Study on the occurrence of Streptococosis in some trout nourishment farms in Chaharmahal va Bakhtiari

Objective: The Province of Chaharmahal va Bakhtiari is one of the important centers of production and nourishment of cold water fishes in Iran. Regarding the prevalence of symptoms such as mortality, vertical swimming, hyper pigmentation, uni or bilateral exophthalmia, gills hyperemia, this study was carried out to investigate the occurrence of streptococosis in this province. Method & Materials: In 2007, 83 suspect fishes of 4 trout nourishment farms at Boroujen were detected. Then samples of kidney were cultured in TSB (Trypton Soya Broth) and Blood Agar and were incubated at 25 centigrade degree. After 24-48 hours white colonies with Beta haemolyse were observed. After Gram staining and observation of Gram positive coccies bacteria and regarding to the clinical signs, the cause was confirmed as Streptococosis. Results & Conclusion: All samples were sunjected to Streptococos iniae serological test. These samples were positive at this test. We found that contamination rate in farms from Boroujen was 35% and mortality rate was 27%-61% and we found that important factors in occurrence of streptococosis were high temperature of water, particularly in that year, handling the fishes at farm from retail, lower quality of water and person transition at farms. Regarding to occurrence of streptococosis in some provinces in Iran preservation suitable quality of water, to make available suitable nourishment and make clean and hygienic environment for fishes are very important to prevent the disease.

کلیدواژه ها:

Streptococosis ، trout