Investigation of the Effect of Oxidative Stress in Gill Tissue on the Brain Tissue c-Fos and BDNF Gene Expression after Chloramine-T Application of Rainbow Trout ( Oncorhynchus mykiss )

Chloramine-T is a chemical used to prevent and/or protect gill diseases in fish. In many fish species, bacterial diseases that occur in the gills are controlled by chloramine-T application. However, the wrong application of chloramine-T causes oxidative stress in aquatic organisms. In this study, it is aimed to investigate the oxidative stress level of chloramine-T applied to rainbow trout (Oncorhynchus mykiss) in gills and to investigate whether this stress affects neuronal activity in brain. For this purpose, rainbow trout were used sublethal dose (2.8 mg / L) 0-1-24-48-72 and 96 hours of chloramine-T. The levels of mRNA transcripts of genes encoding antioxidant enzymes (superoxide dismutase 1 (SOD1), superoxide dismutase 2 (SOD2), catalase (CAT), glutathione peroxidase 1 (GPX1), glutathione peroxidase 4 (GPX4)) were measured by qRT-PCR. Finally, expression levels of c-Fos and BDNF genes were determined by qRT-PCR to measure neuronal activity in brain tissues. It was observed that the expression levels of SOD1, SOD2, CAT and GPX1 genes increased significantly in TÜRK TARIM ve DOĞA BİLİMLERİ DERGİSİ TURKISH JOURNAL of AGRICULTURAL and NATURAL SCIENCES https://doi.org/10.30910/turkjans.515353 Türk Tarım ve Doğa Bilimleri Dergisi 6(1): 78-83, 2019 79 the gills of fish treated with chloramine-T. However, there was no significant increase in GPX4 gene. When the brain tissues of the same fish were examined, it was determined that c-fos and BDNF expressions increased in comparison to the control group. The results of the study show that excessive and/or incorrect chloramine-T application causes oxidative stress in the gill tissues of rainbow trout and negative effects of neuronal activity on brain tissues of fish exposed to oxidative stress.