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Food Glorious Food
by Gerry Preston
Well, that's how the song goes, but is it all so glorious? Strange as
it may seem, the reasons why Koi Keepers feed their fish in the first
place varies greatly; what the fish might need or want usually being
pretty low on the list of priorities. Much more likely, will a particular
brand or ingredient make those 'lack luster reds' deep and shine like a
newly painted pillar box; or will those 'sure fire' minuscule Tategoi
become champion biggies in just a few short months? So why do we choose
one particular brand over another? Believe it or not, advertising
influences all of us. As such, advertising generally falls into two clear
divisions - the informative and the persuasive. Fish food producers,
particularly on the ornamental side, spend a great deal of money on fancy
packaging and persuasive advertising. Highly paid copywriters are employed
to dream up alluring blurb such as 'protein rich', 'highly nutritious', or
'easily digestible' and, in some cases, this may be so. However, first and
foremost it is about enticing us to part with our money by telling us all
the things we want to hear. Sadly, useful information is often lacking on
the pretext that the buying public would not understand it even if given.
My inclination is to interpret this as, were we more learned or given
comprehensive information, we might not be enticed into buying something
just for the picture on the packet! Just how useful, therefore, is the
information given on a packet of fish food? Perhaps before we can attempt
to answer that we also need to address the understanding issue. Leaving
aside the often effusive content of the marketing ploy, what is on the
packet is usually the best we can expect to see. Many have a closed
formula, thus are very minimal in what they tell us. Others, perhaps in
the hope that we will think more is better, claim the inclusion of almost
every ingredient known in their food. Some will simply give percentages of
all, or just a few, of the major nutrients and that is all we have to go
on.
Price, not surprisingly, is the other major factor in the equation.
Market research, itself very costly, largely determines the 'sell price' -
this is the point just below which there might be product resistance.
Conversely, make a food too cheap and everyone thinks it cannot be any
good and, therefore, will resist buying it for that reason! For sure, no
manufacturer is going to put in a more expensive ingredient than he has
to, even though this is highly unlikely to take the price beyond the
expected profit level. Of one thing we can be reasonably certain, the
product price has little to do with ingredient price. Of course, some will
argue that, quite rightly, Koi Keepers expect attractive packaging. Then
there is production, handling and transport cost, particularly with goods
of foreign origin. There is also an unknown, to us, number of middle
merchants before the product finally ends up with a very substantial
mark-up in the retail outlet. In spite of all this, every year sees new
contenders rushing to enter what, to most of us, already appears to be an
over crowded market - each making new claims that their food alone
contains the magic ingredients and additives that make it superior to all
else, yet offering no independent proof of this whatsoever.
Thus returning to our labeling: as already stated, this is often
limited to percentage of protein, oil, fiber, moisture and ash. There may
also be some vitamin advice stated in weight or international units. The
other major nutrient is carbohydrate. Since this is often the largest
component in the formulation, I find its omission suspect. However,
providing one is aware it will be present, we can usually deduce the
percentage by subtraction. Although it is beyond the scope of this article
to detail the biochemical make up of the numerous ingredients most likely
used in fish feeds, perhaps a precis combined with defining the
percentages will suffice. Those specified by the manufacturer will vary
from brand to brand as will the number of individual percentages given,
some being confined to just protein and oil. Since these all seem to be
infinitely variable between brands, and often within the same brand, we
already have a contradiction which begs the question which one is best?
Protein
A major player and vitally important to the well being and growth of
all living organisms. However, protein is just a collective word to
describe the sum of its structural components, which are the amino acids.
There are 10 essential amino acids needed and the same number that, when
necessary, the fish can manufacture, and are thus termed nonessential. Of
great importance is the amino acid ,I)profile, meaning the fish need the
10 essential amino acids in differing proportions. Just as important, the
ratjo required vary to a greater or lesser extent from fish to fish, or
indeed from animal to animal. Thus the required amino acid profile of an
outright fish eater such as pike would be quite different from a
herbivorous fish such as roach. Carp are classed as ,,omnivorous,
suggesting they eat a wide range of food stuffs to include some of
vegetable and some of animal origins.
After digestion by the fish, consumed protein is reduced once again to
amino acids that can either be used to build muscle or, wastefully,
further broken Own for energy. It is only when the balance of amino acids
in the diet is optimal that there is the necessary anabolism to produce
efficient protein synthesis and, therefore, growth; yet even then there
still 7- 10% indigestible protein. Fortunately, the amino acid requirement
for carp is reasonably well defined, and has little tolerance outside that
definition. In other words, if any one of the essential-amino acids is
only available at under the proportional requirement to its neighbors,
then use-f the others will be to that first limiting amino acid ,and the
excessive discharged to waste. This unnecessary breakdown produces
catabolism and -possible fat deposition. Most of all it produces a high
" ammonia load and is, inevitably, bad for waterquality. It will also
compromise growth-rate and, if continued long enough, could have a
detrimental effect on health status. Methionine is usually the first
limiting amino acid in many natural proteins and this plus cystine, which
can reduce the methionine demand is often supplemented to a quality food.
If the packet would generally boldly state this. We can now already see
that a protein declaration is not telling us the entire story, and
certainly gives no indication whatsoever of its suitability for our fish;
neither is the protein percentage figure itself much help.. The
classification of proteins is largely of animal or vegetable origins. The
amino acids contained in many fish meal proteins match well to the profile
requirement of carp. As such their inclusion is generally a prerequisite
to formulating a nutritious diet. The problem to the manufacturer is that
they are expensive, particularly the very high quality white A meals
derived from Alaskan Pollack or similar fish often used in Koi foods. The
use of the much valued oily herring meal tends to be more in diets for
Peruvian anchovy, is regarded as second best but a proportion can be
included without too many problems. In the early days of fish farming it
was common for the inclusion of bovine proteins in feeds. This practice
reduced over the years and since the advent of B.S.E. is now very much
frowned upon when included in rations for fish destined for human
consumption!
Vegetable proteins are mostly poorly digested and many have a
miss-match to am no ac requ rements - a low chemical score when measured
against the ideal. However, some do have an excellent biological value in
their own right and mixing with fish meal proteins brings down the cost of
the total protein expenditure. Soya bean is probably the most widely used
for dilution but is lacking in several essential amino acids, thus its
inclusion above a certain level, although attractive commercially, is
undesirable. It also contains natural feeding deterrents. Heating largely
overcomes this problem with the addition of chemo-palatants, thereby
persuading the fish to eat what its instincts would, almost certainly,
make it refuse. The addition of attractors to stimulate a fish's appetite
is nothing new. Izzack Walton added honey to his baits to catch carp three
hundred years ago. Carp have very well developed gustatory (taste) and
olfactory (smell) senses. Present day carp anglers have a seemingly
unlimited array of flavors, extracts and oils from which to choose. Many
claim even the amino acids themselves to be attractors. Betaine HC1 is
probably the most used stimulator in baits and commercial feeds. However,
should they do so, it is highly unlikely that many ornamental fish food
producers would admit to using chemical palatability enhancers to make
their product more acceptable.
With the ever shrinking bounty from the seas, seeking alternatives to
fish proteins is essential, of that there is little doubt. The inclusion
of dairy shows much promise. Perhaps the genus Scenedesmus, having a crude
protein value of 55%, more than most and SpIrulinae could have
considerably more value as a protein source than its over-hyped powers of
color improvement. However, trials tend to confirm a reduction in growth
as the percentages of these alternatives increase with a corresponding
decrease in the fishmeal. Increasing the percentages further leads to
heavy losses. A notable exception, however, is krill, (Euphausia superba);
these tiny shrimp like creatures abound in massive quantities in the
Antarctic and are expected to make a considerable contribution to future
livestock feed-stuffs. They have long been readily available to the
aquarist. Coincidentally, of course, the much heralded inclusion of chitin
in some Japanese Koi foods sits nicely with the Japanese peoples fondness
for consuming enormous quantities of crustaceans and shell fish!
Wheat germ meal is another protein source well exploited by the
ornamental fish food industry. Whether it is even remotely possible to
justify all the hype, is impossible to say. Never have I seen independent,
or otherwise, trial results published appertaining to growth, health or
anything else. For years Koi scribes have played safe and just repeated
everybody else - and eventually themselves -over and over again.
throughout the summer and winter. Personally, if Koi cannot property
utilize food due to temperatures being too low I can see little point in
feeding them at all. On the other hand, if you are going to feed, it makes
much more sense to use a good quality high protein food all year round,
but especially in the traditional slowing down and warming up period. At
these lower temperatures Koi are going to eat greatly reduced quantities
anyway. Therefore, even with a high percentage protein feed, their actual
intake of protein is very modest.
One only has to examine briefly the sequential events in a natural body
of water to realize the validity of this. In high summer there is a
profusion of plant growth as well as a multitude of insects and organisms
that we can loosely term animal. Nature thus satisfies herbivores,
omnivores and even carnivores. Carp undoubtedly consume large quantities
of easily available plant life at summer temperatures. Duck weed is a
particular favorite and Koi will make short work of any efforts to try to
establish water lilies etc, in an existing pond. Contrast this with the
depths of winter when virtually all of the higher forms of animal life, so
relished by carp in summer, are still available to them in winter should
they wish to feed; yet all of the plant life has completely died away -
hasn't it?
Koi literature is constantly stating the value of wheat germ revolves
around being easily digestible and is, therefore, the ideal low
temperature food. Even assuming that is true, the actual percentage of
wheat germ in the food is very small indeed. Thus begs the question, how
digestible is the rest of the food? Not very much is the easy answer, and
probably a good job too since the major proportion will be carbohydrates.
The universal use of carbohydrate is as a binder, to bulk out a feed, and
as a cheap energy source. As carp's energy requirements in cold water are
very minimal, if these feeds really were highly digestible, much of it
would be retained as saturated (solid) fats within the body cavities and
internal organs of the fish. In practice most of it simply passes through
with little absorption into the blood stream. It probably does no more
harm than it does any good! What it does do is to keep the cash registers
ringing and the hobbyist content in the belief that they are providing
quality food.
Quality and Quantity
Thus returning to the protein in dry diets, it becomes clear that
separating quantity and quality is not so easy. A particular pellet having
a high claimed protein percentage may well have a large amount of plant
proteins in its inclusion. We have no control over this and little hope of
identifying the good from the not so good, even when given a long list of
ingredients. However, quantity is something tangible and it is very
noticeable within the same brand that the higher the protein percentage
the higher the cost. So is it okay, or more economical, to feed the
cheaper lower protein food? Think of it like this: Kol have a daily
quantity protein requirement governed largely by temperature and their
size. Should that requirement not be met they certainly will not grow and
could have trouble repairing damaged tissue, laying down eggs, etc. In
fact most of the functions needed to maintain a fish in good health. Now
to keep the maths simple, supposing two Koi Keepers were to each feed I
OOgm of pellets a day, but M10% protein and the other very with a 30%
protein. We can see instantly that the former gives as a daily protein
intake of 40gm and the latter only 30gm of the same. Also, supposing the
40gm was the correct daily intake, then in order for the lower protein
pellets to meet that requirement, the actual quantity of pellets would
have to increase from 100gm to nearly 135gm Although this is probably
better than not meeting the 40gm protein requirement, it could well make
the cost of feeding a cheaper food more expensive. Also satiation may be
exceeded long before consumption of the required protein quantity. In
addition there is the possibility that the resulting excess of other
nutrients could have a detrimental effect on the health of the fish. For
certain it will have a detrimental effect on water quality, particularly
with increased suspended solids. Unfortunately, many Koi Keepers feed a
quantity of food totally unrelated to protein content! This is exacerbated
by feeding Koi with bread, barley, corn, etc., in the belief, quite
reasonably, that the fish enjoy a change. Such foods, although well
accepted, are very low in proteins and being of vegetable origin have a
poor biological value. Therefore, it is only if t Hess supplements are
used as well as a high quality protein pellet food, is there a wide enough
margin to compensate and maintain adequate daily protein levels. Although
the overall cost of a high percentage protein food Will increase, it
should not do so proportionally as the percentage of other ingredients,
obviously, would have reduced. However, it is certainly gratifying to me
after campaigning for so long that Koi foods are generally too low in
protein, that many producers now offer a range of foods with increased
protein content - usually described as high growth food.
Growth
I suspect that the long held view that carp do not need high protein
arose from carp farming traditionally being extensive - the fish getting
most their nutrition from natural food in the pond. Daphnia (water fleas)
have a protein content of between 48% to 50%, Gammarus (shrimp) 45% to 52%
and Chinronomidae (bloodworms) as high as 55%. Thus it was perfectly
reasonable to supplement with bulky low cost food-stuffs, causing only
modest dilution of the readily available protein rich feeding. A
bio-filtered Koi pond has very little in common with these conditions and
is indeed, in every sense, very intensive. Consequently, with natural
feeding being virtually non-existent Koi, ideally, need foods of an
exceptionally high biological value.
Additionally,
I am afraid we cannot separate growth from temperature. As my own trials
have shown (NI Winter 96/97), it is possible to achieve phenomenal growth
using very high protein foods combined with consistently high water
temperatures. Unheated Koi ponds are very different. Unless the water is
sufficiently warm the fish simply cannot consume enough food to grow at
their full potential. All the more reason to feed to a maximum during the
normal growing season providing, of course, the filter is able to cope
with this, and to feed what makes them grow protein. There have been many
studies to find optimum nutrient levels, but with most arrived at by
considering the economics, If an additional 5% protein costs, say, 10%
more for only a 2% increase in growth-rate, some might not consider that
economical. Koi Keepers rarely worry about such restraints and most will
happily pay more for only a modest return. However, many authorities seem
to concur with around 38% protein as a minimum. I would add, especially if
also regularly giving any legume or pulse feeds, 40% plus would be even
better and just hope you have bought good quality protein in your chosen
brand of food. Certainly if growing on small fish separately, then nearer
to 50% protein would show a marked benefit in size and shape of the fish.
Last but by no means least, it is quite feasible to reduce the feeding
quantity by giving a high protein diet. The benefits, are soon obvious. It
encourages fish to clear-up everything on offer but f , u still meeting
their essential needs. Also realize that most recalculating systems are
far better able to cope with increasing ammonia loads than they are of
solids, which tend to inhibit nitrification. Thus by simply upping protein
levels makes for a cleaner pond and healthier fish.
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