Study was conducted to avaluate the ability of totally or partially replacement shrimp feed by soybean meal. A 60 days period trial included seven triplicated treatments: soybean meal was used to fed juvenile Litopenaeus vannamei (mean initial wt.±Std, 0.7±0.015 g) at 100%, 80%, and 60% of the diet (DN-100, DN-80, and DN-60, respetively); in other three treatments soybean meal were substituted 50% for formulated shrimp feed (TA50-DN50; TA40-DN40, and TA30-DN30); while control (TA-100) is treament in which shrimp was feed with 100% formulated feed (42% Protein; Lotus-CP Group). Rice-flour (RF) was added at Caborhydrate:Nitrogen of 15:1 into culture system to stimulate the microbial biofloc growth. Replacement of 50% formulated feed by soybean meal (TA50-DN50) for Litopenaeus vannamei cultured in biofloc system resulted in equivalent values for survival rate and final weight with the control, while the water quality was improved by reduction of TSS and VSS (71%), TAN (92%), NO₂^- (91%) and Vibrio (65%). Results indicated that soybean meal can be replaced  for 50% of formulated feed for Litopenaeus vannamei; bio-secure shrimp was produced as shrimp was cultured in biofloc system (no chemical or antibiotic was added).