Carbohydrate and Koi
by
Chris Neaves
Posted on NI
Some interesting
facts on carbohydrate that koi keepers may be interested in – after
all we feed our koi carbohydrate each and every day. Not only this, but
we feed carbohydrate several times a day.
The body uses carbohydrate as its primary energy source, using it to fuel
everything from your muscles to your brain. So carbohydrates are good.
There are basically two fuels in koi foods – lipids and carbohydrates (and protein if you must get technical). Of the two fuels – remember the body needs energy to live, breath, metabolise and excrete etc. lipids produce more energy than carbohydrates. However, carbohydrates release their energy more quickly.
In an experiment
by Chris Wood and reported in the Journal of Experimental Biology by Kathryn
Phillips it was found, to their surprise, that when fish were exercised
they utilised carbohydrate as they started but then switched to using
lipids when they had reached a steady pace, after about 10 – 15
minutes.
So carbohydrate is a quick release energy source and is utilised by fish.
Then as has been said before, the carbohydrate is also used as a binder
to deliver the nutrients to the gut.
Carbohydrates are found in all plant sources. Simple or fast carbohydrates are refined carbohydrates sources such as are sugars, honey, jelly, syrup, candy and other sweets. They are rapidly absorbed into the bloodstream, causing a quick but short term burst of energy. Most are considered “empty” calories, since they don’t provide any vitamins, minerals or fibre. Obviously the fast carbs are a problem with people who had blood sugar problems. But are they a problem with koi? (if you feed them sugar?).
I know of no studies
that distinguish between simple and complex carbohydrates in fish, let
alone koi.
Complex carbohydrates are found in starchy foods such as bread, pasta,
potatoes and grains. Made up of hundreds or thousands of simple sugars
linked together, starches are absorbed more slowly than sugars. This results
in a more gradual but longer lasting increase in blood sugar and energy
levels. Complex carbohydrates also tend to provide more vitamins and minerals
than simple sugars.
The carbohydrates
used in koi food are usually complex carbohydrate such as wheat, corn,
bran, flour, etc. The cooking process increases the digestibility of the
carbohydrate. The carbohydrate also adds fibre to the diet.
There is also another reality we must deal with. Koi foods have been around
for a long time. And we have successfully grown some truly beautiful koi
on these foods.
If you have a koi
food with around 38 – 40% protein levels the carbohydrate content
will be around 30% of the total mix. The lower the protein level the higher
the carbohydrate level will be.
On the other hand there was a presentation done by Prof. G. Slama at the
17th International Symposium on Diabetes and Nutrition, in Versailles,
July 1999 – Fast carbohydrates - Slow carbohydrates.
I quote verbatim
- Short Story of a Wrong Idea
Chemistry of Small and Large Molecules : A Simplistic Conception
After being ingested, carbohydrates are digested in the intestine (i.e. broken down into their component parts) by the action of enzymes before being assimilated and passing into the bloodstream. There, in the form of glucose, they cause an increase in the level of glucose in the blood, followed eventually by a return to normal.
Monosaccharides (composed of just one carbohydrate unit) such as glucose or fructose and disaccharides (composed of two carbohydrate units) such as sucrose or lactose were assumed in the past to be quickly digested and assimilated because of their small size. They were therefore considered to be hyperglycaemic, i.e. they were supposed to cause a sudden increase in blood glucose. On the other hand, the long chain of sugars units in starch (a branched glucose polymer) was conventionally considered to be slowly depolymerized and assimilated and, it was thought, gave rise to a much slower rise in blood glucose.
This assumption was not based on any experimental results. In fact, the concept of fast carbohydrates - slow carbohydrates is incorrect. One of the first experiments that overturned this idea (and left researchers perplexed) revealed that breakfasts providing an intake of either 70 g of starch or 50 g of starch with 20 g of sugar had identical effects on blood glucose.
Interesting.
"Starches are
as bad as sugars" – answer - both are carbohydrate and both
are not bad.
"Watch out about comparing mammalian biochemistry to fish" –
answer - exactly. Please list the fast carbs found in koi food.
During slow or normal swimming the red muscles are used. They are capable of using energy quickly. During trials it was found that the red muscles opt for carbohydrate energy initially. However, this is for short periods then the white muscles are called upon to supplement the red muscles when the fish swims quickly and for a sustained time. The muscles are capable of switching between energy from carbohydrates and energy from lipids.
The fact is that we are feeding carbs several times a day (+ all the other goodies in the food of your choice). For the sake of debate, does it really matter which carbs are present in the koi food? Are we not creating a problem where none exists? If fast carbs were bad, and fast carbs are actually present in the koi food we use, then all our koi should be fat, round and diabetic?
But they are not, so what is going on? And how will fast carbs over load the system? (we may have to invent a supplement to counter over active koi and over active children overloaded on fast carbs or a diet pill for obese koi!) If fast carbs do over load the system, then we are doing exactly what JR is correct in saying - comparing mammalian metabolism with fish metabolism. However, we do not have scientific studies that fast carbs are “bad” for koi. (If there is proof, please let me have the references for my records).
And we must take
this point of debate further – if fast carbs and slow carbs were
an issue in koi nutrition then we would not be growing the beautiful koi
we have had for many, many years.
"Of course in the wild, carp wouldn't be eating a whole lot of corn
and potatoes, but water plants and algae, both of which are a lot harder
to break down. Lots of cellulose in there." – answer - this
is an interesting point and a good argument for lots of fibre in the diet
to keep the gut moving and healthy. Over-refined diets are not good.
"Chris, protein
40 % carbs 30%, water 10%, what is the remaining 20%? Fibre, what 4%?
oil 4%? 2% vits and sundries? I'm still short some here."
Answer – Bil, the diet does not work like that. The composition
of a diet is not just xyz. (not even abc) The ingredients that go into
a diet formulation have many different nutrients in each of them. This
detailed analysis has to be taken into account. The addition of an ingredient
or a percentage increase in a single ingredient immediately affects the
“balance” of the final product.
So, generally speaking, if for example, you use fishmeal as a basic protein source then to get to a projected 38 - 40% protein level (when you have looked at the amino acid profile after extrusion) you will use around 47% of the total 100% meal mix. Different carbohydrate sources have different nutrients in them. You may use a refined flour/corn etc + another carb source such as bran etc. A lot of this depends on availability (and to some degree cost at a particular time of the year). So carbohydrate/energy/binding sources amount to around 33 – 35% of the total 100%.
Moisture is used to make the pellets. If you want floating pellets then you use steam to cook the ingredients (wonderful for the digestibility of all the ingredients). After the pellets have been formed they are sent to a dryer to be dried (need a degree in logic for that previous statement!). The moisture content of the food has to be less than 10% before packing or you will have storage problems in the near future. The analysis we have done indicates the Japanese foods available here; some Taiwanese and some South African koi foods are all dried to 3 – 5% moisture. (By the way the food is then analysed after this process to ensure the levels of proteins, vitamins and minerals are at the levels you were aiming for).
So just these three things gives you around 87% of the total mix. Now add a few other bits and pieces such as can be seen on the packets of koi food (vitamins, minerals, colorants (red, green, orange or brown, pink if you like), etc, plus a little fish oil, etc and you will easily get to the 100%.
“What I would ask you is the same as I ask JR, and never get an answer. What good does feeding fast carbs do, and what harm could it do? “ - answer – firstly, please list the “bad fast carbs” in koi food for me. We can then look at each individual component and see if it is actually “bad” for koi. Secondly, in over 30 years of koi keeping I never considered “slow” and “fast” carbs to be an issue in fish metabolism so I never ever worried about it. As I mentioned in the first posting on this subject there is some evidence that slow and fast carbs are an illusion. Taking mammalian metabolism info and then worrying about it from the point of view of fish may be worth exploring if, and only if, the present food we feed our fish is actually a problem. Judging from the wonderful fish I see in koi ponds I don’t think that there is a problem.
Why try to fix that which is not broken?
Speaking from personal experience, my koi are in excellent health, the koi farms that use my food produce excellent fish that grow rapidly, the koi keepers that use my food grow koi in their ponds at around 25cm per year from hatching - with very good body shapes. Independent lab analysis of my food proves that it is comparable with the very best from Japan. So I do not see a problem with most of the reputable brands of koi foods on the shelf today that koi keepers can buy. Yes, there are some el cheapos on the market that do have high carbohydrate and low protein. They are beautifully coloured pellets, which in my opinion should be avoided. This is not because I manufacture my own koi food but because the excess energy/carbs found in these foods is really not good for your koi.
There will be worldwide
fishmeal shortages in the future (next 20 years or so) and the industry
is running trials on alternative protein sources for fish feeds (that
are cost effective). This will still have to be delivered to the gut of
the fish in an aquatic environment so binding the food and keeping costs
down will always count!
Regards,
Chris
