72
M.D. Wiegand
,
INTRODUCTION
Teleost
fishes,
as
a
group,
have
developed
the
capacity
to
deposit
substantial
quantities
of
nutrients,
including
lipids,
in
various
body
depots
for
subsequent
mobilizationo
Stared
reserves
are
mobilized
t0'
support
such
metabolically demanding
processes
as
gonadal recrudescence,
migration,
seasonal
fasting
and
smoltification.
In
the
cyprinds,
mobilization of
stored lipid reserves can provide at least some support for
gonadal recrudescence (de Vlaming, 1975; Delahunty and de Vlaming,
These
observations,
coupled
with
others,
make
an
examination
of
the
processes
of
lipid
deposition
and
mobilization
in
the
cyprinids
of
interesto
The
aim of
this
review is
to
acquaint the reader with recent work and
’
some
pertinent questions relating to several aspects of lipid metabolism in
“
cyprinids…
Because
of
the_ central
importance
of
reproduction.
in
life
history strategies,
some
emphasis is placed on the relationship of lipid
j
metabolism to gonadal recrudescence.
'
'
-
LIPID ACCUMULATION
Under
natural
or
simulated
natural
conditions,
temperate
zone
cyprinids will experience prolonged periods of low temperature and short
photoperiodu
The
major portion of gonad recrudescence commences near the
end
of
winter,
while
water
is
still
cold,
and
may
be
accelerated.
by
increasing
temperature
(eng,
Breton
et
alu,
1980)‘:
Alternatively,
recrudescence may
proceed all the way to the preovulatory stage under cold
conditions
(Peter,
It
is
apparent, then, that metabolism under cold
conditions
is
important
to
the
physiology of gonadal recrudescence.
It
should
be
noted,
however,
that
exposure
to
cold
is
not
essential
for
successful recrudescence in all cyprinids (Gillet et al,, 1978)u
The metabolism of carps
in cold has
long attracted interest, although
not
specifically
pertaining
to
reproduction°
Enhancemeut
of
fat
accumulation in cyprinids under cold conditions has been demonstrated using
a
variety of approaches
(Hear and Cottle,
1952;
Blazka, 1958; Knipprath
and
Mead,
1968;
de
Vlaming,
1975;
de
V1aming
and
Pardo,
1975)
and
is
consistent
with
observations
from
wild
and
cultured
cyprinids that body
lipid reserves
peak during winter
(de Vlaming,
1975;
Delahunty and de
Vlaming,
1980)n
However,
of
fat
over
winter
has
also
been
reported (Sykora and Valenta, 1981, 1982)°
Blazka
(1958) observed that accumulation of fat could occur in carps
in
the
winter
under
conditions
of
anoxia°
Furthermore,
the
carp
produced
002
when
held
experimentally under anoxic conditions;
the
expected
anaerobic metabolite, lactic acid, did not accumulate and the fish did not
display a characteristic oxygen debt (Blazka, 1958)"
It
has
subsequentlÿ
been found that goldfish produce C02
and ethanol as end—products of glucose
metabolism
under
conditions
of
prolonged
anoxia
(Hochachka,
1961;
Shoubridge and Hochachka,
This
is
part of an integrated strategy in
which
red
and
white.
skeletal
muscle
oxidizes
lactate
produced
glycolytically in other tissues (Shoubridge and Hochachka 1983).
The
mechanimn
of
lipogensis
under
anoxic
conditions
remains
to
be
determined.
The
normal
substrate
for
lipogenesis,
acetyl
CoA,
is
an
intermediate
in
anaerobic'ethanol
production in goldfish and the pentose
phosphate
shunt,
which
produces
NADPH
required
for
lipogenesis,
is
also
functional
at
low
levels
under
anaerobic
conditions
(Shoubridge
and
Hochachka
1981)However, the acetyl CoA produced anaerobically seems to
M.D. Wiegand
,
INTRODUCTION
Teleost
fishes,
as
a
group,
have
developed
the
capacity
to
deposit
substantial
quantities
of
nutrients,
including
lipids,
in
various
body
depots
for
subsequent
mobilizationo
Stared
reserves
are
mobilized
t0'
support
such
metabolically demanding
processes
as
gonadal recrudescence,
migration,
seasonal
fasting
and
smoltification.
In
the
cyprinds,
mobilization of
stored lipid reserves can provide at least some support for
gonadal recrudescence (de Vlaming, 1975; Delahunty and de Vlaming,
These
observations,
coupled
with
others,
make
an
examination
of
the
processes
of
lipid
deposition
and
mobilization
in
the
cyprinids
of
interesto
The
aim of
this
review is
to
acquaint the reader with recent work and
’
some
pertinent questions relating to several aspects of lipid metabolism in
“
cyprinids…
Because
of
the_ central
importance
of
reproduction.
in
life
history strategies,
some
emphasis is placed on the relationship of lipid
j
metabolism to gonadal recrudescence.
'
'
-
LIPID ACCUMULATION
Under
natural
or
simulated
natural
conditions,
temperate
zone
cyprinids will experience prolonged periods of low temperature and short
photoperiodu
The
major portion of gonad recrudescence commences near the
end
of
winter,
while
water
is
still
cold,
and
may
be
accelerated.
by
increasing
temperature
(eng,
Breton
et
alu,
1980)‘:
Alternatively,
recrudescence may
proceed all the way to the preovulatory stage under cold
conditions
(Peter,
It
is
apparent, then, that metabolism under cold
conditions
is
important
to
the
physiology of gonadal recrudescence.
It
should
be
noted,
however,
that
exposure
to
cold
is
not
essential
for
successful recrudescence in all cyprinids (Gillet et al,, 1978)u
The metabolism of carps
in cold has
long attracted interest, although
not
specifically
pertaining
to
reproduction°
Enhancemeut
of
fat
accumulation in cyprinids under cold conditions has been demonstrated using
a
variety of approaches
(Hear and Cottle,
1952;
Blazka, 1958; Knipprath
and
Mead,
1968;
de
Vlaming,
1975;
de
V1aming
and
Pardo,
1975)
and
is
consistent
with
observations
from
wild
and
cultured
cyprinids that body
lipid reserves
peak during winter
(de Vlaming,
1975;
Delahunty and de
Vlaming,
1980)n
However,
of
fat
over
winter
has
also
been
reported (Sykora and Valenta, 1981, 1982)°
Blazka
(1958) observed that accumulation of fat could occur in carps
in
the
winter
under
conditions
of
anoxia°
Furthermore,
the
carp
produced
002
when
held
experimentally under anoxic conditions;
the
expected
anaerobic metabolite, lactic acid, did not accumulate and the fish did not
display a characteristic oxygen debt (Blazka, 1958)"
It
has
subsequentlÿ
been found that goldfish produce C02
and ethanol as end—products of glucose
metabolism
under
conditions
of
prolonged
anoxia
(Hochachka,
1961;
Shoubridge and Hochachka,
This
is
part of an integrated strategy in
which
red
and
white.
skeletal
muscle
oxidizes
lactate
produced
glycolytically in other tissues (Shoubridge and Hochachka 1983).
The
mechanimn
of
lipogensis
under
anoxic
conditions
remains
to
be
determined.
The
normal
substrate
for
lipogenesis,
acetyl
CoA,
is
an
intermediate
in
anaerobic'ethanol
production in goldfish and the pentose
phosphate
shunt,
which
produces
NADPH
required
for
lipogenesis,
is
also
functional
at
low
levels
under
anaerobic
conditions
(Shoubridge
and
Hochachka
1981)However, the acetyl CoA produced anaerobically seems to