance is essential to monitor the influence of fish feed and habitat on fish physiology. The influence of two regularly used different commercial feeds and varied environments such as pond and biofloc systems on haemato‐biochemical and growth parameters of Oreochromis niloticus was studied by the results of 4‐month experiment. Fish ponds and biofloc systems where all the fish were supplied either feed A and B were surveyed weekly. The crude protein content of feed A was 30%, while that of feed B was 28%. Physico‐chemical characteristics of water in all culturing systems were suitable for Nile Tilapia production throughout the study period. Results revealed a significant difference (p < 0.05) in most haemato‐biochemical parameters. Growth performance was better in fish fed on feed A than feed B in both culture systems. In between, the habitat wide range of haemato‐biochemical indices and fish growth parameters were significantly higher in biofloc technology than pond culture system. However, no significant difference (p > 0.05) was recorded in fish enzymatic activities in both systems. Furthermore, it was found that both the length and weight gain were positively associated with the crude protein of the feeds. However, in the case of biofloc, crude protein of both feeds works far better than the pond, as indicated by the p‐value and regression R square. Current study delivers the basic knowledge to observe fish blood and growth parameters, which could be essential to understanding the fish culture management and environment. [ABSTRACT FROM AUTHOR]

The aim of this study was to characterize the limnological parameters and analyse the biological effects of different ponds in a commercial fish farm in the Pará State, Brazil. One pond is designated for fingerling production (N) while the other is for fattening and termination (F). The other three ponds are named supply tanks, from which the water from the Parauapebas River is collected to fill N and F tanks. For the physical–chemical analysis, samples from N and F ponds were collected at a depth of 50 cm close to the water's outlets of the ponds, with the aid of a commercial kit for water analysis. Caenorhabditis elegans nematodes were used for water quality biomonitoring and exposed for 24 h to samples from all five tanks collected during three different days, being assessed through physiological endpoints. During the study, values of transparency and pH were higher in N, both with significant differences between the ponds. The other parameters did not show any differences among them in the different days and times analysed. The results showed that the water quality of N and F ponds is in accordance with the current legislation in the country. Despite being in accordance with legislation and with acceptable metal levels, samples caused toxicity to worms, which indicate that for fish production, a continuous supervision is essential for the success of the activity. Therefore, the limnological variables in relation to biomonitoring should be constantly assessed in fish farm enterprises in order to maintain a more efficient and sustainable productive system. [ABSTRACT FROM AUTHOR]

Salinity is one of the main factors affecting physiological performances of teleost fish. Its influence on survival and growth rate of juvenile (five months old) Mugil cephalus (25.33 ± 1.01 mm length) was tested under hatchery conditions. After acclimation, fish were reared for three months at two salinities: freshwater (FW, 0 ppt) and saltwater (SW, 36 ppt). At the end of the experiment, growth, survival, and lipids deposition in the liver and carcasses were evaluated by histological and biochemical methods. Survival was high and similar between treatments. Fish reared in SW showed a significantly higher specific growth rate for body weight while Condition Index was similar. Lipid accumulation in the liver and total lipids and fatty acid profiles in the whole body were also similar among salinity treatments, while the levels of bioactive metabolite N‐acylethanolamines were significantly higher in fish reared in FW. The high survival rate, a similar Condition Index and lipid deposition in both treatments strongly suggest that the transfer of mullet juveniles from SW hatchery conditions to FW is a viable commercial scale production strategy. These results contribute to our understanding of mullet juveniles' performances under different salinities and indicate that FW conditions provide a suitable environment for mullet juveniles. [ABSTRACT FROM AUTHOR]

China is a major agricultural country since ancient times. Nowadays, international cooperation between regions has become increasingly important, with frequent cooperation and exchanges formed around geographical advantages. The study starts with an introduction to the origin and development of China's long history of rice‐fish co‐culture. History could be divided into three stages: the ancient stage, the modern stage and the contemporary stage. As a long‐lasting agricultural cultural heritage, the analysis and exploration of its patterns, characteristics and experiences could provide some inspiration for the cooperation of Lancang‐Mekong countries in agriculture, culture, economy and trade. In this regard, under the framework of Regional Comprehensive Economic Partnership, with a consensus to build "a human community with a shared future" for Lancang‐Mekong countries, this study proposes some measures: (1) Strengthen mutual trust and cooperation to optimize the cooperation environment. (2) Strengthen agricultural technology exchanges to deepen industrial chain cooperation. (3) Promoting diversified exchanges, improving industrial integration and humanistic exchanges to build a human community with a shared future for Lancang‐Mekong countries. [ABSTRACT FROM AUTHOR]

The present study was conducted to evaluate the efficacy of different extenders and cryoprotectants for cryopreservation of Labeo rohita milt. Male brood fish (n = 5) reared at fish seed hatchery, Rawal Town Islamabad, Pakistan, were captured from different rearing ponds, and kept in hatchery ponds for acclimatization. After 6 hours, fish were injected with ovaprim at 0.2 ml/kg. After 8 h, milt was collected in a cooled sterilized falcon tube and maintained at 4°C. Spermatozoa were activated and visual motility was observed. Cooled milt was diluted in experimental extenders (Alsever's solution, sugar‐based extender and modified Kurokura‐2 extender [KE] each with either Me2SO or methanol as cryoprotectant). Diluted milt was filled in 0.5 ml straws and frozen in liquid nitrogen vapours. Cryopreserved milt samples were thawed at 25°C and assessed for fertilization rate and post‐thaw sperm quality. Sperm motility, motility duration, viability and total antioxidant capacity were higher in KE with Me2SO and methanol compared with Alsever's solution and sugar‐based extender. Sperm DNA integrity showed a similar trend in all treatments. Moreover, sperm fertilization rate was higher (p < 0.05) in KE + methanol compared with KE+ Me2SO. In conclusion, modified KE along with methanol as cryoprotectant proved to be the best diluent for cryopreservation of L. rohita sperm. [ABSTRACT FROM AUTHOR]

Dietary lipid manipulation in the feed of commercially cultured finfish is used not only to improve production and culture but also to enhance their reproductive performances. The inclusion of lipid in broodstock diet positively affects growth, immunological responses, gonadogenesis, and larval survival. In this review, existing literature on the importance of freshwater finfish species to aquaculture and the inclusion of dietary lipid compounds in freshwater fish feed to accelerate the reproduction rate is being summarized and discussed. Although lipid compounds have been confirmed to improve reproductive performance, only a few members of the most economically important species have reaped benefits from quantitative and qualitative lipid studies. There is a knowledge gap on the effective inclusion and utilization of dietary lipids on gonad maturation, fecundity, fertilization, egg morphology, hatching rate, and consequently, larval quality contributing to the survival and good performance of freshwater fish culture. This review provides a baseline for potential future research for optimizing dietary lipid inclusion in freshwater broodstock diets. [ABSTRACT FROM AUTHOR]

Binary tournament (BT) selection is known as an established selection operator that has been employed in various problems. However, in the development of evolutionary algorithms (EA), this selection operator has a drawback in providing an efficient implementation of the union procedure, which cannot guarantee a parsimonious knowledge base with reduced number of rules. Therefore, this paper introduces binary-standard deviation (SD) tournament selection into EA as an enhancement of BT that can lead to focus on more exploration in terms of searching for the best solutions. The proposed selection operator has been experimented within fish feed formulation in grouper fish farming as a case study on finding the minimum cost and fulfilling constraints. This approach is better than experimental design in terms of costs and time. The motivation for doing so is to search for alternative ingredients for the grouper fish, as the price of trash fish is too luxurious. It is because grouper fish are carnivorous and need many trash fish for better growth. The novelty of the proposed SD tournament selection is compared with BT selection in terms of searching for an efficient but not myopic algorithm. Hence, based on the comparative study, the findings of the enhanced selection operator towards the EA have been convinced and accepted in terms of better cost and fulfilling constraints requirements. [ABSTRACT FROM AUTHOR]

The application potential of spirulina meal in aquaculture feeds has been well summarized in several descriptive reviews. Nevertheless, they converged on compiling results from all possible relevant studies. Little available quantitative analysis regarding the pertinent topics has been reported. This quantitative meta-analysis was performed to investigate the influences of dietary spirulina meal (SPM) addition on responsive variables in aquaculture animals, including final body weight (FBW), specific growth rate (SGR), feed conversion ratio (FCR), protein efficiency ratio (PER), condition factor (CF), and hepatosomatic index (HSI). The pooled standardized mean difference (Hedges' g) and 95% confidence limit were computed to quantify the primary outcomes based on random-effects model. The sensitivity and subgroup analyses were carried out to evaluate the validity of the pooled effect size. The meta-regression analysis was conducted to investigate the optimal inclusion of SPM as a feed supplement and the upper threshold of SPM usage for substituting fishmeal in aquaculture animals. The results indicated that on the whole, dietary SPM addition significantly improved FBW, SGR, and PER; statistically decreased FCR of animals; had no significant influence on CF and HSI. The growth-enhancing effect of SPM inclusion in the form of feed additive was significant; however, the effect was indistinctive in the form of feedstuff. Furthermore, the meta-regression analysis displayed that the optimal levels of SPM as a feed supplement in fish and shrimp diets were 1.46%-2.26% and 1.67%, respectively. Additionally, up to 22.03%-24.53% and 14.95%-24.85% of SPM as fishmeal substitute did not have a negative effect on growth and feed utilization in fish and shrimp, respectively. Therefore, SPM is a promising fishmeal substitute and a growth-promoting feed additive for sustainable aquaculture of fish and shrimp. [ABSTRACT FROM AUTHOR]

Summary: The rapid intensification of the livestock sector in Southeast Asia has been found to be associated with an expanding use of antibiotics (ABU) and the rise of antimicrobial resistance (AMR) in both humans and livestock. This study aimed to explore the views and practices of commercial pig, poultry and fish farmers regarding antibiotics in Lao People's Democratic Republic, where data on antibiotic use and AMR remain scarce. A multistage cluster sampling method, based on the random selection of villages in two provinces of Vientiane, was used. A total of 364 farmers, corresponding to 454 farm units, were surveyed using a questionnaire and farm visits. This study found a widespread use of antibiotics (261 out of the 454 farm units used antibiotics). The predominance of antibiotics considered critically important antibiotics for human medicine was of great concern. Results from a logistic regression model showed that antibiotics were found less frequently in fish farm units compared to pig and poultry farm units, and more frequently in specialized farms than in livestock‐fish farms. Multiple factor analysis and hierarchical cluster analysis revealed three profiles of farmers, each with distinct patterns on knowledge, attitudes and practices regarding ABU and AMR. Cluster 1 held a positive attitude regarding preventive measures and information about antibiotics. In cluster 2, there was a view that antibiotics should be used for prophylactic treatment such as disease prevention. Cluster 3 was characterized by farmers with weak knowledge who were unfamiliar with antibiotics and uncertain about details concerning antibiotic use. This cluster was associated with a significantly lower use of antibiotics than the two other clusters in the regression model. The results of this study may help the Laotian government to adapt strategies to control AMR by focusing on the use of critical antibiotics and prophylactic treatments and by tailoring measures to farmers' profiles. [ABSTRACT FROM AUTHOR]

The application of probiotics in aquaculture is growing due to its consistently beneficial results as an ecologically sound agent. A study was done in the laboratory using multi‐species probiotics containing Bacillus spp. (1 × 109 cfu/ml) and Lactobacillus spp. (1 × 1011 cfu/ml) to assess the growth performance of Nile tilapia (Oreochromis niloticus). Tilapia fingerlings (5.95 ± 0.07 g) were stocked and evenly distributed into three replicates separated into three treatment groups, each providing probiotics at concentrations of 0, 0.5 and 1.0 ml/L in water for 8 weeks. After completion of the trial, growth factors (weight gain, specific growth rate, hepato‐somatic index and viscera somatic index), feed utilization parameter (feed conversion ratio), gut microbiota and intestinal, liver and muscle morphology were examined. The experiment revealed significant improvements in growth and feed utilization in the fish reared with multi‐species probiotics compared to the control group. Total viable count (TVC) and total lactic acid bacteria (LAB) count increased substantially in the fish gut provided with the multi‐species probiotics. The morphological improvement of the intestine includes increased intestinal length, width and area of the villi, lamina propria and abundance of goblet cells were observed in the probiotics‐treated fish. The livers of treated fish showed irregular‐shaped nuclei turned into regular shaped and reduced spaces between liver tissues. Increased number of nuclei, the diameter of muscle fibre and hyperplastic muscle fibre were also found from morphological observation of the multi‐species probiotics applied to fish compared with the control group. The study indicates administration of multi‐species probiotics can potentially serve as an important growth promoter for the Nile tilapia. [ABSTRACT FROM AUTHOR]

A 16‐week experiment was conducted to assess whether dietary supplementation with Digestarom® as a phytogenic feed additive could reverse the negative influences of high stocking density in Nile tilapia (Oreochromis niloticus). For this purpose, 240 fish (2.4 ± 0.1 g) were divided into six groups. Two groups (D1 and D2) were fed a basal diet and reared under different stocking densities of 125 and 250 fish per m3. The other fish groups (D3, D4, D5 and D6) were raised under a high stocking density of 250 fish per m3 and fed supplemented diets with Digestarom® P.E.P. MGE at levels 50, 100, 200 and 300 mg per kg diet respectively. Growth retardation and impaired feed efficiency resulting from rearing fish at high stocking density were improved in groups fed diets fortified with 200 and 300 mg Digestarom® per kg diet. Moreover, rearing fish at a density of 250 fish per m3 significantly reduced Hb, RBCs, MCV and total protein but increased WBC, MCHC creatinine, urea‐N, ALT and AST. On the contrary, enriched tilapia diets with 200 or 300 mg Digestarom® per kg diet significantly corrected the earlier altered haematological indices and serum biochemical indicators. Furthermore, the addition of 300 mg Digestarom® to the diets of tilapia reared at high stocking density significantly modulated lipid deposition and ash level in their flesh. Conclusively, supplementing the Nile tilapia diet with 300 mg Digestarom® per kg feed could be a promising supplement for combating the negative impacts of high stocking density. [ABSTRACT FROM AUTHOR]

Keywords: BFT; FAPROTAX; IMTA; Litopenaeus vannamei; metagenomics; Oreochromis niloticus EN BFT FAPROTAX IMTA Litopenaeus vannamei metagenomics Oreochromis niloticus 5428 5433 6 09/21/22 20221015 NES 221015 Metagenomics allows for a comprehensive evaluation of the bacterial community in diverse habitats, as the whole collection of genomes in a sample is sequenced, instead of the conventional culture-based approach in which particular strains/species are isolated and cultured in a laboratory setting (Bodor et al., 2020; Wajid et al., 2021). Aquaculture Research, 49, 1699 - 1708. https://doi.org/10.1111/are.13626 56 Zhu, Y., Wang, S., Huang, L., Yan, M., Dong, P., Chen, C., Guo, H., & Zhang, D. (2021). Reviews in Aquaculture, 13 (2), 1077 - 1096. https://doi.org/10.1111/raq.12513 27 Johnson, M., Zaretskaya, I., Raytselis, Y., Merezhuk, Y., Mcginnis, S., & Madden, T. L. (2008). Reviews in Aquaculture, 11 (1), 234 - 245. https://doi.org/10.1111/raq.12237 38 Poli, M. A., Legarda, E. C., Lorenzo, M. A., Martins, M. A., & Vieira, F. N. (2019). [Extracted from the article]

Nocardia seriolae, an opportunistic and facultative intracellular Gram‐positive bacterium, is mainly responsible for nocardiosis in fish. Nocardiosis is a chronic, granulomatous and systemic disease in which lesions are found in the skin as well as several internal organs such as the kidney, liver and spleen with the distinctive nodular granuloma structure. N. seriolae is capable of infecting a wide variety of fish species which poses a devastating impact on the aquaculture sector around the globe, particularly in Asia. Due to the lack of appearance of nocardiosis symptoms at the earlier stages, multiple epidemics of nocardiosis causing high mortality have been recorded. To this end, numerous epidemiological studies have been carried out to characterize and identify Nocardia spp. through several detection techniques, which have favoured the formulation of a multitude of antibiotics and vaccines. After bacterial resistance to antibiotics, nowadays, vaccination has been considered the more appropriate strategy to treat nocardiosis. For valuable information related to N. seriolae and to combat fish nocardiosis, this review extended the existing knowledge, including pathogenesis, virulence characteristics, rapid detection techniques, host immune response and prevention strategies against N. seriolae infection in fish species in aquaculture. [ABSTRACT FROM AUTHOR]

Tenacibaculum piscium, a gram‐negative bacterium isolated from the skin ulcers of sea‐farmed fish, has only been described in Norway. In the present study, we examined 16 Chilean Tenacibaculum isolates recovered from different organs in moribund and dead Atlantic salmon (Salmo salar), Rainbow trout (Oncorhynchus mykiss) and Coho salmon (Oncorhynchus kisutch) cultured at different fish farms between 2014 and 2018. The present study applied biochemical, phenotypic, fatty acid and whole‐genome sequence‐based analyses to confirm the taxonomic status of the Chilean isolates. The obtained results are the first to confirm the presence of T. piscium in Chile and in Coho salmon, thus extending the recognized geographical and species distribution of this bacterium. Subsequent bath‐challenge assays in Atlantic salmon utilizing three T. piscium isolates obtained from different hosts resulted in low cumulative mortality (i.e. 0–35%), even after exposure to an unnaturally high concentration of bacterial cells (i.e. > 107 cells/ml). However, scale loss and frayed fins were observed in dead fish. In silico whole‐genome analysis detected various genes associated with iron acquisition, encoding of the type IX secretion system and cargo proteins, resistance to tetracycline and fluoroquinolones and stress responses. These data represent an important milestone towards a better understanding on the genomic repertoire of T. piscium. [ABSTRACT FROM AUTHOR]

In June 2020, an atypical fatal outbreak in a Brazilian Nile tilapia farm was investigated. Twenty‐three animals were collected and different tissues were used for bacterial isolation, histopathological and electron microscopic examination and viral detection using molecular methods. A large number of megalocytes were observed in the histopathological analysis of several tissues. Icosahedral virions, with a diameter of approximately 160 nm, were visualized inside the megalocytes through transmission electron microscopy of the spleen tissue. The virions were confirmed to be infectious spleen and kidney necrosis virus (ISKNV) through PCR and sequencing analyses of the fish samples. Phylogenetic analysis indicated that the virus belongs to the Clade 1 of ISKNV. This viral pathogen is associated with high mortality in the early stages of cultured Nile tilapia in the United States, Thailand and Ghana; however, until now, there have been no reports from ISKNV affecting cultured fish in Brazil. Additionally, in 14 out of 23 sampled fish, Streptococcus agalactiae, Edwardsiella tarda or Aeromonas hydrophila infections were also detected. This is the first report of fatal ISKNV infections in the Brazilian Nile tilapia fish farms and represents a new challenge to the aquaculture sector in the country. [ABSTRACT FROM AUTHOR]