Sub- lethal toxicity effects of 2, 4- D+ MCPA herbicide on some hematological indices and liver enzymes of rainbow trout, Oncorhynchus mykiss

This study aimed to evaluate the Sub- lethal toxcity effects of 2, 4- D+ MCPA herbicide after 2 week and 3 week on some hematological indices and liver enzymes of rainbow trout, Oncorhynchus mykiss. After determining LC50 by probit model, induced sub- lethal concentration (1/9 LC50) 0.11 mL/L (0.11 mL/L of  this herbicide equal 40 mg/L, 2, 4- D, 35 mg/L MCPA ) of  this herbicide were studied.. Blood samples of rainbow trout with weight mean 97 g were taken in the 72 hours following exposure to sub- lethal  concentration  of 2,4,D- MCPA herbicide after 2 week and 3 week with fish that were not exposed. The results showed that 2, 4, D- MCPA herbicide could changes in blood parameters and liver enzymes of rainbow trout by reducing red blood cell (RBC),  white blood cell (WBC), neutrophil and lymphocyte in treatments were influenced by the herbicide after 2 week and 3 week (P<0.05). The lowest RBC and the highest monocyte, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were observed in the treatment of fish exposed to sub-lethal concentration of herbicide after three week (P>0.05) The results of this study showed that sub-lethal toxicity of 2,4 D- MCPA herbicide after 2 week and 3 week with the reduction of white blood cells, neutrophil and lymphocytes could weaken the activity of the immune system of rainbow trout and increase the level of liver enzymes In blood serum, it also shows the damage caused by exposure to this toxin