fa <p style="text-align:justify;line-height:120%;direction:ltr;unicode-bidi:embed;"><span style="color:black;"><span style="font-size:12.0pt;">The effects of two diets, a control diet (commercial feed with 39% crude protein) and an experimental diet (prepared based on 42% soybean meal with 38% crude protein), on growth performance of western white shrimp (<em>Litopenaeus vannamei</em>) in six 0.4-ha-earthen ponds (three replications per treatment) with 25 per m² density, were investigated. There was no significant difference in final weight (mean final weights were 15.7&plusmn;0.88 and 15.6&plusmn;0.52 g for the experimental and control treatments, respectively) between the treatments during the 115 days rearing period. There were no difference in FCR: 1.80&plusmn;0.08 and 1.76&plusmn;0.06, protein efficiency: 1.46&plusmn;0.01 and 1.45&plusmn;0.05, SGR: 2.38&plusmn;0.04 and 2.38&plusmn;0.03, final production: 2853.58&plusmn;64.14 and 2864.83&plusmn;168.57 kg/ha and survival rate: 91&plusmn;1.78, 92&plusmn;2.41% between experimental and control treatments, respectively (<em>p</em>>0.05) but net protein utilization in experimental treatment (17.05&plusmn;0.38 g) and in the control (11.80&plusmn;0.26 g) revealed significant differences (<em>p</em><0.05). It is concluded that the experimental feed with 42% soybean meal was more efficient than the commercial feed on some growth parameters of western white shrimp.&nbsp;</span></span></p> Plant protein, Western white shrimp, Earthen pond, Growth performance 578 586 http://jifro.ir/browse.php?a_code=A-10-911-1&slc_lang=fa&sid=1 R. Ghorbani Vaghei ghorbani_v2@yahoo.com 100319475328460021325 100319475328460021325 Yes M.H. Abolhasani 100319475328460021326 100319475328460021326 No R. Ghorbani 100319475328460021327 100319475328460021327 No A. Matinfar 100319475328460021328 100319475328460021328 No