U ‘Ju
86
A../. Matty
concentrations
of various metals.
Activated sludges may possibly contain,
in addition to heavy metals a range of biologically harmful materials
including pathogens of feacal origin.
Although the preparation of ASP
‘
involves
temperatures of 60°C for at least 48 hours the risk of pathogen
transmission, although not great,
does
remain
a
hazard
to
be
overcome
before
activated sludge can or should be used in commercial feed for carp.
Amino—
Î
acids
are
also
found to be limiting;
three
amino
acids,
lysine, methionine
Ï
and
tryptophan have been found to be the limiting factors when activated
sludge protein was fed to mammals and this may be so for fish.
The
fermentation industries
including the pharmaceutical industry produce
wastes
that
have been used in
trials
of
carp
feeding.
Distillers
solubles
and
dead yeast cells collected from the bottom of distillation vats have
been evaluated along with spent beers (the expended media in which strains
of bacteria have been
cultured for the production of antibiotics).
The
spent beers,
like
activated sludge protein, have to be rendered sterile
before
they can be used for fish feeding.
Like
activated sludge protein,
distillers yeast products may contain high levels of heavy metals:
very
high levels of copper originating in the copper lined distillation vats have
Ï
been encountered in some
fish trials.
‘
BAKERY WASTE
An
industry which in Europe, Japan and North America produces wastes which
could produce a source of fish feeds,is the bakery and food processing
industry.
In the U.K.
it
has been estimated that
eleven million
loaves
of
bread
are
bought every day and that about 0.1% of this production is waste
in the
form of
unsold
leaves.
Much of
this waste
is bought by farmers for
feeding to pigs.
Blended dried bakery waste products have a crude protein
value
of
about
9% and a nitrogen free extract value of about 67.5%.
In
*
addition
to
feeding of pigs this product has been included in the feed of
several
farm
animals, generally replacing a raw carbohydrate source such as
.
corn.
Until
Jaffa
(1983)
looked at
the use
of
this
material
in
fish nothing
had been published although its use
as
a
supplementary feed had been
mentioned as
long ago as 1933 by Shaperclaus.
When
carp were
fed bread diets
of
40% bread and 35% herring meal then their specific growth rates was
only slightly less than fish fed a diet of commercial trout pellets.
lncreasing levels of bread in the diet of carp appeared to cause little
change in the body composition of the fish carcass.
However, hard fat,
which is
often included in bakery waste in the form of lard does not give
such a
good growth rate for carp as cils when incorporated into test diets.
,This may be
due to reduced utilisation for energy or it may be
that
the
lard
lacks
essential
fatty acids.
However, in contrast to this effect in carp
Reinitz
(1980)
found
that
up
to
50% replacement of fat in the diet of
_
trout by animal fat had no adverse effect on growth.
Bakery wastes are extremely variable in their composition and are,
therefore, more suited as a supplementary feed in extensive pond culture
rather
than
in a complete ration.
In one experiment by Jaffa a standard
pellet was made totally from bakery waste and was fed into ponds of carp
at
approximately l, 2 and 3% of the body weight of the standing crop and
after
six months
the
fish fed
b akery waste had higher weight than the fish
in
the
control pond which had been feeding on indigenous fauna and flora.
ÊÎ_LÆ£E_
Finally in this brief review wastes of animal origin such as offal,
bones,
light, liver and skin must be considered.
Although novel animal
proteins such as earthw0rms, Silk worm pupae, blow—fly larvae, and Krill
have been used
specifically as feeds for fish
experimentally they have not
86
A../. Matty
concentrations
of various metals.
Activated sludges may possibly contain,
in addition to heavy metals a range of biologically harmful materials
including pathogens of feacal origin.
Although the preparation of ASP
‘
involves
temperatures of 60°C for at least 48 hours the risk of pathogen
transmission, although not great,
does
remain
a
hazard
to
be
overcome
before
activated sludge can or should be used in commercial feed for carp.
Amino—
Î
acids
are
also
found to be limiting;
three
amino
acids,
lysine, methionine
Ï
and
tryptophan have been found to be the limiting factors when activated
sludge protein was fed to mammals and this may be so for fish.
The
fermentation industries
including the pharmaceutical industry produce
wastes
that
have been used in
trials
of
carp
feeding.
Distillers
solubles
and
dead yeast cells collected from the bottom of distillation vats have
been evaluated along with spent beers (the expended media in which strains
of bacteria have been
cultured for the production of antibiotics).
The
spent beers,
like
activated sludge protein, have to be rendered sterile
before
they can be used for fish feeding.
Like
activated sludge protein,
distillers yeast products may contain high levels of heavy metals:
very
high levels of copper originating in the copper lined distillation vats have
Ï
been encountered in some
fish trials.
‘
BAKERY WASTE
An
industry which in Europe, Japan and North America produces wastes which
could produce a source of fish feeds,is the bakery and food processing
industry.
In the U.K.
it
has been estimated that
eleven million
loaves
of
bread
are
bought every day and that about 0.1% of this production is waste
in the
form of
unsold
leaves.
Much of
this waste
is bought by farmers for
feeding to pigs.
Blended dried bakery waste products have a crude protein
value
of
about
9% and a nitrogen free extract value of about 67.5%.
In
*
addition
to
feeding of pigs this product has been included in the feed of
several
farm
animals, generally replacing a raw carbohydrate source such as
.
corn.
Until
Jaffa
(1983)
looked at
the use
of
this
material
in
fish nothing
had been published although its use
as
a
supplementary feed had been
mentioned as
long ago as 1933 by Shaperclaus.
When
carp were
fed bread diets
of
40% bread and 35% herring meal then their specific growth rates was
only slightly less than fish fed a diet of commercial trout pellets.
lncreasing levels of bread in the diet of carp appeared to cause little
change in the body composition of the fish carcass.
However, hard fat,
which is
often included in bakery waste in the form of lard does not give
such a
good growth rate for carp as cils when incorporated into test diets.
,This may be
due to reduced utilisation for energy or it may be
that
the
lard
lacks
essential
fatty acids.
However, in contrast to this effect in carp
Reinitz
(1980)
found
that
up
to
50% replacement of fat in the diet of
_
trout by animal fat had no adverse effect on growth.
Bakery wastes are extremely variable in their composition and are,
therefore, more suited as a supplementary feed in extensive pond culture
rather
than
in a complete ration.
In one experiment by Jaffa a standard
pellet was made totally from bakery waste and was fed into ponds of carp
at
approximately l, 2 and 3% of the body weight of the standing crop and
after
six months
the
fish fed
b akery waste had higher weight than the fish
in
the
control pond which had been feeding on indigenous fauna and flora.
ÊÎ_LÆ£E_
Finally in this brief review wastes of animal origin such as offal,
bones,
light, liver and skin must be considered.
Although novel animal
proteins such as earthw0rms, Silk worm pupae, blow—fly larvae, and Krill
have been used
specifically as feeds for fish
experimentally they have not