By—pmdu0is and wastes
87
as
yet proved of any commercial impact and,
although may be reared on wastes
(with the exception of Krill) they cannot be classed as waste products.
However,
there
are
wastes
in
considerable
amounts which arise
from
fish
docks,
slaughter houses and poultry farms.
Although these wastes may be
fed to
fish or other livestock after a minimal treatment
(for example,
the
grinding up of feathers to produce feather—meal) processing such as ensilage
makes
a
more
convenient_feed product.
Ensilage of animal wastes is a
technique that is making great headway in the feeding of some cultured
Species of fish, particularly salmon,
The
ensilage of wastes as a method
of preservation and presentation of feed material has been practiced for
many years.
The waste animal materials
are
liquified by the action of
endogenous enzymes in the presence of added mineral or organic acids such
as
sulphuric, phoSphoric, formic or proprionic acids.
The mixture is then
heated to
inactivate enzymes,
water
is
removed and this
digestate is
incorporated into diets replacing fish meal.
Although this source of
nitrogen appears to be very effective as a growth promoter for a number of
species of fish, preliminary work with ensilaged waste as carp food has
not been very
successful.
This may be because carp,
unlike
trout,
are
stomachless
fish
and
do not
accept diets of low pH.
More research is
required.
CONCLUSIONS
_
The use
of
agricultural by—products and wastes in carp rearing has
developed in an empirical manner.
The
age old practise of adding manure,
rice bran
or
vegetable wastes to fish ponds is a world wide phenomenon
but as Bardach et al. (1972) remarked, "the sheer variety of feeds used
(for carp) is bewildering".
A
feeding schedule for common carp in Japan
can
involve
the
feeding during the year of wheat, snail pupae, soya sauce
waste, earthworms, rice bran,
silkworm pupae,
bean meal, vegetable waste,
and fish meal.
Perhaps the real virtue in rearing common carp is that it is
hardy fish that is fairly omnivorous.
For, in many parts of the world
although cultured and eaten, it is not regarded as a prime fish for taste
and quality of flash.
Carp rearing should be regarded, in many instances,
as
an
economical method of converting animal and plant residues, of which
there
are
immense
amounts
in
the world, into a tolerable food fish.
Although fertilisation and supplementary feeding of carp ponds will
continue in order to increase harvests
from them,
it
is unlikely that an
intensive rearing of carp similar to that for salmonids will develop.
Nevertheless wastes
can
be
incorporated into the production of cheap low
protein pelleted food and such pelleted foods used in these extensive
rearing conditions.
Such controlled use of wastes, with knowledge of their
nutritional properties, is perhaps in the long run a more efficient way
of presenting them to the fish than by feeding them the raw waste.
REFERENCES
ANWAR A.,
ISHAK M.M., EL—ZEINY and HASSENEN G.D.,
1982.
Activated
sewage sludge as a.replacement for bran—cottonseed meal mixtures for
carp.
Aquaculture, ËË, 321—35—
ASHLEY
L.M.,
1972.
Nutritionàl Pathology.
In J.E.Halver
(Editor),
Fish Nutrition, Academic Press, New York, N.Y.,
439—537ATACK
T.H,, JAUNCEY K, and MATTY A.J., 1979.
The utilisation of single
cell
protein by fingerling mirror carp.
Aquaculture, 18, 337—348.
BARDACH J.E., RYTHER J.H. and McLARNEY 'W.o., 1972- Aqua‘ÎU1ture’ .the
farming and husbandry of freshwater and marine organisms.
Wlley—
Interscience, N.Y.
87
as
yet proved of any commercial impact and,
although may be reared on wastes
(with the exception of Krill) they cannot be classed as waste products.
However,
there
are
wastes
in
considerable
amounts which arise
from
fish
docks,
slaughter houses and poultry farms.
Although these wastes may be
fed to
fish or other livestock after a minimal treatment
(for example,
the
grinding up of feathers to produce feather—meal) processing such as ensilage
makes
a
more
convenient_feed product.
Ensilage of animal wastes is a
technique that is making great headway in the feeding of some cultured
Species of fish, particularly salmon,
The
ensilage of wastes as a method
of preservation and presentation of feed material has been practiced for
many years.
The waste animal materials
are
liquified by the action of
endogenous enzymes in the presence of added mineral or organic acids such
as
sulphuric, phoSphoric, formic or proprionic acids.
The mixture is then
heated to
inactivate enzymes,
water
is
removed and this
digestate is
incorporated into diets replacing fish meal.
Although this source of
nitrogen appears to be very effective as a growth promoter for a number of
species of fish, preliminary work with ensilaged waste as carp food has
not been very
successful.
This may be because carp,
unlike
trout,
are
stomachless
fish
and
do not
accept diets of low pH.
More research is
required.
CONCLUSIONS
_
The use
of
agricultural by—products and wastes in carp rearing has
developed in an empirical manner.
The
age old practise of adding manure,
rice bran
or
vegetable wastes to fish ponds is a world wide phenomenon
but as Bardach et al. (1972) remarked, "the sheer variety of feeds used
(for carp) is bewildering".
A
feeding schedule for common carp in Japan
can
involve
the
feeding during the year of wheat, snail pupae, soya sauce
waste, earthworms, rice bran,
silkworm pupae,
bean meal, vegetable waste,
and fish meal.
Perhaps the real virtue in rearing common carp is that it is
hardy fish that is fairly omnivorous.
For, in many parts of the world
although cultured and eaten, it is not regarded as a prime fish for taste
and quality of flash.
Carp rearing should be regarded, in many instances,
as
an
economical method of converting animal and plant residues, of which
there
are
immense
amounts
in
the world, into a tolerable food fish.
Although fertilisation and supplementary feeding of carp ponds will
continue in order to increase harvests
from them,
it
is unlikely that an
intensive rearing of carp similar to that for salmonids will develop.
Nevertheless wastes
can
be
incorporated into the production of cheap low
protein pelleted food and such pelleted foods used in these extensive
rearing conditions.
Such controlled use of wastes, with knowledge of their
nutritional properties, is perhaps in the long run a more efficient way
of presenting them to the fish than by feeding them the raw waste.
REFERENCES
ANWAR A.,
ISHAK M.M., EL—ZEINY and HASSENEN G.D.,
1982.
Activated
sewage sludge as a.replacement for bran—cottonseed meal mixtures for
carp.
Aquaculture, ËË, 321—35—
ASHLEY
L.M.,
1972.
Nutritionàl Pathology.
In J.E.Halver
(Editor),
Fish Nutrition, Academic Press, New York, N.Y.,
439—537ATACK
T.H,, JAUNCEY K, and MATTY A.J., 1979.
The utilisation of single
cell
protein by fingerling mirror carp.
Aquaculture, 18, 337—348.
BARDACH J.E., RYTHER J.H. and McLARNEY 'W.o., 1972- Aqua‘ÎU1ture’ .the
farming and husbandry of freshwater and marine organisms.
Wlley—
Interscience, N.Y.