INFLUENCE OF FEEDING ON HEPATOPANCREAS STRUCTURE AND DIGESTIVE ENZYME ACTIVITIES IN PENAEUS MONODON

This study examines the influence of feeding on digestive enzyme activities in the black tiger prawn, Penaeus monodon, using histological and biochemical techniques. Juvenile P. monodon (>50 mm total length) were sacrificed after feeding at sequential time intervals, with unfed controls also sacrificed at the same time intervals. Resin histology revealed that there were no morphological changes in the digestive gland F-cells between fed and unfed P. monodon over time. There were no significant changes in α-amylase specific activities in fed animals over time post feeding, nor were there any changes in starved animals through time. Trypsin and α-glucosidase activities were significantly higher in unfed animals than fed animals. There was a significant peak in α-glucosidase activities at 0 min post feeding but this could not be conclusively determined as an influence from feeding because of high variability and the near negligible levels of α-glucosidase activities. A peak in lipase activity was observed at 60 min post feeding, but because there was no significant differences in lipase activities between fed and unfed animals it was therefore inconclusive. Results from histological and biochemical analyses failed to prove that feeding had a significant influence on digestive enzyme production of P. monodon and suggest that digestive enzyme production in P. monodon may be continuous and is not strongly influenced by feeding.