The present study was conducted to evaluate the effects of oral administration of hot-water extract of the brown algae, Sargassum ilicifolium on the growth performance, digestive enzymes, and proximate composition in Penaeus vannamei. In this study, 600 shrimps with an average body weight of 4.7±0.55 g were distributed in 4 treatments with 3 replicates. Shrimps were fed a diet supplemented with 0 (control), 0.25, 0.5 and 1% hot-water extract. After a 66-day trial, the results showed a significant increase in the intestine and hepatopancreas amylase and protease activity of the shrimp fed with 0.25 and 0.5% hot-water extract. The intestine lipase activity was significantly lower in both treatments fed with 0.25 and 0.5% of the hot-water extract, while in the 1% treatment was significantly higher than in the control. The shrimps fed with 0.25 and 0.5% hot-water extract showed significantly higher hepatopancreas lipase activity than the control. The proximate composition analysis revealed no differences among the treatments with the control in the amount of fat, ash, protein, and moisture. The growth performance was also not influenced by the different amounts of supplementation. Although the growth parameters were not influenced by the supplemented fed diets, the enhanced enzymatic activity in the intestine and hepatopancreas may result in better efficiency in the prolonged feeding trial. It could be suggested that the use of the hot-water extract of S. ilicifolium as a natural supplementation without any adverse effects on the growth and proximate composition, could be beneficial in shrimp culture.