Considerations in Pigeon Racing
By: Gordon A Chalmers, DVM, Lethbridge, Alberta, Canada
(Note: This material was published originally in the 1992 year book of the Canadian Racing Pigeon Union, and has undergone several modifications and additions since that time.)
Fat is the major fuel needed by racing pigeons during the racing season, and indeed, by any species of wild bird that flies extended distances, as in Spring and Fall migrations. It has been noted that the capability of birds for storing triglycerides as an energy reserve, exceeds that of other classes of vertebrates (Blem, 1976). The fatty acids of these triglycerides are predominantly of the 16 and 18-carbon variety, and generally, are more unsaturated than those of mammals.
The facts about fat as the key fuel for racing were established many years ago, and considerable work on this subject was undertaken in Canada by Dr. John George, his colleagues and graduate students at the University of Guelph, Guelph, Ontario. More recently, it seems that some very exciting work by Professor Rothe, who used pigeons in wind tunnels at Saarbrucken, Germany, reaffirmed the fact that, truly, fat is the main fuel involved in the production of energy for racing. Logically then, providing diets containing increased amounts of fat, could be very helpful in providing the highly important fuel reserves needed for racing, right? Well, possibly......
Perusal of available literature on the metabolism of protein, carbohydrate and fat in birds in general revealed some interesting information that could be very useful in preparing pigeons for racing. Here are some of the facts taken from pertinent scientific literature on birds.
Firstly, in birds, it is known that less than 4% of depot fat, that is, fat found in the body cavity, under the skin, etc., is actually produced in these locations. Where then, is the great majority of fat actually synthesized? Well, not surprisingly, in pigeons the liver is the major organ in which the vast amount of fat is produced.
In fact, in birds, about 47% of the fat produced for use in the body is produced in the liver, 44% in the carcass, 7% in the skin, and 2% in the intestines. It is known that when the relative weights of tissues are taken into account, the liver of birds is 20 times as active per unit of weight in the production of fat as is the carcass.
However, it is interesting to note as well that bone marrowis another important site for fat production in birds, and that bone marrow itself has about two thirds of the fat-producing activity of liver. After it is produced in the liver, fat is transported in the bloodstream to the body depots for storage, and very importantly, to working muscles where it serves as a ready fuel supply for sustained flight.
Fine so far, but there are a couple of interesting points to consider.... Logic would say that the addition of extra fat to the diet of racing pigeons would help the liver with production, and would just add to the amount of fat produced normally by the liver, and subsequently exported to storage sites.
In fact, one study several years ago showed that the addition of the vegetable oil, corn oil (a vegetable oil is simply a liquid fat) in the amount of 5% to the diet of racing pigeons, improved performances, especially from beyond 200 miles, whereas birds that were not supplemented with corn oil had poorer performances overall.
The addition of extra fat to the diet should assist the body in building fat reserves. My reading around the subject of the energy requirements of birds turned up some very interesting, surprising, and potentially useful information that could be of value in the preparation of pigeons for racing. The following facts need to be pondered, mulled over, and if judged to have some merit, acted upon accordingly:
Point #1 -- high levels of fat in the diet of birds will DECREASE the amount of fat produced by the liver (Griminger, 1986).
Point #2 -- high levels of protein in the diet of birds will DECREASE the amount of fat produced by the liver!!
Point #3 -- high levels of carbohydrate in the diet of birds will INCREASE the amount of fat produced by the liver (Griminger, 1986).
In one study in chickens, it was found that the addition of 10% corn oil to the diet of young chicks actually decreased fat production in the liver by a startling 40%! However, it is important to note that when amounts of carbohydrate in the diet are held at a constant level, high levels of dietary fat don't interfere with fat production by the liver! Another important point is that stored fat in the body, including the flight muscles, is obtained not only from production in the liver, but also from fat absorbed from the diet through the wall of the intestines.
Now, let's try to translate some of this information so that it has a bit more meaning for fanciers. Firstly, the great majority of fat in the body of the racing pigeon is produced by the liver, from which it is then transported in the bloodstream to depots (also called storage areas), and to red fibers in the muscles, for direct use as a source of energy during flight.
Fat that is present the diet is also absorbed through the intestines and is transported to muscles and depot areas as well. As fat is needed by working muscle, it is mobilized from nearby sources and from these depots, and moved through the bloodstream to the muscles. Preferential use of fat by flight muscles allows for a more efficient liberation of energy during prolonged, strenuous flights such as those of migrating birds, and of racing pigeons.
There is some difference of opinion among fanciers as to whether depot fat is really utilized as a source of fuel. The information I have at this point is that experiments on pigeons at the University of Guelph showed that after a minimum of 30 minutes of exercise, the amount of fat in depots decreased by almost 25%, and that, correspondingly, the amount of fat in the breast muscles increased by about the same amount.
This work also demonstrated that the amount of fat in the bloodstream increased by about 18%, and in the liver, by about 30%. These investigations indicate to me that fat is indeed mobilized from depot areas, transported in the bloodstream, and taken up by the liver and working muscle.
It has been established in other species such as the laboratory rat that depot fat is not static, and that in this species, there is a complete recycling of depot fat every 10 days. Therefore, depot fat seems to be a dynamic system involved in the synthesis, oxidation, storage and release of fats in some species. Despite this general information, it is known that in pigeons, very little synthesis of fat occurs in depot areas.
However, in migratory birds, it is known that peritoneal or "migratory" fat is distinguished from subcutaneous fat or "winter" fat. Migratory fat accumulates rapidly in large amounts just prior to migration, and is exhausted at the end of migration (Odum and Perkinson, 1951). It may well be that the fat we build each week in racing pigeons is of the "migratory" type, because of the rapid accumulation of large amounts of "pre- racing" fat in the few days before shipping.
Since the amount of glycogen -- a complex sugar which is really the storage form of glucose -- in red fibers is relatively small compared with the amount of fat present, it can't be considered to be a serious contender as a major source of fuel for flying any distance, despite some persisting views that it is.
Incidentally, in less than two hours after feeding glucose, either as the sugar given in water, or after the conversion of starch from grains into glucose in the intestines, there is rapid production of glycogen by the liver of birds. Some glycogen is stored by the liver and some is exported in the blood to muscles and other tissues as a source of energy. Glucose is the major source of fuel for the brain.
As well, a study by Goodridge and Ball (1967) revealed that significant carbon derived from intravenously injected glucose-U- 14C was incorporated into fatty acids of liver within three minutes in pigeons, and that the content of radioactive fatty acids in liver reached a plateau in 15 minutes.
Significant appearance of labelled fatty acids in blood and fat depots was seen first at 15 minutes, and their concentration rose continuously throughout the two-hour experimental period. During this trial, the authors calculated that the liver was converting glucose to fatty acids at a rate 25 times faster than that of the fat depots.
This study concluded that depot fat in the pigeon does not have the capacity for the conversion of glucose to fatty acids, compared with that of liver. It also indicated that the regulation of fat synthesis in the pigeon must occur in the liver.
If we try to assist the liver by adding more fat to the diet, say by the use of grains containing high amounts of fat -- grains such as peanuts that contain almost 50% fat (and a high level of protein, -- about 30%, note) -- actually, we may be causing a marked decrease in the amount of fat that the liver is capable of producing for the energy requirements of flight! A decrease of 40% production of fat by the liver in the face of a high level of fat in the diet could be a pretty significant decrease!
However -- it is possible that compensation for this decrease may occur, by the presence of fat absorbed by the intestines from the diet. When this dietary fat is mixed with bile in the intestines, it is absorbed directly through the wall of the intestines as a source of fuel. However, it seems that most of the fat in storage depots and in red muscle is produced by the liver.
Another important point to re-iterate in this discussion of fat is that fat synthesis by the liver of birds is greatly inhibited when dietary levels of carbohydrate in the ration are concurrently low. By contrast, there appears to be little reduction in the production of fat by the liver when dietary levels of carbohydrate are maintained at a relatively high level.
It is quite possible, and indeed, very likely, given these facts, that adding a high amount of fat through the addition of a significant percentage of peanuts, for example, could significantly reduce the amount of fat manufactured by the liver.
When we add peanuts to a significant level of the ration, in effect we have removed a similar weight of one or more of the other grains already in the diet. Regardless of the number or amounts of grains added to the diet, it is obvious that the total weight of all grains used in a particular mix, adds up to 100%.
The grains that are likely to be replaced by peanuts are the carbohydrate-rich cereal grains, such as wheat, barley, rice, oats and corn, and this may well be the nub of the issue. Remember that diets high in carbohydrate result in a high production of fat by the liver. Remember too that peanuts are very high in fat content, but they are also very high in protein -- and also importantly, low in carbohydrate.
Diets high in fat and high in protein result in decreased fat production by the liver! To offset the effects of diets high in fat, one simple, key method is to maintain a high level of carbohydrate in the diet when the fat-loaded grains are added.
Here is another very important point. As noted by Dr. Pawloski (1991) in his very informative article in the R.P. Bulletin, diets high in protein may also cause increased thirst in pigeons, because of the high amounts of uric acid (from the metabolism of the high per centage of protein in peanuts and other high-protein grains) that have to be excreted through the kidneys.
This uric acid (also called urates) is concentrated in the white tip seen when droppings are passed. This excretory process requires water to flush the uric acid and its salts out of the kidneys. Result: loss of water from the body which, in turn, results in increased thirst to replace the water lost in the flushing process, something that we want to avoid at almost all costs, especially when birds are due to be sent racing.
So the use of diets high in protein, including the use of high amounts of peanuts in the few days just before shipping, probably causes unnecessary thirst on the road and should be avoided, according to Dr. Pawloski. It certainly makes sense.
If high-protein grains are to be fed during the racing season for the repair and maintenance of muscles and other tissues for example, it seems logical then that they should be fed earlier rather than later in the week -- say up to mid-week and no later. As well, protein is not really an energy food, although it certainly can be used for this purpose, but likely only when all other fat and carbohydrate sources of energy have been exhausted.
For these reasons, and because protein tends to be the most expensive component of a diet, it should be reduced in amount in the ration in the few days prior to shipping, to allow for a build up of fat reserves from carbohydrates, and to avoid problems of increased thirst.
What are some methods that we could use to deal with all of these facts?
1. One simple, obvious, safe way to build necessary fat reserves would be to revert to a traditional diet of mainly cereal grains, including a high per centage of corn (say, 40% or more), and completely avoid the high-fat grains when birds are racing. This would also mean that the amount of legumes in the ration during the racing season -- peas, beans, lentils, etc. -- should also be reduced from the amounts used for breeding and rearing, because of their high content of protein, and associated thirst, to say nothing of the cost.
2. Another clue that we can use to advantage is this: eating a meal, as opposed to nibbling in a hopper-feeding situation, increases fat production in birds. So, it seems that those who feed pigeons a meal once or twice a day during racing, may actually bring about a greater production of fat to be used for fuel than those who hopper feed. Would hopper feeding be best for short-distance racing, and meal feeding best for long- distance racing?? Just an idea.....
3. Another practical approach during racing would be to use peanuts or other high-fat grains or seeds, in moderation -- repeat, in moderation, -- and as well once again, to reduce the protein level by reducing the amount of legumes such as peas, lentils, etc. in the diet. (One enterprising and successful fancier I know uses peanuts only early in the week, but makes good use of the cereal grains from mid-week to late in the week before shipping. This procedure likely avoids the pitfall of thirst later in the week, as pointed out so aptly by Dr. Pawloski.)
At the same time, we should be certain that the amount of carbohydrate in the diet is at a high level, ie, by the use of a high proportion of cereal grains, especially grains like corn, wheat, oats and rice, for example. Glucose or table sugar could be added to the drinking water to supply extra carbohydrate if necessary.
(Note: Don't put glucose or other sugars in the water day after day. Use these sugars for only a day at a time, to prevent the growth of yeasts and molds in the crops of your birds, since these yeasts, etc. use the sugar as nutrients for their own growth, and can invade the wall of the crop at this time.)
These measures would take advantage of the fact that when the level of carbohydrate in the ration is at a reasonably high level, increased dietary fat does not seem to interfere with fat production by the liver of birds.
Remember to add grains to a ration by weight, not by volume. For example, wheat, peas and beans tend to weigh about the same, ie, if you use say, a coffee can to measure out grain, one can of wheat will weigh almost the same as one coffee can of peas or beans.
On the other hand, the same coffee can full of barley or corn will weigh, on the average, about one fifth less than the same amount of wheat, peas or beans -- so the result is that you have to add another one fifth of a can of barley or corn to the mix to be sure that all of the grains mentioned in this example weigh the same.
4. One other intriguing but practical method to improve fat production in racing pigeons could be the use of the sugar fructose. Fructose is available here as a powder and can be found in health food stores as well as grocery stores. Compared with table sugar, fructose may be expensive. Speaking of table sugar, it too is a source of fructose, since it is composed of one unit of glucose and one unit of fructose linked together -- two key sugars right in your own home. Another good source of fructose is honey which contains about 40% fructose.
Why use fructose, when glucose seems to be the major sugar in the body of birds, the liver of which has a significant ability to convert glucose to fatty acids in a very short period of time (Goodridge and Ball, 1967)? First, some background. Most grains, especially the cereal grains, contain a high per centage of starch, a complex chemical structure composed of many individual units of the sugar, glucose.
When the starch in grains is digested by pigeons, it is fractionated by digestive juices in the intestines into glucose, which is then absorbed through the intestinal wall into the bloodstream and transported to the liver.
It is known that in birds, the absorption of glucose from the intestine into the bloodstream far outstrips the absorption of fructose. However, if fructose is present, it too will be absorbed from the intestine of birds and transported to the liver where it is metabolized rapidly.
It is significant that the liver of birds is able to metabolize fructose very rapidly and efficiently, even if there are also high levels of glucose present as well. The rapid and efficient metabolism of fructose by birds is not hindered by simultaneously high levels of glucose as it seems to be in mammals.
Another key fact about fructose is that in birds, fat production from the metabolism of fructose exceeds that of all other carbohydrates collectively! Another highly significant point for us as pigeon flyers is that in birds, the metabolism of fructose and its conversion to fat receive very high metabolic priority -- a key fact!
This information offers another practical clue to the process of fueling pigeons for racing--ie, use fructose to build necessary fat reserves, especially for the tougher distance events!
It seems to me that the use of fructose could be a major factor in rapidly rebuilding fat reserves in a pigeon as it races, say in a widowhood situation, for several weeks in a row. Maybe the problem of "picky appetite" and the concurrent need to rebuild fat reserves in widowers might be solved very nicely through the use of fructose, honey or table sugar in drinking water.
A racing widow/widower may have a capricious appetite at times, but the more dependable need for a drink of water, to which fructose can be added for a day to a day and a half, for example, might provide a partial answer for those birds with the touchy appetites.
Fructose could also be valuable in rapidly rebuilding fat reserves in exhausted birds when they return from a gruelling race, looking like shadows of the birds entered originally in the race. It seems to me that, in looking at these facts, it becomes evident that feeding high levels of carbohydrates in general, and that feeding simple sugars such as glucose and fructose specifically, could be highly valuable in rapidly building fat reserves in racing birds, virtually when we want them!!
Maybe we don't even need to use so many peanuts or other fat-containing seeds. Certainly, peanuts and other high-fat grains can be a mixed blessing, and unless you are completely sure that you are using high-quality peanuts in the first place, maybe you should reconsider using them. Those used for human use are probably the best, but I have seen some peanuts used by pigeon fanciers and I have shuddered at the thought of any bird being forced to eat them!
Rancidity because of the very high fat content is a very real danger, especially in the hot summer months if peanuts are not stored under very cool conditions. Also, certain types of molds, such as those seen on moldy bread, for example, can invade peanuts and produce some nasty poisons that can induce cancers of the liver in some species. Obviously, the use of peanuts requires considerable care, and only those of the very best quality are good enough.
As you can see from reading the foregoing material, there is a great deal for all of us as fanciers to learn about the nutritional needs of pigeons! I am fascinated by the number of facts about the physiological and nutritional characteristics of birds in general -- all buried in the scientific literature -- and this article is only a small attempt to expose these facts to the light of day and to the curiosity of the thinking fancier.
Obviously, this article only scratches the surface of the vast amount of information and knowledge yet to be discovered and shared about the feeding of pigeons for racing. As I am not a nutritionist, I certainly don't claim to have many, or even anyof the answers, and I would welcome any further input to this fascinating, important subject.
We need facts and we need to share these facts, rather than burying them as "secrets" to be used only for our own gain.
It would be ideal if a group of thinking fanciers would get their heads together to run well-constructed trials, complete with control groups, say over a 3-5 year period, to explore in a scientific way, the pros and cons of different diets used for racing. For example, one randomly assembled group of racers would receive a certain per centage of peanuts in the ration each week, whereas another randomly assembled group, would be managed, exercised, trained and raced in exactly the same way, but not fed peanuts at all.
Overall race results of the two groups could be tabulated and compared statistically, to determine whether one group raced better than the other.
We need solidly performed studies, not the "I-tried-it-for- a-week-and-it-didn't-work" variety of nonsense that doesn't prove anything. If enough birds are available in one loft, several comparative trials using different grains/sugars could be run at the same time.
Naturally, this information needs to be assembled, evaluated statistically, and just as importantly, published for the information of all fanciers -- not hidden in the files of a few fanciers! The sport is hungry for scientific facts that will help it to develop and grow, and nutrition is certainly a key area for a lot of work and shared ideas!
Some other related points to consider:
1) The multi-vitamin mix that you buy should contain vitamin D3 because it is the most highly active form of the vitamin for birds and animals. Read the label of the product that you intend to buy to be sure that it contains a wide range of vitamins, and that the vitamin D is in the form of vitamin D3. Vitamin products prepared for human use are fine, but are usually more expensive than those available for poultry.
2) We are told that breeding pigeons can do well on a diet containing 13-15% protein. One group of investigators found that when pigeons were offered cereals and peas free choice, the mixture chosen by the birds corresponded to a protein intake of 12.5-13%.
However, these investigators also found that a ration containing 18% protein, obtained by adding soybeans or fish meal to the diet -- which add high-quality protein -- resulted in optimum hatchability, growth and development of youngsters.
They also found that levels of protein higher than 18% did not result in further improvement in growth and weight gains of youngsters. These findings indicated that a ration containing upwards of 18% protein, but not higher, should be ideal for breeding and rearing.
Griminger (1983) also reported that a diet containing 16.5% protein and supplemented with fish meal and distillers solubles resulted in similar weaning weights of squabs as those on a commercial diet, whereas a diet containing 14.7% protein without these supplements was inferior. Protein is the most costly component of the diet, and it is wasteful and expensive to feed amounts of protein greater than those needed for optimum growth of youngsters.
3) To be certain that the systems of both cocks and hens are nutritionally prepared for the breeding season, a change from the bland winter diet to a ration higher in protein needs to take place well in advance of the breeding season. Sheep breeders use a similar approach and apply the term "flushing" to indicate feeding a higher level of quality feed prior to the breeding season. According to one (university) poultry nutritionist contacted, this dietary change in pigeons should be made about four weeks prior to pairing the birds.
4) Iodine should be supplied in a mineral mix for pigeons because of the apparently high demand for this mineral in milk- producing species of birds. Some fanciers use kelp powder or flakes to supply the needed iodine.
5) In racing pigeons, both males and females take part in incubating the eggs and rearing the youngsters. Usually only two eggs are laid, the first one in the late afternoon to early evening, and the second, about 40-44 hours later. The first egg is ovulated on about Day 5 after the birds are first mated, and the second, about three hours after the first egg is laid.
6) Youngsters feed by inserting their beaks into the mouth of the parent, which regurgitates crop milk at first, and later, whole grains. The tip of the beak in newly hatched pigeons is often seen to be pink-white followed by a black or darker band. The purpose may be related to the fact that, by nature, pigeons are cavity nesters where the light is poor.
The light tip on the beak of the newly hatched youngster may help the parents to locate the beak in a dark environment when the youngster is bobbing its head and squeaking to be fed. The adaptive behavior associated with this method of feeding has resulted in the early absence of feathers on the forehead just above the beak, and under the chin of youngsters; these feathers grow in later.
7) Crop milk, produced by the sloughing of fat-laden cells from the lining of the crop, is produced in both sexes under the influence of the hormone prolactin which is released from the pituitary gland at the base of the brain. This release of prolactin is probably triggered by driving and breeding activity prior to egg-laying, since it is likely the hormone responsible for inducing "broodiness" in both males and females.
Evidence of the presence of crop milk is seen first on the wall of the crop at about 8-10 days of incubation, and increases in amount toward hatching. As well, the crop becomes increasingly rough and somewhat folded as milk production increases. Newly hatched youngsters are fed regurgitated milk continually up to about 9-10 days of age, when more grains are added to the diet, and the supply of crop milk decreases.
When crop milk is analyzed it is found to contain about 75% water, 12% protein, 5-7% fat, and 1.2-1.8% mineral. There is almost no carbohydrate in crop milk. Calcium, phosphorus, sodium and potassium are present. Unlike mammalian milk, crop milk has no lactose or casein. It is low in vitamin A, vitamin B1(thiamine) and vitamin C (ascorbic acid), but has about the same amount of vitamin B2 (riboflavin) as milk from cows. When fed to chickens, crop milk stimulates growth.
8) The molt in youngsters begins about 50 days after hatching, and starts with the shedding of the first flight. Often, the voice begins to break between the dropping of the first and second flights. Young males produce sperm and are fertile at 120 days of age; young females of the same age can lay eggs at this time also.
9) Like many other birds other than some passerines, pigeons are believed to synthesize vitamin C (also called ascorbic acid) in their kidneys, so in general, extra supplies of this vitamin are likely not needed. One exception might be during the racing season when it becomes very hot on some race courses. It seems that as an "anti-stress" substance, vitamin C may exert its most important effects during very hot weather, and supplementation before these races may be valuable.
Experimental work with vitamin C in chickens suggested that the anti-stress effects of the vitamin occur in the adrenal glands (Gross, 1992). In chickens, the optimum dose of vitamin C as an anti-stress agent was 100 mg/kg of feed. In these experiments, vitamin C appeared to be valuable in preventing the stress response, respiratory infections, and E. coli infections in chickens. The results also indicated that the effectiveness of vitamin C was additive to those of furaltadone and possibly other anti-bacterial drugs.
10) In the wild, pigeons like a variety of grains. Of course, many of their choices will depend on the availability of various grains, seeds, etc. at any particular time of the year. In some studies, the crops of free-ranging pigeons were found to contain slugs and worms, etc., findings that may indicate a need for dietary proteins of animal origin. It is also puzzling that some species of pigeons and doves seem to do well almost exclusively on a single type of food.
11) During growth of young pigeons, the great pectoral muscles achieve about 11% of their adult weight by Day 13, but the skeleton of the wing has already achieved 86% of its adult length. Leg bones grow faster than wing bones before hatching. By Day 14 after hatching, the leg bones have grown to 87% of their adult length.
12) The sex organs are small during the nestling period, but begin to grow rapidly at seven weeks of age, and reach a maximum development at about 18 weeks of age. Both young males and young females are fertile at this time, and females can lay fertile eggs at this age.
13) In a study on food deprivation, it was shown that pigeons lost 5% of their body weight after three days without food. To regain this lost weight required five days on food. It took eight days without food to achieve a 15% loss of body weight, and 10 days to regain the lost weight. It required 19 days without food to achieve a 25% loss of body weight, and 15 days to regain this loss.
14) The origins of the unflattering expression "stool pigeon" were derived from the use of pigeons as decoys to attract flocks of pigeons into nets. A live bird was tethered to a small platform or stool made of wood or woven wire. In turn, this was attached to the end of a long, flexible pole. The pole was moved up and down by an attached cord or rope and this movement caused the tethered bird to flutter and attract other birds.
15) Plant pollen collected by bees is often touted as a magic ingredient for racing pigeons. It is the male germ seed produced by all flowering plants. However, its nutritional value is somewhat compromised by the high content of fiber. From this point of view, it has lower than desirable digestibility in humans and other monogastric animals. Similarly, pollen in the diet of pigeons could have lower digestibility for the same reasons.
Pollen contains about 24% moisture, up to 30% protein (average - 24%, including up to 17 amino acids), very little starch (average - 2%), 20 - 30% sugars (some samples have averaged 19% fructose, 10% glucose), about 5% fat, 3% ash (including high amounts of calcium, magnesium, and zinc, plus lesser amounts of potassium, sodium, sulfur, and manganese) Pollen is high in B vitamins (except B12), and has a fair amount of vitamin C, but lacks vitamins D and K. It has a pH about 4.
16) Brewer's yeast is another favorite of fanciers. Its name is derived from the beer brewing process of which it is a by-product. Yeast produced by the brewing industry tends to be bitter and difficult to consume in significant amounts. Today however, most yeasts marketed do not come from breweries, but are grown for the sole purpose of food supplements. These yeasts may be marketed as "nutritional" or "primary" yeasts. Unlike baking yeast, nutritional yeast is considered to be a "dead" product, and will not work in the leavening process.
The vitamin and protein content of nutritional yeast depend on the medium in which it is grown. Food yeasts are a rich source of nutrients, and may contain as much as 50% protein. They are an excellent source of B vitamins except for B12, which is now added to some brands.
Yeasts are a good source of minerals, especially selenium, chromium, iron and potassium. Phosphorus is also abundant in yeast; to maintain a favorable balance between calcium and phosphorus, some producers add calcium to their product. Yeast is a good source of nucleic acids, including RNA. It is low in fat, carbohydrates, sodium and calories.
In humans, ingestion of large amounts of yeast can cause problems. In such cases, uric acid levels have been elevated after the intake of three tablespoons of yeast per day, and could lead to articular gout in some individuals. Humans who have yeast infections should avoid all yeasts and fermented foods.
17) Many fanciers like to use garlic during the racing season. The principal, active agent of garlic is allicin, a sulfur-containing compound, which, with its breakdown products, produces the characteristic odor. The odor is related to the presence of sulfur. When the cloves are crushed, allicin is formed by the action of enzymes on a pre-existing chemical known as alliin. Other biologically active compounds related to allicin, such as ajoene, may be extracted from garlic as well.
The positive effects of fresh cloves of garlic seem fairly certain, whereas information for modern commercial preparations in general is not very convincing, to say the least. One reason for the difficulty of showing the effectiveness of garlic is that many active chemical compounds in the cloves may be lost during processing --and this is a major problem with commerciaal products.
For example, carefully dried sliced cloves seem to retain their potency, but extracts or oils prepared by steam distillation or organic solvents may have little activity. Cold- aged extracts have a reduced odor and may retain more of the activity of garlic. Allicin is known to break down during steam distillation for the production of the volatile oils used in many garlic preparations. As well, the alliin content of natural garlic can vary 10-fold.
There is also confusion about the issue of "odorless" garlic preparations. Some of them have no aroma, but neither do they contain any active ingredient. Some active preparations may not have an odor, but if allicin is released when the product is eaten, there is a very good chance that there will be a detectable aroma -- and it is the aroma that is one of the problems. Potency of garlic appears to depend on pungency, - that is, odor. Once garlic is dried into odor-free powders or pills, it loses some of the properties that may make it useful in health!
Given the "touchy" nature of the important, active compounds in garlic, it seems that heating or boiling crushed cloves above 60oC (140oF) (remember that water boils at 100oC (212oF), likely results in a major loss of key ingredients. On the basis of this information, it is logical that home preparations of solutions of garlic should not be heated, in order to retain the important compounds in the solution. Be aware that allicin is readily converted to a more volatile compound called diallyl disulfide -- which means that its effects can be transient.
Allicin is known to have antibacterial properties and has been said to be effective in concentrations as low as 1:125,000. When compared with penicillin, allicin is said to have an activity that is about 1% of the activity of penicillin. Garlic inhibits the growth of, or kills, about two dozen kinds of bacteria (including Staphylococcus and Salmonella spp.), and at least 60 types of fungi and yeasts. Allicin appears to be the major chemical responsible for this effect.
The trace minerals selenium and germanium are two constituents of Japanese garlic, and these minerals may have some effect by their activity firstly, as antioxidants, that is, substances that protect cells and tissues from the damaging effects of peroxides in the body. Secondly they are important in the normal development of the immune system, and thirdly, they may have good activity as anti-cancer agents. Selenium itself has been shown to have a broad spectrum of anti-cancer activity in rats, for example.
There are indications that chemical compounds in garlic may assist the body to de-toxify, neutralize or eliminate noxious substances. In pigeons, the use of garlic after a race may assist the so-called "depurative" diets -- whatever that might mean -- in restoring a bird to normal racing conddition. It is possible that the use of crushed garlic cloves in drinking water at this time might add some extra benefit in allowing the liver and other organs to metabolic products, and to help restore the birds to normal racing condition.
Present evidence from human and laboratory animal work, and the empirical experience of many fanciers, suggest that, when used judiciously, crushed cloves of garlic, used in drinking water, may be a useful product in the loft throughout the year, but especially during rearing and the racing season. At present, garlic-based oils, powders and pills are likely much less useful.
Possibly newer developments in extracting the active principles of garlic may get around the present problems associated with current methods. Until these problems are solved, fresh cloves of garlic from the grocery store are still the best source of the medicinal properties of garlic.
18) Honey is a natural food that contains about 17% water, and 82.4% carbohydrates. It is interesting that honey contains about 38.55% fructose (range 25-44%), 31% glucose (range 25-37%), 7% maltose and 1.5% sucrose, as well as small amounts of several B vitamins and a range of minerals.
19) N,N-Dimethyglycine (DMG), sold under the name Spur-DMG and produced by United States Animal Laboratories, has been used experimentally in horses on the track to determine its effect in lowering blood levels of lactic acid.
Research has shown that DMG can increase the utilization of oxygen, and thereby, decrease levels of lactic acid in animals under extreme stress. In human subjects, research has revealed a 27.6% increase in exhaustion time in trained athletes in treadmill tests when compared with subjects given a placebo. Apparently, DMG can also improve the immune response, both by increasing antibody production and generation of lymphocytes.
Horses given DMG during training had much lower blood values of lactic acid than control animals which did not receive DMG. Some researchers found increased values of lactic acid in the blood of experimentally exercised pigeons, but because of all of the special apparatus attached to the experimental birds, the results were considered to be questionable. Whether lactic acidosis is a problem in returning racing pigeons continues to be debatable. The question needs an answer.
20) Water is a dietary component that most of us take very much for granted, yet some sources of water are decidedly better than others. Interpretation of reports on standard chemical analyses of water sometimes can be difficult. The report usually provides a variety of figures including those on conductivity, total solids, ignition loss, total dissolved solids, hardness, sulfates, sodium, potassium, calcium, magnesium, chloride, alkalinity, nitrate and nitrite nitrogen, iron, fluoride, etc..
Total solids minus the ignition loss equals the figure for total dissolved solids (TDS). These dissolved solids are composed of the main minerals mentioned previously. The values for these minerals in water are expressed in parts per million (ppm). The figure for TDS is a very important one, and certain basic judgments about the suitability of water for different classes of livestock can be made by examining this figure.
For example, as drought conditions result in increased use as well as evaporation of water from dugouts, lakes, etc., the concentration of dissolved solids increases. As a result, the water becomes less and less suitable for birds and mammals that are forced to utilize such a source of drinking water.
TOTAL DISSOLVED SOLIDS (ppm)
USEFULNESS FOR LIVESTOCK
0 - 1500
Very good water.
1500 - 3000
Good water for all except turkey poults under 3 weeks of age.
3000 - 4000
Fair. Usable by all animals except young poultry.
4000 - 5000
Poor but usable by most classes of livestock and adult poultry.
5000 - 7000
Unsatisfactory and can cause diarrhea when first introduced. Usable with reservation.
7000 - 10,000
Highly unsatisfactory and not recommended.
Serious hazard to health and not recommended for any class of livestock.
Hardness is a measure of values of calcium, magnesium, bicarbonate, sulfate and chloride. Values under 100 ppm indicate soft water, and those from 100 - 2000 ppm indicate hard water. There is usually no health problem with either soft or hard water.
Sulfate values [part of epsom salts (MgSO4) and glauber salts (Na2SO4) under 500 ppm usually do not cause problems. Both salts are purgatives, glauber salts more than epsom salts. High values (500 ppm) may interfere with copper absorption. Values of sulfate between 500 - 3300 ppm can cause a laxative effect.
There is an additive effect with chlorides that can cause increased intake of water, wet droppings, and a health hazard to young birds. Sulfates have about twice the laxative effect of chlorides, so the values of these two should be added when water quality is being evaluated. Sulfate values of 3300 - 5000 ppm can cause diarrhea and a definite hazard to health.
Chloride values under 500 ppm pose no health problem in livestock. Those between 500 - 5000 ppm can produce wet droppings in poultry, reduced intake of feed and increased intake of water. Additive effect with sulfates.
Calcium and magnesium in water usually do not cause problems in poultry. Nitrites in trace amounts pose no health problem; levels higher than a trace indicate fecal contamination and may pose a hazard to health. Nitrate (measured as nitrogen) values under 100 ppm pose no health problem. Those from 100 - 300 ppm may be satisfactory.
Water containing over 300 ppm nitrate is unsatisfactory. Iron values under 0.3 ppm cause no health problem. Values over 0.3 ppm may encourage the growth of iron bacteria which can plug water systems, the taste may be bad, but there is a minimal effect on water intake or productivity. Values of fluoride greater than 40 ppm can produce soft bones in poultry.
I have read about one easy home test of dugout or pond water that may be suspect, but I have no experience with it. According to the article, you need a 9-volt clock battery, two 3-inch lengths of bare copper wire, and a glass of the suspect water. Place one length of wire on each battery terminal and hold them in place with your thumb. The two ends of wire should be at least one inch apart. Lower the wires into the glass of water.
If the water contains many dissolved solids, or salts, one wire will be surrounded instantly by a large number of bubbles. Such water can be dangerous. Each of the bubbles will be distinctly visible and will rise to the surface of the water in under a second. Excellent quality water will not form bubbles. Water with a safe level of dissolved solids will produce tiny bubbles slowly. These bubbles will take several seconds to form and will slowly drift to the surface.
To practice the test, to simulate bad water, dissolve a teaspoon of table salt in one cup of drinking water. There should be an immediate reaction. A barely usable water can be produced with a pinch of salt in a cup of water. Bubbles in this case take several seconds to form. *****
References Blem CR. 1976. Patterns of lipid storage and utilization in birds. Am Zool. 16: 671.
Griminger P. 1986. Lipid metabolism. In: Avian Physiology. PD Sturkie, ed. Springer-Verlag. 345-358.
Goodridge AG and EG Ball. 1967. Lipogenesis in the pigeon: in vivo studies. Am J Physiol. 213: 245-249.
Odum EP and JD Perkinson. 1951. Relation of lipid metabolism to migration in birds: Seasonal variation in body lipids of the migratory white-throated sparrow. Physiol Zool. 24: 216-230.
Pawloski JE. 1991. High fat diet....How good is it? Racing Pigeon Bull. C598-C600.
Griminger P. 1983. Digestive system and nutrition. In: Abs, M. Physiology and Behaviour of the Pigeon. Academic Press, New York.
Gross WB. 1992. Effects of ascorbic acid on stress and disease in chickens. Avian Dis. 36: 688-692.