ONTOGENIC CHANGE IN DIGESTIVE ENZYME-ACTIVITY DURING LARVAL DEVELOPMENT OF MACROBRACHIUM-ROSENBERGII

This study was conducted to determine the ontogenetic changes in tryps in, non-specific esterase and amylase activities in Macrobrachium rose nbergii during larval development. Two batches of M. rosenbergii larva e were reared separately in 300-1 tanks at 50 larvae l-1. Rearing temp erature and salinity were maintained at 30 +/- 2-degrees-C and 12 ppt, respectively. The larvae were daily fed with newly hatched Artemia na uplii at 5 nauplii l-1. Trypsin, esterase and amylase activities in th e larvae were estimated using TAME, butyrylthiocholine iodide and com starch, respectively, as substrates. The results showed that maximum p eaks of trypsin and esterase activities occurred at stage V-VI. Amylas e activity remained low until the larvae reached stage VI-VIII, indica ting that the early-stage M. rosenbergii larvae are exclusively carniv orous. Maximum amylase activity was observed at stage X-XI. In general , the ontogenetic digestive enzyme activities in developing prawn larv ae seemed to coincide with hepatopancreas development.