Development of
the pH in the intestinal tract of larval turbot
K. Hoehne-Reitan, E. Kjørsvik, K.I. Reitan-2001
Marine Biology, 139(6): 1159-1164
Abstract:
The pH in the gut of turbot larvae and juveniles of
turbot was studied from day 11 until the completion of metamorphosis.
Dietary effects on the gut pH were estimated when larvae were offered live
feed, a microdiet, only microalgae or no feed. The pH in the gut was weakly
alkaline until day 24 after hatching with no differences between the
foregut, midgut and hindgut. The foregut contents started to turn acidic
from day 28 after hatching when the larvae were already weaned
successfully, which indicates that an acidic pH is not necessary for the
digestion and utilisation of formulated feed. During the following 20 days
the pH in the foregut/stomach decreased further to a minimum of pH 3.5,
while the pH in the midgut and the hindgut increased slightly to a maximum
of pH 9.0. Larvae receiving live feed, microdiet or microalgae had a
similar pH in the midgut on day 11, while starved larvae exhibited a
lower gut pH. This suggests bicarbonate secretion from the larval pancreas
stimulated by ingested microalgae or feed particles.
(Norwegian University of Science and Technology
(NTNU), Department of Zoology, Brattøra Research Centre, 7491 Trondheim,
Norway, Tel: +47-73-590321, Fax: +47-73-596311, E-mail of K.I. Reitan: Katja.Reitan@chembio.ntnu.no)