It's the time of year when we can light the stove in the evening again. That is the woodstove or the fireplace rather than the central heating system. Cozy, those dancing flames in the living room. In order the light the fireplace first I have to gather some kindling, kindling lights easily and burns quickly. Later we add bigger pieces of hardwood. Sometimes these big pieces of wood do not even fit in the stove. Reluctantly, I put on my coat to go outside and chop and cut these large pieces into smaller ones. When cut to the proper size the will fit into the stove.

Actually our bodies are a type of stove, which keeps us warm. The fire wood can be made up of carbohydrates, proteins, or fats. Above all, carbohydrates are fast acting fuels. They can be compared to the kindling we use to start the fireplace. Carbohydrates are sugars, which originate in large quantities in plants. They are produced during the process of photosynthesis. The bodies of humans or animals can only burn monosacharides. These occur in glucose (grape sugar), fructose (fruit sugar), ribose (sugar made up of 5 carbon atoms) and galactose (made up of glucose and part lactose).

Beside warmth these sugars also provide nourishment for the brain. Without this glucose syrup our beloved pigeons can not survive. The fuels are divided into two groups. We will begin with the kindling.

Mono-sacharides (dextrose and fructose)

Glucose is also known as dextrose or grape sugar. Monosacharides

Are the simplest carbohydrates. These are again divided into different groups. For us it is important to know that they provide the most direct fuel for warmth and fuel for muscle activity (the alfa-1, 4 links). There are also sugars that only become active when for example during a race the fats are used up (the alfa-1, 6 links).

The Disaccharides (lactose, maltose and sacharose)

These are again the smaller pieces of wood from the tree. If we split them in two they will fit in the stove and we can burn them. Some of these twofold sugars are for example lactase from milk and maltose from sprouted barley. Sacharose also belongs to this group. It is found in carrot and beet sugar. Tests have shown that more than 4% lactose on the feed or in the drinking water should be avoided. Lactose arrives in the large intestine where it can only be partially converted by the intestinal bacteria. This process drains a lot of water from the intestine. Too much yogurt or whey on the feed can be the cause of watery droppings.

The Polysaccharides (Cellulose, starch and glycogen)

These are the entire trees that still have to cut up into firewood in order to fit into the stove. For the pigeons they are the grains and legumes such as corn, peas, barley and wheat. They belong to the starch group. There is also a cellulose group. This raw cellulose helps in the digestion of different types of carbohydrates. It is easier to cut up some grains then others.

Alfa-1, 6 link between 2 glucose molecules

Alfa-1, 4 link between 2 glucose molecules

We did the following test: on a loft with three sections. Section 1was fed a normal breeding mix. Section 2 was fed 80% corn and 20% breeding mix. Section 3 was fed 80% peeled rice and peeled barley (pearl barley) + 20% breeding mix. The birds were all exercised together. The pigeons fed breeding mix only were always the first birds back. They exercised just above the loft. The corn pigeons fly much higher and the "rice and pearl barley" looked like dots in the sky. There were three layers of pigeons flying at different heights. After half an hour to 45 minutes the "corn" pigeons were flying the highest.

When we switched the breeding mix section over to the "corn mix", we saw that after a few days they were the ones flying the highest after 45 minutes. We kept rotating the feed mixes between sections. The results were always as we have written above. From this we can conclude the following that the energy (fuel) provided by corn becomes available later then the energy out of white rice and peeled barley and that corn apparently is made up of more types of polysaccharides then white rice. Perhaps this explains, why pigeons that are to be sent to longer races, usually have extra corn added to their diets.

Glycogen

All these forms of sugar together are called glycogen. When energy is used in the stove the wood turns black and what is left over is called ash. When the bird uses energy the same type of process takes place. It is called phosphorylyse. The enzyme that catalyzes the phosphorylyse process breaks the Alfa – 1, 4 links down. These are the "Kindling" carbohydrates. For this process vitamin B6 is necessary. Glycogen is found in the liver and muscles.

During the races

During heavy exercise humans use up 60% carbohydrates, pigeons are different. The liver produces glycogen in order to keep the body warm. If we feed more glucose and glycogen then the daily needs of the pigeon, then the liver also can manufacture fatty acids from them. The blood transports these fatty acids to the red muscle fibers. A portion of the glycogen is transported by the blood to the white muscle fibers. A pigeon has approximately 15% white muscle fiber and 85% red muscle fiber. That is much more than a chicken that has practically all white muscle fiber. We can find many red muscle fibers in the breast of the pigeon.

If we make sure that just before the contest proportionally a high percentage of glucose is found in the glycogen then the fuel will burn faster. Also the liver will produce more fatty acids. This is the result of a makes sense.

Actually it only provides a small advantage on short races. After 10 minutes the fuel in the white muscle fiber in the breast is used up. The fuel stored in the white muscle fiber (glycogen) is used by the pigeon to reach flying height and speed. After this uses the fast sugars "kindling" (Alfa- 1, 4 links) stored in the blood and liver are used. When the glucose is depleted then the enzymes process the Disaccharides and finally, the Polysaccharides are split and turned into monosacharides.

When "fast sugars" are all used up then the fatty acids that were built up by the excess sugars in the feed, which the liver turned into fatty acids become the fuel supply. Some of these are still present in the blood. They were on way to the red muscle fibers but had not yet been stored there. These will be used first.

After a short period of time the fatty acids stored in the red muscle fibers come into play. After 40 to 60 minutes of flying the pigeon is using the fatty acids stored in the red muscle fibers exclusively. Fats have the advantage of leaving little waste in the blood stream after being burned as fuel, although they burn slower than glycogen. The pigeon can fly fastest (wing beats per minute) on glycogen, but the fatty acids deliver more energy. Fats are 9.2 kilocalories per kilogram whereas carbohydrates are 4.0 kilocalories per kilogram.

The wood box

When the pigeon is using fats as its fuel and a bird of prey comes along then the pigeon will use any available glycogen (Alfa 1, 6 links) in order to quickly get away. These are what we could call "kindling" in the wood box. It is ready for use whenever we quickly need to light the stove again.

After the race

The pigeon uses firstly glucose and glycogen (the Alfa 1, 4 linkage), after that the fats. When the bird has used all its fatty acids then it will use any remaining glycogen (the Alfa 1, 6 links). When these are depleted then the pigeon will begin to use it "character". That is, it starts to use its own body; It burns its own muscles, the protein. There are many pigeons with little character. These will go down to rest and look for water and food. If they still come home it will be much too late. The "character birds" keep going. Burning protein or muscle is paired with muscle cramps and is very unpleasant for the pigeon. A pigeon that goes through this often will need weeks to recuperate.

Feeding carbohydrates rich food after a race is very important. The pigeon having used all its glycogen has a need to rapidly relight its stove

Carbohydrates and Racing Pigeons by Pieter Mulder