en aquaculture aquaculture پژوهشي Orginal research papers <span lang="TR" style="font-size:11.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">The unique behavior of silver nanoparticles (AgNPs) led to their increasing use in a wide range of products and the high discharge of these particles in the aquatic ecosystem. Regarding little information about the toxicity of AgNPs in the aquatic environment, the prediction of possible environmental hazards is the hot topic of current research studies. This study aimed to investigate the effects of long-time exposure of Asian seabass (<i>Lates calcarifer</i>)</span></span></span><span lang="AR-SA" style="font-size:11.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">&lrm;</span></span></span><span lang="TR" style="font-size:11.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black"> to green (using brown macroalga extract) and chemically synthesized </span></span></span><span lang="AR-SA" style="font-size:11.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">&lrm;</span></span></span><span lang="TR" style="font-size:11.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">AgNPs on oxidant/antioxidant and immunological responses. The LC₅₀ of both synthesized AgNPs was determined on fish (mean weight: 15&plusmn;2.2 g) after 96 h (LC₅₀ for green synthesized AgNPs= 18.27 mg/l and for chemical synthesized AgNPs= 1.32 mg/L). Fish were exposed to green and chemical synthesized AgNPs concentrations of 0 (control), 5, 10, and 25% LC₅₀ for 60 days. For each treatment, 90 juveniles (22&plusmn;1.5 g) were distributed in fiberglass tanks (300 L)and fed for 60 days. Fish were sampled at 1, 30, and 60 days after exposure. The liver tissue of fish samples was isolated and homogenized and then the activity of catalase (CAT), superoxide dismutase (SOD) and glutathione (GSH), and malondialdehyde (MDA) was determined. The complement pathway activity (ACP), total immunoglobulin (Ig), total protein, albumin (ALB) </span></span></span><span lang="AR-SA" style="font-size:11.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">&lrm;</span></span></span><span lang="TR" style="font-size:11.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">concentration, and globulin (GLO) were measured in fish blood samples. The results showed that green synthesized </span></span></span><span lang="AR-SA" style="font-size:11.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">&lrm;</span></span></span><span lang="TR" style="font-size:11.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">AgNPs first </span></span></span><span lang="AR-SA" style="font-size:11.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">&lrm;</span></span></span><span lang="TR" style="font-size:11.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">increased the activity of the antioxidant system and then significantly reduced its activity. However, after exposure to chemically synthesized AgNPs, </span></span></span><span lang="AR-SA" style="font-size:11.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">&lrm;</span></span></span><span lang="TR" style="font-size:11.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">the activity of the antioxidant system showed a significant decrease. Both green and </span></span></span><span lang="AR-SA" style="font-size:11.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">&lrm;</span></span></span><span lang="TR" style="font-size:11.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">chemically synthesized AgNP exposure caused an increase in proinflammatory activities and </span></span></span><span lang="AR-SA" style="font-size:11.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">&lrm;</span></span></span><span lang="TR" style="font-size:11.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">immune proteins, and these activities were more </span></span></span><span lang="AR-SA" style="font-size:11.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">&lrm;</span></span></span><span lang="TR" style="font-size:11.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:black">pronounced after exposure to green-synthesized AgNP.</span></span></span> Nanoparticles, AgNPs, Barramundi, Antioxidant system, Proinflammatory activity 259 275 http://jifro.ir/browse.php?a_code=A-10-4906-1&slc_lang=en&sid=1 J. Shokouhi jamshid.shokouhi@gmail.com 100319475328460055151 100319475328460055151 No Department of Fisheries, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran A. Askary Sary askary_sary@yahoo.com 100319475328460055152 100319475328460055152 Yes Department of Fisheries, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran M. Chelemal Dezfoulnejad m_chelemal@yahoo.com 100319475328460055153 100319475328460055153 No Department of Fisheries, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran M. Khodadadi mjkhodadadi@gmail.com 100319475328460055154 100319475328460055154 No Department of Fisheries, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran S.Z. Masoomizadeh zmasoomi@yahoo.com 100319475328460055155 100319475328460055155 No Department of Fisheries, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran