Lipolytic activities in
developing turbot larvae as influenced by diet
K. Hoehne-Reitan, E. Kjørsvik,
K.I. Reitan-2003
Aquaculture International, 11(5):
477-489
Abstract:
The development of neutral lipase and phospholipase
activities was studied in larval turbot fed live prey. Activities of neutral
lipase and phospholipase (activity larva-1) increased
significantly between days 6 and 24 after hatching in turbot larvae. The
specific activities of both enzymes (activity µg
protein-1) decreased in older larvae. Feeding of a microdiet for
3 days (days 10–13) affected the lipolytic
activity of neutral lipase and phospholipase negatively, compared to the
larvae fed on rotifers. Since neutral lipase activities in whole larval
homogenates and in the gut were significantly lower, it suggests a reduced
synthesis rate and a reduced secretion of the enzyme in larvae fed the
microdiet. A correlation between neutral lipase and phospholipase activities
was found in larvae fed rotifers, but not in larvae fed the microdiet. This
may indicate different regulating and stimulating mechanisms for these
enzymes. The contribution of exogenous enzymes from ingested live prey to
the total larval enzyme activity was about 6% for neutral lipase and 10% for
phospholipase on day 6. The exogenous prey enzymes accounted for only 2% of
the total activities in 12-day-old turbot larvae, suggesting that enzymes
from prey did not contribute considerably to the digestion of lipids.
(Department of
Biology, Norwegian University of Science and Technology (NTNU), N-7491
Trondheim, Norway, tel: +47 73 590321; fax: +47 73 596311, e-mail: Katja.Reitan@bio.ntnu.no)