en Aquaculture and Health management Aquaculture and Health management پژوهشي Original research papers <p style="margin: 0in 0in 10pt; text-align: justify;">This study aimed at determining impacts of various amounts of water-soluble poly-saccharide extracts from brown algae, <em>Padina australis</em> (Hauck) (WPP) on actions of anti-oxidant enzymes, the growth, and non-specific immune response of shrimp, <em>Litopenaeus vannamei</em> (Boone). Triplicate groups of shrimp (1 &plusmn; 0.1g) have been given feed 4 iso-nitrogenous and iso-lipidic diets composing of 4 levels; that is, 0 (control), 0.5, 1.0, and 1.5 g kg^-1 of WPP extract for eight weeks. Analyses showed that significantly positive effects of diets with 1.0 g kg^-1 of WPP extract on the growth function of the studied groups. Additionally, improvements of the anti-oxidant enzyme activities, such as catalase, malondialdehyde, super-oxide dismutase, and glutathione peroxidase via feeding 0.5 and 1 g kg^-1 of WPP extracts. Furthermore, activity of phenoloxidase and lysozyme in the treatment fed by 0.5 and 1 g kg^-1 of WPP extract have been considerably greater in comparison to the controls and 1.5 g kg^-1 treatments. Findings demonstrated that usage of 1.0 g kg^-1 of water soluble poly-saccharides extract of the <em>P. australis</em> are useful on growth function, antio-xidant and non0specific immune variables of the <em>L. vannamei</em>.</p> Antioxidant enzyme and Immune response, Padina australis, Litopenaeus vannamei, Water-soluble polysaccharides 73 85 http://ijaah.ir/browse.php?a_code=A-10-83-6&slc_lang=en&sid=1 P Akbary paria.akbary@gmail.com 10031947532846002017 10031947532846002017 Yes Department of Marine Sciences, Chabahar Maritime University, Fisheries group, Chabahar, Iran Z Aminikhoei pariaakbary1355@gmail.com 10031947532846002018 10031947532846002018 No Agricultural Research Education and Extension Organization (AREEO), Iranian Fisheries Science Research Institute (IFSRI), Offshore Research Center, Chabahar, Iran