effects of the prebiotic in reducing histopathological changes and immune response of cyprinuscarpio after exposer to abamectin

Background: to assess the toxicity of environmental pollutants in fish, there are different physiological parameters including histology. this study aimed to investigate the effect of prebiotic dietary supplement on fish immune response after exposure to toxicant. methods: the study was conducted in the gorgan university of agricultural and natural resources aquaculture laboratory in 2017. common carp species were obtained and exposed to 2 ppm, 3 ppm, 6 ppm abamectin as a toxicant. prebiotic isomalto-oligosaccharides added to diet with spray method as 1 g/kg and histopathological examinations were done after 60 d experiment. there were no significant differences between aquariums in water quality during the test and no mortality and injuries were observed during accumulation. results: the abamectin caused some lesions such as vacuolization latest, bleeding, necrosis, degeneration of the epithelium, the destruction of the villi in the intestine, destruction of liver cells, ascites, hemorrhage, necrosis and nuclear karyolysis in the liver and lymphocytes penetration and degradation of intestinal epithelium in intestine. maximum lesions observed in 6-ppm toxicant concentration. conclusion: the isomalto-oligosaccharides probiotics was not successful in stimulating the immune system and reducing adverse effect of toxicant in common carp, significantly. however, usage of this prebiotic could be useful in some cases.