عنوان مقاله [English]
The histopathological effect of acute toxicity of ammonia an rainbow trout was studied during 24 hours at time zones 2001/May/5-2001/May/20 in Alostan fish culture center, Golestan, Iran. Experiments were done by static water method. Thirteen groups of fish with the average weight of 15g were encountered with different concentrations of total ammonia. Lethal concentration of ammonia during 24 hours was 25 mg/l. The maximum mortalities occurred in early time of experiment (70-80%). High ammonia levels (>15mg/l) induce convulsion, ataxia, bending of body muscle and opened operculum. In microscopic studies tissues of kidney, liver and gills showed hyperemia, hemorrhagi cell necrosis and influx of inflammatory cells.