Effect of Silymarin extract on immune system of Rainbow trout (Oncorhynchus mykiss ) challenged by diazinon

To date, discharge of agriculture pesticides into surface water is one of the biggest environment problems that can threaten the aquatic life. Impact of pollutants on the fish immune system can result in sensitivity and becoming vulnerable to pathogens. Diazinon, one organophosphate pesticides that used in many agriculture areas of Iran, is found in surface water. The purpose of this study was to evaluate effects of diazinon on fish immune system and use of Milk thistle plant extract, Silybum mariamum, in to reducing adverse effects of this toxin on the immune system of rainbow trout. Significantly reduced plasma levels of peroxidase, IgM, total complement, lysozyme of fish that had been exposed to diazinon have well illustrated the impact of diazinon on immune system in long periods. While, no significant change was observed in the fish nourished by complementary diet and challenged by toxin compared with control fish group that indicated this protective and amplified effect of silymarin on immune system of rainbow trout.