en Aquaculture and Health management Aquaculture and Health management پژوهشي Original research papers <p style="margin: 0in 0in 10pt; text-indent: 0.3in; text-align: justify;">The primary aim of the current study has been to examine the impacts of dietary supplementary of <em>Chlorella vulgaris</em> (<a href="https://en.wikipedia.org/wiki/Martinus_Beijerinck" title="Martinus Beijerinck"><span style="color:#000000;">Beijerinck</span></a>) powder (CP) different levels on the anti-oxidant enzyme activities, growth, and immune responses of the juvenile <em>Mugil cephalus </em>(Linnaeus). Experimental Fish (15 &plusmn; 0.1g) was fed diets enriched with 0 (control), 5, 10, and 15 g CP per kg feed for eight weeks period. After the feeding trial period, the fish were challenged against pathogenic bacteria (<em>Photobacterium damselae </em>(subsp. piscicida)) for evaluating the resistance of infected fish to diseases. According to the results, fish growth performance was significantly improved with increasing CP levels&nbsp;at CP10 and CP15.&nbsp;Antioxidant-stimulated activity was observed with dietary&nbsp;CP where total antioxidant capacities (TAC), glutathione (GSH), and super-oxide dismutase (SOD) augmented, while malondialdehyde (MDA) decreased significantly in fish fed CP.&nbsp;Furthermore, serum lysozyme activity of fish fed three levels of CP has been considerably enhanced in comparison with the control group (p <0.05). Moreover, CP supplementation at 10 and 15 g dose induced kidney phagocyte and respiratory burst activity which was maximized at 15 g CP. Meanwhile, feeding 10 and 15 g of CP diets decreased mortality in <em>M. cephalus</em> after challenge with <em>P. damselae</em>.&nbsp; The present study indicated the role of optimal doses <em>Chlorella vulgaris</em> extract (10 and 15 g kg ^-1 feed) on growth and antioxidant defense and immune status of grey mullet.</p> <p style="margin: 0in 0in 10pt; text-indent: 0.3in;"><br> &nbsp;</p> Chlorella vulgaris. Mugil cephalus. Kidney phagocytic, Respiratory burst, Lysozyme, Superoxide dismutase (SOD) 57 70 http://ijaah.ir/browse.php?a_code=A-10-83-7&slc_lang=en&sid=1 P Akbary paria.akbary@gmail.com 10031947532846002202 10031947532846002202 Yes Department of Fisheries, Faculty of Marine Sciences, Chabahar Maritime University, Chabahar, Iran Z Aminikhoei pariaakbary1355@gmail.com 10031947532846002203 10031947532846002203 No Offshore Research Center, Iranian Fisheries Science Research Institute, Agricultural Research Educations and Extension Organization, Chabahar, Iran