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Aquatic animals are viewed as a good source of healthy lipids. Although drying is an effective method for the preservation of aquatic animal products (AAPs), the whole process is accompanied by lipid oxidation. This article reviews the main mechanism of lipid oxidation in the drying process. It also summarizes the effects of lipid oxidation on the quality of dried aquatic animal products (DAAPs), including nutrients, color, flavor, and hazard components, especially for those harmful aldehydes and heterocyclic amines. In addition, it concluded that moderate lipid oxidation contributes to improving the quality of products. Still, excessive lipid oxidation produces hazardous substances and induces health risks. Hence, to obtain high-quality DAAPs, some effective control technologies to promote/prevent lipid oxidation are introduced and deeply discussed, including salting, high-pressure processing, irradiation, non-thermal plasma technology, defatting treatments, antioxidants, and edible coating. A systematic review of the effect of lipid oxidation on quality attributes and control technologies in DAAPs is presented, and some perspectives are made for future research. [ABSTRACT FROM AUTHOR]

The presence of livestock in riparian areas raises several questions about the conservation and sustainable use of water resources and biodiversity in Brazil. Although the Native Vegetation Protection Law (No. 12,651) focuses on riparian vegetation, protected as Permanent Preservation Areas (APPs), it does not exclude the presence of livestock in these fragile areas. Here, we provide an overview of APPs in Brazil and analyze the legal instruments that enable livestock in these areas, gathering the scientific evidence on associated environmental impacts. Currently, cattle in riparian areas represent a direct threat to biodiversity and ecosystem functioning and services, especially because these animals promote trampling, loss of vegetation, soil erosion, siltation, and pollution through urine and feces. To avoid cattle in APPs, legislation should be revised to implement more stringent restrictions; in parallel, alternatives for watering the animals must be sought, such as, for example, the installation of artificial ponds and drinking fountains. It would be appropriate to propose legislation or create incentives to fence livestock in pasture areas to preventing it from accessing APPs. Increasing cattle confinement is an alternative measure to traditional ranching in open pasture. Riparian zones represent a critical environment for biodiversity and society, so the presence of cattle and its associated negative impacts should be seriously considered by authorities. [ABSTRACT FROM AUTHOR]

The Aphanomyces species pose an important global threat and cause damage to aquaculture and agriculture by infecting aquatic animals and plants. Several subpopulations of the seasonal cyprinodont fish genus Nothobranchius with lesions suggestive of infection with Aphanomyces invadans, were observed in ephemeral wetland habitats of the upper Congo drainage in the south-eastern Democratic Republic of Congo. Molecular analyses on samples collected in 2023 revealed evidence of fish-pathogenic oomycetes Aphanomyces invadans and A. laevis, for the first time in the host of fish genus Nothobranchius spp. All Nothobranchius fishes in the upper Congo drainage are subject to a high level of threat and belong to one of the threatened Red List categories, due to habitat degradation of seasonal wetlands. These fishes complete their seasonal life cycle in ephemeral natural habitats. The latter makes them highly vulnerable, as such wetland habitats are often degraded by the cumulative effect of multiple human stressors which include: the cultivation of wetlands for agriculture, the abstraction of water, the expansion of urban areas and the pollution load. Evidence of infection by oomycete pathogens documented in this study, represents a critical additional threat to the unique seasonal aquatic biodiversity of the region. [ABSTRACT FROM AUTHOR]

It never rains in standard lab-confinements; thus we have limited understanding of animal reactions to water and wetness. To address this issue, we sprayed water on different body parts of rats and measured drying and fur temperature by thermal imaging while manipulating behavior, sensory cues and fur. Spraying water on rats resulted in fur changes (hair clumping, apex formation), grooming, shaking, and scratching. Anesthesia abolished behavioral responses, interfered with fur changes, and slowed drying. Spraying water on different body parts resulted in differential behavioral drying responses. Spraying the head resulted in grooming and shaking responses; water evaporated from the head twice as fast as water sprayed on the animal's back or belly. We observed no effect of whisker removal on post-water-spraying behavior. In contrast, local anesthesia of dorsal facial skin reduced post-water-spraying behavioral responses. Shaving of head fur drastically enhanced post-water-spraying behaviors, but reduced water loss during drying; indicating that fur promotes evaporation, acting in tandem with behavior to mediate drying. Excised wet fur patches dried and cooled faster than shaved excised wet skin. Water was sucked into distal hair tips, where it evaporated. We propose the wet-fur-heat-pump-hypothesis; fur might extract heat required for drying by cooling ambient air. [ABSTRACT FROM AUTHOR]

The use of nutraceuticals in aquaculture is getting attention to minimize oxidative stress and increase immunity of aquatic animals. In our experiment, we tested the potency of Phyllanthus niruri, as a stress-reducing and immune-stimulating agent in Nile tilapia, Oreochromis niloticus. We reared fish in a recirculating system for 90 days at low (5 g/L) and high (30 g/L) densities. We fed half of the low and high-density fish with commercial feed (control feed) and the other half, with 5% Phyllanthus niruri incorporated into commercial feed (supplemented feed). We assessed plasma cortisol, blood glucose, packed cell volume, plasma proteins, phagocytic capacity, respiratory burst activity, and lysozyme activity. None of these parameters showed any significant difference among the experimental groups. Based on our findings, we conclude that Phyllanthus niruri does not have any potential role in modulating stress and immune response in fish as a nutraceutical. [ABSTRACT FROM AUTHOR]

Organisms cope with environmental fluctuations and maintain fitness in part via reversible phenotypic changes (acclimation). Aquatic animals are subject to dramatic seasonal fluctuations in water salinity, which affect osmolarity of their cells and consequently cellular function. Mechanosensory lateral line hair cells detect water motion for swimming behavior and are especially susceptible to salinity changes due to their direct contact with the environment. To maintain hair cell function when salinity decreases, neuromast (Nm)-associated ionocytes differentiate and invade lateral line neuromasts. The signals that trigger the adaptive differentiation of Nm ionocytes are unknown. We demonstrate that new Nm ionocytes are rapidly specified and selectively triggered to proliferate by low Ca2+ and Na+/Cl- levels. We further show that Nm ionocyte recruitment and induction is affected by hair cell activity. Once specified, Nm ionocyte differentiation and survival are associated with sequential activation of different Notch pathway components, a process different from other tissue-specific ionocytes. In summary, we show how environmental changes activate a signaling cascade that leads to physiological adaptation. This may prove essential for survival not only in seasonal changing environments but also in changing climates. [ABSTRACT FROM AUTHOR]

Aquatic animals residing in saline habitats either allow extracellular sodium concentration to conform to environmental values or regulate sodium to lower levels. The latter strategy requires an energy-driven process to move sodium against a large concentration gradient to eliminate excess sodium that diffuses into the animal. Previous studies of invertebrate and vertebrate species indicate a sodium pump, Na+/K+ ATPase, powers sodium secretion. We provide the first functional evidence of a saline-water animal, Aedes taeniorhynchus mosquito larva, utilizing a proton pump to power this process. Vacuolar-type H+ ATPase (VHA) protein is highly expressed on the apical membrane of the posterior rectal cells, and in situ sodium flux across this epithelium increases significantly in larvae held in higher salinity and is sensitive to Bafilomycin A1, an inhibitor of VHA. We also report the first evidence of splice variants of the sodium/proton exchanger, NHE3, with both high and low molecular weight variants highly expressed on the apical membrane of the posterior rectal cells. Evidence of NHE3 function was indicated with in situ sodium transport significantly inhibited by a NHE3 antagonist, S3226. We propose that the outward proton pumping by VHA establishes a favourable electromotive gradient to drive sodium secretion via NHE3 thus producing a hyperosmotic, sodium-rich urine. This H+- driven Na+ secretion process is the primary mechanism of ion regulation in salt-tolerant culicine mosquito species and was first investigated over 80 years ago. [ABSTRACT FROM AUTHOR]

Background: It is widely reported that exotic larvicidal fishes like Gambusia and Poecilia have adverse impact on the native aquatic fauna. The present study highlights the efficacy of two colourful native murrels, primarily designated as ornamental fish, Channa bleheri and Channa stewartii as biocontrol agent of mosquito larvae. Methods: Live specimens of Channa bleheri and C. stewartii, collected from the wetlands of Tinsukia district of Upper Assam, were assessed for their larvivorous potential at individual and group levels during day and night by dividing the specimens into two size groups. After 12 hour and 24 hour starvation, the test specimens (mean size for small group 8.67-9.17 cm and that of large group 11.63-13.27 cm) were given known number of mosquito larvae and recorded the consumption rate. Result: The predation rate varied from 33.3±4.36 to 71.6±5.15/min for Channa bleheri and that of C. stewartii from 16.3±0.95 to 68.2±2.77/min. In both species, smaller sized specimens were better performers as predators. Predation rate at 12 and 24 hrs of starvation and between day and night proved that these native murrels are excellent predators of mosquito larvae. [ABSTRACT FROM AUTHOR]

Metrics to be used in noise impact assessment must integrate the physical acoustic characteristics of the sound field with relevant biology of animals. Several metrics have been established to determine and regulate underwater noise exposure to aquatic fauna. However, recent advances in understanding cause-effect relationships indicate that additional metrics are needed to fully describe and quantify the impact of sound fields on aquatic fauna. Existing regulations have primarily focused on marine mammals and are based on the dichotomy of sound types as being either impulsive or non-impulsive. This classification of sound types, however, is overly simplistic and insufficient for adequate impact assessments of sound on animals. It is recommended that the definition of impulsiveness be refined by incorporating kurtosis as an additional parameter and applying an appropriate conversion factor. Auditory frequency weighting functions, which scale the importance of particular sound frequencies to account for an animal's sensitivity to those frequencies, should be applied. Minimum phase filters are recommended for calculating weighted sound pressure. Temporal observation windows should be reported as signal duration influences its detectability by animals. Acknowledging that auditory integration time differs across species and is frequency dependent, standardized temporal integration windows are proposed for various signal types. [ABSTRACT FROM AUTHOR]

Aquaculture is a crucial and rapidly expanding industry in global food production. Fisheries are also an essential socio-economic activity, providing abundant resources and remarkable prospects. However, due to the deteriorating ecological environment, aquatic animals are often exposed to traumatic conditions and are susceptible to bacterial infections that pose significant challenges for aquaculture production. The indiscriminate use of antibiotics in the past has led to the emergence of multidrug-resistant pathogens and sudden outbreaks of infectious diseases, resulting in serious economic losses. Moreover, the use of expensive chemotherapeutic drugs and antibiotics has negative impacts on aquatic environments. Therefore, it is increasingly important to adopt alternative natural agents, such as probiotics and their metabolites, to enhance healthy fish production. Probiotics are microorganisms that have numerous beneficial effects on their hosts. They are environmentally friendly, non-toxic, and cost-effective. This review specifically focuses on the use of Bacillus sp. as probiotics to promote healthy tilapia production in the aquatic sector, while also examining their interactions with the immune system and gut micro-biota. The information presented in this review can guide future research and promote effective and healthy tilapia culture production. [ABSTRACT FROM AUTHOR]

In recent years, with the continuous expansion of aquaculture and the vigorous development of the aquaculture industry, the breeding environment and diseases have become increasingly prominent, and the quality and output of aquaculture products have been affected to a certain extent, which has become one of the important factors restricting the development of aquaculture industry. Clostridium butyricum is a kind of clostridium bacillus, a gram-positive bacterium, strictly anaerobic, which can form spores and produce short-chain fatty acids, biofuel compounds, and biomaterial precursors such as H2, butanol, and 1,3-propanediol in the process of fermenting carbohydrates and sugars. This article reviews the isolation, identification, main biological functions, and mechanism of C. butyricum in the gastrointestinal tract of aquatic animals and summarizes the role of C. butyricum in improving the growth performance, digestibility, survival, immune response, disease resistance, and intestinal structure, as well as regulating the intestinal symbiotic microbiota and metabolic disorders of aquatic animals. To provide insights into the key research directions of C. butyricum in shrimp aquaculture in the future, including research on the relationship between C. butyricum and the host immune system and the possibility of using C. butyricum as an antibiotic substitute for disease prevention and treatment, this study aims to provide a reference for the comprehensive utilization of C. butyricum in shrimp aquaculture and promote the high-quality development of the shrimp aquaculture industry. [ABSTRACT FROM AUTHOR]

Total dissolved gas supersaturation (TDGS) occurs when air mixes with water under pressure, which can be caused by features such as hydroelectric dams and waterfalls. Total dissolved gas supersaturation can cause harmful bubbles to grow in the tissues of aquatic animals, a condition known as gas bubble trauma (GBT). As gills are the primary gas exchange surface for most fish, it is through the gills that elevated total dissolved gases enter the blood and tissues of a fish. We describe the role of the gills in admitting TDGS into the body and discuss potential effects of bubbles in the gills on blood oxygen and carbon dioxide diffusion, blood ion and pH homeostasis, and nitrogenous waste excretion, as well as downstream effects on aerobic swimming performance. [ABSTRACT FROM AUTHOR]

Alkaline water is toxic to cultured aquatic animals that frequently live in pH-neutral freshwater. Overfishing and habitat destruction have contributed to the decline in the wild sturgeon population; consequently, the domestic hybrid sturgeon has become an increasingly important commercial species in China. Hybrid sturgeons are widely cultured in alkaline water, but little is known about the effects of alkalinity stress on hybrid sturgeon liver tissues. We exposed hybrid sturgeons to four alkaline concentrations (3.14 ± 0.02 mmol/L, 7.57 ± 0.08 mmol/L, 11.78 ± 0.24 mmol/L and 15.46 ± 0.48 mmol/L). Histopathology, biochemical index assessment, gene expression level detection and metabolomics analysis were used to investigate the negative effects on liver functions following exposure to NaHCO3. Livers exposed to alkaline stress exhibited severe tissue injury and clear apoptotic characteristics. With increased exposure concentrations, the hepatic superoxide dismutase, catalase, glutathione peroxidase and alkaline phosphatase activities significantly decreased in a dose-dependent manner. NaHCO3 exposure up-regulated the transcriptional levels of apoptosis/ferroptosis-related genes in livers. Similarly, the expression trends of interleukin-1β and heat shock protein genes also increased in high-alkalinity environments. However, the expression levels of complement protein 3 significantly decreased (p < 0.05). Hepatic untargeted metabolomics revealed the alteration conditions of various metabolites associated with the antioxidant response, the ferroptosis process and amino acid metabolism (such as beta-alanine metabolism; alanine, aspartate and glutamate metabolism; and glycine, serine and threonine metabolism). These data provided evidence that NaHCO3 impaired immune functions and the integrity of hybrid sturgeon liver tissues by mediating oxidative-stress-mediated apoptosis and ferroptosis. Our results shed light on the breeding welfare of domestic hybrid sturgeons and promote the economic development of fisheries in China. [ABSTRACT FROM AUTHOR]

Carp is a key aquaculture species worldwide. The intensification of carp farming, aimed at meeting the high demand for protein sources for human consumption, has resulted in adverse effects such as poor water quality, increased stress, and disease outbreaks. While antibiotics have been utilized to mitigate these issues, their use poses risks to both public health and the environment. As a result, alternative and more sustainable practices have been adopted to manage the health of farmed carp, including the use of probiotics, prebiotics, phytobiotics, and vaccines to prevent disease outbreaks. Phytobiotics, being both cost-effective and abundant, have gained widespread acceptance. They offer various benefits in carp farming, such as improved growth performance, enhanced immune system, increased antioxidant capacity, stress alleviation from abiotic factors, and enhanced disease resistance. Currently, a focal point of research involves employing molecular approaches to assess the impacts of phytobiotics in aquatic animals. Gene expression, the process by which genetic information encoded is translated into function, along with transcription profiling, serves as a crucial tool for detecting changes in gene expression within cells. These changes provide valuable insights into the growth rate, immune system, and flesh quality of aquatic animals. This review delves into the positive impacts of phytobiotics on immune responses, growth, antioxidant capabilities, and flesh quality, all discerned through gene expression changes in carp species. Furthermore, this paper explores existing research gaps and outlines future prospects for the utilization of phytobiotics in aquaculture. [ABSTRACT FROM AUTHOR]

The "One Village One Dam (1V1D)" is a rainwater harvesting technology initiated by the Government of Ghana in 2017 to make water available all year round for animal watering, irrigation and domestic use in dryland areas in northern Ghana. However, scepticism about the potential of the 1V1D to stave off water stress and its associated impact on local livelihood activities is still prevalent in the country. This case study of Savelugu Municipality investigated the impact of the 1V1D on local livelihood activities and the work-life balance of women. Using qualitative data collection methods, 12 focus group discussions and seven key informant interviews were conducted in six communities in the municipality. The results showed that after >5 years of implementation, not much has been achieved for the intended purposes of the project, namely water for animal watering, irrigation and household consumption. Non-performance of the dams was attributed to engineering flaws like poor design and small size which often resulted in early dry out of the dams in the dry season. However, emerging activities like water commercialisation have provided a source of sustenance to water vendors. The services of the vendors save women time to fulfil the demands of work, family and personal life. Overall, the persistence of water stress in the study communities and activities of Fulani herdsmen, who allowed their cattle to pollute the dams' water, necessitates the government to address the design flaws through retrofitting the existing dams and mainstreaming future 1V1D projects to effectively tackle water stress in Ghana's dryland areas. [ABSTRACT FROM AUTHOR]

Continental aquatic environments have undergone chemical pollution due to increased anthropogenic activities. Among those substances, petroleum hydrocarbons are a potential hazard for the aquatic animals. Additionally, alterations in the abiotic characteristics of the water, such as temperature and pH, can impose additional stress when those substances are present. We evaluate how alterations in water temperature and pH modified the acute (96 h) toxicity of the water-soluble fraction of gasoline (WSFG) to Astyanax altiparanae through physiological analysis. We also investigated the physiological responses after the fish recovery from exposure (96 h) in clean water. Both isolated and combined exposures to WSFG resulted in significant physiological changes. Alone, WSFG altered energetic metabolism and haematopoietic functions, potentially due to metabolic hypoxia. When combined with changes in water temperature (30 °C) and pH (4.0), A. altiparanae activated additional physiological mechanisms to counterbalance osmoregulatory and acid–base imbalances, likely exacerbated by severe metabolic hypoxia. In both isolated and combined exposure scenarios, A. altiparanae maintained cellular hydration, suggesting a robust capacity to uphold homeostasis under environmental stress conditions. Following a recovery in clean water, energetic metabolism returned to control levels. Nevertheless, plasmatic Na+ and Cl− levels and haematological parameters remained affected by WSFG exposure. Our findings underscore the impact of interactions between WSFG contaminants, temperature and pH, leading to additional biological damage in A. altiparanae. [ABSTRACT FROM AUTHOR]

There are substantial gaps in our empirical knowledge of the effects of chemical exposure on aquatic life that are unlikely to be filled by traditional laboratory toxicity testing alone. One possible alternative of generating new toxicity data is cross-species extrapolation (CSE), a statistical approach in which existing data are used to predict the effect of a chemical on untested species. Some CSE models use relatedness as a predictor of chemical sensitivity, but relatively little is known about how strongly shared evolutionary history influences sensitivity across all chemicals. To address this question, we conducted a survey of phylogenetic signal in the toxicity data from aquatic animal species for a large set of chemicals using a phylogeny inferred from taxonomy. Strong phylogenetic signal was present in just nine of thirty-six toxicity datasets, and there were no clear shared properties among those datasets with strong signal. Strong signal was rare even among chemicals specifically developed to target insects, meaning that these chemicals may be equally lethal to non-target taxa, including chordates. When signal was strong, distinct patterns of sensitivity were evident in the data, which may be informative when assembling toxicity datasets for regulatory use. Although strong signal does not appear to manifest in aquatic toxicity data for most chemicals, we encourage additional phylogenetic evaluations of toxicity data in order to guide the selection of CSE tools and as a means to explore the patterns of chemical sensitivity across the broad diversity of life. [ABSTRACT FROM AUTHOR]

During the Late Pleistocene, stadial and interstadial fluctuations affected vegetation, fauna, and human groups that were forced to cope with these pronounced spatial–temporal climatic and environmental changes. These changes were especially abrupt during Marine Isotope Stage (MIS) 3. Here, we reconstruct the climatic trends in northern Iberia considering the stable isotopic composition of ungulate skeletal tissue found in archaeological deposits dated between 80 and 15 kacalBP. The carbon and oxygen isotopic composition preserved in the carbonate fraction of tooth enamel provides a reliable and high-resolution proxy of the food and water consumed by these animals, which is indirectly related to the local vegetation, environment, and climate, allowing us to estimate palaeotemperatures and rainfall intensity. This study presents new isotope data from 44 bovine, equid, and cervid teeth from five archaeological sites in the Vasco-Cantabrian region (El Castillo, Axlor, Labeko Koba, Aitzbitarte III interior, and El Otero) and one in northeastern Iberia (Canyars), where human evidence is attested from the Mousterian to the Magdalenian. The carbon isotope values reflect animals feeding on diverse C3 plants in open environments and point to differentiated ecological niches for equids and bovines, especially during the Aurignacian in the Vasco-Cantabrian region. Temperature estimations based on oxygen isotopic compositions and rainfall obtained from carbon isotopic compositions indicate colder and more arid conditions than nowadays for the human occupations from the Late Mousterian to the Aurignacian. The contemporary northeastern Iberian site shows slightly lower temperatures related to an arid period when animals mainly grazed in open landscapes. In the Vasco-Cantabrian region, during MIS 2, the Gravettian data reflect a landscape opening, whereas the Magdalenian points to warmer (but still arid) conditions. [ABSTRACT FROM AUTHOR]

Background: Diverse bacterial group behaviors are controlled by quorum sensing, a regulatory network of bacterial gene expression based on cell density, and involving communication through chemical signal molecules called autoinducers. Multidisciplinary research in toxigenic Vibrio cholerae the etiologic agent of cholera, appear to suggest group behavior in the ecology, epidemiology, pathogenesis and transmission of the pathogen. This review summarizes latest advances and known aspects of quorum regulated environmental survival form of V. cholerae, and their role in cholera outbreaks, as well as the significance of this knowledge in tracking the pathogen for prevention of cholera. Main body: Pathogenic V. cholerae naturally exists in aquatic reservoirs, and infects humans, often leading to epidemic outbreaks of cholera. Effective detection and monitoring of the pathogen in surface waters have been a research focus in preventing cholera outbreaks. However, in the aquatic reservoirs, V. cholerae persists mostly in a quiescent state referred to as viable but non-culturable (VBNC), or conditionally viable environmental cells (CVEC), which fail to grow in routine bacteriological culture. The presence of CVEC can, however, be observed by fluorescent antibody based microscopy, and they appear as clumps of cells embedded in an exopolysaccharide matrix. Current studies suggest that CVEC found in water are derived from in-vivo formed biofilms excreted by cholera patients. The transition to CVEC occurs when dilution of autoinducers in water blocks quorum-mediated regulatory responses that would normally disperse the cellular aggregates. Consequently, CVEC are resuscitated to actively growing cells if autoinducers are replenished, either in the laboratory, or naturally by other environmental bacteria or the intestinal microbiota when CVEC are ingested by humans or aquatic animals. Conclusion: Quorum sensing plays a crucial role in the environmental persistence of toxigenic V. cholerae in a latent state, and their periodic emergence to cause cholera outbreaks. Furthermore, the autoinducer driven resuscitation of these cells may be a basis for improving the detection of V. cholerae in water samples, and monitoring V. cholerae in their aquatic reservoirs in cholera endemic areas. [ABSTRACT FROM AUTHOR]

Rampant industrialization has led to widespread reliance on hydrocarbon polymers for various commercial applications. While these synthetic polymers, commonly known as plastics, degrade in slowly in the environments, the toxic effects of their micro-sized particles remain underexplored. In this study, we synthesized polyisobutylene (PIB) microparticles in the lab and evaluated their toxicity and accumulation in a zebrafish model. Pristine and fluorescent PIB-microplastics (MPs), with particle sizes ranging from 2 to 10 μm, were synthesized using the solvent evaporation method. Fourier-transform infrared spectroscopy (FTIR) confirmed the stability of the suspensions. Zebrafish larvae exposed to various concentrations of PIB-MPs exhibited numerous morphological and molecular changes, including delayed hatching, impaired swimming behavior, increased reactive oxygen species levels, altered mRNA levels of genes encoding antioxidant proteins, and reduced survival rates. Dissections revealed PIB-MP accumulation in the guts of larvae and adult fish within 7–21 days, causing damage to the intestinal mucosa. These findings provide insights into how contaminants like PIB can induce pathophysiological defects in aquatic fauna and pose potential health hazards to humans. [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]

With the development of the aquaculture industry, finding effective ways to improve the health and production efficiency of aquatic animals has become a research hotspot. Probiotics help reduce the risk of diseases in aquaculture animals and improve production performance. Lactobacillus acidophilus belongs to the genus Lactobacillus, and is a gram-positive probiotic, which exists widely in the natural environment and the digestive system of animals. It can regulate pH value, improve the growth performance and feed utilization of animals, and enhance the immune function of animals. This paper reviewed the application of Lactobacillus acidophilus in promoting the growth and nutrient utilization of aquatic animals, enhancing the immune function of aquatic animals and improving the intestinal structure and function of aquatic animals. It also discussed the role of Lactobacillus acidophilus in the prevention and control of bacterial diseases and water quality regulation, and put forward suggestions for future research direction of Lactobacillus acidophilus, to provide reference for the research and development of Lactobacillus acidophilus products and the sustainable development of aquaculture industry. [ABSTRACT FROM AUTHOR]

Amomum tsao‐ko Crevost et Lemarie (Zingiberaceae), an aromatic plant, has been considered to have diverse medicinal values and economic significance. It has been reported to possess antibacterial, antioxidant, and antidiabetic effects. With the increasing risk of diseases in aquaculture, there is a need for alternative solutions to chemical antibiotics. Plant extracts have shown promise as natural feed additives for aquatic animals. In this study, the antibacterial effect of Amomum tsao‐ko crude extracts was evaluated using the Oxford cup method. The extracts exhibited significant antimicrobial activity against Salmonella typhimurium and Salmonella enteritidis. Furthermore, the addition of Amomum tsao‐ko to fish feed resulted in notable changes in the gut structure of zebrafish and tilapia. The length and morphology of intestinal villi were enhanced, promoting improved digestion. Analysis of the gut microbial community revealed that Amomum tsao‐ko supplementation induced key changes in the gut microbial community composition of both zebrafish and tilapia. Notably, a 1% inclusion of Amomum tsao‐ko resulted in a marked rise in Proteobacteria levels in zebrafish, which diminished at 10% dosage. The supplement elicited mixed reactions among other bacterial phyla like Actinobacteria and Verrucomicrobiota. Fluctuations were also observed at the genus level, pointing to the concentration of Amomum tsao‐ko playing a pivotal role in influencing the structure of intestinal bacteria. The findings of this study suggest that Amomum tsao‐ko has antibacterial properties and can positively influence the gut health of fish. The potential use of Amomum tsao‐ko as a natural feed additive holds promise for improving aquaculture practices and reducing reliance on chemical antibiotics. Further research is needed to explore the full potential and applications of Amomum tsao‐ko in fish feed development. [ABSTRACT FROM AUTHOR]

Climate change is altering temperature means and variation, and both need to be considered in predictions underpinning conservation. However, there is no consensus in the literature regarding the effects of temperature fluctuations on biological functions. Fluctuations may affect biological responses because of inequalities from non‐linear responses, endocrine regulation or exposure to damaging temperatures. Here we establish the current state of knowledge of how temperature fluctuations impact biological responses within individuals and populations compared to constant temperatures with the same mean. We conducted a meta‐analysis of 143 studies on ectothermic animals (1492 effect sizes, 118 species). In this study, 89% of effect sizes were derived from diel cycles, but there were no significant differences between diel cycles and shorter (<8 h) or longer (>48 h) cycles in their effect on biological responses. We show that temperature fluctuations have little effect overall on trait mean and variance. Nonetheless, temperature fluctuations can be stressful: fluctuations increased 'gene expression' in aquatic animals, which was driven mainly by increased hsp70. Fluctuating temperatures also decreased longevity, and increased amplitudes had negative effects on population responses in aquatic organisms. We conclude that mean temperatures and extreme events such as heat waves are important to consider, but regular (particularly diel) temperature fluctuations are less so. [ABSTRACT FROM AUTHOR]

In prawn farming, the main protein source used in aquafeed formulations is fishmeal. Nevertheless, one estimates that in the coming years, this protein source will no longer be able to meet the demand for the activity. The search for new ingredients is important to meet the increasing demand and minimize environmental impacts, such as the reduction in fish stocks and the eutrophication of aquatic systems. The objective of this study was to determine the apparent digestibility coefficients of dry matter (DM), crude protein (CP), gross energy (GE), and ether extract (EE) of fishmeal, poultry co-products (viscera and hydrolysed feather), and insect meal (Gromphadorhina portentosa) for giant river prawn (Macrobrachium rosenbergii) juveniles. To determine the apparent digestibility coefficients (ADCs), 90 prawns (average weight, 15 g) were randomly distributed among three experimental units. The reference feed was formulated according to the requirements of the giant river prawn, with 35% crude protein and a gross energy of 3600 kcal kg−1. The test diets comprised 70% of the reference diet and 30% of the respective test ingredients. Prawns were fed three times a day until apparent satiety. Faeces were collected using the indirect siphoning method, twice a day at the same feeding site (at 7:30 a.m. and 6:30 p.m.). The water parameters were temperature (27 °C), dissolved oxygen (6.65 mg L−1) and pH (7.76). The ACDs of DM, CP, EE, and GE were, respectively, 61.48; 88.28; 99.89 and 88.25 for fishmeal; 76.48; 81.55; 97.29 and 85.13 for poultry viscera meal; 73.82; 75.21; 73.17 and 76.42 for hydrolysed feather meal; and 52.35; 59,48; 87.95 and 67.64 for G. portentosa meal. The values of protein (%) and digestible energy (kcal kg−1) were 55.20 and 3711 for fishmeal; 47.27 and 4285 for poultry viscera's meal; 65.03 and 4145 for hydrolysed feather meal; and 47.72 and 3616 for G. portentosa meal. These results showed the potential use of insect meals and poultry co-products as ingredients for the diets of M. rosenbergii juveniles, as they present digestible values close to those found for fishmeal, the main raw material used in aquaculture diets. [ABSTRACT FROM AUTHOR]

Diclofenac (DCF, C14H11Cl2NO2) is a widely used non-steroidal anti-inflammatory drug, with a significant occurrence in waste effluents. DCF is especially persistent and difficult to degrade, with numerous toxic effects on aquatic fauna and humans. In 2015, DCF was identified as a priority pollutant (EU Directives on water policy). In this work, UV irradiation and its combination with hydrogen peroxide only or catalyzed by iron salts (photo-Fenton) are analyzed to find the most efficient alternative. DCF aqueous solutions were treated in a stirred 150 W UV photocatalytic reactor. Depending on the case, 1.0 mM H2O2 and 0–5.0 mg/L Fe2+ catalyst, such as FeSO4, was added. During the reaction, DCF, pH, turbidity, UVA at 254 and 455 nm, dissolved oxygen (DO), and TOC were assessed. The degradation of DCF yields a strong increase in aromaticity because of the rise in aromatic intermediates (mono-hydroxylated (4-hydroxy-diclofenac and 5-hydroxy-diclofenac) and di-hydroxylated products (4,5-dihydroxy-diclofenac), which subsequently generate compounds of a quinoid nature), which are very stable and non-degradable by UV light. Thus, only if H2O2 is added can UV completely degrade these aromatic colour intermediates. However, adding ferrous ion (photo-Fenton) the aromaticity remains constant due to iron com-plexes, that generates maximum colour and turbidity at an stoichiometric Fe2+ : DCF ratio of 3. As a result of the study, it is concluded that, with UV light only, a strong yellow colour is generated and maintained along the reaction, but by adding H2O2, a colourless appearance, low turbidity (<1 NTU), and [DO] = 8.1 mg/L are obtained. Surprisingly, photo-Fenton was found to be unsuitable for degrading DCF. [ABSTRACT FROM AUTHOR]

Simple Summary: The giant freshwater prawn (GFP; Macrobrachium rosenbergii) is a tropical aquatic animal with high economic value. However, we found that GFP in the same environment will vary in individuals, growth differences will affect the development of the industry. There are three types of body size in male GFP, namely, large, medium and small, which lead to differences in their phenotypes. Since the gut is responsible for nutrient digestion and the hemolymph is responsible for immunity, we believe that there is a close relationship between the gut, hemolymph, and phenotype. Therefore, we used different research methods to understand the causes of their body size differences. This study can provide a certain reference value for the GFP aquaculture industry and help to improve the development of GFP aquaculture industry. The giant freshwater prawn (GFP; Macrobrachium rosenbergii), a tropical species cultured worldwide, has high market demand and economic value. Male GFP growth varies considerably; however, the mechanisms underlying these growth differences remain unclear. In this study, we collected gut and hemolymphatic samples of large (ML), medium (MM), and small (MS) male GFPs and used the 16S rRNA sequencing and liquid chromatography–mass spectrometry-based metabolomic methods to explore gut microbiota and metabolites associated with GFP growth. The dominant bacteria were Firmicutes and Proteobacteria; higher growth rates correlated with a higher Firmicutes/Bacteroides ratio. Serum metabolite levels significantly differed between the ML and MS groups. We also combined transcriptomics with integrative multiomic techniques to further elucidate systematic molecular mechanisms in the GFPs. The results revealed that Faecalibacterium and Roseburia may improve gut health in GFP through butyrate release, affecting physiological homeostasis and leading to metabolic variations related to GFP growth differences. Notably, our results provide novel, fundamental insights into the molecular networks connecting various genes, metabolites, microbes, and phenotypes in GFPs, facilitating the elucidation of differential growth mechanisms in GFPs. [ABSTRACT FROM AUTHOR]

Simple Summary: Lampreys are a group of about 40 species found all over the world. One representative of this group is the river lamprey, which spends its larvae life initially in fresh water and then in the sea. For spawning, which is the end of their last migration, they return to fresh water. The spawning migration period lasts many months, during which the lampreys do not eat and many changes occur in their bodies. However, knowledge of these processes and their dynamics has not been studied and described, and this is the basis for preparing programs for the restitution of lampreys and their artificial reproduction under controlled conditions. This paper describes the changes occurring during spawning migration in female river lampreys, including the development of ovaries, changes in the liver, and atrophy of the digestive system. More than 40 species of lampreys (Petromyzontiformes) are known worldwide. Some of them are parasitic and feed on the blood of fish or other aquatic animals. Lampreys spawn once in their lifetime, after which they die. One of the representatives of the ichthyofauna of European rivers is the river lamprey, Lampetra fluviatilis. The river lamprey is now an endangered species due to loss and degradation of their habitats. The present study investigated gonadal development without hormonal stimulation in female river lampreys during puberty under controlled conditions for a period of seven months. Female river lampreys were kept in conditions that mimicked the natural environment. During the November–May period, samples were taken monthly to determine the extent of gonadal development and gastrointestinal and liver changes using histological examination. From the results obtained, the dynamical changes were determined for the following: gonadosomatic index (GSI; %), hepatosomatic index (his; %), and digestivesomatic index (DSI; %). With the gonadal development of female lampreys, an increase in GSI (7–23%; November–May) and a decrease in DSI (0.4–0.1%; November–May) histological changes were observed in the gonads (oocyte development), intestines (over time, decreased lipid vacuoles and enterocyte apoptosis), and in the liver (decreased lipid vacuoles and hepatocyte apoptosis over time) and in the digestive system resulting from its degradation. Also, it was observed that there was a change in the color of the liver to green in April. This study demonstrated the key role of the liver in the oocyte maturation process in this species. [ABSTRACT FROM AUTHOR]

Variation in environmental chemistry affects animal health and demographics. For instance, acidification of aquatic ecosystems (e.g., due to acid rain) can have consequences for organismal fitness. Elevated atmospheric concentrations of CO2, which reacts with water to produce carbonic acid, may affect aquatic animal physiology in multiple ways, including via reductions in pH. Such impacts have been assessed to a large extent in marine systems. Similar effects are also likely occurring in freshwater ecosystems but are relatively understudied. The goal of this project was to determine how changes in pH and CO2 concentrations influence traits and survival of animals in freshwater systems, using larval American Bullfrogs (Lithobates catesbeianus (also known as Rana catesbeiana) [Shaw, 1802]) as a model. We hypothesized that elevated CO2 concentrations and reduced pH negatively affect larval frog immune function, growth, and survival, which we tested in a laboratory aquarium experiment. Over the 27-d experiment, tadpoles were exposed to 4 treatments: 1) near-neutral pH and no gas addition (mean ± SE pH = 7.17 ± 0.05), 2) CO2 gas sparged into aquariums (pH = 5.32 ± 0.04), 3) acidified water without gas addition (pH = 6.29 ± 0.08), and 4) ambient air sparged into aquariums (control for effects of gas addition) at near-neutral pH (pH = 7.46 ± 0.03). We measured tadpole innate immune response, growth, and survival. Results from the experiment partially supported our hypothesis, with lower immune function in tadpoles exposed to acidified water or elevated CO2 compared with the control treatments and lower final mass and survival under elevated CO2. These findings motivate additional research on pH and CO2 effects on freshwater animals and suggest that increased environmental acidity and elevated CO2 can lead to negative impacts, which could contribute to reductions in wildlife health and population declines in light of ongoing environmental changes. [ABSTRACT FROM AUTHOR]

The Rab family of proteins is involved in organelle regulation, trafficking, signal transduction, mitosis, phagocytosis, growth differentiation, cytoskeleton protein depolymerization and other cellular functions and abnormal expression has been associated with many pathologies, including cancer. Previous work has focused on Rab function in higher animals but fish, crustaceans and other aquatic animals also express the Rab proteins. The current review summarizes research progress on Rab proteins, focusing on immune defense against pathogens in aquatic animals. Some differences in Rab protein function between aquatic and higher animals were found and greater involvement in the fish and crustacean immune system than that of higher animals. Novel insights into Rab protein in aquatic animals are offered with implications for the development of aquaculture strategies. [ABSTRACT FROM AUTHOR]

Copyright of Aquatic Conservation is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Titanium dioxide nanoparticles (TiO2) are released into the natural waters in different ways and cause toxicity to aquatic life. Although various studies have reported the toxicity of nanoparticles for aquatic animals, there is limited information regarding the effects of environmental factors, especially salinity, on their toxicity. Simultaneous effects of TiNPs and water salinity were studied in the Pacific oyster, Crassostrea gigas. Oysters were exposed to sub-lethal concentrations of TiNPs (low concentration: 50 µg/l, middle concentration: 500 µg/l, high concentration: 5000 µg/l) at different water salinities (Extremely low salinity: 5 g/l, low salinity: 15 g/l, middle salinity: 25 g/l, high salinity (normal salinity): 35 g/l) for 96 h. After nano-TiO2 exposure, the immune components in hemolymph (total hemocyte concentration [THC], phagocytosis), antioxidant enzyme activities in digestive gland (superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase), oxidation stress index (malondialdehyde) in gills and the expression of immune-related genes (Vav-3 protein, cofilin, Galectin 4, pro-Cathepsin L, Rho protein, Ficolin, LPS/-1,3-glucan protein, Lysozyme, Defensin) in hemocytes were measured. The THC, phagocytosis, antioxidant enzyme activities, and immune-related gene expressions mostly decreased at salinities of 5 and 15 g/l in response to 500–5000 µg/l nano-TiO2 compared to non-exposed oysters and 50 µg/l nano-TiO2 group. An increase in water salinity up to 35 g/l mitigated the depressing effects of the nano-TiO2 on the immune and antioxidant components of the oysters. Exposure of oysters to 500–5000 µg/l nano-TiO2-induced oxidative stress at salinities of 5 and 15, since malondialdehyde levels were higher in these treatments compared to control and those in 50 µg/l nano-TiO2 group. The increase of salinity up to 35 g/l ameliorated the TiO2-induced oxidative stress. The results of the present study showed that the toxic impacts of nano-TiO2 can be ameliorated in the Pacific oyster with increase in water salinity, as the immune components, antioxidant enzyme activities recovered and oxidative stress mitigated when the salinity increased up to 35 g/l. [ABSTRACT FROM AUTHOR]

With the development of China's economic level and improving people's living standards, the state's supervision of food health and safety has increased. Consumer demand for many people has gradually changed from being satiated to eating well, and high-quality, environmentally friendly, and healthy aquatic products have become increasingly popular with consumers. However, intensive and high-density aquaculture causes the deterioration of water environmental conditions, the increase of anti-nutrient factors and nutritional imbalance caused by the replacement of animal protein with plant protein in feed, and changes in the growth, immunity, and digestive ability of aquatic animals caused by changes in feed nutrients, traditional processing methods, and transportation stress. The above situations encountered in aquaculture have a common impact on aquatic animals and inevitably cause a reduction in the muscle quality of aquatic animals. Therefore, improving the muscle quality of aquatic animals and the quality of aquatic products is an urgent problem with significant research value and potential.To improve aquatic quality, first, it is necessary to first identify the indicators of muscle quality in aquatic animals to improve aquatic quality. However, there is still a lack of a systematic muscle quality evaluation index system in the current aquaculture research. Therefore, this study reviewed the evaluation indices of muscle quality, including meat content, muscle nutrient composition, muscle fiber structure, muscle texture characteristics, and muscle physicochemical indices, to provide a reference for establishing scientific muscle quality evaluation indices. In addition, factors affecting muscle quality must be considered in studies aimed at improving the muscle quality of aquatic animals. Only by understanding the factors affecting muscle quality in aquatic animals can the key factors regulating muscle quality and their mechanisms be studied more comprehensively and scientifically. This study reviewed the factors affecting the muscle quality of aquatic animals, including feed nutrients, feed additives, and the culturing environment, and found that nutrients are key factors in improving the muscle quality of aquatic animals.Protein is an important nutrient, the main component of muscle, and an important indicator of muscle quality. Amino acids are the basic units of proteins and have a vital impact on muscle quality and flavor. Therefore, it is important to study the effects and mechanisms of action of amino acids on muscle quality in aquatic animals. Therefore, the effects of dietary amino acids on the muscle quality of aquatic animals were reviewed in this study, including the effects of amino acids on muscle nutrients, flavor, texture indices, and physical and chemical properties of aquatic animals. Furthermore, the effects of amino acids on muscle quality, including the promotion of protein synthesis, regulation of fat deposition, enhancement of antioxidant activity, and maintenance of intestinal health, were reviewed.In summary, this study summarized the influence of amino acids on the muscle quality of aquatic animals and its mechanism from the aspects of muscle quality evaluation indices, factors affecting meat quality, and the influence of amino acids on muscle quality, providing a reference for further research on the regulation of muscle quality by amino acids and the improvement of feed nutrients on the meat quality of aquatic animals.

The ability to impact the immune response of the host has been recognized as essential for the success of a virus during infection. A few groups of viruses can combine these immunomodulatory mechanisms with specific patterns of their own transcriptional and replication regulation to achieve persistence within the host long term. The Herpesvirales order is one of those groups and the resultant state is known as latency. Throughout the years, latency has been studied in many host‐herpesvirus models to attempt to understand the complex and profound effects of this state on the host's systems, and in the hopes of deciphering a way to eliminate the latent state from survivors of the primary infection. Most studies of herpesvirus latency have been conducted on mammalian host species, but this review summarizes the data available regarding herpesviruses in fish species and their latent state. As the field of aquatic animal health research continues to advance, the elucidation of these complex mechanisms will be crucial for disease control, prevention, and treatment. [ABSTRACT FROM AUTHOR]

Taurine (2-aminoethanesulfonic acid) is a sulfur-containing non-protein amino acid that is widely present in the body in a free state. Taurine is a nutritional additive that maintains the normal physiological functions of fish and plays an important role in the growth and development, metabolism, osmoregulation, digestive physiology, immune enhancement, and antioxidant properties of aquatic animals. The addition of taurine can improve the negative effects of low-fishmeal feed on the production performance, health, and quality of aquatic products. The article introduces the characteristics of taurine and its synthesis and metabolic pathways, reviews the recommended dosage of taurine in lowfishmeal feed, and summarizes the impact of taurine addition in low-fishmeal feed on the growth and health of aquatic animals, providing a reference for the rational use of taurine in low-fishmeal feed for aquatic animals. [ABSTRACT FROM AUTHOR]

Seals, sea lions, and other aquatic animals rely on their whiskers to identify and track underwater targets, offering valuable inspiration for the development of low-power, portable, and environmentally friendly sensors. Here, we design a single seal-whisker-like cylinder and conduct experiments to measure the forces acting on it with nine different upstream targets. Using sample sets constructed from these force signals, a convolutional neural network (CNN) is trained and tested. The results demonstrate that combining the seal-whisker-style sensor with a CNN enables the identification of objects in the water in most cases, although there may be some confusion for certain targets. Increasing the length of the signal samples can enhance the results but may not eliminate these confusions. Our study reveals that high frequencies (greater than 5 Hz) are irrelevant in our model. Lift signals present more distinct and distinguishable features than drag signals, serving as the primary basis for the model to differentiate between various targets. Fourier analysis indicates that the model's efficacy in recognizing different targets relies heavily on the discrepancies in the spectral features of the lift signals. [ABSTRACT FROM AUTHOR]

Sulfonamides are not only widely applied in clinics but also highly valued in animal husbandry. Recently, it has become common for sulfonamide residues to exceed the standard limits in food, which can affect human health. Current regulations limit these residues. Therefore, we constructed a new limit test method to rapidly determine the levels of sulfonamide residues. Six sulfonamides were detected using the latest method called TLC-SERS, namely, sulfamethasone (A), sulfamethazine (B), sulfadoxine (C), sulfamethoxydiazine (D), sulfamethoxazole (E), and sulfathiazole (F). The optimal conditions for SERS detection were investigated for these six drugs, and the separation effects of different TLC spreaders on them were compared. Then, we successfully established a separation system using dichloromethane–methanol–ammonia in a ratio of 5:1:0.25 (v/v/v), which provided good separation effects on the six drugs. The residues were preliminarily separated via TLC. A silver sol solution was added to the spot on the silica gel G plate at the corresponding specific shift values, and SERS detection was performed. The sample solution was placed on the spot under a 532 nm laser, and the SERS spectrum was collected and analyzed for the six sulfonamides. The results showed obvious variations in the SERS spectrum among the six sulfonamides, with the LODs being 12.5, 6.4, 6.3, 7.1, 18.8, and 6.2 ng/mL from A to F, respectively, and an RSD of <3.0%. Within 48 h, the SERS signal for each sulfonamide drug was kept stable, with an RSD of <3.0%. The detection results of 20 samples using the TLC-SERS method were consistent with those obtained by UPLC-MS/MS. The established TLC-SERS method is simple and fast, providing a useful reference for the rapid detection of residue limits in food. [ABSTRACT FROM AUTHOR]

Simple Summary: While the gut microbiota and gut–brain sNPF are known to play crucial roles in diet restriction, research on their response to feed deprivation and starvation stress remains limited. This work investigated the alterations in the gut microbiota of juvenile mud crabs under feed deprivation and starvation conditions and identified the location of sNPF in the brain and gut. This suggests a potential interplay between diet restriction, gut microbiota, and gut–brain sNPF. The increased expression levels of sNPF across various levels of feed deprivation further support this notion. This study suggests that sNPF may regulate digestive activities and immunity through interactions with the gut microbiota. These findings provide novel insights into the dynamic interplay between the gut microbiota and sNPF in response to diet restriction, emphasizing their crucial roles in physiological adaptation to starvation stress. Aquatic animals frequently undergo feed deprivation and starvation stress. It is well-known that the gut microbiota and the gut–brain short neuropeptide F (sNPF) play essential roles in diet restriction. Therefore, investigating the responses of the gut microbiota and sNPF can enhance our understanding of physiological adaptations to feed deprivation and starvation stress. In this study, we examined the alterations in the gut microbiota of juvenile mud crabs under feed deprivation and starvation conditions. The results reveal differences in the richness and diversity of gut microbiota among the satisfied, half food, and starvation groups. Moreover, the microbial composition was affected by starvation stress, and more than 30 bacterial taxa exhibited significantly different abundances among the three feeding conditions. These results indicate that the diversity and composition of the gut microbiota are influenced by diet restriction, potentially involving interactions with the gut–brain sNPF. Subsequently, we detected the location of sNPF in the brains and guts of mud crabs through immunofluorescence and investigated the expression profile of sNPF under different feeding conditions. The results suggest that sNPF is located in both the brains and guts of mud crabs and shows increased expression levels among different degrees of diet restriction during a 96 h period. This study suggested a potential role for sNPF in regulating digestive activities and immunity through interactions with the gut microbiota. In conclusion, these findings significantly contribute to our understanding of the dynamic changes in gut microbiota and sNPF, highlighting their interplay in response to diet restriction. [ABSTRACT FROM AUTHOR]

Simple Summary: In commercial aquaculture, aquatic animals are generally administered medicine ad libitum (at one's pleasure) via medicated feed. However, the estimation of withdrawal times for aquatic medicine is mostly carried out through the forced administration of medicine via oral gavage, which is not consistent with commercial aquaculture. This process may influence the absorption, distribution, metabolism, and excretion of medicine in aquatic animals and further affect the calculation of withdrawal times (WTs) for medicines. Therefore, in the current study, we selected the important aquatic medicine enrofloxacin (EF) to estimate its WTs in largemouth bass (Micropterus salmoides) after the administration of medicated feed. This study will obtain practical estimations of the WT of EF in actual aquaculture to aid in the surveillance of medication residue in fish products. The present study investigated the residue depletion and WTs of EF and its main metabolite, ciprofloxacin, in largemouth bass after ad libitum administration in commercial fish farming based on statistical approaches. Samples collected at pre-determined time points were assessed using high-performance liquid chromatography. If the concentrations of medicine were less than the quantitative limit, they were set to be half of the limit of quantitative. The terminal elimination of the target compound was assumed to fit a one-compartment model. The statistical methods of Bartlett's test and Cochran's test were used to inspect the homogeneity of the log-transformed data. The lack-of-fit test and F-test were used to check the linearity of the regression line. Outliers were assessed using standardized residuals. The final WT was estimated using the 95% percentile with a 95% confidence level. The WTs of EF were calculated to be 46, 29, 33, 46, and 20 days for the muscle + skin, plasma, gill, kidney, and liver, respectively. After the risk assessment, the values of the hazard quotient were calculated to be far less than 1, indicating that the risk of residual EF was particularly low in the edible tissues of largemouth bass after medicine depletion for various WTs. [ABSTRACT FROM AUTHOR]

Understanding the critical thresholds of dissolved oxygen (O2) that trigger adaptive physiological responses in aquatic organisms is long hampered by a lack of robust, non-lethal or non-invasive methodologies. The isotope fractionation of triple O2 isotopes (18O/17O/16O) during respiration is linked to the amount of oxygen utilised, offering a potential avenue for new insights. Our experimental research involved measuring the oxygen isotope fractionation of dissolved O2 in closed-system aquatic respirometry experiments with wild sticklebacks (Gasterosteus aculeatus). These fish were either naturally adapted or experimentally acclimated to hypoxic and normoxic conditions. The aim was to observe their oxygen usage and isotope fractionation in response to increasingly severe hypoxia. Initial observations revealed a progressive 18O enrichment from the preferential uptake of 16O to a dissolved oxygen threshold of 3–5 mg O2 L–1, followed by an apparent reversal in oxygen isotope fractionation, which is mixing of 16O and 17O with the remaining O2 pool across all populations and indicative of a systematic change in oxygen metabolism among the fish. Unexpectedly, sticklebacks adapted to hypoxia but acclimated to normoxia exhibited stronger oxygen isotope fractionation compared to those adapted to normoxia and acclimated to hypoxia, contradicting the hypothesis that hypoxia adaptation would lead to reduced isotope discrimination due to more efficient oxygen uptake. These preliminary experimental results highlight the novel potential of using dissolved O2 isotopes as a non-invasive, non-lethal method to quantitatively assess metabolic thresholds in aquatic organisms. This approach could significantly improve our understanding of the critical oxygen responses and adaptation mechanisms in fish and other aquatic organisms across different oxygen environments, marking a significant step forward in aquatic ecological and physiological research. [ABSTRACT FROM AUTHOR]

A critical component of animal conservation in a changing world is an understanding of the physiological resilience of animals to different conditions. In many aquatic animals, hypoxia (low environmental oxygen levels) is a regular occurrence, but the likelihood and severity of hypoxia vary across habitats. Fast-flowing, stream-like habitats are never hypoxic, so long as flow is maintained. Do animals from such habitats retain the capacity to survive hypoxic conditions? We use aquatic frog tadpoles to test the effects of natural habitat on performance in hypoxia in an experimental framework, finding that stream-living tadpoles have reduced performance in hypoxia. Tadpoles also vary in lung presence, with some species able to breathe air during hypoxia. We found that among lunged tadpoles, air-breathing rates increase in hypoxia in pond-living species but not stream-living species. Lung presence was also found to influence hypoxia performance, as lungless, stream-living tadpoles were found to be especially vulnerable to hypoxia, while pond-living, lungless tadpoles appeared largely resilient to hypoxia. We consider the ramifications of our findings on conservation outlooks and strategies for frogs and their tadpoles, suggesting that stream-living tadpoles, and especially lungless, stream-living tadpoles, may be particularly at risk to factors that reduce stream flow. Thus, a primary goal for conservation and management of species with stream-living tadpoles should be the maintenance of year-round streamflow, which oxygenates waters and prevents hypoxia. [ABSTRACT FROM AUTHOR]

Vibrio harveyi is a normal flora present in seawater, but in recent years, with large density aquaculture, V. harveyi has become one of the causative organisms in fish and shrimp. In this study, V. harveyiVieA gene was used as the target to design primers and establish the loop-mediated isothermal amplification (LAMP) combined with visual lateral flow test strip (LFD). The optimal reaction conditions were optimized as 60°C, 45 min, 1.2 mM Mg2+, 0.64 mM dNTPs, 0.25 mM betaine, and 16:1 ratio of internal/external primers. The results showed that the established LAMP assay was able to specifically detect V. harveyi with a sensitivity of 3.4 × 10–5 ng/µL. Clinical applicability analysis revealed that only V. harveyi was detected in the samples for pearl gentian grouper and whiteleg shrimp artificially infected by Vibrio. Therefore, we established a visual, reliable, rapid and sensitive LAMP-LFD method for detecting V. harveyi in aquatic animals. [ABSTRACT FROM AUTHOR]

In order to gain better understanding of the Neanderthals' subsistence exploitation of marine crustaceans, this work presents evidence on the consumption of brown crabs using experimentation following-up from the archaeological evidence recovered from the 2010-2013 excavation of Gruta da Figueira Brava (Portugal). Amongst the aquatic fauna from occupation phase FB4, which dates to MIS-5b, brown crabs (Cancer pagurus) are numerous. The average carapace width estimated from their remains is 16 cm, and skeletal part analysis reveals the introduction of complete animals and their on-site processing. Due to the lack of a referential corpus for the interpretation of archaeological crab taphonomy, we experimented with the processing of two raw, two boiled, and two roasted brown crabs. We found that manual processing of large adult Cancer pagurus is only possible for the disarticulation of the walking legs, and the separation of the claws. Experimental results indicate that archaeological crabs were roasted, which weakened the shell and facilitated breaking it open. Though it is also possible to manually disarticulate the fingers, most times it requires a small hammerstone. Impact scars and longitudinal fractures bear witness to the use of such tools to access the meatier parts of both the propodus and the dactylopodus. [ABSTRACT FROM AUTHOR]

Global ornamental fish transportation ranging from hours to days can produce multiple stress factors impact fish health and cause mortality. Clownfish, particularly Amphiprion ocellaris, are among the most traded saltwater ornamental fish. Vibrio includes several pathogenic strains that affect aquatic animals. Consequently, prophylactic treatment of the water or fish is recommended. In this study, six Vibrio strains including V. alginolyticus, V. parahaemolyticus and V. harveyi isolated from sick A. ocellaris and one V. harveyi strain from a sick East Asian fourfinger threadfin (Eleutheronema rhadinum) were tested for their sensitivity to a popular disinfectant, chlorine dioxide (ClO2). The results showed that 0.25 ppm ClO2 effectively suppressed five of the seven tested Vibrio strains for 24 h; however, 0.1 ppm ClO2 is safer for A. ocellaris. Meanwhile, ClO2 2.5 ppm reduced the bacterial counts to below 3.3 × 105 CFU/mL for 24 hours. The LC50 of ClO2 for A. ocellaris was 0.87 ppm at 10 min and 0.72 ppm at 24 h post treatment. Mild changes in water quality, including dissolved oxygen (DO), temperature and pH, were recorded during the trial. More research is necessary to understand the sensitivity of various aquatic animal pathogens to ClO2 and its toxicity to different aquatic animals. [ABSTRACT FROM AUTHOR]

Copyright of South China Fisheries Science is the property of South China Fisheries Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In Brazil, glyphosate is present in more than 130 commercial formulations, and its toxic effects have already been tested in different species to understand its impact on biota Decapod crustaceans are widely used as experimental models due to their biology, sensitivity to pollutants, ease of collection, and maintenance under laboratory conditions. We evaluated the changes in metabolism (hemolymph) and oxidative balance markers (gill and hepatopancreas) of a crayfish (Parastacus promatensis) after exposure to Roundup® (active ingredient: glyphosate). The crayfish were captured in the Garapiá stream within the Center for Research and Conservation of Nature Pró-Mata, Brazil. We collected adult animals outside (fall) and during (spring) the breeding season. The animals were transported in buckets with cooled and aerated water from the collection site to the aquatic animal maintenance room at the university. After acclimatization, the animals were exposed to different concentrations of glyphosate (0, 65, 260, 520, and 780 µg/L). The results showed a significant variation in the hemolymph glucose, lactate, and protein levels. We observed variations in the tissue antioxidant enzymatic activity after exposure to glyphosate. Finally, the increase in oxidative damage required a high energy demand from the animals to maintain their fitness, which makes them more vulnerable to stress factors added to the habitat. [ABSTRACT FROM AUTHOR]

The threat posed by microplastics has become one of the world's most serious problems. Recent reports indicate that the presence of microplastics has been documented not only in coastal areas and beaches, but also in water reservoirs, from which they enter the bodies of aquatic animals and humans. Microplastics can also bioaccumulate contaminants that lead to serious damage to aquatic ecosystems. The lack of comprehensive data makes it challenging to ascertain the potential consequences of acute and chronic exposure, particularly for future generations. It is crucial to acknowledge that there is still a substantial need for rapid and effective techniques to identify microplastic particles for precise evaluation. Additionally, implementing legal regulations, limiting plastic production, and developing biodegradation methods are promising solutions, the implementation of which could limit the spread of toxic microplastics. [ABSTRACT FROM AUTHOR]

Outbreaks of bacterial diseases occur in farmed Chinese longsnout catfish (Leiocassis longirostris). Due to limited information on aquatic Klebsiella variicola-infected animals, this study aimed to identify strain LL2208 isolated from diseased L. longirostris, determine its biological features, and evaluate its risk to public health. Strain LL2208 was tested for molecular identification, challenge, string, biofilm formation, and antimicrobial susceptibility. Furthermore, the whole genome of the strain was sequenced and analyzed. Based on molecular identification, strain LL2208 was identified as K. variicola. Artificial infection showed that this strain was moderately virulent to L. longirostris with an LD50 = 7.92 × 107 CFU/mL. Antibiotic sensitivity tests showed that this strain was resistant to penicillins, macrolides, aminoglycosides, amphenicols, glycopeptides, and lincosamide, indicating multidrug resistance. Strain LL2208 has a genome size of 5,557,050 bp, with a GC content of 57.38%, harboring 30 antimicrobial resistance genes and numerous virulence-related genes. Its molecular type was ST595-KL16-O5. Collinearity analysis showed that strain LL2208 was highly similar to the human-derived K. variicola strain. In conclusion, the multidrug-resistant and virulent K. variicola strain LL2208 was isolated from fish and may have originated from humans. These results provide a foundation for further studies on the transmission of K. variicola between humans and aquatic animals. [ABSTRACT FROM AUTHOR]