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Öğe A Contribution on the Diet of the Warty Crab, Eriphia verrucosa (Forskal, 1775) by Informative Bayesian Stable Isotope Mixing Models(Maik Nauka/Interperiodica/Springer, 2022) Acar, Seçil; Ertürk Gürkan, Selin; Ateş, A. Suat; Yalçın Özdilek, ŞükranThe present study aims to determine the diet composition of Eriphia verrucosa using an informative and uninformative approach in which the stomach content results were assigned as prior based on this model. A stable isotope mixing model and stomach content analysis were used together to determine the diet and prey-predator relationships of E. verrucosa. A total of 24 crabs and benthic material were collected from depths between 1.5 and 2 m in the Strait of canakkale in July, 2020. The contribution of two different diets was assessed both by prior assignment (informative) and uninformative. According to the stomach content analyses, among the prey, Echinodermata contributed 37% to the diet, followed by Mollusca, especially Gastropoda (18%). In the uninformative model without prior assignment and in the informative model (prior assignment), Gastropoda contributed the most to the diet (57, 66%, respectively).Öğe Alabalık yetiştiriciliğinin Biga yarımadasındaki (Karamenderes ve Kocabaş çayları) akarsu balıklarının bazı biyolojik özellikleri ve trofik ilişkileri üzerine etkisi(Çanakkale Onsekiz Mart Üniversitesi, Lisansüstü Eğitim Enstitüsü, 2018) Ertürk Gürkan, Selin; Yalçın Özdilek, ŞükranBu çalışmada alabalık yetiştiriciliğinin, tatlısu balıklarının çeşitlilik ve bollukları, beslenme özellikleri ve komünite ilişkileri üzerindeki olası etkilerinin değerlendirilmesi amaçlanmıştır. Bu kapsamda; üzerinde alabalık tesisi bulunan Çanakkale'deki iki akarsu sisteminde (Karamenderes ve Kocabaş) bir yıl boyunca aylık olarak örnekleme yapılmıştır. Balık ve ortam örnekleri, her iki akarsuda belirlenen 2 istasyondan (alabalık tesisisinin üst ve altında belirlenen iki istasyon) ve balık çiftliği etkisinin olmadığı bir kolundan seçilmiş kontrol istasyonlarından gerekli etik izin alınarak elektroşoker ve çeşitli av araçları ile toplanmıştır. Örnekler Ağustos 2015 ile Temmuz 2016 arasında aylık olarak toplanmıştır. Çalışma sonuçları yetiştiricilik ünitesinden etkilendiği düşünülen istasyonlardan yakalanan balıkların çeşitliliklerini etkilemediği; ancak bolluklarında artış meydana getirdiğini göstermiştir. Beslenme özellikleri sindirim kanalı içeriği ve kararlı izotop analizleriyle değerlendirilmiştir. Türlerin kaynak sıkıntısı çektiklerinde besin tercihlerinde değişiklikler meydana geldiği ve özellikle Salmo sp. ve Phoxinus phoxinus bireylerinin Kocabaş Çayı'nda çiftlik kaynaklı yem ile de beslendikleri belirlenmiştir. Komünite yapısını anlamaya yönelik yapılan niş genişliği ve niş çakışmaları tespiti ile yetiştiricilik ünitesinin özellikle altında bulunan istasyonlarda besin bolluğuna bağlı olarak niş çakışmalarının daha fazla olduğu belirlenmiştir. Bu çalışma ile, yetiştiricilik yapılan bölgelerdeki doğal balık populasyonlarının, yetiştiricilik faaliyetlerinden bolluk, besin tercihleri ve türler arası etkileşimler açısından etkilendiği gözlenmiştir. Akarsular üzerine kurulan yetiştiricilik işletmelerinde balık, yem ve atık geçişini sınırlayan kapalı sistemler tasarlanması yerinde olacaktır.Öğe Assessing spinel zinc ferrite nanoparticles in aquatic ecosystems: Toxic threat or beneficial detoxifier for aquatic life?(Elsevier B.V., 2025) Ertürk Gürkan, Selin; Gürkan, Mert; Yanık, Ece Büşra; Kutlu, Elif; Sarıtunç, Volkan; Güneş, Berkay; İbiş, Ezgi CanThe effectiveness of magnetic nanoparticles in removing pollutants during water treatment is well established, but their introduction into aquatic ecosystems raises significant toxicity concerns. This study investigates the histological and physiological effects of zinc ferrite magnetic nanoparticles (ZnFe2O4−MNPs) on the Mediterranean mussel (Mytilus galloprovincialis) and examines the impact of concurrent exposure to these nanoparticles and the insecticide thiomethoxam (TMX). Mussels were exposed to nominal concentrations of ZnFe2O4−MNPs (1, 10, 100 mg/L) both individually and with TMX. Physiological assessments included measuring antioxidant enzyme levels (superoxide dismutase, catalase, glutathione S-transferase) and oxidative stress markers (malondialdehyde). Results showed that ZnFe2O4−MNPs increased antioxidant activity but also caused dose-dependent pathological changes. In contrast, combined exposure with TMX significantly (p < 0.05) reduced antioxidant defenses, indicated by lower superoxide dismutase (SOD) levels and higher malondialdehyde (MDA) concentrations, suggesting oxidative stress and potential cellular damage. These findings highlight the need for comprehensive toxicity assessments of nanoparticles in aquatic environments and advocate for their complete removal from water sources post-treatment. Further research is crucial to define the toxicity profiles of spinel ferrites to ensure their safe application in environmental remediation.Öğe Assessment of toxicity and oxidative stress induced by rare earth oxide nanoparticles in brine shrimp (Artemia salina)(Elsevier Ltd, 2024) Ünal, İlkay; Ertürk Gürkan, Selin; Aydoğdu, BurcuThis study meticulously explored the oxidative stress effects induced by lanthanum (III) oxide (La2O3), erbium (III) oxide (Er2O3), and yttrium (III) oxide (Y2O3) nanoparticles on Artemia salina, with the objective of evaluating the environmental toxicity of rare earth oxide nanoparticles. The characterization of the nanoparticles was conducted using a suite of advanced techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), dynamic light scattering (DLS), and zeta potential analysis. Artemia salina, a widely recognized model organism in ecotoxicological research, was exposed to these nanoparticles under meticulously controlled laboratory conditions. The investigation focused on quantifying oxidative stress markers, such as reduced glutathione (GSH), malondialdehyde (MDA), and antioxidant enzymes including catalase (CAT), superoxide dismutase (SOD), and glutathione-S-transferase (GST). The findings revealed significant alterations in these biomarkers, indicating nanoparticle-induced oxidative stress, which varied according to the type of nanoparticle and the duration of exposure.Öğe Assessments of antioxidant capacities of Mediterranean mussel (Mytilus galloprovincialis Lamarck, 1819) from the different stations of Dardenelles Strait (Turkey)(Universitatea din Oradea, 2020) Ertürk Gürkan, SelinThe use of biomarkers to determine the negative effects of chemical contaminations on the aquatic organisms is an important instrument for identifying and evaluating chemical pollution on environment. In this study, it was aimed to determine the effects on the Mediterranean mussel (Mytilus galloprovincialis) living in a coastline (Dardanelles Strait, Turkey), under the influence of urbanization, active ship / ferryboat traffic and agricultural activities using superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) antioxidant enzymes. M. galloprovincialis samples collected in October 2017 from 7 regions thought to be under the influence of different pollutants were used. The lowest SOD values measured (4.3-9.5) in the samples collected from Kepez station where the port is located and the highest values (14.1-43.3) were found in the samples of Kilitbahir station where ferry traffic is heavy. CAT and GSH-Px levels were higher in Güzelyalı (CAT: 81.6-96.4 and GSH-Px: 4.3-9.3) and Dardanos (CAT: 64-95.5 and GSH-Px: 6.7-7.9) stations where tourism was effective and Kepez station (CAT: 89.3-99 and GSH-Px: 6.2-7.2) where the port was located. According to statistical analysis, there is no significant difference in enzyme levels between stations. It is considered useful to investigate the seasonal variations of these levels in order to understand biomarker responses to pollutants and to assess changes between pollutant exposure and environmental conditions. © Biharean Biologist, Oradea, Romania, 2020Öğe Comparative Toxicity of Alpha and Gamma Iron Oxide Nanoparticles in Rainbow Trout: Histopathology, Hematology, Accumulation, and Oxidative Stress(Springer, 2021) Gürkan, Mert; Ertürk Gürkan, Selin; Yılmaz, Sevdan; Ateş, MehmetIn this study, alpha and gamma iron oxide nanoparticles, characterizations, toxic effects after being exposed to rainbow trout (Oncorhynchus mykiss) at 0, 1, 10 and 25 mg/L concentrations for 10 days, and then 10-day recovery period without any nanoparticle exposure were examined for histopathological (kidney, liver and gill), hematological, iron accumulation and potential for oxidative stress (TBARS and GSH). Histopathological damages significant at the exposure of increasing concentrations of both nanoparticles (increase in melanomacrophage aggregations, epithelial tissue deformations, cytoplasmic vacuolizations, fatty changes, necrosis, pyknosis, hyperplasia, hypertrophy, lamellar fusions, capillary dilatations). Gamma nanoparticles were determined to accumulate more than the alpha nanoparticles. The most Fe accumulation was detected in the liver. The findings of oxidative stress parameters showed that both nanoparticles have the potential to generate oxidative stress. It was concluded that the exposure of alpha and gamma nanoparticles at specified concentrations and durations had a toxic effect on rainbow trout and the toxicity of these nanoparticles was similar.Öğe Dual and multiple exposures to metal oxide nanomaterials: Unveiling histological and oxidative stress dynamics in Mytilus galloprovincialis(Elsevier B.V., 2025) Ertürk Gürkan, Selin; Gürkan, Mert; Kutlu, Elif; Yanik, Ece Büşra; Saritunç, Volkan; Güneş, BerkayDue to their increasing industrial applications, metal oxide nanoparticles (NPs) have emerged as significant environmental pollutants with potential ecotoxicological effects on aquatic organisms. This study evaluated the acute effects of binary and ternary mixtures of ZnFe?O? (10 mg/L), SiO? (10 mg/L), and NiO (100 mg/L) NPs on Mytilus galloprovincialis. Following 96-hour exposures, oxidative stress biomarkers (SOD, CAT, GST, MDA) and histopathological alterations were assessed in gill and digestive gland tissues. Notably, the ternary mixture induced significant elevations in MDA levels. Among binary combinations, SiO?–NiO NPs enhanced antioxidant responses, whereas NiO–ZnFe?O? NPs caused pronounced tissue damage. The results underscore that NPs in the environment may not act independently but rather interact additively or synergistically, thereby amplifying their toxic potential. These findings highlight the need to consider mixture effects in ecotoxicological risk assessments, reflecting the complex and multicomponent nature of nanoparticle pollution in real-world aquatic environments. © 2025 Elsevier B.V.Öğe Effects of Mineral Proteinate Mixture Inclusion Levels on Oncorhynchus mykiss Fry: Growth, Digestion, and Antioxidant Status(Central Fisheries Research Institute, 2026) Şahin, Tolga; Ertürk Gürkan, Selin; Gürkan, Mert; Ergün, SebahattinTo improve growth, digestion, antioxidant status, and feed efficiency, this study sought to identify the ideal inclusion level of an organic mineral mixture (OMM®; proteinates of Zn, Cu, Mn, Fe, Co, Se) to partially replace inorganic mineral premixes in rainbow trout (Oncorhynchus mykiss) fry diet. Four isoproteic diets (0% control, 0.5% OMM-50, 0.75% OMM-75, 1.0% OMM-100) were subjected to triplicate testing using over 60 days. Final weight (13.55±0.03 g), SGR (3.99±0.02%/day), and trypsin activity (2.46±0.10 U/mg protein), were maximum in the OMM-50 group and lowest FCR (1.02±0.01). Both moderate OMM (0.5–0.75%) increased the SOD (8.79±1.9, 7.67±1.3 U/mg protein) and GPx (0.32±0.11, 0.17±0.06 U/mg protein) activities, decreasing MDA (1.60±0.87, 2.83±0.76 nmol/mg protein), suggesting enhanced antioxidant defense. Conversely, OMM-100 reduced growth (11.19±0.06 g), SGR (3.49±0.18%/day), and survival (84.29±0.82%), but increased feed intake (3.37±0.03%/day), indicating mineral imbalance. The peak of whole-body mineral contents was observed at OMM-50, validating higher bioavailability. Thus, 0.5% OMM replacement optimizes physiological outcomes and offers a sustainable alternative to inorganic minerals in aquafeeds. © 2026, Central Fisheries Research Institute. All rights reserved.Öğe Evaluation of Possible Toxic Effects of Boric Acid in Palourde Clam (Ruditapes decussatus) Through Histological Changes and Oxidative Responses(Springernature, 2024) Ertürk Gürkan, Selin; Gürkan, Mert; Sarıtunç, Volkan; İbiş, Ezgi Can; Güneş, BerkayThe extensive utilization of boric acid, particularly in industrial and agricultural sectors, also engenders concerns regarding the toxicity of boron and its derivatives. Particularly, the behavior of boric acid at increasing concentrations in aquatic ecosystems remains poorly understood. In light of these concerns, this study aimed to investigate the toxicity of boric acid in bivalves, which occupy a critical position in the food chain. Specimens of Ruditapes decussatus, which had not been previously exposed to any pollutants and were cultivated under controlled conditions, were subjected to three different concentrations of boric acid (0.05 mg/L, 0.5 mg/L, and 5 mg/L) in vitro for 96 h. Following the exposure period, the specimens were assessed for histological changes (the mantle, gill, and digestive gland) and specific oxidative parameters (the gill and digestive gland), including superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase, and lipid peroxidation (LPO). The research findings indicated that boric acid primarily induced oxidative damage at the applied concentrations and increased antioxidant levels (p < 0.05). Moreover, although no significant histopathological abnormalities were observed in the examined histological sections, subtle changes were noted. This study evaluated the potential adverse effects of boric acid on bivalves, which are crucial components of the aquatic food chain, utilizing histological and specific physiological parameters following its introduction into aquatic environments. It is anticipated that the findings of this study will contribute to the development of new insights and perspectives regarding the extensive use of boric acid.Öğe Evaluation of the health of Mediterranean mussels ( Mytilus galloprovincialis Lamarck, 1819) distributed in the Çanakkale strait, Turkey(Elsevier Sci Ltd, 2024) Gürkan, Mert; Ertürk Gürkan, Selin; Künili, İbrahim Ender; Acar, Seçil; Özel, Osman Tolga; Düzgüneş, Zehra Duygu; Türe, MustafaThe observation of mortality in Mediterranean mussels ( Mytilus galloprovincialis ) distributed in the Çanakkale Strait in recent years was influential in developing the research question for this study. In this study, the presence of bacteria ( Vibrio spp.) and parasites ( Marteilia spp. and Haplosporidium spp.) in mussels collected from Kumkale, Kepez, and Umurbey stations in the Çanakkale Strait was investigated seasonally. Microbiological findings, histopathology, oxidative stress enzymes and their gene expressions, lipid peroxidation, lysosomal membrane stability, and changes in haemolymph were examined. In summer samples, both the defence system and the extent of damage were higher in gill tissue. In winter samples, enzyme activities and lipid peroxidation were found to be predominantly higher in digestive gland tissues. Histological examinations and Hemacolor staining revealed the presence of protozoan cysts, and for bacterial examination, molecular analysis performed after culturing revealed the presence of 7 Vibrio species. While the total numbers of heterotrophic bacteria detected in all samples were at acceptable levels, the predominance of Vibrio spp. numbers among the total heterotrophic bacteria detected in almost all samples were noteworthy. The total hemocyte count was calculated as 5.810(4) +/- 0.58 (cells/mm 3 ) in winter and 7.210(4) +/- 1.03 (cells/mm 3 ) in summer. These factors are considered to be possible causes of mussel mortality.Öğe Evaluation of the role of enzyme activities in the silvering process of European eels (Anguilla anguilla)(Springer, 2023) Ertürk Gürkan, Selin; Mestav, Burcu; Yalçın Özdilek, ŞükranThis study was carried out to determine the relationships between various morphological parameters, body condition data, and digestive and stress enzyme activities due to silvering in European eel (Anguilla anguilla L.) collected from four locations in Turkey. The yellow and silver eels were caught from Asi River, Köyceğiz, Güllük Bay, and Bafa Lake in November–December 2020. Total body length, eye diameter, and pectoral fin length were measured as morphological parameters. In addition, body fat percentage, gonado-somatic index, and Fulton’s condition factor were calculated, and also weight was assayed as body condition data. The variations of α-amylase, lipase, trypsin, and pepsin enzymes, and superoxide dismutase, catalase, and glutathione peroxidase enzyme activities were measured. The results supported the differences of yellow and silver stage samples in terms of both morphological and physiological parameters and also showed that the digestive and stress enzyme activities of the silver and yellow stage samples were significantly different (p ≤ 0.05). We think this study will make a physiological contribution in terms of digestive and stress enzyme levels to better understand and elaborate the silvering stage of eels.Öğe Impact of oregano (Origanum vulgare ) supplementation on antioxidant status, and related gene expression in Black Sea salmon, Salmo labrax(Hellenic Veterinary Medical Soc, 2024) Özel, O.; Düzgüneş, Z.; Ertürk Gürkan, Selin; Çakmak, E.The aim of this study was to to evaluate the effect of diets containing 0, 50, 100, 200, and 400 mg kg-1 oregano (Origanum vulgare) essential oil on antioxidant enzymes including glutathione proxidase (GPx), superoxide dismutase (SOD) and catalase (CAT) and expression levels of their-relevant genes in liver and muscle tissues of Black Sea salmon (Salmo labrax) juvenile. This study was conducted in the freshwater recirculating aquaculture system (RAS). Fish with average initial weights of 3.52 +/- 0.01g were distributed randomly in triplicate to 50 liter fiberglass tanks, and 45 fish were placed in each experimental tank. Fish were fed 3% level of live weight for 90 days. The ad- dition of oregano essential oil had no significant impacts on CAT in liver and GPx in muscle (p>0.05), but increased SOD activity was observed in muscle. The increased GPx gene expression were observed in both muscle and liver tissues. The addition of oregano essential oil had no significant impacts on the mRNA expression of SOD in muscle, nevertheless increased SOD genes expression were determined in liver. In terms of the mRNA expression of CAT, con- trol and 200 mg kg-1 concentration were similar to each other and had the highest level. Present study suggests that the addition of oregano essential oil can enhanced the antioxidant enzyme activities, and related gene expression of Black Sea salmon (Salmo labrax) juvenile.Öğe Influence of Dietary Fennel (Foeniculum vulgare) Essential Oil on Immune-Antioxidant Response in Black Sea Salmon (Salmo labrax PALLAS 1814)(Springer Int Publ Ag, 2025) Özel, Osman Tolga; Düzgüneş, Zehra Duygu; Ertürk Gürkan, Selin; Cimagil, RecayiThe work was conducted to investigate the immune and antioxidant status and their-related gene expression in the muscle and liver of Black Sea salmon (Salmo labrax PALLAS 1814) juvenile fed with dietary fennel (Foeniculum vulgare) essential oil in different levels. Fish fed with diets have at different concentrations of fennel essential oil (EO) such as 50, 100, 200, and 400 mg kg-1. Fish with initial weights of 3.52 +/- 0.01 g were placed randomly 45 fish per 50-L fiberglass square tanks (15 in total). Experimental study was carried out as triplicate. Fish fed by hand 3% level of live weight with diets including fennel essential oil at 50, 100, 200 and 400 mg/kg, and control. At the end of 90-day experimental, there were no differences in superoxide dismutase (SOD) and catalase (CAT) in muscle. In liver, the highest glutathione peroxidase (GPx) activity was obtained in F400 group while the highest SOD and CAT were determined in F200 group. As the concentrations of fennel EO in diet increased, SOD activity in liver increased. The addition of fennel EO had no significant impacts on gene expression of CAT in liver and GPx in muscle and liver but decreased SOD expression was obtained in muscle. Besides, liver il1-b gene expression decreased significantly by administration of fennel EO. The fact that essential oils partially increase antioxidant enzyme activity has led to the conclusion that they may play a healing role in the antioxidant defense system. Hovewer, to understand the mechanisms related to the immune-antioxidant response of dietary fennel EO in Black Sea salmon, further research should be conducted on its expression and mode of action on the relevant genes.Öğe Pathological and oxidative stress responses of Mytilus galloprovincialis to Vibrio mediterranei infection: An in vivo challenge(Academic Press Ltd- Elsevier Science Ltd, 2024) Ter, Ümmugülsüm; Ertürk Gürkan, Selin; Gürkan, Mert; Künili, İbrahim Ender; Aksoy, EmircanSince the identification of Vibrio mediterranei as a causative agent in mass mortalities of pen shells across the Mediterranean, elucidating its pathogenicity, virulence, and interactions with other bivalves has gained importance. While the cellular and immune responses of bivalves to various Vibrio species have been extensively studied, the infectious characteristics of this Vibrio species, particularly in the context of pen shell outbreaks, remain unclear for other bivalves. Therefore, to evaluate its pathogenicity, we investigated the histological and oxidative effects on the Mediterranean mussel (Mytilus galloprovincialis), a key species in aquaculture. Two distinct infection setups were established: one involving the inoculation of seawater with the bacterial isolate and another involving direct injection of the bacteria into the mussels. After a 24-h exposure period, histological evaluations were conducted on the mantle, gill, and digestive gland tissues of the mussels. Additionally, measurements of superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), and lipid peroxidation levels were performed in the gill and digestive gland tissues. Oxidative responses were significantly elevated in both infection setups compared to the control group, with the directly injected samples exhibiting the highest oxidative responses (p < 0.05). Histological findings indicated that tissue-specific responses to host-pathogen interactions were consistent under both infection conditions. Notable observations included intense hemocytic infiltration in tissues, epithelial hyperplasia, and vacuolization in the gills, as well as focal necrotic areas in the digestive gland. The findings of this study indicate that V. mediterranei, a relatively novel pathogen, can provoke significant acute immune responses and tissue-level reactions in M. galloprovincialis, a species that is both widely distributed and vital to the food chain. These insights into the potential susceptibility of mussels underscore the need for further comprehensive research and inform the development of effective management strategies.Öğe The effects of biosynthesized silver nanoparticle on oxidative stress parameters in model organism Artemia salina (Linnaeus, 1758)(Taylor & Francis Inc, 2024) Ünal, İlkay; Ertürk Gürkan, SelinEvaluation of the effects of nanomaterials in various habitats and living groups is increasing with in vitro and in vivo studies. This study aims to describe a biological procedure to synthesize silver nanoparticles using an extract of Marrubium astracanicum and to determine the aquatic environment's oxidative stress on Artemia salina. Silver nanoparticle formation was visually observed with color change. Its structural properties, such as size, shape, morphology, and stability, were characterized by UV-Vis spectrophotometer, TEM, SEM, XRD, and DLS analyses. TEM image showed that the synthesized AgNPs have a size of between 20 and 50 nm. The effects of biosynthesized silver nanoparticles at different concentrations (control,0.2, 1, 5, 10, 25, and 50 mg/mL) and exposure times (24, 48 and 72 h) on total glutathione (GSH) and lipid peroxidation levels (MDA) were investigated on the Artemia salina organism, which is one of the most common saltwater organisms frequently used in ecotoxicity tests.
