Briefly, proteins are used in the building and repair of tissues in the body, and so are useful in preparing pigeons for the breeding season, for improved fertility and hatchability. and for improved growth and development of young pigeons. For example, studies in the USA have shown that an 18%protein ration, in which soy beans or fish meal were used as sources of protein, resulted in marked improvements in all of the situations just mentioned. No further improvement was found when diets containing higher than 18% protein were fed, so it seems that diets containing upwards of 18% proteinare ideal for breeding and rearing.
Carbohydrates are the simple and complex sugars in feeds, and along with fats, represent the energy components of the diet, which allow the body to perform work of any kind. Carbohydrates and particularly fats - are important for our purposes as racing pigeon fanciers because they are the fuels that supply the energy for our birds to exercise around the loft, and to fly from both the shortest toss and the longest race, One of the important Carbohydrates- for many birds and animals including humans, is the sugar glucose, sometimes also called dextrose. In grains/seeds. the starch component (visible to the naked eye when a grain such as corn is cracked open) is comprised of many units of glucose, linked together in a particular, large chemical configuration. After grains are ground in the gizzard, and the resulting mash is passed into the intestines, the starch is broken down (metabolized) into individual units of glucose which are then absorbed across the wall of the intestine into the blood stream, and delivered to the liver. Here, many units of glucose are assembled into a large chemical structure that is different from that of starch, and is known as glycogen. Hence, it becomes clear that starch is the storage form of glucose in plants and their seeds, and glycogen is the storage form of glucose in the tissues of birds and animals.
When glucose is needed by tissues in the body, glycogen in the liver is broken down to individual units of glucose which are then exported in the bloodstream to these tissues. For example, the chief fuel of the brain is glucose, a steady supply of which must be provided by the liver - which is why birds normally have a high blood level of glucose. Both red and white muscle in the breast of pigeons must have a ready supply of glucose, many units of which are built up into glycogen for storage in the muscle, and for later use. During the explosive launch phase of flight, or during dodging bursts of energy during cruising flight, white muscle fibers in the breast utilize only glycogen as a source of energy for these actions. As a result, the glycogen supplies in white muscle are completely depleted very quickly (within the first 10 minutes or so after launch), and must be replenished to take care of other dodging emergencies that could occur during cruising flight. To replenish glycogen supplies in the muscle, the liver then begins to break down its supplies of glycogen to glucose, which is released to the bloodstream and is transported to the white fibers in the breast muscles where it is again built up into glycogen, to be used as needed during emergencies in flight.
The other highly important role for glucose in pigeons is in the production of fat for sustained flight. Fat is unquestionably the key fuel for any flight lasting more than a few rminutes, from a short training toss to a 500 mile race, and on to the marathons of 600 miles and more. You may recall a US study in which one group of pigeons was supplemented with 5% fat, and a second group was not supplemented. In races up to 200 miles, there wasn't much difference in the performances of the two Groups. However, after 200 miles, birds in the fat-supplemented group definitely had better performances than those in the unsupplemented group. Once clocking began, there were more birds clocked from the fat-supplemented group in a given period of time than from the un-supplemented group. These findings demonstrated the marked benefits of fat in providing birds with the improved stamina and endurance needed to complete these races. It is known that the liver of pigeons produces almost 50% of the fat for use in the body and that it regulates fat production in the body. (Of course, fat for use in the body is also derived directly from the diet.) One study in the US several years ago showed that when glucose was injected intravenously into hungry young pigeons, there was rapid conversion of this glucose into fatty acids in the liver - within three minutes - a fact that indicates an amazingly rapid ability of the liver to produce fat from glucose!
The source of the glucose for conversion to fat in the diet is primarily the starch component of grains and seeds, and can also be supplied as glucose powder added to drinking water. Fat is stored in the liver but it is also exported from the liver in the form of fatty acids through the blood stream to storage depots in the body cavity among the intestines. Some of the fatty acids are also exported to the breast muscles and stored in the red muscle fibers as microscopic droplets where they are ready to be used as the key source of energy for prolonged, rapid flight.
Now, in birds, in general, it has been found that:
1) HIGH levels of fat in the diet will REDUCE the amount of fat the liver is capable of producing,
2) HIGH levels of protein in the diet will also REDUCE the amount of fat the liver can produce; and,
3) HIGH levels of carbohydrate in the diet will INCREASE the amount of fat the liver can produce.
On the basis of these facts, it seems obvious to me, firstly, that in preparation for a race, high protein grains like peas should be fed at a reduced level, and, secondly that high fat grains should be fed in moderation, and, thirdly, that when high fat grains are used a all, there should should also be a lot of high carbohydrate grains fed, as well.
Strictly speaking, the. fiber component of a grain is classified under carbohydrate, but is often listed separately in nutritional tables. Fiber in a ration is important because of its ability to absorb intestinal components that could be harmful to the system. But in high amounts, fiber can interfere with digestion of other nutritional components of the ration. For this reason, it is often suggested that the fiber component of a ration for livestock be no greater than 5%. You will note that I have included odd items such as cheese, simply because some fanciers I know, as well as some European fanciers, feed it, and the birds seem to enjoy it! Fish meal is included, as well, because of its high level of top quality protein and because, in some cases, it may be included in pelleted feeds for livestock, although it is expensive. Brewer's yeast is mentioned because some fanciers use it on their feed mix, along with lemon juice, at feeding time.
Kafir is the same as sorghum and dari.
Milk powder, both whole and skim, along with ingredients such as rolled
oats If, from thee kitchen, are mentioned because some fanciers include
a number of these and other ingredients into a cake that they bake in the
oven the sun, and later feed to the birds. Malt Malt sprouts, and by extension,
other sprouted grains, are high in protein and some. vitamins at the time.
of sprouting, and once they get used to them. birds relish them and will
eat them avidly. Hulled oats are the same as oat groats. As long as they
are cooked first, soybeans can be fed to pigeons as well as to other classes
of livestock, Don't feed raw soybeans to any livestock, including pigeons,
because of the anti-nutritive substances they contain. Cooking destroys
these substances and renders these beans suitable for feeding.