Regarding carbohydrate utilization, Bautista & Subosa (1997) mentioned that protein contents in diets improve growth when combined with carbohydrate contents. This means that carbohydrate is used as an economical energy source. In this study, two relative contents of carbohydrate were used: low content (16.3 to 23.5%) and high content (34.6 to 35.8%). Results showed that low relative content is enough to keep better growth parameters. In this sense, carbohydrate is used to build quitine (main component of exoskeleton) and also a component of fatty acids and sterols (Clifford & Brick, 1978; Kucharski & Da Silva, 1991; Cruz-Suarez, 1996). Diaz-Herrera et al. (1992) reported carbohydrates as main energy sources for metabolic requirements in post larvae and juveniles of M. rosenbergii; later supported by Luna et al. (2007). Rosas et al. (2000) stated the possibility to reduce protein contents in diets by carbohydrates included as starch ingredient.