Search

We conducted a study to investigate the potential effects of nutrients released from a fish farm, which fell within the typical range found in oligotrophic offshore waters of the Aegean Sea, on phytoplankton growth. We designed an in situ bioassay experiment at a fish farm and incubated natural phytoplankton assemblages inside dialysis membrane bags for six days. Changes in phytoplankton growth in samples of ambient seawater collected throughout the experiment served as controls and were considered indicative of the net population change rates. Half of the bags were filled with seawater filtered through a 150-µm mesh, while the other half contained unfiltered seawater. The growth rates, estimated based on chlorophyll a concentrations and phytoplankton cell numbers inside the filtered and unfiltered bags, showed no significant differences. While no detectable net phytoplankton growth occurred in the ambient seawater, there was an exponential increase in chlorophyll a content and cell numbers within the bags. Moreover, the species richness within the bags gradually declined throughout the experiment. The findings of the study confirm that continuous nutrient releases from fish farms can promote high population growth rates in oligotrophic environments, provided that phytoplankton losses due to grazing, advection, and sinking are minimized or eliminated. [ABSTRACT FROM AUTHOR]

The quality of water used in aquaculture ponds is one of the crucial factors influencing the smell and sensory properties of fish. The water samples were taken from the rainbow trout fish ponds from three different fish farms in three provinces in Türkiye in four different seasons. The samples were analyzed for the volatile components by employing HS-SPME/GC–MS. Seven different volatile groups including aldehydes, ketones, esters, alcohols, volatile phenols, terpenes and other aromatic substances were identified in the samples. Among these, aldehydes were found to be the most dominant. (E)-2-Heptenal, nonanal, acetophenone, and 2-ethyl-1-hexanol are thought to be responsible for the off-odors in the water that have the potential to cause off-odors in fish. It was also determined that the amounts of these compounds increases in winter due to lower water temperature. Fish producers should monitor water quality on a regular basis to prevent off-odor compounds that degrade fish quality. [ABSTRACT FROM AUTHOR]

Fish swimming speed is a standard measurement used for assessing the environment and behavior of fish in aquaculture. However, methods involving propeller-type data loggers, ultrasonic telemetry, and cameras have some limitations. Estimates of swimming speed by cameras are based on swimming trajectories; however, obtaining the swimming trajectories is difficult because the relative positions of the camera and fish body change owing to wave effects. The aim of this study was to describe and present a novel method to estimate the swimming speed of masu salmon (Oncorhynchus masou) influenced by artificially generated waves. Tail-beat frequency was estimated from periodic changes in fish length measured using a stereo camera. The swimming speed was estimated from tail-beat frequency according to the relationship between them as obtained by camera measurement; we found that a fixed stereo camera can help estimate tail-beat frequencies. The estimated data from the moving stereo camera were within the 95% prediction interval of the swimming speed estimation model constructed using the fixed stereo camera. Our study proves the potential of this method in aquaculture. Overall, this approach is a novel method to estimate the swimming speed influenced by wave conditions. In the future, this method can be automated for the identification of abnormal behaviors and detection of malformed fish. [ABSTRACT FROM AUTHOR]

Mesopelagic fishes are a vital component of the biological carbon pump and are, to date, largely unexploited. In recent years, there has been an increased interest in harvesting the mesopelagic zone to produce fish feed for aquaculture. However, great uncertainties exist in how the mesopelagic zone interacts with the climate and food webs, presenting a dilemma for policy. Here, we investigate the consequences of potential policies relating to mesopelagic harvest quotas with a dynamic social-ecological modeling approach, combining system dynamics and global sensitivity analyses informed by participatory modeling. Our analyses reveal that, in simulations of mesopelagic fishing scenarios, uncertainties about mesopelagic fish population dynamics have the most pronounced influence on potential outcomes. The analysis also shows that prioritizing the development of the fishing industry over environmental protection would lead to a significantly higher social cost of climate change to society. Given the large uncertainties and the potential large impacts on oceanic carbon sequestration, a precautionary approach to developing mesopelagic fisheries is warranted. [ABSTRACT FROM AUTHOR]

Pisciculture encounters an array of intricate challenges that span disease management, preservation of water quality, prevention of genetic hybridization, ensuring the integrity of net systems, sourcing sustainable aquatic feed, and comprehending fish growth and reproductive dynamics. Addressing these multifaceted challenges necessitates a comprehensive research approach. This study employs an innovative synergy of fuzzy logic and deep learning techniques, resulting in a robust strategy to tackle these obstacles effectively. Fuzzy logic excels in assessing stressed fish conditions by handling inherent uncertainties. Simultaneously, YOLOv7 with fuzzy color enhancement (YOLOv7FCE) is used to detect damaged fish nets, thereby mitigating losses and upholding the integrity of the net infrastructure. This approach also leverages YOLOv7FCE for identifying Cobia fish within shoals, streamlining the identification process. Subsequently, DeepLabv3 is implemented to meticulously segment the recognized Cobia fish, facilitating precise measurements of their physical attributes. This comprehensive methodology yields profound insights into growth patterns and feeding tendencies within the confined aquatic environment. By embracing this approach, the research presents a versatile and adaptive framework that not only enhances our comprehension of piscine dynamics but also holds the potential to revolutionize the aquaculture industry. [ABSTRACT FROM AUTHOR]

Postharvest and supply chain losses are the main global challenges. The security of future food demand requires certain availability of natural resources and useful application of limited means. This study is based on maximizing the productive use of baren fish farms to meet future food demand. In this work, the simulation optimisation model was used to determine the estimated findings. We developed the life cycle measurement technique to examine the percentage loss occurred during postharvest and supply chain process and the assessment of its economic, environmental and social influences. Results demonstrate the variate average change of postharvest loss and supply chain loss of a farmer, processors, trader, wholesalers and retailers are, respectively, 7.06%, 8.89%, 6.23%, 9.10% and 13.05% regarding sample fish-form as compared to same capacity healthy land fish-form with a productive supply chain operation. The total healthy mud of land and quality water consumed to produce this lost food accumulated 60 thousand hectares and 255 million cubic meters apart from other producing inputs. It is estimated cost $380 million annually 7.8 million tons of growth. The study reveals the significance of better prevention approaches of life cycle waste to reduce the environmental, economic and social impacts. Additionally, it helps to diminish the postharvest loss percentage to decrease the perishability of products throughout the supply chain of aquaculture field and the mechanisms that protect the products until these are sold out to consumers. In order to reduce postharvest losses, the study suggests that farmers be included as supplier actors and measured twice, first at the production stage and then at the supply chain stage. With the use of well-organized techniques, the farmer's education is a key component in reducing postharvest losses of perishable goods and boosting aquaculture sectors. Therefore, sustainable economic growth requires from farmers to supplier and productive coordination in reducing environmental impacts. This could improve their learning, skills and practices towards sustainable growth achievement in perishable products for meaningful use of natural resources. [ABSTRACT FROM AUTHOR]

Estuarine systems that provide valuable ecosystem services to society and important foraging and rearing habitat for fish and wildlife species continue to undergo degradation. In Puget Sound, WA, as much as 70–80% of historic estuarine habitat has been lost to anthropogenic development, and continued losses are expected through the end of the twenty-first century due to rising sea levels. To evaluate whether Puget Sound's estuarine habitats will keep pace with current and projected sea-level rise (SLR), we assessed vertical rates of elevation change from a regional network of surface elevation tables and marker horizons (SET-MH). Over the past two decades, SET-MH equipment has been installed throughout a variety of habitats in five Puget Sound estuaries: the Nisqually, Snohomish, Stillaguamish, and Skagit River estuaries, and Padilla Bay. These data provide a unique opportunity to assess elevation change and habitat resilience across a spatiotemporal and environmental gradient. We observed different rates of surface elevation change among estuaries and habitats (Nisqually = 4.64 ± 2.81 mm/year, Snohomish = 5.71 ± 5.83 mm/year, Stillaguamish = 12.82 ± 10.29 mm/year, Skagit = 16.13 ± 7.57 mm/year, Padilla = − 1.25 ± 1.58 mm/year). The highest rates were found at restoring sites with regular sediment input in the Stillaguamish and Skagit estuaries, whereas rates were consistently negative at low elevation sites in sediment starved Padilla Bay. Many sites in Puget Sound appear to be keeping pace with current rates of relative SLR, and some areas are on track to exceed projected rates through the end of the century. These findings indicate that Puget Sound's estuarine habitats can be resilient to rising tidal levels—as long as sediment delivery is maintained. [ABSTRACT FROM AUTHOR]

One of the hallmarks of invasive species is their propensity to spread. Removing an invasive species after establishment is virtually impossible, and so considerable effort is invested in preventing the range expansion of invaders. Silver carp (Hypophthalmichthys molitrix) were discovered in the Mississippi River in 1981 and have spread throughout the basin. Despite their propensity to expand, the 'leading edge' in the Illinois River has stalled south of Chicago and has remained stable for a decade. Studies have indicated that contaminants in the Chicago Area Waterway System (CAWS) may be contributing to the lack of upstream movement, but this hypothesis has not been tested. This study used a laboratory setting to quantify the role of contaminants in deterring upstream movement of silver carp within the CAWS. For this, water was collected from the CAWS near the upstream edge of the distribution and transported to a fish culture facility. Silver carp and one native species were exposed to CAWS water, and activity, behavior, avoidance, and metabolic rates were quantified. Results showed that silver carp experience an elevated metabolic cost in CAWS water, along with reductions in swimming behavior. Together, results indicate a role for components of CAWS water at deterring range expansion. [ABSTRACT FROM AUTHOR]

Environmental variables, such as resource quality, shape growth in organisms, dictating body size, an important correlate of fitness. Variation in prey characteristics among populations is frequently associated with similar variation in predator body sizes. Anthropogenic alterations to prey landscapes impose novel ecological pressures on predators that may shift predator phenotypes. Research has focused on determining the adaptability of the phenotypic response by testing its genetic heritability. Here, we asked if anthropogenic shifts in prey size across the landscape correlate with juvenile growth rates among populations of watersnakes with divergent life-history phenotypes. We sought to determine if growth rate variation is the product of genetic adaptation or a non-heritable phenotypic response. Using a common-garden design, we measured growth of neonate snakes from fish farms varying in prey size. We found juvenile growth rates are faster for snakes with larger initial body sizes and from populations with larger average prey sizes. Our data suggest variability in juvenile grow rates within and among populations are not the product of genetic adaptation, but the indirect consequence of initial offspring size variation and prey consumption. We propose larger offspring sizes may favor increased juvenile growth rates, mediated through a larger morphological capacity to consume and process energy resources relative to smaller individuals. This experiment provides evidence supporting the growing body of literature that non-heritable responses may be significant drivers of rapid phenotypic divergence among populations across a landscape. This mechanism may explain the stability and colonization of populations in response to rapid, human-mediated, landscape changes. [ABSTRACT FROM AUTHOR]

Curcumin, a polyphenol, targets multiple signaling molecules and shows activity at the cellular level, supporting its various health benefits. Thereafter, the present study examines the effects of different doses of dietary curcumin on growth indices, feed efficiency, serum metabolites, redox (oxidation) status, immunity, histological assessment, and antioxidant-related genes in red tilapia (Oreochromis sp, Oreochromis aureus x O. mossambicus). A total of 1200 red tilapia with an average weight of 19.1±0.03 g were distributed in 12 cement ponds (3×3.5×1m). Each treatment was assigned three pounds (n=100 replicates). For 60 days, fish were fed baseline diets containing 0, 0.4, 0.6, and 0.8 g of curcumin/kg of diet. The treated fish showed increased body weight and SGR (specific growth rate) compared to the T0 group (P<0.05). Curcumin in the diet significantly improved weight gain, percentages, and FCR (feed conversion ratio), with a dose-dependent effect (P < 0.05). Curcumin supplementation showed no influence on feed intake, fish mortality, or survival rate (P >0.05). The curcumin-treated fish groups improved tissue structure in hepatocytes, pancreatic lumens, hepatic blood sinusoids, and intestine tissue layers, particularly the mucosal layer. The T0.8 group had reduced liver enzymes (AST and ALT) and greater total protein and albumin levels (P<0.05). The T0.6 and T0.8 groups showed significantly lower MDA levels than the other groups (P < 0.05). Curcumin groups demonstrated significantly higher antioxidant indices (CAT, GPx, and SOD) compared to the basal diet (P<0.05). Curcumin administration resulted in significant improvements in IgM and lysosome levels (P<0.05). All supplemented groups had considerably (P<0.05) higher levels of SOD, CAT, and GPx mRNA than the control group. Consequently, administering 0.6–0.8 g/kg of curcumin to red tilapia (Oreochromis sp.) diets may improve the fish's growth, health, tissue composition, and antioxidant response. [ABSTRACT FROM AUTHOR]

The aim of this survey was to investigate the latest insights on different aqua inputs available in freshwater fish farming in Andhra Pradesh, India. The present survey on the use of aqua inputs was conducted in 520 freshwater fish farms, 50 aquaculture dealer shops, and 10 manufacturing units between September 2020 and December 2022 using a prescribed questionnaire. The present study documented a total of 336 different aquaculture inputs represented by more than 50 different manufacturing and packaging units. The aquaculture inputs was dominated by disinfectants and toxin binders (29.8%), followed by feed additives and growth promoters (21.5%), probiotics (20%), unlabeled group (10.4%), pesticides (8.9%), antibiotics (5.2%), and fertilizers (4.2%). Furthermore, the present survey revealed that infectious diseases, inadequate knowledge on aquaculture practices, lack of professionals, over-the-counter sales of antimicrobials, reliance of farmers largely on peers and company representatives, inconsistency in recommending dosage, and a lack of stringent regulations are major risk factors in aquaculture. Educated and experienced farmers were aware of the risks associated with antimicrobial use. This may help to implement successful interventions towards reduced antibiotic use in freshwater fish farming in Andhra Pradesh. In addition, the present survey identified a large number of aqua inputs that are currently in use, but that require further regulations and evaluation. Hence, there is an urgent need for awareness, effective surveillance, proper diagnosis, and disease advisory services. Stringent regulation and evaluation regarding the imprudent use of antimicrobials and their environmental and human health impacts can make a significant difference in promoting sustainable aquaculture for many years to come. [ABSTRACT FROM AUTHOR]

The effect of different feed rations on RAS-based pikeperch juveniles' growth parameters was studied. Juvenile pikeperch were reared in three separate experiments (I, II, and III) at a temperature of 24 °C with initial body weights of the fish at 1.3, 9.4, and 25.6 g, respectively. Four applied feed rations increased by 0.5% in each experiment: 3.0, 3.5, 4.0, and 4.5% of body weight per day (BW day−1) in experiment I; 2.0, 2.5, 3.0, and 3.5% BW day−1 in experiment II; 1.0, 1.5, 2.0, and 2.5% BW day−1 in experiment III. Each experiment in triplicates lasted 28 days. The fish were reared in tanks with working volumes of 1.0 m3 each. All experiments were performed in the same recirculating aquaculture system. The stocking density in experiments I, II, and III was 800, 400, and 200 individuals per tank, respectively. The results of experiment I showed the highest specific growth rate (SGR), weight gain (WG), and biomass gain at the feed ration of 4.5% BW day−1 (P < 0.05). In experiment II, feed ration from 2.5 to 3.5% BW day−1 showed the highest final weight (P < 0.05). In experimental III, feed ration of 2.0 and 2.5% BW day−1 showed the highest final weight, SGR, and WG (P < 0.05). Only in experiment III, based on SGR and WG, second-order polynomial regression showed that the optimal feed ration for pikeperch was 2.35–2.39% BW day−1. [ABSTRACT FROM AUTHOR]

Nanotechnology is an emerging branch of science that incorporates the nanomaterials recognized as nanoparticles ranging from 1–100 nm in size. This technology is being used in the food industry, pharmaceutical industry, agricultural industry, medical treatments, environmental science, biological research, and aquaculture industry. Increasing disease susceptibility, pathogenic emergence and divergence, less efficient vaccines, probiotics, and ineffective antibiotics forced us to seek an alternative approach to tackle these challenges. Nanotechnology can change our views, perceptions, and perspectives, as it has provided us with a necessary tool to address these challenges. This technology has revolutionized aspects of providing solutions to many hazardous issues like disease control, nutrient delivery, water purification, vaccines, and drug delivery in aquaculture using nanoparticles. Several nanoparticles have been used as growth promoters, e.g., zinc, iron, and selenium nanoparticles. Many of them have antibacterial properties, e.g., silver and copper nanoparticles. Besides that, these nanoparticles have few toxicological effects, when they are used without proper knowledge and lead to unrealistic results. Therefore, there should be complete information and standard observation regarding their administration (e.g., time, dosage, exposure, and concentration), and certain parameters (temperature, pH, and salinity) should also noted before their use in aquaculture. This review aims to critically analyze and thoroughly discuss the meta-role of various nanoparticles regarding disease control, drug delivery, water treatment, nutrition, and growth performance as well as their toxicological impacts in fish aquaculture. [ABSTRACT FROM AUTHOR]

Women's empowerment and gender equality are key goals for development and human rights. However, a significant gap still exists in achieving these twin goals. Formulating appropriate strategies for women's empowerment requires first understanding context-specific patterns and sources of disempowerment. We use data collected using a questionnaire survey from 1653 households in Rangpur and Rajshahi districts in Bangladesh. Guided by an analytic tool that measures women's empowerment, inclusion and agency (the project level Women's Empowerment in Fisheries and aquaculture Index (pro-WEFI)), and using seven empowerment indicators, we provide findings on the status of women's empowerment, participation, and engagement in aquaculture in Bangladesh. Results show that women were highly involved in making household decisions, mainly jointly with their husbands. However, data suggest a substantial gap in women's access to financial services, in participation in aquaculture activities, and in access to and control over productive capital and remuneration for aquaculture labor. Finally, despite some women achieving adequacy on some indicators, most women in fish farming households in Bangladesh lack adequacy on many of the selected indicators. [ABSTRACT FROM AUTHOR]

In this study, we investigated the effects of the dietary addition of lavender essential oil (LEO) on mitigating the adverse effects of high stocking densities (HSD) in the Nile tilapia, Oreochromis niloticus. We used 216 fingerlings and randomly distributed them according to a 2 × 3 factorial design, comprising two stocking densities: a low stocking density (LSD, 2.92 kg/m3) and a high stocking density (5.85 kg/m3) and three levels of LEO, 0, 0.5%, and 1%, for 70 days. We evaluated their growth, digestive enzyme activity, blood biochemical parameters, immune/antioxidant indices, and intestinal morphology. All fish were intraperitoneally inoculated with Aeromonas veronii for a bacterial challenge test at the end of the feeding trial and monitored for 14 days. After 14 days, head kidney samples were collected from all fish to assess the level of expression of immune-related and apoptosis-related genes. Additionally, tissue samples were collected from the liver, kidney, and intestine to investigate the immunohistochemistry and histopathological alterations. The results showed that the final body weight and weight gain were lower and the feed conversion ratio was higher in fish cultured under HSD compared to those cultured under LSD. The fish cultured under LSD and HSD had higher final body weight when administered dietary LEO compared to the fish that were fed the non-supplemented diet. Adding 1% LEO increased the intestinal villus height and muscular coat thickness (MT). The MT was lower in fish cultured under HSD compared to those cultured under LSD. The amylase and lipase activities were lower in the fish cultured under HSD than in those cultured under LSD. However, LEO addition increased the lipase activity in fish cultured under LSD and HSD. Fish cultured under HSD showed lower immune/antioxidant indices (lysozymes, nitric oxide, complement 3, catalase, superoxide dismutase, and glutathione-S transferase) than those cultured under LSD. However, LEO addition significantly increased the immune response and antioxidant activity in fish cultured under LSD and HSD (P < 0.01). The level of expression of the IL-1β, IL-6, IL-8, NF-kB, and TLR-4 B genes was upregulated in the LSD + LEO1, LSD + LEO0.5, and HSD + LEO1 groups. The expression of TGF-β and IL-10 was upregulated in fish that received 1% and 0.5% LEO, irrespective of whether they were cultured under LSD or HSD. The level of expression of apoptosis-related genes (caspase 3 and BAX) was upregulated in the HSD + LEO0 group and modified by the addition of LEO in their diet. The immunoexpression of NF-kB and IL-1β after bacterial challenge increased in the tissues of fish cultured under LSD and HSD after LEO was administered. These results indicated that the dietary addition of 1% LEO mitigated the harmful effects of HSD on the growth, immunity, antioxidant activity, and disease resistance of the Nile tilapia. [ABSTRACT FROM AUTHOR]

The assessment of the spatiotemporal dynamics of biogenic element accumulation in the bottom sediments of a trout farm located in the northern part of Lake Ladoga was conducted for the first time. Sediment cores were sampled during different hydrological seasons both near the fish cages and at a distance from them. Analyses of total nitrogen and labile phosphorus compounds in the sediments were conducted layer by layer. The dependence of biogenic element content on the organic matter content in the bottom sediments was analyzed. The results showed that the temporal dynamics of biogenic element accumulation in the bottom sediments in the area influenced by the trout farm were closely related to the seasonal feeding intensity of the fish cages. The increase in biogenic element content in the bottom sediments, resulting from the functioning of the fish farm, did not affect the control points. The seasonal formation of an anaerobic reducing environment in the surface layer of sediments may contribute to the increased influx of the studied elements from the bottom sediments into the water column. [ABSTRACT FROM AUTHOR]

This study explored how increased water turbidity in open-aquaculture ponds as a result of enhanced fertilization influences piscivorous bird assemblages and predation pressure on fish. Fertilization treatments were applied to 24 earth-bottom ponds, and bird assemblages, visitation frequencies, diversities and predation rate responses were compared at species richness and across four functional group scales during six months. Bird visitation frequency, species richness and functional diversity increased around unfertilized ponds, especially for large wading birds. Fertilization and bird species richness were each negatively related to bird predation rate, whereas functional diversity was positively associated with predation rate regardless of pond fertilization. Furthermore, predation rate reduced in response to pairwise interactive effects of fertilization and functional group identity, but increased with fertilization's respective interaction with functional diversity and visitation frequency. Contrastingly, species richness showed no interactive effect with fertilization or visitation rate. Thus, in applying enhanced pond water fertilization as a mitigation measure for controlling and tracking damage impact caused by piscivorous birds, it is potentially more beneficial to adopt a bird functional rather than species-based approach, given the observed higher sensitivity of functional diversity in predicting predation rates. The findings present novel, farmer-centered and affordable strategies for piscivorous problem-bird control toward sustainable aquaculture. [ABSTRACT FROM AUTHOR]

Water quality in land-based fish production can be controlled through either instantaneous water exchange or costly wastewater treatment followed by recirculation. Agricultural-aquaculture integration is an excellent alternative technique for reducing nutrient discharge levels, boosting profitability, and converting fish culture wastewater into valuable products. The current study employed a solar energy system to power two separate IMTA-aquaponics systems (Nutrient Film Technique, NFT, and Floating Raft Systems, FRS) for the cultivation of Nile tilapia, African catfish, thin-lipped grey mullet, freshwater crayfish, freshwater mussels, and a variety of vegetables. Tilapia and catfish were fed exclusively on diets under the IMTA system. All wastewater from tilapia and catfish ponds, both dissolved and solid, flows sequentially to ponds containing other cultivated species. The water then flows through the IMTA system's terminal point to the NFT and FRS systems before returning to the tilapia and catfish ponds, allowing complete control of the nutrient flow throughout this entire circular system. Two 147-day production cycles were concluded. The results from the second production cycle are reported. Total biomass gain for aquatic species in the IMTA system was 736.46 kg, compared to 145.49 kg in the tilapia and 271.01 kg in the catfish monoculture systems. The current IMTA system had a cumulative feed conversion ratio (FCR) of 0.90, while the FCRs for tilapia and catfish were 1.28 and 1.42, respectively. Nile tilapia and catfish consumed 571.90 kg of feed containing 25.70 kg of nitrogen (N) and 9.70 kg of phosphorus (P), reflecting, and gaining 11.41 and 3.93 kg of dietary N and P, representing 44.40 and 40.46% dietary N and P retention, respectively. In the IMTA system, the addition of mullet and prawn as detrivores aquatic animals improves dietary N and P utilization efficiency to 59.06 and 51.19%, respectively, while the addition of mussels as herbivore animals improves dietary N and P utilization efficiency to 65.61 and 54.67%, respectively. Finally, using FRS and NFT as hydroponic systems increased dietary N and P efficiency to 83.51% N and 96.82% P, respectively. This study shows that the IMTA-Aquaponic system, as a bio-integrated food production system, can convert the majority of fish-fed residues into valuable products suitable for desert, rural, and urban areas in impoverished and developing countries. [ABSTRACT FROM AUTHOR]

The practice of hybridization is carried out globally in fish farms. Here, we present the first record of the parasitic fauna of hybrids among genus Colossoma and Piaractus in natural environments. We identified a total of 48 hybrids, nine F1 hybrids (nuclear DNA from both species present in the cross) and 38 advanced hybrids (nuclear DNA from one species), both from crosses between Piaractus brachypomus and Piaractus mesopotamicus, and one F1 "tambacu" corresponding to cross between Colossoma macropomum and Piaractus mesopotamicus. This is the first record of Anacanthorus penilabiatus, Anacanthorus toledoensis, Mymarothecium viatorum, Mymarothecium ianwhittington, Haementeria sp., Dadaytrema oxycephala, Rondonia rondoni, and Echinorhynchus gomesi parasitizing hybrids collected in a natural environment. With this, we expand knowledge about the diversity of fish and parasites in the upper Paraná River and warn about the risk that fish escapes can cause in the basin. [ABSTRACT FROM AUTHOR]

In recent years, the environmental pollution caused by microplastics (MPs) has attracted extensive attention. Numerous studies have shown that MPs could cause liver damage in aquatic animals. However, there is a limited range of technical approaches available to mitigate and minimize the detrimental impact of MPs on both wild fish populations and aquaculture operations. Thus, this study aimed to investigate the impact of dietary chitosan supplementation on the prevention and treatment of liver damage induced by exposure to polystyrene microplastics (PS-MPs) in Nile tilapia (Oreochromisniloticus). The results indicated that after two weeks of exposure, the liver of tilapia showed oxidative stress, inflammatory response and fibrosis. Meanwhile, after the chitosan addition, the oxidative stress, inflammatory response and fibrosis of tilapia liver were reversed, the pyroptosis and ferroptosis in tilapia liver were inhibited, the combination of mitochondria with PS-MPs in tilapia liver cells was inhibited, and the mitochondrial damage was reversed. In summary, the study confirmed the potential prophylaxis and treatment effect of dietary chitosan supplementation on PS-MPs exposure-induced liver damage in tilapia, and provided basic data for further studies on prophylaxis and treatment of the toxic effects of MPs. This study also presented efficacious strategies for alleviating the deleterious impacts of MPs on fish farming, thereby fostering sustainable and eco-friendly approaches in aquaculture. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of different feeding rates on the rearing of the curimba Prochilodus lineatus under biofloc (BFT) conditions. One hundred and sixty juvenile P. lineatus with average weights and lengths of 27.33 ± 2.07 g and 13.52 ± 0.16 cm, respectively, were randomly distributed in 16 experimental units (80 L) under BFT conditions and subjected to four feeding rates: 1.0%, 3.0%, 5.0%, and 8.0% of the fish biomass, for 60 days. During the assay, water quality variables and the proximate composition of the biofloc were monitored, as well as the productive performance and hematology of fish were evaluated. Compared to fish that received the diet at a rate of 1.0% of the biomass, the final length (14.47 ± 0.43 cm), final weight (35.55 ± 3.21 g), and gain in length (1.21 ± 0.34 cm) were significantly higher than those that received 5% of the biomass, while the fish that received 5.0% and 8.0% of the biomass, weight gain, and specific growth rate were significantly higher than those that received 1.0% of the biomass. Final biomass (296.89 ± 18.30 g) was significantly greater in fish that received the diet at a rate of 8.0% of the biomass than those that received 1.0% of the biomass (198.30 ± 49.36 g). The feed conversion rate (1.74 ± 0.26) was significantly lower in fish that received the diet at a rate of 5.0% than those that received 1.0% and 3.0% of the biomass. The protein efficiency (− 10.35 ± 5.37%) decreased significantly in fish in the 1.0% of the biomass. The survival rate of fish was significantly lower in fish from the 5.0% of the biomass (66.32 ± 14.03%) than in fish that received 3.0% of the biomass (100.00 ± 0.00%). The concentration of dissolved oxygen was significantly higher in the culture water of fish that received 1.0% and 3.0% of the biomass. The amount of sedimentable solids in the water was significantly higher in the culture water of fish at 8.0% of the biomass (242.50 ± 181.18) than in the groups of 1.0% and 3.0% of the biomass, while the hardness significantly decreased in the culture water of fish that received a diet at a rate of 5.0% of the biomass. Carbon dioxide was significantly greater in the water of the 3.0% of the biomass than in the 5.0% of the biomass. Regarding the proximal composition of the bioflocs, the dry matter significantly increased in the groups that were fed with a feeding rate of 8.0% (28.58 ± 0.01%), while the lowest contents were observed in the groups that received a feeding rate of 3.0% of the biomass. Crude protein was significantly lower in the groups that received a feeding rate of 1.0% of the biomass (28.94 ± 0.01%) than in the groups of 3.0% of the biomass. Ether extract was significantly greater in the groups of 8.0% of the biomass (1.62 ± 0.00%) than in the 3.0% of the biomass. Monocytes were significantly increased in fish that received a diet at a rate of 1.0% of the biomass compared to fish from the 5.0% and 8.0% of the biomass. Neutrophils were significantly increased in fish that received a diet at a rate of 5.0% of the biomass compared to fish in the 1.0% of the biomass. Hemoglobin was significantly decreased in fish that received a diet at a rate of 1.0% of the biomass. Hematocrit was significantly decreased in fish that received a diet at a rate of 1.0% and 8.0% of the biomass compared to fish from the 3.0% of the biomass. The results suggest that the cultivation of P. lineatus under biofloc conditions could be viable. Considering the productive performance, hematology, and water quality, a feeding rate of 5.0% of the biomass proved to be adequate for the experimental conditions adopted in the study. [ABSTRACT FROM AUTHOR]

Organic acid salts can modulate fish growth performance and antioxidant/immune systems, thus they can be used as feed additives for intensive fish culture. Hence, this study investigated the effects of dietary sodium butyrate (NaB) supplementation on growth, antioxidant, immunological and stress indicators in common carp, Cyprinus carpio, reared at high stocking density. Three levels of dietary NaB (0, 1 and 2 g/kg) and two stocking densities [5 (L) and 10 (H) g/L, corresponding to 20 and 40 fish/aquarium, respectively] were combined to have six triplicate treatments: B0-L: 0 g/kg NaB + L; B1-L: 1 g/kg NaB + L; B2-L: 2 g/kg NaB + L; B0-H: 0 g/kg NaB + H; B1-H: 1 g/kg NaB + H; B2-H: 2 g/kg NaB + H. Fish (10.5 ± 0.17 g) were daily fed at a rate of 3% of biomass for eight weeks. The results showed that NaB contributed to stress mitigation by lowering plasma glucose levels and hepatic transaminases, while increasing plasma triiodothyronine levels. NaB boosted antioxidant capacity by increasing hepatic/intestinal superoxide dismutase, catalase and total antioxidant capacity and lowering malondialdehyde levels. NaB supplementation increased blood leukocyte count, neutrophil percentage, alternative complement activity, mucosal/humoral immunoglobulin levels and mucosal/intestinal lysozyme activities. NaB improved growth performance and feed efficiency, likely due to a reduction in stress and energy expenditure and/or an improvement in overall gut and hepatopancreas health and function. Overall, the inclusion of 1 g/kg NaB in the feed is recommended for optimal health and growth performance of common carp kept at high stocking densities. [ABSTRACT FROM AUTHOR]

The objective was to identify the best stocking density in the initial grow-out phase of tambaqui (Colossoma macropomum) using biofloc technology (BFT) and evaluate the effects of the densities on water quality, zootechnical performance and the metabolic profile of fish and production costs. Juveniles (56.5 ± 1.69 g) were reared in the densities: 15 (BFT15), 30 (BFT30) and 45 (BFT45) fish.m−3, in triplicate, for 80 days. The use of BFT inoculum at the beginning contributed to the maintenance of adequate ammonia and nitrite concentrations at all densities, though with a higher nitrite concentration in BFT45. Electrical conductivity (EC), nitrite, total suspended solids (TSS), pH, alkalinity and hardness were different (p < 0.05) between BFT15 and BFT45. EC and TSS increased according to the increase in density, and were higher in BFT45. The highest final weight and specific growth rate were observed in BFT15, while the apparent feed conversion was lower for BFT15 and BFT30 compared to BFT45 (p < 0.05). Biomass and productivity were higher (p < 0.05) in BFT45. The values of hematocrit, number of erythrocytes and the hemoglobin concentration were higher in BFT45 (p < 0.05). Regarding production costs, the highest average feed expenditure occurred in BFT45; however, expenditure with electricity was lower at this density. The increase in biomass in BFT45 generated the reduction of the partial average cost (ACp). It can therefore be concluded that the best stocking density for initial grow out of tambaqui is 45 fish.m−3, since it presents better productivity and biomass, lower ACp and average expenditure on electricity when using BFT. [ABSTRACT FROM AUTHOR]

Filamentous fungi, mainly those belonging to genera Aspergillus, Fusarium, and Penicillium, the main producers of mycotoxins and responsible for food and feed contamination, exhibit metabolites that are highly toxic to animals and humans. This scoping review compiles data on occurrence of mycotoxins in fish feed, assesses distribution of metabolites across continents by the hierarchical cluster analysis, and establishes risks posed to the main global orders of farmed fish by exposure to mycotoxins. Resulting data showed that fish of different orders in both fingerling and juvenile phases are exposed to high concentrations of mycotoxins. [ABSTRACT FROM AUTHOR]

Aeromonas hydrophila is an important etiologic agent, triggering an increased trend of disease outbreak in fish farming. In this investigation, we evaluated pathological response in the midgut and liver of three types of grass carps after gut infection. Severe pathological levels of tissue necrosis were observed in common grass carp (GC) and gynogenetic grass carp (GGC), but mild pathological symptom was detected in hybrid grass carp (DRGC), along with the dramatically increased number of goblet cells. Moreover, three types of grass carps showed upregulated levels of immune gene patterns and antioxidant abilities, whereas inflammatory cytokine expression levels in hybrid grass carp (DRGC) were lower than that of gynogenetic grass carp (GGC) and common grass carp (GC). These results suggested that DRGC may exhibit a disease tolerance against A. hydrophila-induced tissue inflammation. [ABSTRACT FROM AUTHOR]

This study investigated the influence of visual and chemical stimuli from live prey on juvenile Florida pompano (Trachinotus carolinus) growth. Twelve tanks within four independent recirculating systems housed fish of similar weight (obtained from a commercial fish farm) in groups of ten. Prior to their morning feeding (they were fed twice daily at 10 h and 16 h with commercial pellets), fish were exposed to one of four stimuli: visual and chemical cues from Artemia, mole crab, feed pellets (control for stimuli), or seawater (control for procedures). Key growth parameters were monitored weekly for seven weeks, including feed intake, weight gain, and specific growth rate (SGR). Fish exposed to Artemia and mole crab stimuli exhibited significantly higher feed intake (23.11 ± 1.37 and 23.45 ± 1.38 g/fish), weight gain (169.28 ± 7.59 and 172.75 ± 12.57%), and SGR (2.02 ± 0.05 and 2.04 ± 0.09% day−1) compared to those exposed to feed pellets (stimuli control) and seawater (procedures control): feed intake (20.81 ± 0.684 and 19.30 ± 0.39 g/fish), weight gain (136.25 ± 4.51 and 140.23 ± 6.36%), and SGR (1.75 ± 0.03 and 1.78 ± 0.05%.day−1). These findings highlight the importance of visual and chemical cues from live prey as feeding incitants and stimulants. By enhancing feeding motivation and intake, these stimuli promote growth and potentially improve the welfare of juvenile Florida pompano. [ABSTRACT FROM AUTHOR]

African catfish farmers used animal waste as feed to reduce production costs, a practice that raised concerns among consumers, causing them to avoid it. Consequently, this study aimed to explore factors that influenced the acceptance of farmed African catfish. The data survey involving 2294 participants from Egypt was analyzed using descriptive statistics and the chi-square test. The results indicated that 67% of participants abstained from consuming it, while 2.30% consumed it regularly. The chi-square test revealed significant consumption pattern variations (p < 0.05) based on most demographic factors. Entirely, 43% were uninformed about the nutritional value, market availability, and the potential impact of using aquafeeds on pricing. About 55–57% lacked information on feeding practices, had quality concerns, viewed catfish consumption as a health risk, and were unaware of its prices. Additionally, 68% were worried about pollution, and 76% found the available information insufficient. The main reasons for this challenge lie in consumers' health, religious, and psychological concerns. To address this, we propose a targeted marketing strategy focusing on improving safety and quality through safe and cost-effective aquafeeds. This involves requiring farmers to obtain quality certifications and adhere to best management practices, adding value to the product, and transparent communication with consumers to provide them with reliable information about cultivation practices and the nutritional value of African catfish. Effective collaboration among key stakeholders in implementation, efficient sector management, establishing an activity licensing system, and prohibiting current feeding practices will enhance sustainable demand and reverse the declining production trend of this promising species. [ABSTRACT FROM AUTHOR]

A 75-day rearing trial was completed to investigate the effectiveness of different biofloc systems (BFT) on the water quality, growth performance and health status of Florida red tilapia (FRT) grown in brackish groundwater (BGW). The trial consisted of the control and three types of BFT using different carbon sources (CS), starch (ST), rice bran (RB), and wheat bran (WB) in triplicate, expressed as BF-0, BF-ST, BF-RB, and BF-WB, respectively. Fish weighing 4.98 ± 0.01 g/fish were stocked in 250-L tanks at an initial stocking density of 25 fish. The findings demonstrated significant reductions in inorganic nitrogen by-product (NH3 and NO2) levels in all BFT groups compared to the control, with an increase in floc volume and floc nutritional value, in the BF-ST and BF-RB groups. Furthermore, fish in the BF-ST and BF-RB groups showed significant improvements in fish growth indices (final weight, weight gain, and FCR). Fish in the BFT groups showed significant improvement in kidney function indices and plasma lipids with no significant changes in liver enzyme activity compared to the control. Lower stress markers (glucose and cortisol) and higher digestive enzyme activity (lipase and protease), innate immune parameters and antioxidants were reported in fish of the BF-ST and BF-RB groups compared to the control fish. Histopathological inspection revealed that the BF-ST fish exhibited healthier livers and shared healthier intestines with BF-RB fish compared to the control group. In conclusion, RB is an appropriate CS with BGW for desert aquaculture due to its availability, inexpensiveness, and comparable outcomes with ST. [ABSTRACT FROM AUTHOR]

The present study was designed to investigate the cytotoxic effects and bioaccumulation of heavy metals iron (Fe), zinc (Zn), copper (Cu), cadmium (Cd), lead (Pb), manganese (Mn), nickel (Ni), and chromium (Cr) in different parts (muscle, gills, and liver) of Tilapia zillii occurring in polluted drainage canal and fish farm, which is located in Abiece region in front of village number 10, Alexandria governorate, Egypt. Results of water analysis revealed the concentration of Cd, Pb, Mn, Ni, and Cr exceeded the limits defined by the American Public Health Association (APHA) in the polluted drainage canal. In addition, the concentration of Ni elevated to the standard limits of APHA and Cu was not detected in the fish farm. Different types of chromosomal aberrations were recorded (e.g., stickiness, fragmented chromosomes, centromeric gaps, chromatid break, chromatid deletion, and tetraploid). Micronucleus frequency was found to be 5.58 in the polluted drainage canal group and 0.32 in the fish farm group. Other nuclear abnormalities such as blebbed nucleus, segmented nucleus, enucleated erythrocyte, kidney-shaped nucleus, heart-shaped nucleus, polymorphic irregular nuclei, binucleated cell, nuclear fragmented erythrocyte, long nucleus, putative fragmented notched nucleus, lobed nuclei, fused erythrocytes, necrotic erythrocyte, and vacuolated nucleus were recorded. The total of erythrocytes nuclear morphological abnormalities was 70.33% in the polluted drainage canal and 1.78% in the fish farm. [ABSTRACT FROM AUTHOR]

The aquaculture industry is suffering from significant financial setbacks due to an increasing frequency of disease outbreaks, posing a threat to the sector's sustainability. Various bacterial, viral, parasitic, and fungal pathogens have led to massive mortalities in farmed fish worldwide. Throughout the years, the management of fish diseases has predominantly centered around the utilization of conventional antibiotics and chemicals. Nevertheless, their indiscriminate use has given rise to serious implications, including an increase in resistant pathogens, disruptions in the metabolic processes of fish, degradation of the aquatic environment, the presence of drug residues in aquatic products, and a potential threat to human health. Various effective bio-based and immunoprophylaxis alternative therapies have been developed to overcome these impediments. Recent alternative therapeutic approaches to fish diseases encompass a range of strategies, including phytotherapeutics, nanotherapeutics, probiotics, prebiotics, synbiotics, phage therapy, vaccination, quorum quenching, antimicrobial peptides, biosurfactants, bacteriocins, stem cells, and diagnostic-based therapy. Advancements in biotechnology have significantly enhanced the efficacy of these therapies. However, additional research is essential to refine the utilization of these therapeutic approaches. Critical concerns, such as efficacy, cost, risks, availability, and adverse effects on fish and the ecosystem, need to be addressed to establish guidelines for their sustainable application in aquaculture. This review will increase aquaculturists' awareness of recent therapies used in fish farming, their mechanisms, challenges, and impacts while promoting the sustainability of commercial aquaculture. [ABSTRACT FROM AUTHOR]

Biosecurity plans are crucial for preventing economic and environmental impacts caused by disease outbreaks in aquaculture. These plans focus on prevention, early detection, and effective control measures. With the global threat of emerging infectious diseases and the need for sustainable production practices, the importance of biosecurity continues to grow. Scientometric analysis is a valuable tool for assessing the impact and influence of scientific research within a particular field or discipline. Scientometric analysis of aquaculture biosecurity publications reveals significant activity in the field, with the highest number of publications recorded in 2021. Cottier-Cook EJ emerged as the most prolific author, while USA and the Centre for Environment Fisheries Aquaculture Science were identified as leading contributors. Physical biosecurity measures prevent the entry of pathogens and wild fish into aquaculture systems. Biological biosecurity measures enhance immunity and reduce disease risks. Operational biosecurity measures, such as feed management and hygiene protocols, maintain animal health. Innovative technologies such as sensors and artificial intelligence improve biosecurity efficiency. Effective management of disease outbreaks requires coordination, risk assessment, and established response plans. Aquaculture biosecurity offers benefits such as disease prevention, environmental protection, and food safety, but may have disadvantages including costs and negative environmental impacts. The industry should focus on implementing effective and sustainable biosecurity measures, improving disease prevention, reducing environmental impact, and ensuring product safety and quality. [ABSTRACT FROM AUTHOR]

This review presents the main modern ideas about the biosynthesis of long-chain polyunsaturated fatty acids in teleost fishes and about the genes encoding key enzymes, desaturases and elongases, involved in this process. The authors summarized basic information about the set of elongases and desaturases genes and the features of their functioning in the Atlantic salmon Salmo salar and the rainbow trout Oncorhynchus mykiss, as the most studied and valuable commercial salmon species. The data can be used when conducting research to improve and modify the biotechnology of fish farming with the possibility of targeted regulation of lipogenesis (primarily to control the content of essential FAs) in their body. [ABSTRACT FROM AUTHOR]

Fish phenotyping serves as a cornerstone for refined management and sustainable development in industrialized aquaculture. High-precision instance segmentation for high-density fish is a key step in obtaining fish phenotypic data; however, it remains challenging in practical production. Given this, an innovative instance segmentation method that synergistically integrates fish body surface features with motion features was developed in this study to tackle the complex issue of high-density fish segmentation in real production effectively. In this method, the Gunnar Farnebäck optical flow is leveraged to express the motion features of fish quantitatively, following which a convolutional neural network of different depths is used to extract the depth feature information of the optical flow images. Simultaneously, the body features output by the backbone network are fused with the motion features. Subsequently, the final fish instance segmentation model was constructed based on SOLOv2. The results of experiments conducted on a self-built dataset of tiger puffer (Takifugu rubripes) revealed that integrating the body surface and motion features resulted in an enhancement of over 12% in the segmentation accuracy of the fish (APm = 48.0%, APl = 84.5%, AP = 84.5%) compared with the baseline (SOLOv2). Compared with other mainstream models of instance segmentation, the AP of the proposed method was improved by 8.3 to 12.8%. Thus, the proposed method can provide technical support for fish phenotypic data in industrialized aquaculture. [ABSTRACT FROM AUTHOR]

The 8-week study evaluated the effect of dietary protein reduction on growth performance and water quality of blue streak hap (Labidochromis caeruleus) using biofloc technology (BFT). Fish averaging 0.67 ± 0.13 g in weight were distributed into 15 polyester tanks, each with a water volume of 60 L within 100 L tanks, accommodating 15 fish per tank. Four isolipidic and isoenergetic diets were formulated with gradually decreasing protein levels (40%, 35%, 30%, and 25%). Four biofloc groups (40P + BF, 35P + BF, 30P + BF, and 25P + BF) and control (C) (40P + without BF) were fed twice daily (09:00 and 17:00) at a rate of 5% of their body weight. Molasses was added to the experimental tanks on a daily basis as an organic carbon source. This ensured that the biofloc tanks had a balanced carbon/nitrogen (C/N) ratio and facilitated control of total ammonia nitrogen (TAN), nitrite-nitrogen (NO2-N), and nitrate-nitrogen (NO3-N) levels. The nutritional composition of the bioflocs obtained from the experimental groups revealed that the crude protein and crude lipid contents were 37.00–38.14% and 1.45–1.52%, respectively (P > 0.05). The best specific growth rate (SGR) (1.68%) and feed conversation ratio (FCR) (2.21) were determined in the 35P group. Based on the overall evaluation of the study's data, it can be concluded that the dietary protein for the blue streak hap (L. caeruleus) can be reduced from 40 to 35% in a biofloc system without any negative effects on health. Improving water quality and providing additional food to fish through zero water exchange and organic carbon addition (BFT) can be considered a sustainable aquaculture technique that can be used in ornamental fish farming. [ABSTRACT FROM AUTHOR]

Water quality management is a critical factor in recirculating aquaculture systems (RASs) that significantly influences the growth and health of fish. The present research aimed to investigate the effects of humic acid (HA) added at three concentrations (0, 1.5, and 3 mg L−1) to water on total ammonia nitrogen (TAN) removal efficiency of biofilter unit, growth performance, and some blood biochemical indices of Nile tilapia (Oreochromis niloticus) in a water recirculating system. The Nile tilapia fish with an average weight of 83.44 ± 1.32 g were cultured in nine individual experimental units for 30 days. The removal efficiency of the biofilter for TAN reached to 81.23% and 82.76% in the systems with 1.5 mg L−1 and 3 mg L−1 HA, respectively. The systems with HA had higher nitrate (NO3−) concentration than the the system without HA (control) (p < 0.05). HA adding to the water increased the fish final body weight and the specific growth rate (SGR) compared to the control group (p < 0.05). The feed conversion ratio (FCR) in the HA-groups was significantly lower than the control (p < 0.05). The highest crude protein content of muscle tissue was observed in the fish cultured in the system with 3 mg L−1 HA (p < 0.05). There were no significant differences in the plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) concentrations among treatment groups (p > 0.05). The plasma glucose concentration was significantly lower in the fish exposed to HA compared to the control (p < 0.05). The highest plasma triglyceride concentration was recorded in the HA-3 mg L−1 (p < 0.05). These results indicated that the addition of low-cost commercial HA to RASs has a high potential to improve water quality and fish growth performance. [ABSTRACT FROM AUTHOR]

Branchiura are a crustacean parasite widely known around the world as fish lice. In South America, they have been most studied in Brazil as with high levels of infestation, the parasites can be harmful to the health of fish and cause economic losses in fish farms. The objective of the present study is to provide, for the first time, significant information about the parasitic indices, infestation sites, and morphology of Dolops carvalhoi, and to report the appearance of a new host in the Amazon region of Peru. A total of 24 specimens of Colossoma macropomum, Piaractus brachypomus, and Calophysus macropterus from fish farms were individually analyzed to identify the presence of the ectoparasites. The Branchiura collected from the body surfaces of the fish were separated according to sex, the parasitic indices were calculated, and the parasites were clarified in 90% lactic acid for taxonomic identification. They were also preserved in 2.5% glutaraldehyde, and dehydration and critical point procedures were applied by scanning electron microscopy to visualize the detailed structures. The taxa identified was D. carvalhoi, which had a prevalence of 64.7%, a mean intensity of 1.6, and a mean abundance of 1 parasite/fish in C. macropterus; a prevalence of 100%, a mean intensity, and mean abundance of 2.8 parasites/fish in P. brachypomus; and a prevalence of 100%, but a mean intensity and mean abundance of 15 parasites/fish in C. macropomum. The pectoral and dorsal fins and the urogenital opening had the highest occurrence of D. carvalhoi in the host. Dolops carvalhoi has sexual dimorphism, and we reported for the first time the infestation of this parasite in leather fish C. macropterus. [ABSTRACT FROM AUTHOR]

The reference intervals (RIs) for clinical parameters of fish are crucial to identify abnormal test results. The well-established RIs for hemato-biochemical analytes are lacking for Pangas (Pangasianodon hypophthalmus) reared in different culture systems. The present study aimed to analyze the condition factor and generate RIs for hemato-biochemical parameters in diverse culture systems, which are very critical to improve fish welfare and production. Briefly, the fish sampling was conducted from three different fish farms practicing extensive (no supplemented food with a relatively low stocking density of 10–15 fish/m3), semi-intensive (supplementary feed provided with a stocking density of 80 fish/m3), and intensive culture systems (feed-based culture with a high stocking density of 100–150 fish/m3). Results showed that Fulton's condition factor for fish reared in an intensive culture system was significantly higher (0.98 ± 0.18), followed by semi-intensive (0.85 ± 0.30) and extensive (0.72 ± 0.16) systems. Hematological parameters such as hemoglobin, total erythrocyte count, and packed cell volume were significantly (P < 0.05) higher in the semi-intensive system. Total leucocyte count and mean corpuscular hemoglobin were significantly (P < 0.05) higher in the intensive system. Serum biochemical parameters, including glucose, cortisol, protein profile, and lipid profile, were significantly (P < 0.05) high in the intensive and semi-intensive systems. The study indicated that the condition factor and haemato-biochemical parameters could serve as indicators of the health status of P. hypophthalmus. The intensive and semi-intensive culture systems of P. hypophthalmus demonstrated better health indicators compared to the extensive system. The established normative database can ensure the correct assessment of health and the growth of P. hypophthalmus in diverse culture systems. The reference intervals established for hemato-biochemical parameters in the current study can provide valuable benchmarks for monitoring the fish in different culture systems, enabling effective management and reducing economic losses associated with stress-related issues. [ABSTRACT FROM AUTHOR]

Good management practices are essential to ensure a sustainable aquaculture promoting fish health and environmental protection. Among these practices, the acclimation procedure is important to mitigate post-transport stress allowing the fish to adapt to new rearing environment; however, it is often neglected. This study evaluated acclimation procedures for fish tambaqui Colossoma macropomum. The fish were transported for 400 km and then submitted at different acclimation procedures (NOAC—no acclimation, AC30—fish acclimated in 30 min, and AC60—fish acclimated in 60 min) and pathogens (Aeromonas hydrophila and Saprolegnia parasitica). Blood analysis was performed before the fish transportation (baseline values) and at 01, 24, 48, 72, and 96 h after acclimation procedures, determining the biochemical parameters, erythrogram, leukogram, ions, gasses, and hematimetric indices. As expected, the transport was a stressor for fish, increasing 700% glucose and 300% cortisol compared to the baseline values. In addition, fish after transport, submitted to acclimation procedure for 60min and exposed to pathogens presented 15% mortality. However, fish that underwent the acclimation procedure for 30 min showed early return of glucose, total plasmatic protein, hemoglobin, hematocrit, erythrocyte, MCV, MCH, MCHC, Na, K, and pH to the baseline, mitigating the post-transport stress. Contrary, the acclimation procedure for 60 min was not adequate for tambaqui causing more stress, not returning blood parameters to baseline, and mortalities. The fish not acclimated showed similar results to AC30; however, blood parameters remain altered through 96 h compared to AC30. The AC30 was the best management practice to mitigate the post-transport stress in tambaqui promoting early return to homeostasis and prevent mortality. [ABSTRACT FROM AUTHOR]

Tilapia, a valuable fish species, ranks as the world's second-largest farmed fish. In Thailand, it is a prominent cultured species, specifically the red tilapia hybrids (Oreochromis spp.). Understanding the factors influencing tilapia's microbiome is essential to mitigate fish mortality and production decline. The study assesses the rearing water and fish gill microbiome in red tilapia culture, comparing closed earthen pond and open river cage culture systems across five provinces in Central Thailand. We conducted 16S rRNA amplicon sequencing (V3-V4 hypervariable regions) on bacterial DNA from 30 gills and 27 rearing water samples The results revealed that the location had a more significant impact (p < 0.05) than the culture system on both gills and water microbiomes. No association between abiotic factors and gill microbiome diversity was observed, while significant associations were observed between the water microbiome with ambient temperature (Ta) (p < 0.00), water temperature (Tw) (p < 0.00), pH (p < 0.03), and salinity (p < 0.01). Fish pathogens such as Streptococcus agalactiae and Mycobacterium spp. were consistently among the top 5 most abundant bacteria found in both water and fish gill samples across all provinces. Furthermore, several significant fish pathogens, including Vibrio spp., Aeromonas hydrophila, Flavobacterium spp., and Edwardsiella spp., which pose a threat to public health and food safety and security, were detected, albeit in relatively low abundance (< 0.04%). In summary, this study has identified several bacterial species present in both rearing water and red tilapia gills, some of which can cause human disease as well. Interestingly, the culture system did not have a significant impact on microbial diversity, while the farm's location played a significant role. Further investigations into other factors such as farming practices and environmental conditions that may contribute to the presence of pathogenic bacteria in both rearing water and gill samples are warranted. [ABSTRACT FROM AUTHOR]

Prebiotics are fibers that promote beneficial gut bacteria and play a pivotal role in enhancing host health. This study delves into the impact of various levels of prebiotics, specifically fructooligosaccharides and β-1,3 glucan (Fβ), on the growth performance, biochemical, hematological parameters, gene expression, histological variations in the internal organs, and disease resistance to Fusarium oxysporum in tilapia (Oreochromis niloticus). Two hundred forty Nile tilapia, initially weighing 34.0 ± 0.1 g, were distributed into four groups and given a commercial diet with varying Fβ treatments: control (0 g/kg) (C), T1 (0.5 g/kg), T2 (1.0 g/kg), and T3 (1.5 g/kg) for 70 days. The study revealed significant improvement of the biochemical, hematological, and digestive enzyme activities, as well as histological changes in hepatopancreatic, intestine, and spleen sections with the use of Fβ. Moreover, the expression of innate humoral genes significantly increased (P < 0.05) in tilapia at the 1.5 g/kg Fβ group compared to the control. Notably, challenging with F. oxysporum exhibited lower mortality rates in the three treatments supplemented with additive prebiotics (P < 0.05). Consequently, the feed additives utilized in this study emerge as a viable alternative to enhance growth performance, biochemical and hematological parameters, gene expression, histological variations in internal organs, and disease resistance in fish farming on a large scale. [ABSTRACT FROM AUTHOR]

Fish farming practices currently make effective use of probiotic Bacillus species, specifically Bacillus subtilis and B. licheniformis. The current study assessed the water quality, growth performance, body composition, hemato-biochemical activities, immune regulatory genes, and resistance to Aspergillus flavus in order to determine the effectiveness of the water additive probiotic Bacillus species mixture (SANOLIFE®PRO-W) on Nile tilapia aquaculture. Fish were kept in four groups (control, 0.01, 0.02, 0.03) gm. /m3for 56 days using Bacillus species in-water treatment. The results showed that the fish treated with SANOLIFE® performed significantly better (P < 0.05) in terms of growth. Significant (P < 0.05) improvements were also observed in the immune regulatory genes, antioxidant capacity, and haemato-biochemical parameters. A. flavus challenged fish showed significantly (P < 0.05) lower mortalities, indicating that Bacillus species probiotic enhanced the fish's innate immune response. In order to improve water quality, fish growth, and antioxidant activities together with innate the immune responses, Bacillus species mixture (SANOLIFE®PRO-W) can be recommended to be used in Nile tilapia aquaculture. [ABSTRACT FROM AUTHOR]

The greater amberjack Seriola dumerili is a promising candidate for aquaculture production. This study compares the ovary transcriptome of greater amberjack sampled in the wild (WILD) with hatchery-produced breeders reared in aquaculture sea cages in the Mediterranean Sea. Among the seven sampled cultured fish, three were classified as reproductively dysfunctional (DysF group), while four showed no signs of reproductive alteration (NormalF group). The DysF fish showed 1,166 differentially expressed genes (DEGs) compared to WILD females, and 755 DEGs compared to the NormalF. According to gene ontology (GO) analysis, DysF females exhibited enrichment of genes belonging to the biological categories classified as Secreted, ECM-receptor interaction, and Focal adhesion. Protein–protein interaction analysis revealed proteins involved in the biological categories of ECM-receptor interaction, Enzyme-linked receptor protein signaling, Wnt signal transduction pathways, and Ovulation cycle. KEGG pathway analysis showed DEGs involved in 111 pathways, including Neuroactive ligand-receptor interaction, Steroid hormone biosynthesis, Cell cycle, Oocyte meiosis, Necroptosis, Ferroptosis, Apoptosis, Autophagy, Progesterone-mediated oocyte maturation, Endocytosis and Phagosome, as well as Hedgehog, Apelin, PPAR, Notch, and GnRH signalling pathways. Additionally, DysF females exhibited factors encoded by upregulated genes associated with hypogonadism and polycystic ovary syndrome in mammals. This study -which is part of a broader research effort examining the transcriptome of the entire reproductive axis in greater amberjack of both sexes-, enhances our comprehension of the mechanisms underlying the appearance of reproductive dysfunctions when fish are reared under aquaculture conditions. [ABSTRACT FROM AUTHOR]

In the uplands of northern Vietnam, many Hmong and Mien (Yao/Dao) ethnic minority farmers are adapting to economic reforms and market integration by diversifying their livelihoods. For those with the necessary resources, this has included the cultivation of trout and sturgeon, both introduced species. This move into fish farming, propelled by state policies and growing demand from lowland consumers, signifies an intriguing shift from farmers' previous small-scale trade of non-timber forest products and upland livestock. In this paper we explore the complex commodity chains of these 'lively commodities' and assess their integration into local economies, drawing on extensive ethnographic fieldwork. We evaluate the socio-economic, cultural, and environmental impacts of fish farming on ethnic minority communities, noting the continuous learning, community networks and collaboration, and innovative problem-solving required for farmers to succeed. We then proceed along these commodity chains, highlighting other dynamic relationships and challenges. While we question the potential for new market dependencies to economically entrap farmers, our findings reveal that fish farming often serves as supplemental income, allowing the continuation of long-standing agricultural practices alongside new market engagements. We highlight the adaptability of Hmong and Mien households, critiquing the notion of complete and inescapable market dependency when farmers diversify into new livelihood options. Our paper thus contributes to broader discussions on livelihood change, market integration, and socioeconomic transformations in rural ethnic minority regions of Vietnam. [ABSTRACT FROM AUTHOR]

Over the past two decades, there has been a growing alarm about the role of unintended hybridization in shaping the current biodiversity. Major carps (Labeo rohita, Catla catla, and Cirrhina mrigala) are commercially important freshwater fish for aquaculture and are also found exclusively in the riverine ecosystems of Punjab, Pakistan. One of the main concerns is the genetic integrity of major carps. In this study, we employed both nuclear and mitochondrial DNA markers to determine the potential hybridization and patterns of genetic variation in major carps. Association tests of both nuclear and mtDNA markers provide evidence of recent hybridization, and patterns of genetic variations were also found consistent with observed pattern of admixture in major carps. In all hybridization events, L. rohita is detected to hybridize with C. catla and C. mrigala, whereas C. catla and C. mrigala are established to hybridize with L. rohita. Overall, two levels of hybridization; F1 hybrids reported in hatchery-reared stocks and few backcrosses individuals in wild populations suggest that anthropogenic or demographic dynamics accelerate inter-generic gene flow. Moreover, the disparity in amplified mtDNA COI subunit shows strong directional bias towards Labeo–Catla first-generation hybrids (100%) containing L. rohita maternal lineage while Labeo-Cirrhina hybrids (75%) exhibit C. mrigala maternal lineage. The results of this study endorse that culture-based fish farming and restocking activities of major carps in riverine ecosystems demand regular genetic monitoring of these species. The current genetic evidence and proclamation of practical information should encourage management and conservation efforts to strictly limit the genetic integrity of these species. [ABSTRACT FROM AUTHOR]

We herein investigated Lactobacillus rhamnosus as a probiotic, paraprobiotic and their synbiotic combination in the diet of dourado Salminus brasiliensis. Two hundred and forty juvenile S. brasiliensis with average weight and length of 6.78 ± 1.65 g and 8.97 ± 0.42 cm were randomly distributed in 16 experimental units (300 L) under four treatments: diet without additive (control), 0.02% probiotic (L. rhamnosus 108 CFU), 2.0% paraprobiotic (inactive L. rhamnosus 1010 CFU) and synbiotic (probiotic + paraprobiotic), all in quadruplicate, for 45 days. Then, zootechnical performance, hemato-biochemicals (pre-and post-challenge), intestinal and hepatic histomorphometric analyses were performed, in addition to a bacterial challenge with Aeromonas hydrophila. The feed intake was significantly lower (p < 0.05) in the probiotic group. The allomeric condition factors were significantly higher (p < 0.05) in fish from the paraprobiotic and synbiotic groups. No significant differences (p > 0.05) were observed in the blood count between the supplemented groups and the control group. However, significant differences (p < 0.05) were observed in the blood count between the pre- and post-challenge periods. Fish in the synbiotic groups had higher total villi height and villi height when compared to fish in the probiotic and control group. The serosa were significantly (p < 0.05) thicker in the intestines of fish from the probiotic and synbiotic groups. Goblet cells were significantly numerous (p < 0.05) in fish from the synbiotic group. In conclusion, the use of 0.02% probiotic, 2.0% paraprobiotic, and synbiotic proved to be a promising practice due to their action on productive performance, enabling weight gain similar to that of control group with lower feed intake. In addition to improving intestinal immune-histomosphometric parameters, possibly promoting an improved condition in facing intestinal pathogens. [ABSTRACT FROM AUTHOR]

Fungal diseases in fish cause economic losses all over the world, and knowledge about them is scarce and outdated in Aswan Governorate, Egypt, making interpretation, prevention, and treatment difficult. The necessity to find a fungicide that is natural, environmentally friendly, and does not emerge drug resistance is a must. Therefore, the current study aimed to isolate and diagnose fungal infection in farmed Oreochromis niloticus, causing mortalities, in Aswan Governorate. During 2021, 200 fresh O. niloticus samples were collected from the Sahary Fish Hatchery and Aswan General Authority for Fish Resources Development fish farm. Some fish showed hemorrhagic lesions all over the body, detachment of scales, and fin erosion. Collected tissue samples were cultured on potato dextrose agar and Sabouraud dextrose agar for phenotypic characterization. Macroscopic and microscopic analyses were used to identify the isolated fungi. A total of 18 fungal species and two varieties appertaining to ten fungal genera were recovered from 48 samples out of 200 examined O. niloticus (24%), with Aspergillus flavus being the most prevalent at a rate of 25.6%. The isolated A. flavus was proven to be pathogenic to farmed O. niloticus, as by experimental infection. The natural herb Persicaria salicifolia had an LC50 value of 41.68 mg/l in exposed O. niloticus and was used to treat A. flavus-infected O. niloticus. It can be concluded that A. flavus poses a major hazard to O. niloticus aquaculture and can be treated with 40 mg/kg in feed or 20 mg/l in water of P. salicifolia for 6 days. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess whether activity and heart rate sensor implants can be used to measure stress and thus estimate one important welfare indicator for fish in aquaculture pens, and if such measurements correlate to physiological factors measured through blood sampling. The experiment consisted of two parts: i) a bio-logger study where implanted sensors were used to monitor activity and heart rates for fish undergoing stress (crowding); and ii) an analysis of blood constituents (cortisol, glucose, lactate, and chloride) of a second group of fish undergoing the same treatment. We found that activity measurements can be used to track high-impact stress events but may not be suitable to discern possibly nuanced reactions to stress impacts of lower magnitude. While heart rate was measured reliably, e.g., in showing clear circadian rhythms, it was no credible proxy for predicting stress in this study. Our results thus underline challenges observed in previous work around the use of heart rate as stress indicator, and imply that the translation of its meaning into a proxy for stress needs further work. Although tag-based monitoring of stress is not without its difficulties, studies such as this provide a wealth of information on salmon behaviour and physiology, and the links between these. [ABSTRACT FROM AUTHOR]

There is a great demand for precision fish farming in aquaculture, and accurate fish counting is essential for precise control and monitoring of fish farming processes. Traditional fish counting is manual, time-consuming, and labor-intensive. Image recognition is an effective method for automatic counting. However, the accuracy of automatic detection in real environments is limited by the different sizes, swimming styles of fish, and the potential for mutual occlusion between multiple moving objects. This study introduces a BoTS-YOLOv5s-seg model based on YOLOv5s to achieve accurate detection of fish edge by using the YOLOv5s instance segmentation model and improving the loss function to SIoU loss while improving non-maximum suppression to reduce missed detection of overlapping objects, and finally incorporating a bottleneck transformer to make the model more focused on valid image information and reduce the model parameters. The BoTS-YOLOv5s-seg model proposed in this study to a realistic scenario with a farmed fish dataset had better performance and resulted in a small model size of only 7.1 M, and the values of mAP@0.5 and GFLOPs of the proposed algorithm reached 90.9% and 25.4, respectively, surpassing the traditional YOLOv5s-seg, YOLOv5m-seg, and YOLOv5l-seg in terms of detection results. This research proposes a method that can effectively support accurate fish counting in the context of intelligent aquaculture. [ABSTRACT FROM AUTHOR]

Dietary L-carnitine (LC) and nucleotides (NT) are additives used independently in fish feeds. However, whether they work antagonistically or synergistically in fish nutrition is currently unknown. We explored the interactive effect between dietary LC and NT on growth performance, feed utilization, antioxidant capacity, and hepatic lipid metabolism in juvenile largemouth bass (Micropterus salmoides) juvenile fed a high dietary lipid level of 160 g/kg. Four experimental diets including basal diet (BD; no additives), 0.2 g/kg LC and 0 NT g/kg (LCNT0), 0.2 g/kg LC and 5 g/kg NT (LCNT5), and 0.2 g/kg LC and 10 g/kg NT (LCNT10) were formulated. These diets were administered twice daily to 30 fish weighing 10.3 ± 0.2 g in triplicate tanks for 9 weeks. We found that fish reared on diet LCNT10 increased significantly final body weight and weight gain than those reared on BD and LCNT0 diet (P ˂ 0.05). Feeding LCNT5 diet increased significantly feed intake than LCNT0 diet (P < 0.05). Fish fed with LCNT0 and LCNT10 diets lowered significantly FCR compared to BD and LCNT5 diet (P ˂ 0.05). Retention efficiency of nitrogen, phosphorus, and energy increased significantly in fish fed with LCNT10 diet than on BD and LCNT0 diet (P ˂ 0.05). The LCNT0, LCNT5, and LCNT10 diets reduced serum superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities and malondialdehyde content of largemouth bass than BD (P < 0.05). Furthermore, LCNT5 and LCNT10 diets increased liver GSH-Px and CAT activities in fish compared to BD (P < 0.05). The BD upregulated the mRNA expression of carnitine palmitoyltransferase-1 and peroxisome proliferators-activated receptor α genes than LCNT0, LCNT5, and LCNT10 diets (P < 0.05). Taken together, dietary LC and NT supplementation synergistically promote growth rate, feed utilization efficiency, and antioxidant capacity in juvenile largemouth bass. [ABSTRACT FROM AUTHOR]

Understanding of risk factors for parasite introduction and amplification within fish farms is crucial to design effective biosecurity and control management strategies but currently, quantitative data on the relevance of such risk factors is largely absent. We have designed the questionnaires for stakeholders to characterize the risk factors and estimate their relevance for infections causing major economic burden on gilthead seabream (Sparus aurata) and European seabass (Dicentrarchus labrax) production: the myxozoan Enteromyxum leei, the monogenean Sparicotyle chrysophrii, the crustacean Ceratothoa oestroides and the dinoflagellate Amyloodinium ocellatum. Twenty-two experts (Belgium, Croatia, Greece, Italy, Norway, and Spain) were invited to participate in an online questionnaire, followed by a physical meeting to discuss the most probable values for parameter estimates. Quantitative estimates were obtained for the relevance of risk routes of parasite spread (e.g., the likelihood of parasite transmission from an infected to an uninfected net cage 5 m away was estimated to be 90% for E. leei), and the relevance of management procedures and environmental factors that may have an impact on the probability of infection to lead to disease (e.g., where mortalities are removed at > 5-day intervals, the likelihood that infection will lead to disease was 30% for S. chrysophrii). These quantitative estimates were appraised, including the delay in reaching harvest size, or cumulative mortality during phases of production, being essential for calculation of the burden of these diseases in aquaculture. The data presented are highly valuable to the development of economically viable biosecurity and specific integrated pest management strategies. [ABSTRACT FROM AUTHOR]