Browsing by Author "Oğuz, A.R."

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The Changes of Mucous Cells İn The Skin of Van Fish During Freshwater Adaptation
(ABADER (Adıyaman Bilimsel Arastırmalar Dernegi), 2020) İribuğday, F.; Oğuz, A.R.
Van fish, an anadromous fish, migrate in flocks to fresh water poured into the lake from the extreme conditions of Van Lake for breeding. The fish that complete their breeding return to the lake for feeding. In these two different aquatic environments, skin is exposed to different physicochemical effects of water. In the present study, morphometric and histological changes in mucous cells of the skin during reproductive migration were studied. The thickness of the epidermis was found to be thicker in the freshwater than in the lake environment. It has been determined that both the diameter and the chemical content of the mucus cell vary in different aquatic environments (freshwater and lakes). For this reason, it is thought that mucus cells are present in different types in the skin of Van fish. Also, these changes are different in several parts of the body (dorsal and lateral). These histological and histochemical changes in Van Fish are thought to be necessary for the adaptation of fish to aquatic environments. © 2020, ABADER (Adıyaman Bilimsel Arastırmalar Dernegi). All rights reserved.
Hematological and Biochemical Response in the Blood of Alburnus Tarichi (Actinopterygii: Cypriniformes: Cyprinidae) Exposed To Tebuconazole
(Scientific Society of Szczecin, 2020) Çilingir Yeltekin, A.; Oğuz, A.R.; Kankaya, E.; Özok, N.; Güneş, İ.
Background. Lake Van, the second-largest soda lake in the world, has a pH 9.8 value. A fish, locally known as Van fish, Alburnus tarichi (Güldenstädt, 1814), is an endemic fish of Lake Van and known also as pearl mullet, tarek, or Van bleak. Tebuconazole is a widely used pesticide around Lake Van. In this study, we will focus on the effects of tebuconazole on Van fish blood to provide critical information on the environmental risk assessment of pesticides in various aquatic environments. Materials and methods. The Van fish were exposed to tebuconazole for 24, 48, 72, and 96 h at a concentration of 2.5 mg ·L–1. Subsequently, the resulting hematological and biochemical parameters were determined. Results. There was a statistically significant decrease in erythrocytes (RBC), hemoglobin (Hb), and hematocrit (Hct) in the blood parameters (P < 0.05). The levels of serum, aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), urea, and creatine increased significantly (P < 0.05). The serum cortisol level increased significantly at all hours after the administration of tebuconazole (P < 0.05). Conclusions. As a result, toxicity caused by pesticides caused negative changes in the biochemical and hematological values of Van fish. Changes in these parameters have shown that it can be used as a biomarker for toxicity. © 2020, Scientific Society of Szczecin. All rights reserved.
Histopathology of the Gills of Lake Van Fish Alburnus Tarichi (Güldenstädt, 1814) Infected With Dactylogyrus Spp. Parasites
(Western Philippines University, 2023) Erdemir, A.N.; Alkan, Z.; Azizoğlu, B.E.; Sepil, A.; Oğuz, E.K.; Oğuz, A.R.
The Lake Van fish is an anadromous carp endemic to the Lake Van basin. In this study, the histopathological effects of Dactylogyrus spp. parasites, which naturally infected fish, on the gills were determined during reproductive migration. Fish gills were stained with hematoxylin and eosin after routine histological procedures and apoptotic cells in the gills were determined immunohistochemically. Dactylogyrus spp. parasites were found in 8 of the 60 fish caught in the study. No parasites were found in the fish sampled from the lake. It was observed that the parasites caused hypertrophy, hyperplasia, edema, epithelial desquamation, hemorrhage, fusion of secondary lamellae, and necrosis in the gills. Immunohistochemically, no increase in the number of apoptotic cells was observed in the gills of the parasite-infected fish when compared with the non-infected fish gills. As a result, it can be inferred that the lake water has a restrictive effect in fish against parasites. Histopathologic lesions caused by the observed parasites in fish caught in fresh water could significantly affect gill functions. © Western Philippines University.
Oxidative Damage in Some Tissues of Van Fish (Alburnus Tarichi Güldenstädt, 1814) Having Abnormal Ovary
(Centenary University, 2017) Özok, N.; Oğuz, A.R.; Doğan, A.; Ergöz, B.
Van Lake is the largest soda lake of Turkey and there is only one fish species (Van Fish, Alburnus tarichi Güldenstädt, 1814) that can survive under the extreme conditions of the lake. There are several researches carried out on the issue of lake contamination recently. Gonad abnormalities observed among these fish are one of the most important issues. In the present study, the malondialdehyde (MDA) and reduced glutathione (GSH), and the antioxidant enzyme levels such as superoxide dismutase (SOD) and glutathione peroxidase (GSH - Px) are compared in gills, livers, and gonads of the Van Fish (the ovary abnormality of which are determined in Van Lake) and the normal fish. Compared to the normal fish, the MDA levels of the abnormal fish show a considerable amount of increase in all of the tissues (P<0.05). There is a significant decrease in the SOD activity in the gill and ovary tissue and in the GSH - Px activity in the livers of the abnormal individuals compared to the normal individuals (P<0.05). As for the GSH levels, there is no difference found when the normal and abnormal tissues are compared. Consequently, when the fish with ovary abnormalities which are thought to be exposed to contaminators in a certain time period is compared to the normal fish, it can be said that their antioxidant defense systems are affected. © 2017, Centenary University. All rights reserved.