Gastric evacuation time and digestive enzyme activity in abalone<i>Haliotis midae</i>fed a formulated diet

Abstract

Gut evacuation time and enzyme activity were monitored over 46 h in juvenile Haliotis midae fed a formulated diet. Gut fullness peaked 6 h after feed was offered and returned to pre-feeding levels within 24 h. Enzyme secretion began with the onset of feeding and continued for at least 6 h after peak gut fullness was attained. Protease activity increased significantly following ingestion, whereas amylase activity was maintained at a fairly constant level. A low level of lipase activity was observed, suggesting that the ability of H. midae to digest fat is limited. When formulated food is used, a feeding frequency of once per day is recommended.