Shrimp feeds are presently formulated to contain a high protein level. Protein is one of the major and most expensive components of feeds. A reduction in protein content of feeds or the use of less expensive protein supplements could considerably reduce feed costs. The most researched area in shrimp nutrition has been proteins. It is generally believed that postlarval shrimp require a higher protein level than larger shrimp. Recommended protein levels vary from 30% to 57% in various species and sizes of marine shrimp. Regardless of differences in protein requirement, it is believed that sub-optimal growth occurs due to imbalance in, rather than deficiencies of, the essential amino acids. If the culture system is not totally dependent on commercial feeds, i.e. if natural foods are available, protein levels may be reduced (Akiyama et al., 1992).