Using enriched-zeolite to increase survival rate of rainbow trout fingerlings (Oncorhynchus mykiss) in toxicity test with ammonia in emphasis to improve environmental conditions

The experiment was done during 24 hours in laboratory conditions. Fifteen fishes with mean weight of 524g and total length of 213cm exposed to lethal concentration of total ammonia (N-NH4) under stable conditions. For zeolite enrichment, zeolites frequently were exposed to solution of 10% NaCl and temperature of 90ºC for 30 minute. In lethal concentration of ammonia (25mg/l), amount of 1, 3, 5, 7, 8g/l enriched–zeolite was used. The results showed, there was significant difference between treatments (P<0.05). Using 8g/l enriched–zeolite could prevent mortality of fishes. Behavioral symptoms were investigated during tests. Samples were taken from gill of fishes and histopathological sections were prepared. The major lesions in the gills were hemorrhage, hyperplasia, edema and epithelial cells necrosis.