en aquaculture aquaculture پژوهشي Orginal research papers The blue-green algae <em>Spirulina</em> <em>platensis</em> was cultured with different nitrogen regimes (NH₄Cl, NH₄NO₃ and KNO₃) with concentrations of 0.010, 0.025 and 0.050 M and then fed to Litopenaeus <em>vannamei</em> at 19 days post hatch (PL_I) to evaluate the nutritional quality. At the end of the experiment, growth and survival rate were determined, and the larval development was calculated. The maximum protein content was obtained in culture media containing NH₄NO₃ followed by NH₄Cl and KNO₃ (<em>p</em>>0.05). Moreover, in all <em>S.</em> <em>platensis </em>cultures<em>, </em>increases in nitrogen concentrations led to increases in protein content. The present study showed that, with the exception of shrimp larvae at 5 days post hatch, <em>L.</em> <em>vannamei</em> shrimp larvae fed on <em>S.</em> <em>platensis</em> cultured in NH₄NO₃, as a nitrogen regime, generally developed significantly (<em>p</em><0.05) faster to next stages compared with the other treatments. However, the survival rate (%) and total length (mm) of shrimp larvae fed on <em>S.</em> <em>platensis</em> did not show any significant difference (<em>p</em>>0.05) when the nitrogen was varied in terms of regimes. Overall, the study points to the potential effectiveness of using NH₄NO₃ as a nitrogen regime in <em>S.</em> <em>platensis</em> culture media in producing live food for the hatchery production of <em>L. vannamei</em> shrimp larvae. Nitrogen, Spirulina platensis, Survival rate, Larval development, Litopenaeus vannamei 358 369 http://jifro.ir/browse.php?a_code=A-10-3224-2&slc_lang=en&sid=1 M. Gorgij Jaski sontderafshrimp@yahoo.com 100319475328460039265 100319475328460039265 Yes Bandar Abbass Azad University, Bandar Abbas, Iran K. Rohani Ghadikolaei roohani2001ir@yahoo.com 100319475328460039266 100319475328460039266 No Head of Aquaculture Department M. Yahyavei maziar_yahyavi@yahoo.com 100319475328460039267 100319475328460039267 No University Lecturer A.R. Salarzadeh aquaculture2011@gmail.com 100319475328460039268 100319475328460039268 No University Lecturer