1
126
C. Weileta1.
migration but
no
ovulation
was
obtained after 5 daily intracardiac LHRH
injections at
1pg/kg (SOKOLOWSKA 1982) or two intracardiac injections at 3
ug/kg given 3 hrs apart (WEIL et al.
1980).
Single dose of LHRHa,
1ug/kg given by intracardiac injection in females
held
in
aquaria
or
spawning ponds (BILLARD et al.
1984) or 50
g given
traperitoneally in females held in concrete tank (BILLARD et al.
1983a) were
also
ineffective
in
inducing
ovulation.
Repeated
doses, 5 Hg/Kg plus 50
pg/Kg given
6 hrs apart, given by intraperitoneal injection in females held
in
aquaria with or without vegetation were ineffective in inducing ovulation
while
they were partially effective in females held in cages maintained in a
pond. The
authors
think
that
the
response was
faciliated
by the occurrence
of circadian
changes
in
dissolved 02, CO2 and pH, changes similar to those
observed
in
spawning
ponds.
This
point will be discussed in a next para—
graph. In
this
latter
experiment plasma GtH levels were similar in ovulated
and
non
ovulated
females
but were higher than those of females held in aqua—
ria.
However
measured
levels were
lower
than those
circulating during spontaneous
ovulation.
This
lack
of efficiency of LHRH in carp was also reported
by KOURIL
et
al.
1983 for doses ranging from 10 to 200 pig/kg° The same au—
thors
report successful results for tench at a dose of 100—200 ug/kg of LHRH
and
10—40
pg
of
LHRHa
and
for grass
carp
at a
dose of 200 pg of LHRH and
Ï
20pg/Kg of
LHRHa.
In China LHRH analogue is routinely used to induce spawning of different species of chinese carp. Trials performed in 2ü fish farms
1
and conducted on 500 animals are reported in ANONYMOUS 1977a —1977b° In summary the
recommended
doses
for
the
different species held at temperature
‘
lying within the normal range (20 —28°C) are the following. For black carp a
1
single dose of 10 pg/kg is efficient ; effectivness is increased when injec—
tion
of
LHRHa is
followed by that of 1 —2mg of pituitary. In grass carp 5 -
10
pg/kg of LHRHa in one injection is prescribed while in bighead a priming
dose
of
1
—
2
ug/kg followed by 8—9 ug/kg 12 hrs later for matured fish or
2H hours
later
for
less
matured
fish, is suggested. For silver carp 5 -
10pg/kg of LHRHa in one injection is recommended for first time spawners or
10—25 pg
in
two
injections
for
repeated
spawners
(10Hg/kg + 0,1 - 1mg
cAMP/kg in two injections spaced 12h apart enhances effectivness)°
From
the literature it is noteworthy that there is a prolonged latency
in the
ovulatory response to LHRH or LHRHa, in goldfish, tench, chinese carp
when compared
with
hypophysation or HCG treatment. This treatment presents
the
advantage of decreasing the rate of mortality in chinese carp (ANONYMOUS
1977b, ROTTMANN and SHIREMAN 1985).
Recent
promising
works
from
BIENIARZ
et al.
1985 report that salmon
GnRH
analogue
is
very active
in
inducing ovulation in common carp as compa—
red
to LHRHa.
Action in male
Chinese
studies
(ANONYMOUS 1977a) report that LHRHa in very effective
in inducing
SPermiation
in
carp.
Injection of 10—30ug induces milt release
in
the
black carp after
12
—
2Ah. The effect is remarkable in spotted silver
carp which shed notile spermatoza whithin 6 1/2 hrs following the injection.
In
common
carp LHRH and LHRHa analogue induce also an increase in col—
lectable milt
volume.
One
injection
of LHRH at
the
dosage of 50 wg/ks is
more
effective
than
at
the
dosage of 10pg/kg while with LHRHa both dosages
have the
same
effect
(BILLARD
et
al.
1983b). Following an injection
of
5O“Æ/kë collected milt volume is increased the first two days and then begin
to
decrease
by
day
3
for
reaching basal levels on day 5 (BILLARD et al.
1983a).
TAKASHIMA
et
al.
1984
report that smaller dosage of the analogue
adm1nistered by 5 daily injections of lug/kg does not stimulate the increase
of collectable milt volume while collected milt volume is increased with 5
126
C. Weileta1.
migration but
no
ovulation
was
obtained after 5 daily intracardiac LHRH
injections at
1pg/kg (SOKOLOWSKA 1982) or two intracardiac injections at 3
ug/kg given 3 hrs apart (WEIL et al.
1980).
Single dose of LHRHa,
1ug/kg given by intracardiac injection in females
held
in
aquaria
or
spawning ponds (BILLARD et al.
1984) or 50
g given
traperitoneally in females held in concrete tank (BILLARD et al.
1983a) were
also
ineffective
in
inducing
ovulation.
Repeated
doses, 5 Hg/Kg plus 50
pg/Kg given
6 hrs apart, given by intraperitoneal injection in females held
in
aquaria with or without vegetation were ineffective in inducing ovulation
while
they were partially effective in females held in cages maintained in a
pond. The
authors
think
that
the
response was
faciliated
by the occurrence
of circadian
changes
in
dissolved 02, CO2 and pH, changes similar to those
observed
in
spawning
ponds.
This
point will be discussed in a next para—
graph. In
this
latter
experiment plasma GtH levels were similar in ovulated
and
non
ovulated
females
but were higher than those of females held in aqua—
ria.
However
measured
levels were
lower
than those
circulating during spontaneous
ovulation.
This
lack
of efficiency of LHRH in carp was also reported
by KOURIL
et
al.
1983 for doses ranging from 10 to 200 pig/kg° The same au—
thors
report successful results for tench at a dose of 100—200 ug/kg of LHRH
and
10—40
pg
of
LHRHa
and
for grass
carp
at a
dose of 200 pg of LHRH and
Ï
20pg/Kg of
LHRHa.
In China LHRH analogue is routinely used to induce spawning of different species of chinese carp. Trials performed in 2ü fish farms
1
and conducted on 500 animals are reported in ANONYMOUS 1977a —1977b° In summary the
recommended
doses
for
the
different species held at temperature
‘
lying within the normal range (20 —28°C) are the following. For black carp a
1
single dose of 10 pg/kg is efficient ; effectivness is increased when injec—
tion
of
LHRHa is
followed by that of 1 —2mg of pituitary. In grass carp 5 -
10
pg/kg of LHRHa in one injection is prescribed while in bighead a priming
dose
of
1
—
2
ug/kg followed by 8—9 ug/kg 12 hrs later for matured fish or
2H hours
later
for
less
matured
fish, is suggested. For silver carp 5 -
10pg/kg of LHRHa in one injection is recommended for first time spawners or
10—25 pg
in
two
injections
for
repeated
spawners
(10Hg/kg + 0,1 - 1mg
cAMP/kg in two injections spaced 12h apart enhances effectivness)°
From
the literature it is noteworthy that there is a prolonged latency
in the
ovulatory response to LHRH or LHRHa, in goldfish, tench, chinese carp
when compared
with
hypophysation or HCG treatment. This treatment presents
the
advantage of decreasing the rate of mortality in chinese carp (ANONYMOUS
1977b, ROTTMANN and SHIREMAN 1985).
Recent
promising
works
from
BIENIARZ
et al.
1985 report that salmon
GnRH
analogue
is
very active
in
inducing ovulation in common carp as compa—
red
to LHRHa.
Action in male
Chinese
studies
(ANONYMOUS 1977a) report that LHRHa in very effective
in inducing
SPermiation
in
carp.
Injection of 10—30ug induces milt release
in
the
black carp after
12
—
2Ah. The effect is remarkable in spotted silver
carp which shed notile spermatoza whithin 6 1/2 hrs following the injection.
In
common
carp LHRH and LHRHa analogue induce also an increase in col—
lectable milt
volume.
One
injection
of LHRH at
the
dosage of 50 wg/ks is
more
effective
than
at
the
dosage of 10pg/kg while with LHRHa both dosages
have the
same
effect
(BILLARD
et
al.
1983b). Following an injection
of
5O“Æ/kë collected milt volume is increased the first two days and then begin
to
decrease
by
day
3
for
reaching basal levels on day 5 (BILLARD et al.
1983a).
TAKASHIMA
et
al.
1984
report that smaller dosage of the analogue
adm1nistered by 5 daily injections of lug/kg does not stimulate the increase
of collectable milt volume while collected milt volume is increased with 5