Gaxiola (1994) found protein requirements of L. setiferus is 40% for PL and 10–40
50% for PL , showing a decrease in protein requirements according to age. The 10–30
protein requirements of early postlarvae of L. setiferus (PL ) are unknown, but results 1–10
from our study indicate the 50% protein content in MCD may not be enough to fulfill
protein requirements of these stages. The requirements of these early stages could also
have been affected by the quality of protein and lipid present in the MCD. Shrimp fed on
mixed live and artificial diet could have obtained a higher quality and quantity of
nutrients from food, which improved their physiological state and growth (protein
content of Artemia nauplii 55–56.5%, Leger and Sorgeloos, 1992; Rodr´ıguez et al.,
1994; Lemos and Rodriguez, 1998). In the present study, L. setiferus fed on MCD alone,
in the absence of live food, were affected in their growth rate and protease activity,
suggesting that nutritional requirements may not have been met by this diet. In other
shrimp larvae, feeding on artificial diets combined with live food enhanced growth and
decreased protease activity, as shown by Le-Vay et al. (1993) in Marsopenaeus
japonicus, and Kumlu and Jones (1995) in Fenneropenaeus indicus.