84
A.J. Matty
Probably the most important and the best known of the plant wastes are
the nut
and seed cakes
from which oil has been extracted.
These have forso
long been used in the animal feed industry that perhaps they should no‘Ï
longer be regarded as wastes.
Ground nut,
sunflower,
soya,
rape
seed and
}
cotton seed all provide sources of protein for enhancing fish growth.
However,
even
at
their very best
these plant proteins will not give as good
È
a
growth rate as fish fed with animal protein (Dabrowski and Kozak,
1978;
Atack.
Jauneey
and Matty,
1979; Jackson, Capper and
]Watty}982).
Again, as
with
leaf proteins, toxic substances (aflatox1n in ground nuts,
glossypol
in cotton seed,
goitrogens in rape seed)
can
have
an
adverse effect
ongrmh
in
fish
(Ashley, 1972).
SINGLE
CELL PROTEINS
The
feeding of single cell proteins enhances growth in carp but whether
we
should regard single cell proteins as waste products is problematic.
Certain1y brewers yeast can be regarded as a waste,
as
can
fungi or
bacterial protein when these have been grown on a substrate that can
ï
clearly be classified as waste.
Perbaps we should remember here that, in
Î
the manured pond, single cell protein possibly plays a significant part in
carp
diet
in the
form of bacteria adhering to manure fragments.
Growth is
good in experimental conditions when carp are fed &
?
methanophilic bacterium (Ataok et al.
1979).
Carp fed on yeast grow more
:
slowly.
Possibly the easiest way to present single—cell protein, grown on
waste, to carp is by allowing manure which is introduced into ponds to act
as
the
organic substrate for the growth of bacteria and other single celled
ï
organisms.
There
is
a
risk, however,
as
already mentioned,
from the use
of
organic wastes in fish ponds due to the depletion of oxygen in the water
‘
as
a
result
of the
decay of the added organic matter.
Wong, Luk, Liu and
Ï
Kuan,
(1979)
advocate no more
than 0.2% of sewagesludge to be added to
,
ponds.
The
adding of manures or organic wastes directly to ponds will in
future be
restricted to
the more primitive and extensive methods of carp
farming.
Much more
control
over
the
environment, and of growth, is obtained
if waste
is
incorporated into a feed.
For
example,
anaerobically digested
piggery waste has been successfully fed to carp at levels of up to 20% of
the
total
protein in the diet (Watson,
1985).
This
is
seen
in Figure 1
and Table
1.
Watson has
suggested that the lack of difference 111performance
between
the
controls
and the
substituted diets, coupled with the fact that
there is
low copper uptake, suggests that processed piggery waste may have
potential as a feedstuff.
ACTIVATED SLUDGE
An alternative
to
applying animal excreta, human sewage or municipal
waste,
to
carp ponds is to feed dried activated sewage sludge to the fishActivated sludge is a flocculent mass of micro—organisms along with
adsorbed material
obtained from the
degradation of organic wastes suspended
in liquid which is aerated by some means.
This
sewage
disposal System is
used in many parts of the world.
Activated sludge has a high protein
value —
some
30 to 40 percent crude protein (Tacon & Ferns 1976)
and when
dried can be incorporated into pelleted diets or mixed as doughs.
The
results
obtained with carp
after
feeding activated sludge have, however,
been mixed.
Trout
show no
loss
in growth rate or food conversion when
activated sludge protein accounts for up to 37% of the ration (Tacon 1978).
Anwar, Ishak, El—Zeiny and Hassanen, 1982) found that acceptable growth in
carp was
obtained when activated sludge protein representing 70% Of the
total
protein in the diet.
However, Wong and Cheung (1980) found adecrease
ln
growth after forty days.
This
sludge contained comparatively high
A.J. Matty
Probably the most important and the best known of the plant wastes are
the nut
and seed cakes
from which oil has been extracted.
These have forso
long been used in the animal feed industry that perhaps they should no‘Ï
longer be regarded as wastes.
Ground nut,
sunflower,
soya,
rape
seed and
}
cotton seed all provide sources of protein for enhancing fish growth.
However,
even
at
their very best
these plant proteins will not give as good
È
a
growth rate as fish fed with animal protein (Dabrowski and Kozak,
1978;
Atack.
Jauneey
and Matty,
1979; Jackson, Capper and
]Watty}982).
Again, as
with
leaf proteins, toxic substances (aflatox1n in ground nuts,
glossypol
in cotton seed,
goitrogens in rape seed)
can
have
an
adverse effect
ongrmh
in
fish
(Ashley, 1972).
SINGLE
CELL PROTEINS
The
feeding of single cell proteins enhances growth in carp but whether
we
should regard single cell proteins as waste products is problematic.
Certain1y brewers yeast can be regarded as a waste,
as
can
fungi or
bacterial protein when these have been grown on a substrate that can
ï
clearly be classified as waste.
Perbaps we should remember here that, in
Î
the manured pond, single cell protein possibly plays a significant part in
carp
diet
in the
form of bacteria adhering to manure fragments.
Growth is
good in experimental conditions when carp are fed &
?
methanophilic bacterium (Ataok et al.
1979).
Carp fed on yeast grow more
:
slowly.
Possibly the easiest way to present single—cell protein, grown on
waste, to carp is by allowing manure which is introduced into ponds to act
as
the
organic substrate for the growth of bacteria and other single celled
ï
organisms.
There
is
a
risk, however,
as
already mentioned,
from the use
of
organic wastes in fish ponds due to the depletion of oxygen in the water
‘
as
a
result
of the
decay of the added organic matter.
Wong, Luk, Liu and
Ï
Kuan,
(1979)
advocate no more
than 0.2% of sewagesludge to be added to
,
ponds.
The
adding of manures or organic wastes directly to ponds will in
future be
restricted to
the more primitive and extensive methods of carp
farming.
Much more
control
over
the
environment, and of growth, is obtained
if waste
is
incorporated into a feed.
For
example,
anaerobically digested
piggery waste has been successfully fed to carp at levels of up to 20% of
the
total
protein in the diet (Watson,
1985).
This
is
seen
in Figure 1
and Table
1.
Watson has
suggested that the lack of difference 111performance
between
the
controls
and the
substituted diets, coupled with the fact that
there is
low copper uptake, suggests that processed piggery waste may have
potential as a feedstuff.
ACTIVATED SLUDGE
An alternative
to
applying animal excreta, human sewage or municipal
waste,
to
carp ponds is to feed dried activated sewage sludge to the fishActivated sludge is a flocculent mass of micro—organisms along with
adsorbed material
obtained from the
degradation of organic wastes suspended
in liquid which is aerated by some means.
This
sewage
disposal System is
used in many parts of the world.
Activated sludge has a high protein
value —
some
30 to 40 percent crude protein (Tacon & Ferns 1976)
and when
dried can be incorporated into pelleted diets or mixed as doughs.
The
results
obtained with carp
after
feeding activated sludge have, however,
been mixed.
Trout
show no
loss
in growth rate or food conversion when
activated sludge protein accounts for up to 37% of the ration (Tacon 1978).
Anwar, Ishak, El—Zeiny and Hassanen, 1982) found that acceptable growth in
carp was
obtained when activated sludge protein representing 70% Of the
total
protein in the diet.
However, Wong and Cheung (1980) found adecrease
ln
growth after forty days.
This
sludge contained comparatively high