A Study on Qualitative and Quantitative Bacterial Flora of the Rainbow Trout (Oncorhynchus mykiss) Living in Different Fish Farms

In this study, the qualitative and quantitative aspects of aerobic bacterial flora of the skin, gills, intestine, liver, kidney and spleen of rainbow trout in relation to pond water in two different fish farms were analysed. The bacterial load of pondwater in Seniçbey Farm was 10 2 -10 5 cfu/ml. It was determined that the total viable counts of aerobic microorganisms of pond water in this farm were higher than these in Aksu Farm (10 2 -10 4 cfu/ml). The total bacterial counts in the skin of rainbow trout in Seniçbey Farm were 10 2 -10 7 cfu/g, while in Aksu Farm they were 10 1 -10 6 cfu/g. the number of bacteria in the fish feed was also found to be 10 2 -10 4 cfu/g. In this study, a total of 1083 strains was isolated from rainbow trout and pond water. interestingly, the predominant bacterial group present in the rainbow trout and pond water of both farms was identified as coryneforms. The majority of the bacterial groups isolated from the gill, skin, viscera and intestine comprised Gram positive cocci, Enterobacteriaceae, coryneforms, Vibrio and Aeromonas,which was similar to the bacterial flora of the pond water in the farms. The results of this study showed that hygienic conditions in pond water in fish farms have an effected on qualitative and quantitative aspects of bacterial flora in the rearing of fish and on fish health.