Fish Muscle Research Articles

The inhibitory effect of Maillard reaction products on fish and chicken muscle oxidation

The inhibitory effect of Maillard reaction products on fish and chicken muscle oxidation

Hyperspectral imaging and deep learning for parasite detection in white fish under industrial conditions

Parasites in fish muscle present a significant problem for the seafood industry in terms of both quality and health and safety, but the low contrast between parasites and fish tissue makes them exceedingly difficult to detect. The traditional method to identify nematodes requires removing fillets from the production line for manual inspection on candling tables. This technique is slow, labor intensive and typically only finds about half the parasites present. The seafood industry has struggled for decades to develop a method that can improve the detection rate while being performed in a rapid, non-invasive manner. In this study, a newly developed solution uses deep neural networks to simultaneously analyze the spatial and spectral information of hyperspectral imaging data. The resulting technology can be directly integrated into existing industrial processing lines to rapidly identify nematodes at detection rates (73%) better than conventional manual inspection (50%).

Comparative Study of the Nutritive and Elemental Composition of Smoked and Raw Clarias gariepinus from Three Selected Fish Farms in Ado Ekiti, Ekiti State, Nigeria

Clarias gariepinus is of economic importance in aquaculture due to its rapid growth, omnivorous diet, and potential as food source. It has been widely cultured and dispensed both in raw and smoked forms in various regions to meet the demand for fish protein This study assessed and compared the nutritional quality and elemental composition of smoked and raw samples of Clarias gariepinus. A total of twelve fish samples were analysed, six raw samples and six smoked samples with two fishes sampled from each farm tagged A, B and C. The Proximate and elemental analysis were done using standard procedures. The result of the study showed that moisture content measured in the raw Clarias gariepinus which ranged between (73.074 ± 1.59) % and (71.52 ± 1.83) %. was higher than that of the smoked fish ranging from (26.69±0.03) % to (32.21± 0.02) %. The protein content of smoked fish ranged (43.2±0.02) % to (46.78±0.01) while that of raw fish was between (20.52 ± 1.12) % and (22.15 ± 0.43) %. Similarly, the crude fat, ash, carbohydrate, and fibre content were higher in the smoked fish than raw catfish samples. The elemental composition of both smoked and raw catfish were within the permissible limit of World Health Organization. Arsenic was not detected in the muscle of the raw fish, while cadmium, chromium, lead and magnesium were present in values within WHO permissible limit and similar results was observed for the smoked fish samples. The result of this study presents the possibility of smoked catfish being more nutritious than the raw samples aside from the fact that it has more shelf life than raw fish. Also, both smoked and raw samples of the fish are safe as the values of heavy metal observed were all within the permissible limit of WHO.

Carangiform‐Like Magnetic Milliswimmer With Negative Buoyancy for Agile 3D Navigation in Confined Fluid Environments

AbstractMiniature soft robots designed with magnetoelastic materials have the potential for noninvasive navigation in narrow spaces and innovative clinical therapies. However, the complex environment inside the body imposes stringent requirements on the motility and environmental adaptability of robots. Inspired by carangiform fish morphology and kinematics, a 3D free‐swimming magnetic milliswimmer with enhanced controllability, maneuverability, and environmental adaptability is developed. This milliswimmer is negatively buoyant like most fishes and employs magnetic torque to actuate its body. It mimics fish muscle contractions and generates a carangiform‐like body curvature distribution that results in comparable swimming behavior and performance. Compared with previous designs, it achieves over six times the equivalent motion performance and enables gravity‐resisting free‐swimming, with fish‐like maneuverability (a minimum turning radius of just 0.05 body length and a maximum turning rate of up to 4737 deg s−1). Its ability to transport and release cargo precisely while navigating three‐dimensionally in an ex vivo porcine urinary system is demonstrated. The designed bionic magnetic soft robot is expected to advance biomedical applications of magnetoelastic materials, particularly in urinary and other clinical treatments.

Bioaccumulation and tissue distribution of pharmaceuticals and their transformation products in fish along the pollution gradients of a wastewater-impacted river

A field study on the occurrence and distribution of forty-three pharmaceutically active compounds (PhACs) in water and fish samples from anthropogenically impacted section of the Sava River (Croatia) was performed to estimate the importance of bioaccumulation for the environmental risk assessment of PhACs. The study was performed using a highly specific LC-MS/MS method, tailored to include the most prominent PhACs from different therapeutic categories as well as their major metabolites and/or transformation products (TPs). The results revealed a widespread occurrence of PhAC residues both in water and fish samples with a large spatial variability reflecting the distance from the dominant wastewater discharges. The most prominent PhAC categories in less polluted upstream part of the river were common psychostimulants caffeine and cotinine, therapeutic opioids and cardiovascular drugs, while in the river section affected by the local municipal and industrial wastewater inputs, antibiotic drugs became clearly predominant, especially in fish tissue samples. The apparent bioconcentration factors (BCFs) of investigated PhACs varied over several orders of magnitude, from 0.02 ± 0.01 Lkg−1 for O-desmethyl tramadol in fish muscle to 784 ± 260 Lkg−1 for terbinafine in fish liver, indicating rather large differences in their bioconcentration potential and affinity to different tissues, with the tissue-specific BCFs increasing in the following order: muscle < gills < gonads < heart < liver < kidneys. The bioconcentration potential of most of the PhACs included in this study was only low to moderate however moderately high BCFs of certain PhACs (e.g. sertraline, terbinafine, loratadine, diazepam and azithromycin) in some tissues should be taken into consideration when assessing their potential environmental risks. Moreover, it was shown that BCFs could be strongly affected by biotransformation in fish. Risk prioritization based on risk quotient (RQ) and ToxPi index, revealed antibiotics, in particular azithromycin, and therapeutic psychoactive substances as the most hazardous pharmaceutical contaminants in the Sava River.

Influence of water chemistry and contaminant occurrence on the oxidative stress ecology of Cottus gobio in a high-mountain lake (Carnic Alps)

Understanding oxidative stress in high-mountain lake fish offers crucial insights into their health, resilience, and adaptation to extreme environmental changes. This study investigates the oxidative stress response of Cottus gobio in a high-mountain lake (Dimon Lake) located in the northeast Italy during the ice-free season, focusing on the relationship between oxidative stress biomarkers and physicochemical water parameters, as well as persistent and emerging contaminants. Significant seasonal variations were observed in water parameters, with lower oxygen, pH, conductivity, and phosphate levels in summer compared to autumn, while temperature, ammonium, and nitrate were higher in summer. Metal concentrations in C. gobio muscle were higher in autumn, with Zn showing the most significant increase. PAHs, NDL-PCBs, and pesticides were all below the limit of quantification in the fish muscle samples. No microplastics items were found in the gastrointestinal tracts of fish. Oxidative stress biomarkers revealed organ-specific and seasonal variations. The liver exhibited the highest activities of catalase (CAT), glutathione peroxidase (GPx), glutathione S-tranferase (GST), and glutathione reductase (GR), highlighting its central role in detoxification and metabolic processes. Superoxide dismutase (SOD) activity was notably higher in muscle tissue during summer, suggesting increased metabolic activity. A strong correlation was found between pH and the activities of SOD, CAT, GPx, GR, and metallothioneins (MTs), emphasizing the importance of water chemistry in influencing oxidative stress responses. This approach not only aids in understanding the local adaptations of these fish but also highlights the impacts of environmental stressors on high-mountain ecosystems. Continuous monitoring of water chemistry, particularly pH, is crucial for understanding and managing oxidative stress in aquatic organisms, especially in the context of global environmental changes.

Basal Expression Profile of Seven Glutathione-S-Transferases (GSTs) Genes in Six Tissues of Tilapia (Oreochromis niloticus) for Polymerase Chain Reaction Array

Study’s Excerpt The differential expression patterns of Glutathione-S-transferase (GST) isoforms in six tissues of Nile tilapia are investigated. Seven specific GST genes are examined across six tissues, and it is determined that the liver, spleen, and intestines are key sites of significant gene expression. GST isoforms could be potentially used as biomarkers for assessing xenobiotic stress in aquatic environments. Full Abstract Because aquatic habitats are being destroyed and biodiversity is declining, xenobiotic pollution of water is a critical environmental problem that has garnered a lot of attention in the past few decades. This study looked at the expression patterns of Glutathione-S-transferases isoforms (GSTMA, GSTO1LA, GSTA, GSTR1, GSTK, GSTT1, and MGST), which are genes involved in xenobiotic metabolism, in Nile tilapia. From adult Nile tilapia, six tissues—liver, spleen, intestines, gills, heart, and muscle—were chosen, and seven genes that were optimised via quantitative polymerase chain reaction (qPCR) were used for validation. Gene expressions were assessed using a PCR array that included duplicate tissues in 96-well qPCR plates, with each gene/plate being assayed six times. Water is used in the remaining wells as no template control (NTC). As reference genes, Pan Ribosomal Protein L3 (RPL3) and Pan 18S ribosomal RNA (18S RNA) were employed. The genes’ basal tissue mRNA expression was measured in each tissue. The muscle was utilised to renormalise the expression levels of all genes throughout the remaining tissues since, under assay’s circumstances the muscle showed very low signal for most of the genes. Using quantitative real-time PCR (qPCR), the result demonstrated widespread differential expression patterns of the seven GST mRNA in the liver, spleen, intestine, gills, heart, and muscle of an untreated fish. However, it was clear that the highest significant expression level of most genes (different GST’s isoforms) was in the liver, followed by the spleen and gut, then the heart and gills compared to muscle (P&lt;0.05). The findings demonstrated widespread differential expression of the GST’s isoforms at basal level and highlighted their utility as biomarkers for xenobiotic stress in aquatic environments.

In-vitro and in-vivo assessment of the bactericidal potential of peracetic acid and hydrogen peroxide disinfectants against A. hydrophila infection in Nile tilapia and their effect on water quality indices and fish stress biomarkers

This study aimed to assess the in vitro and in vivo disinfectant potential of peracetic acid (PAA) (1 mg/L) and hydrogen peroxide (H2O2) (20 mg/L) on the physicochemical and microbiological water quality parameters of fish aquaria, the microbial density of Nile tilapia muscular tissue, fish hepatic cortisol levels, and antioxidant biomarkers. In vitro, PAA and H2O2 reduced A. hydrophila colony viability by 5 log units after 30 and 5 min of contact time, respectively. PAA and H2O2 were added to aquaria water twice a week for the three-week experiment. Increased fish escape reflexes were observed only in the PAA group, which returned to normal within 10 min. No mortalities were reported in either the PAA or H2O2 groups. An in vivo experimental challenge with a pathogenic strain of A. hydrophila revealed a 20% reduction in mortality in the PAA group, with no mortalities in the H2O2 group. Cortisol levels and antioxidant markers were measured to assess the impact of PAA and H2O2 on fish health. Cortisol levels in the PAA and H2O2 groups were significantly higher than in the control group after disinfectant exposure, but they progressively returned to normal. A significant reduction in superoxide dismutase (SOD) and catalase (CAT) activity, along with considerably higher glutathione peroxidase (GPx) and malondialdehyde (MDA) enzymatic activity, was observed in the PAA and H2O2 groups compared to the control group. A substantial increase in total antioxidant capacity (TAC) was recorded in the PAA group. Physicochemical analyses revealed reduced pH and increased dissolved oxygen levels in the PAA and H2O2 groups. Microbiological analyses showed a significant reduction in bacterial density in water by 64% and 76% after 30 min of exposure to PAA and H2O2, respectively, with a non-significant increase in microbial count after bacterial challenge. Additionally, aerobic bacterial count, Aeromonas spp., and psychotropic bacterial count in fish muscle showed a significant reduction in the H2O2 group compared to the PAA and control groups before and after infection. The study concludes that regular application of PAA and H2O2 can temporarily reduce bacterial load in aquaria and fish muscle, regulate stress responses, and improve fish health by reducing A. hydrophila-induced infections and improving survival.

Microplastic and associated emerging contaminants in marine fish from the South China Sea: Exposure and human risks

Microplastics can act as vectors of chemical contaminants in aquatic environments, but the extent to which this phenomenon contributes to chemical exposure in marine organisms remains poorly understood. We investigated the occurrence of microplastics and emerging contaminants (ECs), including antibiotics and per- and polyfluoroalkyl substances (PFAS) in 14 marine fish species. Microplastics were detected in all marine fish species, mainly in the gastrointestinal tract. Fluoroquinolones and tetracyclines were the dominant antibiotics in fish muscles with maximum concentrations of 24.84 and 26.95 ng g−1 ww, while perfluorooctanesulfonic acid (PFOS, 0.039–0.95 ng g−1 ww) was the dominant component in the PFAS profile. Fish with more microplastics had significantly higher concentrations of fluoroquinolones and perfluoroalkyl acids than fish with less microplastics (p < 0.05), but the correlation was not observed in other chemicals. Structural equation modeling revealed the contribution of microplastics in fish on the level of ECs contamination. The health quotient value indicated the low health risk of single compounds via fish consumption to humans; however, the combined risk of microplastics and ECs still needs to be considered. This work highlights the link between microplastics with associated ECs ingested by aquatic organisms and the human health risk of consuming polluted seafood.

Tissue distribution, biomagnification, human health risk, and risk mitigation of perfluoroalkyl acids (PFAAs) in the aquatic food web of an urban fringe lake: Insights from urban-rural and seasonal scales

Perfluoroalkyl acids (PFAAs), renowned for their exceptional physical and chemical properties, are ubiquitous in urban and rural environments. Despite their widespread usage, more knowledge is needed concerning their accumulation and transfer mechanisms within the aquatic food webs of urban fringe lakes, especially across rural-urban and seasonal scales. This study investigated the tissue distribution, bioaccumulation, biomagnification, associated human health risks, and potential risk mitigation strategies of 15 PFAAs within the food web of Luoma Lake, a prototypical urban fringe lake. All targeted PFAAs were detected in samples, with ∑PFAA concentrations ranging from 116.97 to 564.26 ng/g dw in muscles and 26.96–1850.95 ng/g dw in viscera. Spatial variations revealed significantly higher ∑PFAA concentrations in the muscles from the urban subregion (∑PFAA: 359.66 ± 76.48 ng/g dw) compared to the rural subregion (∑PFAA: 328.86 ± 87.51 ng/g dw). Seasonal fluctuations impacted PFAA concentrations in fish and crustacean muscles but exhibited negligible effects on bivalve muscles. Spatial variations only influenced PFAA concentrations in specific viscera (gill, liver, kidney), while seasonal changes had minimal effects on viscera. The organisms demonstrated varying bioaccumulation capacities, with crustaceans displaying the highest bioaccumulation potential, followed by crustaceans and fish. Both spatial and seasonal variations modulated the bioaccumulation patterns of PFAA in muscles, whereas bioaccumulation in viscera was only influenced by seasonal factors. Notably, PFAA biomagnification along the food web was exclusively governed by spatial distribution, remaining unaffected by seasonal changes. The human health risk assessment underscored the potential adverse health impacts of PFOS and PFOA, particularly on young children (aged 2 to <6 years). This study further proposed comprehensive recommendations for mitigating PFAA-induced health risks, encompassing source control, selective consumption, pre-cooking treatments, and strategic cooking method selection. This research provides crucial insights into the ecological behaviors and health implications of PFAA in urban fringe lakes.

Assessment of heavy metal concentration in pelagic fish species and associated health risks along the Kanyakumari coast, India – a baseline study

ABSTRACT This research examines heavy metal concentration in fish from the Kanyakumari coast of India, emphasising its ecological consequences and possible health hazards for consumers. The study investigates the levels of several heavy metals such as zinc, manganese, iron, cadmium, copper, chromium, cobalt, lead, and nickel in different organs of multiple pelagic fish species obtained from the Kanyakumari fish landing site. Concentrations of heavy metals exhibit considerable variation among different fish organs and species, with distinct patterns identified for each metal. Muscle tissue often demonstrates reduced amounts of heavy metals in comparison to other organs. Except Zn and Fe, other heavy metals in fish muscle were above the acceptable limits set by health organisations. Cadmium was found to be 36-fold higher than the permissible limit, followed by nickel (30.4) and lead (7.6). Copper, nickel, and cadmium provide possible health hazards according to the Target Hazard Quotient (THQ). Lead and cadmium exhibit Excessive Lifetime Cancer Risk (ELCR) markedly above tolerable thresholds. Large predatory fish, such as Thunnus thynnus, exhibit elevated levels of contaminants such as cadmium. Environmental conditions, aquatic habitat, and dietary intake affect metal build-up in fish. The research employs multiple analytical methods and statistical methods, such as Atomic Absorption Spectrophotometry, correlation and Principal Component Analysis, to evaluate heavy metal concentrations and their interrelations. The study underscores the critical necessity for monitoring and mitigation techniques to combat heavy metal pollution in coastal waters and its possible effects on human health through fish intake.

Assessing Heavy Metal Contamination in Commonly Used Fertilizers for Polyculture Fish Ponds and Its Implications for Human Health: A Comprehensive Investigation.

Over-fertilizing fish ponds can cause pollution, introducing heavy metals into the food chain and posing health risks. The present study investigated the incidence of heavy metals (Pb, Cu, Cd, and Cr) in commonly applied fertilizers, including nitrogen, phosphorus and potassium (NPK), triple superphosphate (TSP), and di-ammonium phosphate (DAP), and their association with heavy metals in water, sediment, and cultured fish species (Catla catla, Labeo rohita, and Cyprinus carpio) in polyculture fish ponds. The study was conducted over 4months, with four groups in triplicates: control (no fertilizer), group 1 (NPK), group 2 (TSP), and group 3 (DAP). Heavy metal analysis was carried out using atomic absorption spectrophotometry before and after fertilizer application. Significantly (p < 0.05) higher levels of heavy metals were observed in water and sediment after applying fertilizers, with the most pronounced results in group 3 (DAP) followed by group 2 (TSP). The concentration of heavy metals was significantly (p < 0.05) higher in group 3 (DAP) fertilizers compared to other groups. Compared to the control, the concentration and bioaccumulation of heavy metals were significantly (p < 0.05) higher in the fertilizer-applied groups, with notably higher levels in group 3 (DAP). Cluster analysis and the correlation matrix did not show any significant association between the heavy metals and the fertilizers, indicating a complex interplay between the biotic and abiotic factors of the system. The health index (HI) value was < 1 in fish muscles of all studied groups, indicating the fish are safe for consumption. The study recommends monitoring and regulating fertilizer use, especially DAP, to prevent heavy metal contamination, and exploring sustainable alternatives to minimize environmental and health risks.

Detrimental effects of glyphosate on muscle metabolism in grass carp (Ctenopharyngodon idellus)

Glyphosate, a commonly used herbicide, has been associated with environmental pollution and potential health risks to aquatic organisms. This study investigated the effects of glyphosate on the muscle metabolism of grass carp (Ctenopharyngodon idellus) following exposure to environmentally relevant concentrations. Over a 14-day exposure period to varying glyphosate levels, significant disruptions were observed in antioxidant capacity and muscle health. These disruptions were evidenced by reductions in total antioxidant capacity (T-AOC), increases in malondialdehyde (MDA) levels, and decreases in activities of glutathione peroxidase (GSH-PX) and catalase (CAT). Furthermore, exposure to glyphosate resulted in a reduction of vitamin E content and an elevation of hormonal levels, suggesting the potential for endocrine disruption. Metabolomics analysis identified 605 distinct metabolites, with notable alterations in amino acid, carbohydrate, and nucleotide metabolism pathways. Specifically, arginine and glutathione metabolisms were severely impacted, with decreases in key amino acids such as glycine and glutathione at higher glyphosate concentrations. Nucleotide metabolism, particularly purine synthesis, was also significantly affected, with reduced levels of deoxyguanosine and other purine-related compounds. The study further investigated the origins of these differential metabolites using the MetOrigin platform, suggesting a potential involvement of the intestinal microbiota in the metabolic response to glyphosate. These findings highlight the multifaceted adverse effects of glyphosate on fish muscle, including oxidative stress and metabolic dysregulation, which may contribute to diminished muscle quality and health risks for aquatic organisms.

Effect of Temperature and Protease on The Desalting Process of Scomberoides commersonianus (Talang Queenfish)

This study evaluated the effects of temperature and protease (Alcalase) on the desalting process of salted Talang Queenfish (Scomberoides commersonianus) and the resulting textural and sensory properties of the fish. Salted fish samples were desalted using different temperatures (25°C, 40°C, 60°C, and 80°C) and Alcalase concentrations (1%, 2%, and 3%) at pH 7 and 60°C. The results showed that higher desalting temperatures or increased Alcalase concentrations significantly (p &lt; 0.05) increased salt removal, reducing the salt content in the fish muscle. The addition of Alcalase accelerated the desalting process, reducing desalting time compared to traditional methods. Textural analysis indicated that the fish’s hardness, cohesiveness, and chewiness decreased as desalting temperature and Alcalase concentration increased. Sensory evaluations revealed no significant changes in overall acceptability, with desalting at 60°C and 1% Alcalase yielding the best balance of saltiness and texture. Furthermore, retort-processed salted fish curry prepared from desalted samples maintained favorable sensory properties. These findings suggest that alternative desalting methods using Alcalase and elevated temperatures can enhance desalting efficiency while maintaining product quality.

Dietary effect of turmeric and ginger powder supplementation on growth performance of Common carp (Cyprinus carpio)

A study was conducted with the aim to find out the effect of ginger and turmeric supplementation on the growth performance of Common carp fingerlings. A total of 270 fingerlings were divided into 6 groups including control (C). The group C was fed with basal feed and the treatment groups T5, T5B5, G2, G5, G8 were fed with turmeric powder @0.5%, turmeric @0.5% + black pepper powder @0.5 %, ginger powder @2%, 5% and 8%, respectively. The growth parameters, i.e Gain in weight, Feed Conversion Ratio (FCR), Specific Growth Rate (SGR), Relative Growth Ratio (RGR), Protein Efficiency Ratio (PER) and Feed Efficiency Ratio (FER) were recorded for 60 days. Measurements were taken for gain in total length (TL) and body depth (BD) after 60 days of trial. Turmeric powder supplementation @0.5% showed significantly better growth performance in Common carp fingerlings. The fingerlings of T5 group showed highest gain in weight (48.7), SGR (1.35), RGR (126), FER (48.17), PER (1.24) and improved FCR (2.23). This group also gained significantly higher TL (3.74) and BD (1.42). There was no significant difference observed in survival per cent, moisture and acid insoluble ash content of fish muscle. T5 showed the highest crude protein concentration (78.29) and significantly highest total fat concentration (11.59). Fish muscles of all the treatments had significantly higher total mineral content as compared to that of the control group.

Deciphering the impact of stickwater hydrolysate on growth performance, immune response, and IGF-1/PI3K/AKT/mTOR signaling pathway in Siberian sturgeon (Acipenser baerii) fingerlings.

A feeding trial lasting 56days was carried out to assess how the inclusion of stickwater hydrolysate (SWH) in the diet of Siberian sturgeon (Acipenser baerii) fingerlings affected their growth performance, immunity, digestive enzyme activity, and gene expression linked to the IGF-1/PI3K/AKT/mTOR signaling pathway. Siberian sturgeon fingerlings were acclimatized and fed isonitrogenous, isoenergetic diets with varying SWH concentrations (0%, 0.5%, 1.5%, and 2.5%). Growth parameters, serum proteins, immunological and digestive enzyme activities, and gene expression levels were assessed post-trial. Results demonstrated that 0.5%, and 1.5% SWH treatments significantly improved weight gain, specific growth rate, feed conversion ratio, and protein efficiency ratio. Notably, these diets also elevated serum protein and plasma globulin levels, reduced albumin-to-globulin ratios, and enhanced lysozyme, myeloperoxidase (MPO) activities, and immunoglobulin (Ig) M levels, indicating an immunostimulatory effect. Digestive enzyme activities were markedly increased in the SWH groups, particularly at 1.5%. Gene expression analyses revealed upregulation of mtorc1, s6K, akt, pi3k, and igf1, with concurrent downregulation of 4e-bp1 in the muscle of fish, signifying activation of the IGF-1/PI3K/AKT/mTOR pathway, which is central to protein synthesis and muscle growth. In conclusion, SWH at appropriate levels significantly enhances growth, digestive efficiency, and immune function in Siberian sturgeon fingerlings, while also activating key metabolic pathways.

Seasonal variability of microplastic contamination in marine fishes of the state of Gujarat, India.

Seasonal variation in microplastics abundance, occurrence, and distribution in pelagic and demersal fishes was observed in this study during December 2021 to November 2022. One hundred percent presence of microplastic in inedible (gut and gills) tissue, while 82% and 54% in edible tissue (muscle) of pelagic and demersal fishes respectively were seen. Post-monsoon period showed high prevalence of microplastics followed by monsoon and the least during pre-monsoon in both pelagic and demersal fishes. In pelagic fishes, the edible tissue had microplastics abundance of 1.56 to 13.34 numbers per 10g of tissue whereas inedible tissue had 3.36 to 16.67 numbers per 10g of tissue. In demersal fishes, the edible tissue had microplastics abundance of 1.04 to 5.26 numbers per 10g of tissue while it was 2.67 to 8.34 numbers per 10g of inedible tissue. There was significant variation in abundance of microplastic in edible and inedible tissue of all the fishes (Mann-Whitney test, p < 0.05). The most dominant microplastics size was 0.005-0.05mm followed by 0.05-0.5mm and the least of greater than 0.5mm in pelagic and demersal fishes respectively. Taking microplastic shape into consideration, the most dominant was fiber followed by fragment and the film in inedible tissue of all the fishes. The edible tissue of all the fishes had only fiber in them (100% occurrence). The dominance of blue color microplastics was observed followed by red, green, yellow, and orange at least in edible as well as inedible tissues of the fishes. More than 99% microplastics polymer observed in this study include polyethylene (PE), polypropylene (PP), and polystyrene (PS); only less than 1% was unidentified. This is the first study done on seasonal variation of microplastic in the marine fish population of Gujarat waters, Northeast Arabian Sea. The study highlights the nature of micro-pollutant in marine environments, emphasizing the need for comprehensive monitoring and management strategies.

Investigating the toxicity of polylactic acid microplastics on the health and physiology of freshwater fish, Cirrhinus mrigala.

The widespread presence of microplastics (MPs) in aquatic ecosystems has raised growing concerns among ecotoxicologists regarding their potential toxicity. This study explored the impacts of polylactic acid (PLA) MPs on the physiology and health of freshwater fish, Cirrhinus mrigala, by dietary exposure for 90 days. The experiment consisted of six groups: five treatment groups (0.5%, 1%, 1.5%, 2%, and 2.5% PLA-MP) and a control group (0% PLA-MP). Each group was comprised of fifteen fish, and the experiment was replicated three times. The exposure severity of PLA-MPs varied from low to high, with treatment levels ranging from 0.5% to 2.5% PLA-MPs, relative to the control group. This exposure significantly affected their growth performance. Additionally, the apparent digestibility of the SFM-based diet decreased with increasing PLA-MPs concentration. Exposure to PLA-MPs induced considerable changes in body composition, characterized by increased moisture and crude fat content and decreased ash content and crude protein. The blood profile, including MCHC, RBCs, Hb, PLT and PCV exhibited significant declines in the high treatment group (2.5% PLA-MPs), while MCH, WBCs and MCV showed notable increases. Furthermore, histopathological examination of the intestine revealed an increase in abnormalities in the intestine at 2.5% PLA-MPs level. The high treatment group (2.5% PLA-MPs) showed the lowest mineral content in the fish muscles. In summary, dietary exposure to PLA-MPs led to alterations in overall body performance across the treatment groups, ranging from low to high severity levels.

New Insight into Mercury Removal from Fish Meat Using a Single-Component Solution Containing cysteine.

A novel approach for reducing mercury content in fish meat during post-packaging storage is developed to extend the margin of their safe consumption. It involves employing a single-component aqueous medium containing cysteine, as the active agent responsible for displacing mercury from fish proteins and its stabilization in the medium without the need for pH adjustments. The mercury removal efficiency depends on the cysteine concentration and its ratio to fish muscle. Using 1.2wt% cysteine enables a reduction of mercury in canned Albacore tuna by 25-35%, depending on the fish product type and the exposure time of up to 2 weeks. The potential for the successful application of the developed method in active food packaging solutions is studied for the simultaneous or subsequent purification of the extraction solution through adsorption. Using thiolated silica could potentially enable the extraction process but it is shown that the presence of cysteine significantly hinders the adsorption.

Growth and Depuration of Off‐Flavors in Rainbow Trout Oncorhynchus Mykiss in a Partial Recirculating Aquaculture System (PRAS)

ABSTRACTIn recirculating aquaculture systems (RAS), off‐flavours accumulated in fish muscle tissue can be problematic in terms of consumer acceptance and the reputation of farmed fish products. Off‐flavours often give fish earthy, muddy, or other undesirable flavours. Typically, off‐flavours are removed during a depuration period in which fish are fasted and held in clean water. Unfortunately, this causes additional costs and delayed sales, while fish lose weight and show a decrease in lipid content. First, we studied fish growth in a partial RAS (PRAS) where the conditions are very similar to those in depuration with a water exchange rate of 4000 L kg−1 feed, compared to RAS with a 650‐L water kg−1 feed. Rainbow trout (Oncorhynchus mykiss) was reared in both systems. Our aim was to combine the benefits of a higher water exchange rate: the lack of need for biofilters and a lower accumulation of off‐flavours while obtaining stable rearing conditions. Additionally, we studied the effects of moderate feeding and H2O2 addition during depuration. The fish grew faster in a PRAS than in a RAS when fed ad libitum. Thirteen off‐flavour compounds were found in the fish flesh and 11 in the circulating water. The H2O2 addition led to decreased levels of off‐flavours in the tank water and in fish muscle. The results showed no significant differences in off‐flavours between the fed and not‐fed systems, showing that moderate feeding did not prevent a good depuration result. However, the lipid content and the overall fish weight were higher in the fed systems, which suggests more effective depuration. Increased depuration efficiency can be an important tool when considering ways to improve the profitability of production.