The effects of two microencapsulated feeds were evaluated on development, growth, survival, proteolytic activity, and biochemical composition of white shrimp, Litopenaeus vannamei, larvae. The treatments were: (1) basal microcapsules (BM), (2) microcapsules containing krill hydrolysate (BMK), and (3) live food control (LFC: Artemia franciscana nauplii) with all treatments receiving algae (Chaetoceros ceratosporum and Tetraselmis chuii). No significant differences were found in development index and survival among larvae. Growth rate was significantly higher in larvae fed LFC (15 +/- 0.06%/d) as compared with those offered the BM diet (7.5 +/- 0.5%/d) with the BMK (11 +/- 0.04%/d) treatment producing intermediate results. The activity of total proteases and chymotrypsin decreased significantly after Mysis I (MI) in larvae fed LFC or BMK. Protein content of larvae increased significantly toward PL1. The acylglycerides content in MIII fed on LFC (2.3 +/- 0.2%/dw) was higher than that MI fed BM (1 +/- 0.01%/dw). No difference was observed in the cholesterol (CH) content of the larvae. The acylglycerides/protein and cholesterol/protein ratios showed a decreasing pattern between MI and PL1, indicating that these two ratios were related to ontogenetic shifts. These results demonstrate improvements in microparticulate diets when krill hydrolysates are included in the formulation.