02123naa a2200241 a 450000100080000000500110000800800410001910000150006024501060007526000090018152014510019065300200164165300140166165300250167565300200170065300120172070000170173270000170174970000180176670000230178470000200180777300540182711215562014-09-05       2014    bl uuuu     u00u1 u    #d1 aJATOBA, A.  aProtein levels for Litopenaeus vannamei in semi-intensive and biofloc systems.h[electronic resource]  c2014  aThe aims of this research were to evaluate the zootechnical performance and dietary cost for the marine shrimp (Litopenaeus vannamei) cultured in a superintensive biofloc system and a conventional semi-intensive system using diets containing different protein levels. Four different diets, with crude protein (CP) contents of 24.3, 30.3, 32.9 and 36.7% were produced. In the laboratory, experimental culture in the biofloc system was performed in twelve experimental units at a density of 250 shrimp m− 3, the four treatments were performed in triplicate. The semi-intensive culture system was applied at the commercial farm in eleven ponds containing 15.5 shrimp m− 2. After 49 days, the zootechnical performance of the shrimp was rated, and the cost per kilogram of shrimp was produced by both culture systems. In the semi-intensive system, the shrimp fed with a diet containing 32.9% CP showed a higher final weight and weight gain and a lower dietary cost. In the biofloc culture, a higher final weight, weight gain, growth rate and productivity were observed in shrimp fed diets containing 30.3, 32.9 and 36.7% CP compared with those fed a diet containing 24.3% CP. The lowest dietary cost of shrimp farming in the biofloc system was registered in the shrimp fed the 30.3% CP diet, whereas, in the semi-intensive system, the highest final weight, highest weight gain and lowest cost were observed in shrimp fed the 32.9% CP diet.  aFarming systems  aNutrition  aPacific white shrimp  aProduction cost  aProtein1 aSILVA, B. C.1 aSILVA, J. S.1 aVIEIRA, F. N.1 aMOURI??O, J. L. P.1 aSEIFFERT, W. Q.  tAquaculture, Amsterdamgv. 432, p. 365-371, 2014.