Gastrointestinal Tract Of Fish Research Articles

Probing into the impacts of endogenous and exogenous short chain fatty acids (SCFAs) in fish health and growth

Abstract Short-chain fatty acids (SCFAs) are small organic acids exist in the fish gastrointestinal tract, mainly acetate, propionate, and butyrate. These SCFAs are produced through anaerobic fermentation of dietary non-digestible carbohydrates by gut microbes. Though enough studies have been devoted to showcasing the potential of SCFAs in human nutrition, the research on their production, potential, and existence in fish has been comparatively limited until recently. This review aims to provide a comprehensive overview of the current knowledge regarding SCFAs in aquaculture. It starts with commenting on the different sources, such as substrate and microbial species that are responsible for the production of SCFAs and their transportation and ends up depicting the relationship between biofloc technology and SCFAs production. This review also discusses the factors influencing SCFA production, such as environment, diet, and feeding habits of fish. Furthermore, the biological functions of SCFAs have been highlighted, and critical findings were compiled, including immunomodulatory effects, physiological response, gut health, and immunity.

Occurrence of microplastics and metals in European seabass produced in different aquaculture systems: Implications for human exposure, risk, and food safety

Microplastics (MPs) are emerging contaminants of increasing concern as they may cause adverse effects and carry other contaminants, which may potentially compromise human health. Despite occurring in aquatic ecosystems worldwide, the knowledge about MP presence in different aquaculture systems and their potential impact on seafood products is still limited. This study aimed to determine the levels of MPs in water, feed, and European seabass (Dicentrarchus labrax) from three relevant aquaculture systems and estimate human exposure to MPs and metals through seabass consumption. The recirculating aquaculture system (RAS) had the highest MP occurrence in water and feed. MP levels in seabass followed the aquaculture system's levels in water and feed, with RAS-farmed fish presenting the highest MP load, both in the fish gastrointestinal tract (GIT) and muscle, followed by pond-, and cage-farmed fish. MPs' characteristics across aquaculture systems and fish samples remained consistent, with the predominant recovered particles falling within the MP size range. The particles were visually characterized and chemically identified by micro-Fourier Transform Infrared Spectroscopy (μFTIR). Most of these particles were fibres composed of man-made cellulose and PET. MP levels in GIT were significantly higher than in muscle for pond- and RAS-farmed fish, MPs' bioconcentration factors >1 indicated bioconcentration in farmed seabass. Metal concentrations in fish muscle were below permissible limits, posing low intake risks for consumers according to the available health-based guidance values and estimated dietary scenarios.

Assessment of microplastic contamination in some commercial fishes of the southern Caspian Sea and its potential risks.

This study examined the occurrence of microplastics (MPs) in the gastrointestinal tract (GIT) of 384 fishes classified into four species from 11 sites in 2022 from the southern part of the Caspian Sea. GITs of fishes were collected and digested in H2O2 and KOH at 45°C for 72h. After filtration, extracted MPs were observed under a stereomicroscope, and selected MP particles were identified using FTIR. Presence of MPs was 68.98% in the GIT of the investigated fish. The mean abundance of MPs was 5.9 ± 0.9 MPs/GIT in Rutilus kutum, 9.2 ± 1.2 MPs/GIT in Chelon auratus, 3.6 ± 0.7 MPs/GIT in Alosa braschnikowi, and 2.7 ± 0.5 MPs/GIT in Vimba vimba. The predominant form of MPs was fiber (58.21%), followed by fragment (34.77%). Black (34.4%), white (19.07%), and blue (14.58%) were the most frequently detected colors of MPs. Overall, 6 MP polymers were identified, dominantly polypropylene (42.86%), polystyrene (17.86%), and cellophane (14.28%). The western part of the Caspian Sea (mostly tourist spots and urban areas) showed more MP pollution in fish compared to the eastern part. Polymer hazard index (PHI) revealed alarming microplastic contamination in the southern Caspian Sea. The PHI value of the present study showed that PES (PHI = 8403.78) and PS (PHI = 535.80) were "Extreme danger" and "Danger" risk categories, respectively.

Occurrence of microplastics in fish gastrointestinal tracts belongs to different feeding habits from the Bangladesh coast of the Bay of Bengal.

The Bay of Bengal (BoB) is home to a range of commercially important species with different food habits and feeding features. Microplastic (MP) contamination in the fish of BoB, like in many other marine environments, is a significant environmental concern. The study aimed to investigate the presence of microplastics (MPs) in the gastrointestinal tracts (GITs) of selected commercial marine fishes from the Bangladesh coast of the BoB. Six fish species (Escualosa thoracata, Tenualosa ilisha, Johnius belangerii, Trichiurus lepturus, Planiliza parsia, and Mystus gulio) were investigated (n = 120) following hydrogen peroxide digestion, and floatation (saline solution) protocols. After analyses, a total number of 696 MPs (dimension 0.3 to 5 mm) were identified. Moreover, the highest occurrence of MPs in fish GITs was found in planktivorous fish (average of 7.7 items/individual), followed by omnivorous (average of 5.2 items/individual), and carnivorous fish (average of 4.6 items/individual) (p < 0.001). However, planktivorous E. thoracata showed the highest number of MPs per g of GIT (average of 30.99 items/g GIT), whereas T. ilisha showed the lowest count (average of 0.77 items/g GIT). Different types of MPs (fibers (19 to 76%), fragments (6 to 61%), films (8 to 35%), microbeads (0 to 5%), and foams (0 to 2%)) were also observed. In terms of the color of MPs, the transparent, black, green, and blue types were the most common. Polymers were found as polyethylene (35 to 43%), polyethylene terephthalate (28 to 35%), polyamide (20 to 31%), and polystyrene (0 to 7%). The study provides a significant incidence of MPs in fish from the Bangladesh part of the BoB, which is very concerning. Therefore, long-term research is indispensable to ascertain the variables affecting the presence of MPs in fish, their origins, and their potential effects on the BoB fisheries. Stringent policies on plastic use and disposal should be strongly urged in this coastal region.

Environmental and ecological risk of microplastics in the surface waters and gastrointestinal tract of skipjack tuna (Katsuwonus pelamis) around the Lakshadweep Islands, India.

The presence of microplastics (MPs) in marine ecosystems is widespread and extensive. They have even reached the deepest parts of the ocean and polar regions. The number of articles on plastic pollution has increased in recent years, but few have investigated the MPs from oceanic islands which are biodiversity hotspots. We investigated the possible microplastic contamination their source and characteristics in surface waters off Kavaratti Island and in the gastrointestinal tract (GT) of skipjack tuna, Katsuwonus pelamis collected from Kavaratti Island of the Lakshadweep archipelago. A total of 424 MP particles were isolated from the surface water samples collected from off Kavaratti Island with an average abundance of 5 ± 1nos./L. A total of 117 MPs were recovered from the GT of skipjack tuna from 30 individual fishes. This points to a potential threat of MP contamination in seafood around the world since this species has a high value in local and international markets. Fiber and blue color were the most common microplastic morphotypes and colors encountered, respectively, both from surface water and GT of fish. Smaller MPs (0.01-1mm) made up a greater portion of the recovered materials, and most of them were secondary MPs. Polyethylene and polypropylene were the most abundant polymers found in this study. The Pollution Load Index (1.3 ± 0.21) of the surface water and skipjack tuna (1 ± 0.7) indicates a minor ecological risk for the coral islands, while the Polymer Hazard Index highlights the ecological risk of polymers, even at low MP concentrations. This pioneer study sheds preliminary light on the abundance, properties, and environmental risks of MPs to this highly biodiverse ecosystem.

Assessment of microplastic contamination in commercially available fishes

Plastics have widespread applications for human use, but their disposal poses a significant threat to living organisms and these plastics end up in the marine environment. They will be fragmented into small pieces as a result of ultraviolet exposure, climatic changes, and temperature changes; Microplastics (MPs) are plastics that are less than 5 mm in size. The level of MP (Microplastic) pollution in commercially harvested fish from different habitant in Vellore, India is currently unknown. Therefore, this study aimed to determine the presence and characteristics of ingested or inhaled MPs in marine and freshwater fishes highly consumed by the local population. Fish gills and gastrointestinal tracts were aseptically dissected and digested (30% hydrogen peroxide), then filtered and examined under a microscope for the presence of MPs. Further analysis was performed on the samples using Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Scanning Electron Microscopy (SEM) with Energy Dispersive X-Ray (EDAX). Of the samples analysed, a total of 875 MPs were recovered from 32 fishes, with 478 from marine fishes and 397 from freshwater fishes. The most common colours of the MPs were blue and black, while stereo microscopy analysis revealed that the majority of MPs were fibers (91%), followed by fragments (8%) and a small number of films. The ATR-FTIR analysis identified polyvinyl alcohol (39.76%), polyethylene (16.51%), methylcellulose (12.84%) and styrene (9.07%), as the predominant types of MPs in the fish samples. This study highlights the significant impact of MP pollution on marine ecosystems. The research provides insight into the nature and extent of MPs in fish from both marine and freshwater habitats, with an aim for policies and interventions aimed to reduce plastic pollution in the locality.

Plastic, It's What's for Dinner: A Preliminary Comparison of Ingested Particles in Bottlenose Dolphins and Their Prey.

Microplastic ingestion was reported for common bottlenose dolphins (Tursiops truncatus) inhabiting Sarasota Bay, FL, USA, a community that also has prevalent exposure to plasticizers (i.e., phthalates) at concentrations higher than human reference populations. Exposure sources are currently unknown, but plastic-contaminated prey could be a vector. To explore the potential for trophic exposure, prey fish muscle and gastrointestinal tract (GIT) tissues and contents were screened for suspected microplastics, and particle properties (e.g., color, shape, surface texture) were compared with those observed in gastric samples from free-ranging dolphins. Twenty-nine fish across four species (hardhead catfish, Ariopsis felis; pigfish, Orthopristis chrysoptera; pinfish, Lagodon rhomboides; and Gulf toadfish, Opsanus beta) were collected from Sarasota Bay during September 2022. Overall, 97% of fish (n = 28) had suspected microplastics, and GIT abundance was higher than muscle. Fish and dolphin samples contained fibers and films; however, foams were common in dolphin samples and not observed in fish. Suspected tire wear particles (TWPs) were not in dolphin samples, but 23.1% and 32.0% of fish muscle and GIT samples, respectively, contained at least one suspected TWP. While some similarities in particles were shared between dolphins and fish, small sample sizes and incongruent findings for foams and TWPs suggest further investigation is warranted to understand trophic transfer potential.

Fungi and Actinobacteria: Alternative Probiotics for Sustainable Aquaculture

Aquatic animals are continually being exposed to stressors under farming conditions, increasing risks to gut health that result in dysbiosis. Since restrictions are imposed on the frequent use of antibiotics in aquaculture, there is emerging demand for economically viable, environmentally safe, and sustainable alternatives for the intensive production of aquaculture species. The application of beneficial microorganisms as probiotics has been suggested and widely practiced in recent times. Bacteria and fungi are ubiquitous microorganisms that can grow in various environments where organic substrates are available. Being rich in nutrients, a fish’s aquatic environment and gastrointestinal tract confer a favorable culture milieu for the microorganisms. However, the colonization and probiotic potential of fungi and mycelial bacteria resembling fungi (actinobacteria), either in the culture environment or within the gastrointestinal tracts of fish, have received less emphasis. Apart from bacilli and lactic acid bacteria, as the most conventionally used probiotics in aquaculture, numerous studies have focused on other promising alternatives. Diverse species of yeasts and molds belonging to the kingdom ‘Fungi’ have been characterized for their prospective roles in nutrition, immunomodulation, and disease prevention in fish. Bioactive compounds such as manno-oligosaccharides and β-glucans are recognized as fungal postbiotics that improve innate immunity and disease resistance in fish. Actinobacteria are known to possess different hydrolytic enzymes and novel secondary metabolites representing their probiotic attributes. The application of these groups in water quality amelioration has also been explored. Thus, this paper presents an overview of the present status of knowledge pertaining to the effects of yeasts (Candida, Cryptococcus, Debaryomyces, Geotrichum, Leucosporidium, Pichia, Rhodosporidium, Rhodotorula, Saccharomyces, Sporidiobolus, Sporobolomyces, Trichosporon and Yarrowialipolytica), molds (Aspergillus spp.) and actinobacteria (Streptomyces) as probiotics in finfish aquaculture, as well as their occurrence within the gastrointestinal tracts of finfish. Furthermore, probiotic mechanisms, selection criteria, and future perspectives on using fungi and actinobacteria as promising probiotics are discussed.

Microplastics in commercial fish digestive tracts from freshwater habitats in Northern Thailand

Microplastics (MPs) contamination in fish species was one of the emerging environmental issues as a result of the widespread presence of plastic pollution in the environment. The presence of MPs in Thailand's freshwater was scant, and in contrast to other countries, little was known about the presence of this contaminant in freshwater fish. Hence, the purpose of this study was to examine the abundance, characteristics, and variation of MPs in various Thai commercial freshwater fish species. In order to compare the differences in MP ingestion rates across different feeding zones, 166 fish representing 24 species from various feeding zones were collected. MPs were found in the gastrointestinal tracts (GIT) of all fish samples tested, which was a substantially larger number than previously reported in other locations. Of all the fish species, Anabas testudineus, Labeo rohita, and Oreochromis mossambicus had the highest concentration of MPs (34.90 ± 21.43, 34.50 ± 7.78, 34.10 ± 11.15 items/individuals). Microscopical examinations showed that the majority of MPs were fiber-shaped and blue in color. Fourier transform infrared analysis (FTIR) showed that the polymers found in fish GIT were polyethylene, polypropylene, polyethylene terephthalate, polyvinyl acetate, poly (methyl vinyl ether), poly (methyl vinyl ether), polybutadiene, poly (ethylene-co-propylene), poly (ethylene glycol) tetrahydrofurfuryl ether, poly (methyl phenyl siloxane), poly (styrene-co-divinylbenzene), and polyvinylidene fluoride. The results of this study demonstrate that demersal fish had a higher concentration of MPs than benthopelagic and pelagic fish, indicating that plastic ingestion in fish may be related to the feeding habitat. However, it was not discovered that differences in the fish's body weight and length affected the MPs' ingestion. Our findings will help people in Thailand understand which freshwater fish and fish from which feeding zones are more contaminated with MPs for human consumption.

The involvement of Pseudoterranova decipiens fish infestation on the shelf-life of fresh Atlantic cod (Gadus morhua) fillet

Zoonotic nematodes of the family Anisakidae are highly common in many marine fish species, which act as paratenic hosts for the third larval stage. In the fish, these parasites may migrate from the fish's gastro-intestinal tract (GI-tract) further to the coelomic cavity and muscles, making them a possible contamination source of bacteria they carry on their cuticle and in their GI-tract. A previous study revealed no apparent effect of Anisakis simplex on spoilage of fish, but the equally common anisakid species Pseudoterranova decipiens has a larger body surface potentially increasing the bacterial load brought into the fish muscle upon migration. As the presence of shelf-life reducing spoilage bacteria in the microbiome of this anisakid species has been demonstrated, the objective of the present study was to assess the potential shelf-life reducing effect of P. decipiens in fresh fish fillets stored in a domestic refrigerator.Atlantic cod was used as a model since members of the cod family are the third most consumed marine fish globally and it has the highest prevalence of P. decipiens infections. Infected and non-infected codfish fillet portions were collected and microbiologically analyzed at day 0 and day 4 of storage in a domestic fridge. Three isolation media were used to enhance maximum bacterial recovery and isolates were identified using MALDI-TOF MS and 16S rRNA gene sequencing. In parallel to the microbiological examination, sensory analysis was performed daily on the cod fillets to evaluate the freshness of the fish.Results revealed the presence of typical spoilage bacteria (e.g., Pseudomonas sp., Photobacterium sp.) in all fish, but based on the total viable counts, total H2S-producing bacteria, and sensory analysis, there were no objective indications to assume an increased fish spoilage rate by the presence and migration P. decipiens. Additionally, a beta-diversity comparison revealed no significant differences in microbiota composition between infected and non-infected fish parts, though individual heterogeneity in microbiome composition among Atlantic codfish individuals was found. As total viable counts did, however, exceed the guideline limits for fresh fish, further research should now focus on the role of the candling step as a potential source of post-harvest contamination. As such, anisakid infection might still accelerate fish spoilage, though now in an indirect way.

DETERMINATION OF MICROPLASTIC IN SELECTED FRESHWATER FISH SPECIES FROM AGRICULTURE FISHPOND IN TANJONG KARANG, SELANGOR, MALAYSIA

As the amount of plastic in the environment continues to rise, one of the most significant environmental challenges that has emerged is the contamination of seafood with microplastics (MPs). This study was conducted in Tanjong Karang, Selangor, in order to investigate the prevalence of MPs, their properties, and the range of variation among them in different species of freshwater fish. Twelve different fish species from a variety of feeding zones were investigated to establish the degree to which MPs consumption rates differed from zone to zone. It was found that MPs were present in the gastrointestinal tracts (GIT) of 29.2% of the fish samples, which is a higher percentage than what has been found in other regions that have been documented. When compared to the other fish species, the Anabas testudineus has the greatest concentration of MPs. Examinations at a microscopic level indicated that the film morphotype and the colour white were predominant among MPs. Fourier Transform Infrared analysis showed that the fish gastrointestinal tract contained high-density polyethene and polypropylene as the predominant polymers. Plastic ingestion in fish may be related to the feeding zones, as indicated by the fact that demersal fish have a greater concentration of MPs compared to benthopelagic and pelagic fish. This finding will help people have a better understanding of which types of freshwater fish and which types of feeding zones contain greater levels of MP contamination.

Bacillus indicus and Bacillus subtilis as alternative health and colouration promoters to synthetic astaxanthin in cyprinid aquaculture species

One of the largest challenges for the sustainable development of global aquaculture is the threat of infectious diseases. Preventative strategies that reduce antibiotic use are required to ensure fish health, minimise infectious diseases and subsequent pharmaceutical interventions. Recent strategies involve health-promoting feed supplements, such as astaxanthin and probiotic bacteria. Astaxanthin, a widely used carotenoid, offers colouration and antioxidant properties that can improve fish growth and fish survival when challenged with a pathogen. Probiotics can provide fish with a range of health benefits ranging from enhanced feed digestion, synthesis of vitamins, boost of innate immune response and active defence against potential pathogens.In this study, we tested if novel probiotic blends (Bacillus subtilis and/or Bacillus indicus) can be used as alternative health and/or colouration supplements to astaxanthin in two cyprinid species, mirror carp (Cyprinus carpio) and Red Comet goldfish (Carassius auratus auratus). Using experimental feed trials and 16S rRNA microbial profiling, the impact of the probiotic on fish growth and microbial community within the distal gastrointestinal tract was assessed. In addition, in mirror carp, blood samples were tested for immunology and haematological parameters, while in goldfish colouration of the skin was analysed.Mirror carp fed astaxanthin showed significantly increased growth whereas B. substilis /B.indicus supplementation had non-significant effects on growth performance. Our results provide the first insights into how the supplementation of astaxanthin changes the microbial composition in cyprinid species. In mirror carp, astaxanthin and the probiotic blend induce a significant shift in gut microbial communities. Mirror carp fed B. substilis/ B.indicus showed several indices of potential microbial and health benefits such as increased diversity, an abundance of potentially beneficial bacteria and enhancement of the phagocytic activity and creatinine blood levels. However, no effect on colouration, growth or the microbial community was found in goldfish, highlighting substantial species-specific differences in response to probiotics, in two closely related cyprinid species. Further research into the efficacy and site of colonization of supplemented bacteria in fish gastrointestinal tracts, and the mechanisms underlying the observed shifts in the host microbiota, is required to fully understand species-specific responses to probiotic supplementation.

Ability of Lactobacillus brevis 47f to Alleviate the Toxic Effects of Imidacloprid Low Concentration on the Histological Parameters and Cytokine Profile of Zebrafish (Danio rerio).

In the present article, the possible mitigation of the toxic effect of imidacloprid low-concentration chronic exposure on Danio rerio by the probiotic strain Lactobacillus brevis 47f (1 × 108 CFU/g) was examined. It was found that even sublethal concentration (2500 µg/L) could lead to the death of some fish during the 60-day chronic experiment. However, the use of Lactobacillus brevis 47f partially reduced the toxic effects, resulting in an increased survival rate and a significant reduction of morphohistological lesions in the intestines and kidneys of Danio rerio. The kidneys were found to be the most susceptible organ to toxic exposure, showing significant disturbances. Calculation of the histopathological index, measurement of morphometric parameters, and analysis of principal components revealed the most significant parameters affected by the combined action of imidacloprid and Lactobacillus brevis 47f. This effect of imidacloprid and the probiotic strain had a multidirectional influence on various pro/anti-inflammatory cytokines (IL-1β, TNF-α, IL-6, IL-8). Therefore, the results suggest the possibility of further studying the probiotic strain Lactobacillus brevis 47f as a strain that reduces the toxic effects of xenobiotics. Additionally, the study established the possibility of using imidacloprid as a model toxicant to assess the detoxification ability of probiotics on the kidney and gastrointestinal tract of fish.

Comparing microplastics ingested by the bogue Boops boops (Teleostei: Sparidae) to those available in its feeding areas: A case study on the Portuguese west coast

Understanding the exposure of wild marine fish to microplastics (MPs) has been frequently assessed through the quantification and characterization of MPs found in stomachal contents. However, whether such particles mirror the MPs available in the environment or suggest a selectivity ability in the species, it has been scarcely analyzed. Here, in addition to investigating temporal patterns in the abundance and diversity of MPs ingested by Boops boops (Linnaeus, 1758) caught in coastal waters between Setúbal and Sesimbra (Portugal), we also aimed at comparing them with the patterns of MPs occurring locally, namely where the bogue feeds: at both surface water and seabed sediments. A total of 200 fish, 50 per month, were supplied at the local fish first sale concurrently with the water and sediments sampling (from October 2018 to January 2019). Fibers accounted for 93% of all MPs ingested and were also the main type of MPs extracted from sediments. Both food intake (inferred by fish gastrointestinal tract) and abundance of MPs per fish (1.80 ± 1.26; mean ± SD, n = 102) significantly decreased during the 4 month-period analyzed. Such decreasing tendency is potentially related to this species reproduction season. Despite the distinct fluctuations observed in the abundance of MPs found in both feeding areas of the bogue, it was possible to detect similarities between fish and sediments regarding the predominance of fibers, namely those belonging to the smaller size class. Yet, the prevailing colors differed, suggesting a selection capability of the bogue. Further studies taking place in spring/summer months (out of the reproduction season) are thus needed to clarify how MPs ingestion will vary in this species and consequently interfere with its ability to mirror the MP pollution patterns in this coastal region.

Preliminary assessment of microplastic pollution in commercial freshwater fish species collected from four districts in Bac Ninh province

Microplastics (MPs) are of emerging widespread concern, but amount of research done in freshwater environments and organisms is scarce compared to that in marine environments. Thus, the MPs identification in four freshwater fish at four districts of Bac Ninh province were documented, including common carp (Cyprynus carpio), grass carp (Ctenopharyngodon idella), tilapia (Oreochromis niloticus), and red-tilapia (Oreochromis sp.). MPs were found in the gastrointestinal tracts (GIT) of 100% of examined fish. MPs abundances have significant differences between all freshwater fish collected from ponds and local markets (except for red-tilapia), while no difference by individual of each species neither in pond nor in local markets. The median sizes of microplastics ranged from 1410 µm to 2706 µm. The MPs were dominated by purple in color (in pond with average 38%; in local market with average 33%). µ-FTIR analysis showed that polymers found in fish GIT mainly were polyethylene terephthalate, polyethylene, polypropylene and nylon. These results showed that the microplastics was widely ingested by freshwater fish and help to aware people which fish are more contaminated with MPs to human consumption in Bac Ninh province.

The pervasiveness of microplastic contamination in the gastrointestinal tract of fish from the western coast of Bangladesh

This study investigated the prevalence of microplastics (MPs) in the gastrointestinal tract (GIT) of fish from the western coast of Bangladesh, the world's largest mangrove ecosystem. Altogether, 8 different species of fish (5 demersal and 3 pelagic) were examined. Microplastics were detected in every individual fish with an average abundance of 7.1 ± 3.14 particles per specimen. The demersal species were observed to consume more microplastics (7.78 ± 3.51) than the pelagic species (5.92 ± 2.06). Moreover, small-sized fish was found to accumulate higher MPs/body weight than large-sized fish. Polypropylene was the most abundant polymer type (45 %) and fiber was the most prevalent shape (71 %). SEM analysis revealed cracks, pits, and foreign particles on the microplastics' surface, representing their ability to bear organic pollutants and heavy metals. This study will be a source of information for future research and a guide for policy-makers to take better actions to protect and restore marine resources.

Effects of microplastic ingestion on feeding activity in a widespread fish on the southwestern Atlantic coast: Ramnogaster arcuata (Clupeidae)

The presence of microplastics (MPs) in the fish gastrointestinal tract has been documented in several studies. However, it is unclear whether this ingestion is active or passive and whether it affects feeding activity in natural environments. In this study, three sites with different anthropogenic pressure were selected from the Bahia Blanca estuary, Argentina, and the small zooplanktivorous pelagic fish Ramnogaster arcuata was used to evaluate MP ingestion and its effect on specie's trophic activity. We analyzed the zooplanktonic composition, levels, and types of MPs in both the environment and the stomach contents of R. arcuata. Moreover, we assessed the trophic behavior of R. arcuata to determine electivity, stomach fullness, and vacuity indexes. The results showed that despite the availability of prey in the environment, 100 % of the specimens ingested MPs, and their levels and characteristics were different according to the site. Stomach contents at sites related to harbor activities presented the lowest MPs concentrations, most of them were paint fragments, with the smallest sizes and a low diversity of colors. The highest MP ingestions were found near the principal sewage discharge, being mostly microfibers, followed by microbeads, and with a greater variety of colors. Electivity indices showed that R. arcuata has a passive or active ingestion according to the size and shape of MPs. In addition, the lowest stomach fullness index and the highest vacuity index values were associated with the highest level of MP ingestion near the sewage discharge. Altogether, these results demonstrate a negative effect of MPs in the feeding activity of R. arcuata and help to elucidate some mechanisms by which these particles are ingested by a bioindicator fish used in South America.

Abundance and Characteristics of Microplastics Found in The Gastrointestinal Tract of Commercial Marine Fish from Bitung, North Sulawesi – Indonesia

Microplastic (MP) pollution is an emerging environmental problem that threatens food security, food safety, and human health since it has been reported to be found in commercial fish consumed by humans. Bitung, North Sulawesi, is one of the biggest contributors to capture fishery production in Indonesia. However, there is no data on microplastic pollution in commercial marine fish from Bitung. Therefore, this research aimed to investigate the presence and identify the visual characteristics (color, shape, size) and the polymer type of microplastics found in the gastrointestinal tract of commercial marine fish from Bitung, North Sulawesi. The gastrointestinal tract was extracted using KOH 10%, and the microplastic was observed under a stereo microscope. A total of 753 microplastic particles were found in the gastrointestinal tract of 74 individuals (prevalence 99%), and there was a statistically significant difference in the abundance of microplastics found in the gastrointestinal tract of pelagic and demersal fish. The average number of microplastic particles found in the gastrointestinal tract of pelagic fish (12,24 ± 2,43) is higher than in demersal fish (7,38 ± 3,48). The dominant color and shape of microplastic found in the gastrointestinal tract of the fish were black and fiber, respectively. At the same time, the dominant microplastic size found in the gastrointestinal tract of demersal fish was bigger (1,001-5,000 µm, 39,4%) compared to pelagic fish (150-500 µm, 47%). The Fourier Transform Spectroscopy (FTIR) analysis result shows that microplastics of the same polymer type can be found in the gastrointestinal tract of both pelagic and demersal fish.

Abundance and Characteristics of Microplastics Found in The Gastrointestinal Tract of Commercial Marine Fish from Bitung, North Sulawesi – Indonesia

Microplastic (MP) pollution is an emerging environmental problem that threatens food security, food safety, and human health since it has been reported to be found in commercial fish consumed by humans. Bitung, North Sulawesi, is one of the biggest contributors to capture fishery production in Indonesia. However, there is no data on microplastic pollution in commercial marine fish from Bitung. Therefore, this research aimed to investigate the presence and identify the visual characteristics (color, shape, size) and the polymer type of microplastics found in the gastrointestinal tract of commercial marine fish from Bitung, North Sulawesi. The gastrointestinal tract was extracted using KOH 10%, and the microplastic was observed under a stereo microscope. A total of 753 microplastic particles were found in the gastrointestinal tract of 74 individuals (prevalence 99%), and there was a statistically significant difference in the abundance of microplastics found in the gastrointestinal tract of pelagic and demersal fish. The average number of microplastic particles found in the gastrointestinal tract of pelagic fish (12,24 ± 2,43) is higher than in demersal fish (7,38 ± 3,48). The dominant color and shape of microplastic found in the gastrointestinal tract of the fish were black and fiber, respectively. At the same time, the dominant microplastic size found in the gastrointestinal tract of demersal fish was bigger (1,001-5,000 µm, 39,4%) compared to pelagic fish (150-500 µm, 47%). The Fourier Transform Spectroscopy (FTIR) analysis result shows that microplastics of the same polymer type can be found in the gastrointestinal tract of both pelagic and demersal fish.

Evaluation of Microplastic Contamination in Commercially Edible Fresh Water and Marine Fishes Bought from Fish Markets, Tiruchirappalli, Tamil Nadu, India

Microplastics have become ubiquitous in aquatic environments worldwide, that there is rising worry about their potential influence on aquatic biota. Data demonstrate widespread plastic contamination in coastal regions all over the world; however, no quantitative studies on the ingestion of microplastics by commercial fish bought from Fish markets which belong to Fresh water and Marine environments have been conducted so far. In this work, we looked at the presence and their quantity, features, species - specificity distribution of microplastics in ten commercial fish species among which five species belong to Freshwater habitat and five species belong to marine habitat. Two Hundred fish samples were collected from four different sampling locations (Kallanai, Cauvery paalam fish market, Gandhi Fish Market, Vengur Fish Market). The average abundance of microplastics in commercial fish gastrointestinal tracts was 5mg/species of fish, indicating possible food safety. The majority of microplastics were fragment type with a diameter of less than 5mm. The study findings demonstrate the prevalence of microplastics in fish and pave the path for future research to better elucidate the mechanisms driving the incidence of microplastics in fishes along with possible risk assessment.