Augusto E. Serrano, Jr
This study aimed to measure the exogenous enzyme contribution derived from live feed to the endogenous amylase and total protease activities in the mud crab, Scylla serrata larvae at various stages of development. Crab larvae at various stages were fed live food (A) or inactivated live food (B): Enzyme activity of A group was the endogenous activity while [(A-B)/A] x 100 was the percent contribution of exogenous enzyme derived from live food. Amylase activity level derived from live food were significantly different at various stages of development (P<0.05). Exogenous amylase activity started very low at Z1 (10.3%) increased to 23.3% at Z2 and to more than double at Z3. The activity decreased abruptly to less than half (22.1%) at Z4 and remained at almost similar levels at Z5, megalopa and CI stages (28.8, 25.0, and 17.5%, respectively). Total protease activity varied significantly among development stages. The contribution of live food-derived total protease activity was very high level (84.4%) at Z1 and decreased abruptly at Z2 (33.1%). It increased to a small peak at Z3 (47.0%), remained low at Z4 and Z5 (34.8 and 31.9%, respectively) and increased at the megalopa stage (43.2%) and decreased at its lowest level at CI stage (24.6%). Endogenous total protease activity reflected the reported anatomical development of the digestive system in S. serrata larvae
