Comparison of Huwa-San TR-50 solution efficiency with malachite green and Formalin on fungal contamination control of rainbow trout (Oncorhynchus mykiss) eggs in incubation stage

This research was conducted in autumn and winter of 2016 in Shahid Motahary Coldwater Fishes Genetic and Breeding Research Center. The purpose of this study was to evaluate the effect of Huwa-San TR-50 solution on controlling rainbow trout fungus contamination at incubation stage and comparing its effects with malachite green and formalin. To do this, 27 Californian traphs were used in 9 treatments and 3 replicates, and 700 eggs of rainbow trout were stoked  in each traph. 5 treatments with different concentrations (50, 100, 200, 300 and 500 ppm) of Huwa-San TR-50 solution, one treatment with malachite green (2ppm) and one treatment with formalin (1000ppm), by bathing for 30 minutes were disinfected; a positive control (contaminated with fungi and without medication) and a negative control (non-infected with fungi and without medication) were also considered. The results showed that solution of 300 ppm Huwa-San TR-50 was suitable concentration for disinfection of eggs. Percentage of eyed egg and hatching at higher doses and lower than 300 ppm Huwa-San TR-50 showed a decreasing trend.