THE EFFECT OF FEED TYPES ON SURVIVAL AND TRYPSIN ACTIVITY IN TEMORA-LONGICORNIS (CRUSTACEA, COPEPODA)

In this study, the effects of different diets on the survival and tryp sin-like activity of a calanoid copepod Temora longicornis were invest igated in the laboratory. The animals were starved or fed live algae ( Diet A), a microencapsulated diet (Diet B), or the microencapsulated d iet plus frozen algal cells (Diet C) for 10 days. The highest survival (69%) was obtained with those fed Diet A, whereas the lowest (11%) wi th the starved control (p<0.05). At the end of the experiment, animals fed Diet C displayed a significantly better survival (53%) than those fed Diet B (32%; p<0.05). Measurement of trypsin-like activity reveal ed that the animals adapted their digestive enzymes to live or dead al gal cells more rapidly (within 24 h of feeding) than to formulated die t particles (after 5 days of feeding). The animals fed Diet A had the highest trypsin-like activity (p<0.05). Addition of frozen algal cells into the culture (Diet C) induced a significantly higher trypsin-like activity over Diet B fed animals (p<0.05). It seems that proteolytic enzymes of copepods feeding on artificial or live feeds have similar r esponses to other planktonic decapod crustaceans feeding at the primar y consumer level.