122
C. Wah” et al.
made and
must
be
made
to
improve the estimation of egg development. This
implies firstly
the
use
of
a
technique for egg sampling and secondly the
determination of
criteria
for
egg maturity° Samples of eggs can be obtained
by aspiration
either by inserting a tubing into the ovary through the genital pore as
described by CHEN et al.
1969 for chinese carp or by inserting a
needle
through
the
abdominal wall
cavity as described by BIENARZ and EPLER
1976 in
common
carp.
Criteria of egg maturity used in carp are : the colour
of the
oocytes, their size or the position of the nucleus and the nucleolus
after clearing the egg as described by BRZUSKA and BIENIARZ 1977.
B — Administration of exogenous
gonadotropins.
1)
Hypophysation.
Hypophysation is the traditional method of induced fish breeding and is
widely practiced
with
the
major
indian carp,
chinese
carp
and
the
common
carp.
In
these
species it consists in the injection of homoplastic or hete —
roplastic pituitary
extracts.
However
pituitaries
collected
from marine
catfish have been used
for indian carps
(VARGHESE et al.
1975).
Details
of techniques employed in the collection, preservation of pi
—
tuitaries
and
preparation
of
extracts have
been presented in PICKFORD and
ATZ
1957
and often reviewed
(SHEHADEH 1975, CHAUDHURI 1976, HARVEY and HOAR
1980, MARCEL 1980, ROTHBARD 1981).
In summary the
following dosages,expressed in mg of dry weight,are used:
—
common
carp
:
In
females
1
pituitary/kg is injected in two injections
(equivalent to
about
3mg/kg).
The
first
injection or priming consists in
1/10 of
the
dose,
the remaining 9/10 are given in a second injection. For
males, 2mg/kg are given in one injection at the time of the second injection
of females.
—
indian carp : the female is given a priming dose of 2—3mg/kg b.w. and
after an
interval
of H—6h a final dose of 5—8mg/kg b.w. At the time of the
second
injection males are given 2—3mg/kg b.w.
_
chinese CâPP
:
4 to H.5mg/kg b.w. is given in two injections for females, 2mg/kg
b.w
in one
injection for males. A more precise determination
of the
dose
can
be
made
by estimating the gonadal status of the females.
This
is
done
by measuring the girth of the female in the deepest part of the
body. A dose relative to the body girth is given and the diagram is reported
in MARCEL
1980 and ROTHBARD 1981
.
…
Results
obtained
on
carp
(ANONYMOUS 1978) and goldfish (STACEY et al.
1979a) have shown that the periovulatory GtH surge is very brief during
spontaneous ovulation.
Classical hypophysation induces GtH increase of longer
duration
i.e.
3—11
days
(JALABERT
et
al.
1977, FOSTIER et al. 1979,
BIENIARZ et
al.
1980). Priming dose induces a significant GtH increase one
hour after
the
injection
and
then
GtH
levels
continue
to
increase
for 3
hours}
and
remain
high
during
the
next
12 hours
(WEIL et al.
1980) . The
mêSSlVÊ pituitary dose
(given
as
a
second
injection or as a single injec—
mon) lnduœs
higher“
GtH
levels
(250-u00ng/m1)
which
can
last 3-4 days
according the
case
as
described by BIENIARZ et al.
1980. In fact these au—
thors recorded
high
levels
for
3 days in spawning fish and for 4 days in
unspawned ones.
This
fact suggests that, following hypophysation, circulalevels
may depend on the physiological conditions of the
ovaries
and
in
the case of spawning the ovaries can take up gonadotropi f0f
maturation PP0C€SS—
Priming
dose
induces shifting of the germinal vesicle
towards to
the
micropile
in
resDonding and unresponsive fish whereas the
second injection
induces
maturation
amd
ovulation in responding fish and
C. Wah” et al.
made and
must
be
made
to
improve the estimation of egg development. This
implies firstly
the
use
of
a
technique for egg sampling and secondly the
determination of
criteria
for
egg maturity° Samples of eggs can be obtained
by aspiration
either by inserting a tubing into the ovary through the genital pore as
described by CHEN et al.
1969 for chinese carp or by inserting a
needle
through
the
abdominal wall
cavity as described by BIENARZ and EPLER
1976 in
common
carp.
Criteria of egg maturity used in carp are : the colour
of the
oocytes, their size or the position of the nucleus and the nucleolus
after clearing the egg as described by BRZUSKA and BIENIARZ 1977.
B — Administration of exogenous
gonadotropins.
1)
Hypophysation.
Hypophysation is the traditional method of induced fish breeding and is
widely practiced
with
the
major
indian carp,
chinese
carp
and
the
common
carp.
In
these
species it consists in the injection of homoplastic or hete —
roplastic pituitary
extracts.
However
pituitaries
collected
from marine
catfish have been used
for indian carps
(VARGHESE et al.
1975).
Details
of techniques employed in the collection, preservation of pi
—
tuitaries
and
preparation
of
extracts have
been presented in PICKFORD and
ATZ
1957
and often reviewed
(SHEHADEH 1975, CHAUDHURI 1976, HARVEY and HOAR
1980, MARCEL 1980, ROTHBARD 1981).
In summary the
following dosages,expressed in mg of dry weight,are used:
—
common
carp
:
In
females
1
pituitary/kg is injected in two injections
(equivalent to
about
3mg/kg).
The
first
injection or priming consists in
1/10 of
the
dose,
the remaining 9/10 are given in a second injection. For
males, 2mg/kg are given in one injection at the time of the second injection
of females.
—
indian carp : the female is given a priming dose of 2—3mg/kg b.w. and
after an
interval
of H—6h a final dose of 5—8mg/kg b.w. At the time of the
second
injection males are given 2—3mg/kg b.w.
_
chinese CâPP
:
4 to H.5mg/kg b.w. is given in two injections for females, 2mg/kg
b.w
in one
injection for males. A more precise determination
of the
dose
can
be
made
by estimating the gonadal status of the females.
This
is
done
by measuring the girth of the female in the deepest part of the
body. A dose relative to the body girth is given and the diagram is reported
in MARCEL
1980 and ROTHBARD 1981
.
…
Results
obtained
on
carp
(ANONYMOUS 1978) and goldfish (STACEY et al.
1979a) have shown that the periovulatory GtH surge is very brief during
spontaneous ovulation.
Classical hypophysation induces GtH increase of longer
duration
i.e.
3—11
days
(JALABERT
et
al.
1977, FOSTIER et al. 1979,
BIENIARZ et
al.
1980). Priming dose induces a significant GtH increase one
hour after
the
injection
and
then
GtH
levels
continue
to
increase
for 3
hours}
and
remain
high
during
the
next
12 hours
(WEIL et al.
1980) . The
mêSSlVÊ pituitary dose
(given
as
a
second
injection or as a single injec—
mon) lnduœs
higher“
GtH
levels
(250-u00ng/m1)
which
can
last 3-4 days
according the
case
as
described by BIENIARZ et al.
1980. In fact these au—
thors recorded
high
levels
for
3 days in spawning fish and for 4 days in
unspawned ones.
This
fact suggests that, following hypophysation, circulalevels
may depend on the physiological conditions of the
ovaries
and
in
the case of spawning the ovaries can take up gonadotropi f0f
maturation PP0C€SS—
Priming
dose
induces shifting of the germinal vesicle
towards to
the
micropile
in
resDonding and unresponsive fish whereas the
second injection
induces
maturation
amd
ovulation in responding fish and