Carbohydrates
Carbohydrates in KiGen koi food
Carbohydrates
Carbohydrates in KiGen koi food
In the previous pages, we went into depth about the role of the types of proteins used in koi food. We also explained why KiGen ultimately chose the most expensive form of protein for almost all its feeds, namely LT-71 fishmeal.
Besides proteins, fats and carbohydrates form an important nutritional source in koi food.
In this section, we focus primarily on carbohydrates and explain why KiGen chose expensive millet as its primary carbohydrate source.
It is striking that while a lot of attention is always paid to the proteins used, the choice of carbohydrates receives hardly any attention.
Technically speaking, carbohydrates are not an essential nutrient for koi, but they do play a functional and economic role in koi food. Below is a technical overview of the most commonly used carbohydrate sources in koi food, including their function, benefits, and points of interest.
Most commonly used carbohydrates in koi food.
1. Wheat (wheat flour / wheat middlings / wheat starch)
By far the most commonly used carbohydrate source in koi food.
Function
- Energy source
- Binding agent during extrusion
- Improves pellet structure and water stability
Properties
- High starch content
- Easily digestible for koi (especially in extruded food)
- Low in anti-nutritional factors
Why it’s popular
- Reliable
- Consistent quality
- Relatively cheap
Wheat is often used as the “base carrier” of the food.
Most commonly used carbohydrates in koi food.
2. Corn (corn flour / corn starch)
Commonly used secondary energy source.
Function
- Energy source
- Supports the extrusion process
Properties
- High starch
- Easily digestible after thermal processing
- Relatively neutral taste
Point of interest
- Lower protein and micronutrient content than wheat
- Too high a dosage can lead to fat storage instead of growth
Most commonly used carbohydrates in koi food.
3. Rice (rice flour / rice bran)
Premium carbohydrate source, especially in high-quality feeds.
Function
- Easily digestible energy
- Supports intestinal function
Properties
- Very easily digestible
- Low in fiber and ANFs
- Gentle on the digestive tract
Why it’s used
- Suitable for:
- Colder water temperatures
- Sensitive koi
- Maintenance feeds
These 3 carbohydrate sources are most often used in the production of koi food.
Wheat, corn, or rice. Additionally, peas, barley, potato, and sugars are also sometimes used.
KiGen looked beyond the ‘usual suspects’ and settled on millet as a source of carbohydrates. Just like with the LT71 protein, millet is not an obvious or cheap solution for a carbohydrate source, but it is a very good one.
Advantages of millet compared to common carbohydrates
1. Starch structure and digestibility
Millet contains starch with:
- Small starch granules
- Good enzymatic breakdown in the gut
- Stable, even energy release
2. Lower content of anti-nutritional factors (ANFs)
Compared to:
- Soy
- Certain wheat fractions
millet will contribute to:
- A calmer intestinal environment
- Less irritation of the intestinal wall
- Better nutrient absorption in sensitive koi
3. Gluten-free: functional advantage
Millet contains no gluten.
Why that can be relevant:
- Gluten does not contribute to nutritional value for koi
- In some fish, it can contribute to sticky feces
- Affects the water stability of feces
Millet will result in:
- More compact feces
- Fewer fine particles in the water
(this effect is subtle, but sometimes noticeable in practice)
4. Millet contains relatively more:
- Magnesium
- Phosphorus (organically bound)
- Silicon (in small amounts)
While this isn’t a primary reason to use millet, it can:
- Contribute to enzyme activity
- Support cell metabolism
The benefit is small, but positive.
5. Better pellet structure and extrusion properties
Millet starch:
- Gelatinizes well
- Contributes to stable pellet formation
- Will contribute to slow water absorption by the pellet
Result:
- Pellet stays intact longer
- Less leaching of soluble substances
- Lower direct water load
Comparison between common carbohydrates and KiGen MILLET
DIAGRAM
*1 What do ANFs do?
ANFs can:
- Inhibit protein digestion
- Bind minerals (such as calcium, phosphorus, zinc)
- Cause intestinal irritation
- Slow down growth
- Strain the immune system
In koi, you mainly see this as:
- Poorer growth
- More waste (cloudy water)
- Poorer color development
- Sensitivity to stress/disease
*2
A glycemic spike in koi food means a rapid rise in the koi’s blood sugar level after eating the food. Simply explained:
- Some ingredients (especially fast carbohydrates like wheat, corn, or sugars) are digested very quickly.
- As a result, a lot of glucose enters the blood in a short time → that is the glycemic spike.
Why is this important for koi?
Koi are not mammals and handle large fluctuations in blood sugar worse than we do. Spikes that are too high or too fast can lead to:
- Metabolic stress
- Fat storage in the liver and organs
- Reduced resistance
- Poorer growth in the long term
- More waste products → poorer water quality
What causes a high glycemic spike in koi food?
Ingredients with a high glycemic index, such as:
- Wheat (flour)
- Corn (flour)
- Sugars
- Poorly processed starches
- Cheap binding agents
When you see the benefits of millet compared to, for example, wheat and corn, the question arises: Why isn’t millet used more often?
Key reasons:
- Price (more expensive than wheat/corn)
- Availability and consistency
- Extrusion expertise required (not every factory optimizes for millet)
- Limited visible gain in bulk feed
The advantage of millet is most apparent in high-quality, technically formulated food, not in standard mass production.
Conclusion (short and honest)
Millet offers a real, technical advantage as a carbohydrate source in koi food due to:
- Good digestibility
- Low ANF load
- Gluten-free composition
- Potentially better feces and water appearance
- More stable energy release
KiGen claim
KiGen uses millet as a standard carbohydrate source because of the combination of high processability in extrusion, good starch utilization, and the possibility of low nutritional ‘noise’ (fewer unwanted plant-based side effects).
In cyprinids (Cyprinus carpio), it has been shown that adding pearl millet to the diet showed no negative effects on growth parameters/FCR compared to the control.
Why this is relevant in koi food: carbohydrates in fish food are not just energy; they are also functionally important for pellet binding, stability, and limiting leaching/feed loss—factors that directly impact feed utilization and water load.
Millet is a functional, easily processable starch source that, when correctly processed (extrusion), contributes to stable pellets and efficient utilization, with a potentially beneficial effect on waste products compared to less optimal carbohydrate choices.
