The study aimed to measure the exogenous enzyme contribution to the endogenous enzyme activities of trypsin and leucine aminopeptidase in mud crab during early 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. Percent contribution to trypsin activity by live food was significantly higher (about 50%) at Z2 to C1 stages which were not significantly different from each other. The range of contribution to trypsin activity was 0.3 – 57% with the peak observed at the megalopa stage. The range of contribution to LAP activity was 47-93% with peaks at Z4 and megalopa stages. Thus, the importance of live food as source of trypsin and leucine aminopeptidase in the early developing crab larvae was demonstrated in the present study.
