This study was conducted to evaluate the impact of dietary addition of polyethylene glycol (PEG) or activated sodium bentonite as tannins deactivation materials on the performance of Saanen goats fed diets containing pistachio by-products (PBP). Twenty-one Saanen male goats (27±3 kg, 10 months) were assigned to three dietary treatments in a completely randomized design and fed for 60 days. Three experimental diets consisted of a diet containing 30% dry matter (DM) pistachio by-products with no additive (control); control diet supplemented with PEG at 1.0% of DM (PEG group), and control diet supplemented with activated sodium bentonite at 1.0% of DM (G-bind group). Results indicated that dry matter intake (DMI), total gain, average daily gain (ADG), and ruminal pH were not affected by treatments (P≥0.05). There were no significant differences among treatments in hematological parameters (P≥0.05) except monocyte count (P<0.05). The plasma concentrations of total triglycerides (TG) decreased (P<0.05) by adding G-bind. Serum Insulin concentration was also increased significantly (P<0.05) in the PEG group compared to the control. Besides, the G-bind increased the calcium content of this muscle compared to the control and PEG group (P<0.05). Zinc content in muscle showed a significant increase in the PEG treatments in comparison to other experimental groups (P<0.05). Furthermore, Iron (Fe) content in muscle improved by both additives (P<0.05). Data showed that there were no significant differences among treatments for hair fiber characteristics (P≥0.05). It can be concluded that activated sodium bentonite can be an appropriate substitute for PEG as a tannin-deactivation material in diets containing 30% DM PBP for feeding goats. Manuscript profile