Effect of dietary prebiotic supplement of oyster mushroom powder (Pleurotus ostreatus) on the P450 and Hsp70 genes expression in liver tissue of Nile tilapia (Oreochromis niloticus) in exposure to chlorpyrifos

Increased entry of pesticides such as chlorpyrifos into aquatic ecosystems can cause harmful damage to aquatic animals. The aim of this study was to investigate the effect of dietary supplement of Pleurotus ostreatus mushroom powder on the relative expression of immune-related genes (P450 and Hsp70) in the liver tissue of Nile tilapia (Oreochromis niloticus) in response to chlorpyrifos toxin. In this study, 120 juveniles of Nile tilapia with an average weight of 20±0.4g were divided into four treatments in three replications and fed with diet containing 0 (control), 0.05, 0.1 and 0.2% fungus for 42 days. At the end of the feeding trial, all treatments were exposed to the sub-lethal concentration of chlorpyrifos for 14 days. Liver tissue samples were taken to evaluate the relative expression on the last day of the mushroom feeding period and on the 14th day of exposure to chlorpyrifos. The relative expression of P450 in treatments of 0.2 and 0.1 were significantly increased, but the treatments of 0.05 and 0.1 after exposing to poison was not significantly different from the control group (P>0.05). Expression of Hsp70 gene in treatments fed with dietary supplement before and after exposure to toxin was significantly different (P<0.05). It increased in 0.2 treatment, but it was not significantly different in 0.05 treatment from control (P>0.05). The results of this study indicate the positive effects of Pleurotus ostreatus prebiotic dietary supplements on the relative expression of Hsp70 and P450 genes in Nile tilapia juveniles and its immune system strengthen in the face of contaminants and stressful substances such as chlorpyrifos