Turkish Journal of Science & Technology Volume 5, No 2, 79-84, 2010 Effect of Sulfamerazine on Plasma Ceruloplasmin Levels in Rainbow Trout (Onchorhynchus Mykiss, Walbaum, 1792) M. Enis YONAR*, Naim SAĞLAM*, Ünal İSPİR** * Department of Aquaculture and Fish Diseases, Faculty of Fisheries, Firat University, Elazig ** Department of Fisheries, Faculty of Agriculture, Bingöl University, Bingol meyonar@gmail.com (Received: 01.11.2009; Accepted: 10.08.2010) Summary In this present study, the plasma ceruloplasmin (Cp) level was examined in rainbow trout (Oncorhynchus mykiss, W.) feed on a diet with three different doses (100, 200 and 400 mg/kg) of sulfamerazine. Four groups of rainbow trout (Oncorhynchus mykiss) were fed experimental diets containing either no sulfemerazine (control) or supplemented with sulfamerazine at 100 mg/kg (Exp-A), 200 mg/kg (Exp-B), or 400 mg/kg (Exp-C) for 21 days. Blood samples were taken for the plasma Cp levels from fish on days 3, 7, 14 and 21 of feeding. The plasma Cp levels in fish fed with three different doses of sulfamerazine are significantly higher (p<0.01, p<0.001) than those in control fish. All values of the plasma Cp levels increased on the third day post-feeding and continued significantly (p<0.01, p<0.001) until the end of the experiment. Keywords: Sulfamerazine, Rainbow trout (Oncorhynchus mykiss), Ceruloplasmin (Cp). Gökkuşağı Alabalığında (Onchorhynchus Mykiss, Walbaum, 1792) Plazma Seruloplazmin Düzeyine Sulfamerazinin Etkisi Özet Bu çalışmada sulfamerazinin üç farklı dozunu içeren yemle (100, 200 ve 400 mg/kg) beslenen gökkuşağı alabalığında (Oncorhynchus mykiss, W.) seruloplasmin (Cp) düzeyi araştırıldı. Gökkuşağı alabalığının (Oncorhynchus mykiss) dört gurubu hem sulfamerazin içermeyen (kontrol) hem de 100 mg/kg (Exp-A), 200 mg/kg (Exp-B) ve 400 mg/kg (Exp-C) sulfamerazin içeren deney diyetleriyle 21 gün süreyle beslendi. Beslemenin 3, 7, 14, ve 21. günlerinde plazma seruloplazmin düzeyleri için balıklardan kan örnekleri alındı. Sulfamerazinin üç farklı dozunu içeren diyetle beslenmiş balıklarda plazma Cp düzeyi control grubu balıklarından önemli oranda daha yüksekti (p<0.01, p<0.001). Beslemeden sonra 3. günde plazma Cp düzeyinin bütün değerleri yükseldi ve deneme sonuna kadar önemli şekilde (p<0.01, p<0.001) devam etti. Anahtar Kelimeler: Sulfamerazin, Gökkuşağı alabalığı (Oncorhynchus mykiss), Seruloplasmin (Cp). 1. Introduction Sulphonamides are prepared by the reaction of a sulfonyl chloride with ammonia or an amine. Certain sulphonamides are sometimes mixed with the drug trimethoprim, which acts against dihydrofolate reductase. Sulphonamides are structural analogs and competitive antagonists of para-aminobenzoic acid (PABA). They inhibit normal bacterial utilization of PABA for the synthesis of folic acid, an important metabolite in DNA synthesis. The effects seen are usually bacteriostatic in nature. Folic acid is not synthesized in fish, but is instead a dietary requirement. This allows for the selective toxicity to bacterial cells (or any cell dependent on synthesizing folic acid) over fish cells. Bacterial resistance to sulfamerazine is caused by mutations in the folic acid enzyme that prevents the drug from binding and blocking folic acid synthesis [1, 2]. Sulfamerazine is a sulphonamide bacteriostatic antibiotic. It is most often used as part of a synergistic combination with trimethoprim. Its primary activity is against susceptible forms of Streptococcus, Staphylococcus aureus, Escherichia coli, Haemophilus influenzae, and oral anaerobes. It is commonly used to treatment Furunculosis