1063-0740/05/3103- © 2005 Pleiades Publishing, Inc.
Russian Journal of Marine Biology, Vol. 31, No. 3, 2005, pp. 196–199.
Original Russian Text Copyright © 2005 by Biologiya Morya, Korostelev, Nevalenny, Levchenko.
Membrane digestion in freshwater ﬁsh species has
been extensively studied [1, 8–10, 12, 13, 17, and many
others]. The intestinal digestive enzymes of sea ﬁshes
have been investigated less thoroughly [3, 6, 7, 11, 22],
and virtually no studies have investigated ﬁshes of the
Far Eastern seas in this aspect.
revealed the activity of trypsin, amy-
lase, lipase, and alkaline phosphatase in the yolk-sac
larvae of the Atlantic halibut
(Linnaeus, 1758) and showed that enzymatic activ-
ity increased with the age of larvae . Similarly,
have demonstrated that the larvae of
Kaup, 1858 are capable of full digestion
of food a month after hatching as a result of the increas-
ing activity of acid and alkaline phosphatase, lipase,
and aminopeptidase in the larval digestive tract
Study of adult
Platichthys ﬂesus luscus
from the Black Sea  has demonstrated a high level of
total amylolytic activity [2.95
mole/(min g)] and
low values of total proteolytic and sucrose activity
0.13 and 0.44
mole/(min g), respec-
tively] in the intestinal mucous membrane.
This paper focuses on study of the activity and tem-
perature dependence of the chief digestive enzymes in
the intestine of the Paciﬁc halibut and starry ﬂounder
inhabiting the Far Eastern seas.
MATERIALS AND METHODS
Studies were carried out in 2002–2003 by the Kam-
chatka Research Institute for Fisheries and Oceanogra-
phy and by Astrakhan State Technical University. Ten
specimens of Paciﬁc halibut (length 41–51 cm, weight
0.9–1.66 kg) and 10 specimens of starry ﬂounder
(length 26–33 cm, weight 100–500 g) were investi-
gated. Paciﬁc halibut were caught with a bottom trawl
in October 2002 in Olyutorsky Bay at a 64-m depth.
Starry ﬂounder were captured with a beach seine in July
2003 in Avachinskaya Bay at A 2- to 4-m depth.
Immediately after capture, ﬁsh were immobilized
and morphometry was made. The intestine (without
pyloric ceca) was taken out and washed with 20 ml of a
cooled Ringer’s solution for cold-blooded animals
(pH 7.3) to remove its contents and cavity enzymes.
The intestines were placed on a cooled glass, cleansed
of fat, measured, and weighed. Material was then fro-
zen at –18 to –20
C in a thermos and stored until exper-
imentation. After thawing, the intestine mucous mem-
brane was removed using a scraper, weighed on a VT-
500 torsion balance, and homogenized in a cooled
C) Ringer’s solution (1 : 9) on a RT-1 homoge-
nizer with a Teﬂon piston. The resultant homogenate
was then diluted with Ringer’s solution to determine
the linear enzymatic activity.
Characterization of Digestive Enzymes
in the Intestine of the Pacific Halibut
Schmidt, 1904 and the Starry Flounder
S. G. Korostelev
, A. N. Nevalenny
, and O. E. Levchenko
Kamchatka Research Institute for Fisheries and Oceanography,
Petropavlovsk-Kamchatski, 683000 Russia
Astrakhan State Technical University,
Received November 27, 2004
—The activity and temperature characteristics of hydrolases (maltase,
-amylase, total proteinase,
alkaline phosphatase) in the intestine of Far Eastern ﬂatﬁshes were studied. The character of the temperature
dependence differed among the investigated enzymes. The activity of individual hydrolases in the two ﬁsh spe-
cies varied. The results of this study suggest that ﬂatﬁsh intestinal hydrolases are efﬁcient at low temperatures
and that the digestive process in ﬂatﬁshes is well adapted to the conditions in which it functions, thus ensuring
optimal vital activity at low temperatures in the Far Eastern seas.
Flatﬁshes, digestive enzymes, temperature, enzymatic activity, temperature optimum, activation
energy, adaptation, Far Eastern seas.