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Abstract
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The study was conducted to determine LC50 96 hours of NeemAzal toxin and chronic effects of sublethal doses (0.073, 0.15 and 0.22 ppm) on gill morphology and blood biochemical parameters of grass carp (Ctenopharyngodon idella) with an average weight of 3/2 ± 2/7. Atotal of 120 fish were distributed equally between three treatments and a control group. The fish?s were exposed to different concentrations of the biopestiside for 96 hours and mortality were recorded. The 96h Lc50 was analyzed using Finney's probit, 0.73 ppm was obtained. Fish?s behavior was observed during the test. irregular swimming, rotation, reaction increased response versus stimulus exterior, solitary and imbalance was observed. The results of analysis of biochemical parameters after 28 days demonstrated significant effect of NeemAzal toxin on the levels of ALT, AST, LDH and ALP (p<0.05) so, these values were decreased with increasing doses of toxin. The highest levels of ALT (9.00), AST (59.5), LDH (1131) and the level of ALP (240.4) in the control group were observed. Protein and albumin levels were decreased by increasing the dose of toxin (p>0.05). In histology studies, samples were taken from gill tissue of the treated and control groups. The common alterations observed were hyperplasia and fusion of gill lamellae, epithelial uplifting (swelling) and necrosis of gill epithelial cells. The results showed that sub lethal doses of NeemAzal toxin, decreased protein and serum albumin levels (p>0.05) and it significantly decreased the liver enzymes such as LDH, ALT, AST and ALP (p<0.05) and the after exposure gills to the toxin phenomena such as hyperplasia and fusion of gill lamellae, epithelial uplifting and necrosis of gill epithelial cells were observed.
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