Prevention of acute ammonia toxicity in bluga (Huso huso), using natural zeolite

The research was accomplished in order to study the efficiency of natural zeolite to prevent acute toxicity of ammonia on Huso huso. The study was performed using Water static method for 96 h. Fish with average weight 46 ± 5 g and total length 22 ± 4 cm were exposed to four different concentrations (15, 30, 50, 75 mg L-1) of ammonia salt. A group of fish was considered as control. Under stable condition, the lethal concentration of ionized ammonia was 50 mg L-1 during 96 h. In the lethal concentration of total ammonia, different amounts of 5, 10, 15 g L-1 granulated clinoptilolite zeolite were used. Results indicate significant differences between treatments and also with control (p < 0.05). With increasing clinoptilolite zeolite in each treatment, the survival rate of fish also increased significantly (p < 0.05). In lethal concentration of ammonia, the use of 15 g L-1 zeolite could prevent the mortality rate. Histopathological findings showed that major lesions were hemorrhage, hyperemia, hyperplasia, epithelial cells necrosis, degenerated tubules of kidney, expansion of Bowman's capsule and hepatocytes necrosis. Key words: Ammonia, histopathological, lethal concentration, zeolilte, Huso huso.