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Aquaculture is incessantly infected with various types of micro‐or‐ganisms from different origin, including bacteria. Immunostimulants are profusely and efficiently used as feed additives in aquaculture (Dawood, Koshio, Abdel‐Daim, & Van Doan, 2019; Dawood, Koshio, & Esteban, 2018). Lipopolysaccharide (LPS) is a product of gram‐neg‐ative bacteria cell wall, act as a potent immunomodulator of innate immune response (Bishop, 2005; Raetz & Whitfield, 2002), which is characterized by a production of proinflammatory cytokines, and reactive oxygen species (ROS)(Abo‐Al‐Ela, 2018b; West & Heagy, 2002). Once the production of ROS exceeds the cellular antioxidant capacity (Agnisola, 2005; Palumbo, 2005), it leads to oxidative stress (Feng, Zhang, Zheng, Xie, & Ma, 2008; Halliwell & Whiteman, 2004) that results in severe cellular injury (ie lipid, protein and DNA de‐structions)(Abo‐Al‐Ela, 2019; Abo‐Al‐Ela, El‐Nahas, Mahmoud, & Ibrahim, 2017b; Mujahid et al., 2007). This injury shifts cellular net charge and disturbs cellular osmotic pressure that in turn result in swelling of cell and eventually cell death (van Hoorn et al., 2001). The deleterious effect of excessive ROS is balanced by many cellular defence activities, including antioxidant defence mechanisms (Paital & Chainy, 2010). The antioxidant defence system works to keep ROS at lower levels (Paital & Chainy, 2010) by improving the efficiency of the mitochondrial electron chain (Fazio, Piccione, Saoca, Caputo, & Cecchini, 2015). The main molecules of the antioxidant defence network are three antioxidant enzymes: superoxide dismutase (SOD), glutathione peroxidase (GPx) and …