The Important Role of Protein in Racing

[Guest CS]

Gordon A Chalmers, DVM

Lethbridge, Alberta, Canada

 

It is a long-established fact that fat and glycogen are the key fuels

involved in the flight of birds, and that fat is the major fuel that

supplies the energy requirements for prolonged flight in birds,

including racing pigeons.  Fat yields far more energy per unit of

weight than similar weights of carbohydrates or protein put together.

For example, a gram (about 1/30th of an ounce) of fat yields about

9200 calories of energy whereas similar weights of carbohydrate yield

only 4200 calories, and protein, only 4100 calories.  The importance

of fat and carbohydrate in flight is unquestioned, but we also need to

explore the possibility that there could also be an important role for

the highly vital nutrient, protein.

To begin any exploration for a possible role for protein in pigeon

racing, it is important to review of our knowledge of the breast

muscles of pigeons.  Firstly, the great muscles we can feel with our

fingertips are the most powerful in the avian body, and in the pigeon,

they make up 20 to over 32% of the weight of the bird.  These muscles

are so powerful that one of them alone is capable of exerting a force

equal to ten times the weight of the bird!  These great muscles are

responsible for the powerful downstroke that launches the bird into

the air, and also provides lift and forward propulsion during rapid

cruising flight.

Secondly, beneath the great breast muscles and in the angle formed by

the breastbone and the projecting keel, is a much smaller muscle known

as the deep pectoral that makes up only 3-4% of the weight of the

bird, and is responsible for the upstroke.  These two muscles allow

the wings to beat at an average rate of about 5.5 beats per second,

330 beats per minute, and 19,800 beats per hour for the duration of a

race.  Theoretically, a 500-mile race that is completed in 12-14 hours

would require 237,600 - 277,200 wingbeats!  Incidentally, pigeons

inhale during the upstroke and exhale during the downstroke to provide

a massive flow of oxygen to these working muscles.

  If we examine the great breast muscles at the microscopic and

biochemical levels, we see that they are composed of thread-like cells

called fibers, and that there are fibers of two different diameters.

One is a broad-diameter fiber that is present in relatively small

numbers, and the other, a narrow-diameter fiber that is present in

much greater numbers.  For every 100 fibers, there are 86-94 red

fibers compared with only 6-14 white fibers.  The much more numerous

narrow fibers are the red fibers that contain many tiny droplets of

fat plus lesser amounts of glycogen.  The broad fibers are the white

fibers that are loaded with glycogen, their major fuel.

When these fibers function, by conventional description they are said

to 'twitch'.  In mammals, including humans, the white fibers are

designated as 'fast twitch' fibers that obviously operate very

quickly, and the red fibers as 'slow twitch' since they twitch more

slowly than the white fibers.

In birds like the pigeon however, both red and white fibers are fast-

twitch; however, the red fibers have been especially adapted for

prolonged flight and as a consequence, they are much different from

those in mammals.  The white fibers twitch very rapidly indeed, at

speeds ranging from 31 37 milliseconds.  A millisecond is 1/1000 of a

second, which means that one complete contraction or twitch of these

white fibers takes a mere 31/1000 to 37/1000 of a second!  At such

rapid twitch speeds, the white fibers are utilized for extremely

swift, even explosive actions, such as launching from the transport

vehicle, sudden dodging bursts of speed during flight, and braking to

land, etc..  Not surprisingly, the white fibers tire very quickly as

their supply of fuel (glycogen) is depleted.  The rapidity of their

twitch speed can be seen very nicely in the trembling wingtips of a

bird in top condition or in a bird shivering in the cold.

Although the red fibers also have very fast twitch speeds that range

from 47 to 62 milliseconds     which means they complete one twitch in

47/1000 to 62/1000 of a second! -- they are obviously not quite so

fast as the white fibers, and as a result, they tire much more slowly

than the white fibers.  Hence, the red fibers are responsible for the

sustained effort of prolonged flight.

In the powerful launch phase of flight, the white fibers in the great

breast muscles utilize their stores of glycogen that are metabolized

(means utilized, or broken down) quickly to glucose for its provision

of rapid, explosive energy in order to allow the birds to climb

swiftly to reach cruising speed.

By the time the birds reach cruising speed, the white fibers have been

exhausted of fuel and effectively stop working.  However, over the

next few hours, they are refueled with glycogen that originates in the

liver.  Here, glycogen is converted to glucose that is released to the

bloodstream and delivered to the white fibers, and once again re-

assembled into glycogen reserves.  These reserves are a source of

quick energy in the event of emergencies such as explosive bursts of

speed and dodging to escape attacks from aerial predators, avoiding

power lines, etc..  As well, if there are head or cross winds that

cause the rate of the wing beat to become more irregular and forceful,

or when birds are braking to land, etc. - in fact any change in the

wing beat - initiates use of the white fibers.

Utilizing mainly fat, the red fibers are recruited for sustained,

rapid flight once the explosive action of the white fibers has allowed

the birds to climb quickly and reach cruising velocity.  Since there

are insufficient supplies of fat within the red fibers to allow them

to function for the duration of an entire race, stores of fat are

found in depots located primarily in the body cavity among the

intestines.  From these depots, fat is mobilized in the form of fatty

acids that are transported in the bloodstream attached to albumin to

make them water-soluble in the fluid medium of the blood.  These fatty

acids are delivered to the individual red fibers where they are

transferred to numerous structures that are, in a sense, really

'biological power plants' known as mitochondria.  Within the many

mitochondria in the red fibers, the fatty acids are metabolized in a

stepwise fashion to produce a very high-energy compound known as

adenosine triphosphate, ATP for short.  This compound provides the

massive amount of power needed for sustained flight, whether the

distance is a 30-mile toss or a 500-mile race or more.

During cruising flight, the red fibers operate in shifts that begin

with the fibers closest to the outer surface of the muscle.  As their

fuel supplies are consumed during flight, these fibers tire and cease

to operate until they are refueled.  In the meantime, their function

is taken over by the next deeper layer of red fibers and so on, for

the duration of the flight.

So, as expected, the key fuels for flight are unquestionably glycogen

for explosive bursts of quick energy, and fat in particular for

prolonged swift flight.

But is there an important role for protein in flight, especially in

long distance flights?

At this point, it is important to digress momentarily to discuss

proteins and their role in the body.  You may recall that proteins are

composed of many smaller units called amino acids that

characteristically contain nitrogen.  There are 22 different amino

acids that, in varying proportions, comprise different proteins.

Within cells of the body, these 22 amino acids are linked in various

combinations to make up proteins, much as a number of individually

coloured bricks make up a brick wall.  It is important to note that

not all of the 22 amino acids are contained in every protein.  Because

of this fact, it becomes obvious that some proteins are of very high

quality, and others are of very low or poor quality.  To expand on

this point -- because the subject is not just an academic exercise and

has very practical implications -- amino acids are classified as

essential or nonessential.

Ten of the 22 amino acids are essential amino acids, which means that

the body either can't manufacture them at all, or can't manufacture

them in sufficient quantities to be of use.  The important message

here is that the essential amino acids must be supplied in the diet.

By contrast, nonessential amino acids are those that can be produced

in cells of the body, and need not be supplied in the diet. The

following is a list of the essential and nonessential amino acids:

 

Essential Amino Acids   Nonessential Amino Acids

 

Arginine                Alanine

Histidine               Asparagine

Isoleucine              Aspartic acid

Leucine         Cystine

Lysine          Cysteine

Methionine              Glutamic Acid

Phenylalanine           Glutamine

Threonine               Glycine

Tryptophan              Hydroxyproline

Valine          Proline

                Serine

                Tyrosine

 

In the production of a particular protein in the body, amino acids

that are obtained during the digestion of proteins present in feed,

are linked together in sequences that are pre-programmed by body

cells.  If even one essential amino acid is missing from the diet, the

production of any protein requiring that amino acid is halted.  This

is exactly why the quality of the protein in feed is so important.  A

feed or a grain with high quality protein is one that contains a high

proportion of essential amino acids, whereas a feed with low quality

protein is one that is deficient in perhaps several essential amino

acids.  Some grains are known to be deficient in particular amino

acids.  One example is corn, which is deficient in the essential amino

acid lysine.  Fortunately, other grains can compensate for these

deficiencies, and this brings up again, the very important point in

the feeding of pigeons, namely, the feeding of a wide variety of

grains and even some pellets.  If a variety of grains is fed, or if

pelleted commercial feeds that often contain various plant and animal

sources of protein are used for pigeons, the fancier can be more

assured that his birds are receiving all of the essential amino acids

needed for the production of different proteins in the body.

Historically, and even to this day, advocates of marathon competitions

(700-800 miles +), such as those in Australia and the UK, continue to

recommend high levels of protein in the form of peas or beans in

preparing birds for these events.  Much of this practice appears to be

long-established custom based on experiences handed down from

successful fanciers of the past to newer generations of equally

successful fanciers whose pigeons fly extremely well from these

distant points - they are formidable performances of which any fancier

would be proud.

To my knowledge, there has been no published scientific study on the

role of protein in long distance flights by pigeons.  However,

Professor Bill Mulligan formerly of Glasgow University in Scotland,

worked with racing pigeons flown from distances up to 366 miles, and

the following information taken from his studies provides us with some

important insights into the role of protein in flight.

As we have seen, at the onset of flight, racing pigeons use

carbohydrates but draw on fat as the most important fuel for working

muscle during prolonged flight.  However, the brain can use only

glucose (also called dextrose) as a source of energy.  It is probable

that during flight, pigeons utilize certain reserves of protein to

help supply glucose for the brain.  This could occur through two

processes.

Firstly, it is important that the liver release a high level of

glucose to the bloodstream to supply the brain with energy.  Food in

the intestines is definitely a source of glucose from digested

carbohydrates, but because glucose is being withdrawn constantly from

the bloodstream by the brain, muscles and other tissues, the blood

level of glucose would fall sharply between feedings.  This situation

is prevented by the liver which stores glucose in the form of

glycogen, and releases it to the bloodstream when it is needed.  One

important source of glycogen for the liver is certain of the amino

acids such as alanine that is readily converted to glucose.

Another source of glycogen is muscle itself.  When glycogen in muscle

is needed as a source of energy, one of its breakdown products is

pyruvic acid, some of which is converted to the amino acid alanine

that is transported to the liver in the bloodstream.  In the liver,

alanine is reconverted to pyruvic acid that is then converted to

glucose and then to glycogen.  This seems to be an effective way to

transfer glycogen from muscle to the liver.  Because the liver -- but

not muscle -- can maintain the highly important flow of glucose to the

brain, this transfer of glycogen from muscle to the liver may be

needed.  Thus, one of the key roles of protein in flight could be to

provide those highly important amino acids that are readily converted

to glucose.

To improve our understanding of a role for protein in any race, but

especially in long distance flights of pigeons, we may find some of

the most useful information in the truly marathon performances of

various species of migratory birds, especially shore birds.  Some of

these birds are capable of prolonged non-stop flights lasting up to

several days without an intake of food as they take advantage of both

the Arctic and sub Antarctic summers, which means that they must reach

the other side of the world in 2-3 months, and that they must travel

several hundred miles per day.

In one example, flocks of shore birds known as Red Knots (Calidris

canutus) begin a marathon 6200-mile one-way journey from Siberia to

West Africa, stopping only briefly to refuel, and arrive at their

destination more than four days later -- and ounces lighter in

weight.  In wind tunnel experiments --  which do not compare very well

with free flight since it is known that birds flying in a wind tunnel

have greater requirements for energy than free-flying birds -- these

birds were found to switch rapidly (within an hour) from the use of

glycogen to the utilization of high-energy fuel -- fat -- for the

duration of the flight.

In another extreme example, Bar-tailed Godwits (Limosa lapponica

baueri), another species of shore bird, perform non-stop flights

lasting 50-100 hours over several thousand miles.  These birds fly

from New Zealand to eastern Siberia and Alaska, a distance of 6800

miles.  Depending on the effects of wind, some of these birds cover

the distance between Australia and China in a non-stop trans-oceanic

flight of over 100 hours, covering at least 5000 miles as they make

their way to the Arctic - a truly remarkable feat of endurance, with

one of the highest requirements for energy among vertebrate creatures

(those with vertebral columns).

A number of studies on such birds, particularly those of an

international team from Sweden, Switzerland and Holland, working with

Red Knots in a wind tunnel, showed that as these birds prepare for

their journey from Siberia to Africa, they consume substantial

quantities of both fat and protein.

It is known that the energy density of stored fats is over seven times

higher than that of glycogen and protein.  In terms of the high-energy

compound ATP, fat from storage areas yields eight times more chemical

energy than wet protein, and 8-10 times more than glycogen.  This is

mainly because fat in storage depots contains only about 5% water,

compared with 70% (or more) for muscle or stored glycogen.

Fat in storage depots is not immediately available at the start of

flight but must be mobilized and then begins to flow through the

bloodstream from these depots in the form of fatty acids to the red

fibers as the birds reach cruising speed.  Incidentally Red Knots are

able to switch to the utilization of fat more quickly (within 1 hr)

than pigeons -- which require 1-2 hours of flight to reach a steady

level of contribution by fat to the energy needs for flight --

possibly because these shore birds have become well adapted to

endurance flight over thousands of years.  By comparison, pigeons have

been involved in endurance flights for a relatively short period of

time.

Within the red fibers, fatty acids are metabolized in the presence of

oxygen (aerobic metabolism) to produce ATP in a biochemical system

known as the Citric Acid Cycle.  One problem during flight is that the

various biochemical components of the Citric Acid Cycle itself are

constantly drained away and have to be replaced.  Replacement of these

components occurs through the use of carbohydrates, or certain amino

acids derived from supplies of protein in the body.

Several studies of marathon flights in birds such as the Red Knot,

etc., have shown that not only carbohydrates and fats, but also

proteins are utilized during endurance flight.  As we have seen, there

are special stores of carbohydrates (in liver and muscle) and fats

(depots in the body cavity, small amounts in the red fibers), but

there is no special site for the storage of proteins.  The sources of

these proteins are any tissue of the body -- including working muscle,

which obviously results in a decrease in the lean mass of the breast

muscles, other muscles and the digestive organs, during prolonged

flight.

A key question is this:  if fat is the main fuel for prolonged flight,

especially endurance flight, why is protein needed as well?

The partial answer to this question is that, as expected, proteins are

used to maintain the structure and repair of all tissues, including

the muscles of flight.  However, it seems that the foremost reasons

for the use of proteins during flight are:

·      to provide amino acids such as alanine that can be converted readily

to glucose to nourish the brain, as well as to replenish stores of

glycogen in the liver and breast muscles and,

·      to restore and maintain the biochemical components of the Citric

Acid    Cycle itself in order that fat can continue to be metabolized

in the production of energy during flight.  For example, the amino

acids asparagine and aspartic acid are needed in the production of one

of these components called oxalo-acetate.  Another component called

succinyl-CoA is produced from the amino acids isoleucine, valine and

methionine, and so on - facts that point up the importance of high

quality protein prior to and during flight.

Another important question:  is there any supporting evidence that

protein is actually utilized during flight?  It is known that in

birds, when protein is metabolized, the end product is uric acid that

is seen commonly as the white tip on droppings.  More specifically,

studies in Switzerland have shown that levels of uric acid in the

bloodstream increase steadily in pigeons flown for at least 4-5

hours.  Such increases in levels of uric acid indicate the increased

utilization of protein over the hours of a race.

Given these facts, we can see that there is an exceedingly important

role for high quality protein in the nutrition of racing birds,

regardless of the distance flown.  It is also evident that there is a

relationship between the use of fats and  protein in the need to

replace components of the Citric Acid Cycle during flight.  Thus,

amino acids can be used to supply the much needed flow of glucose, and

to restore components of the Citric Acid Cycle, as well as to aid in

the maintenance and repair of tissues.

According to research on marathon flights by shore birds, the optimum

relationship between fat and protein assembled before and used during

migratory flight depends on the length of the non-stop flight.  This

research suggests that for long flights, the relative amount of energy

derived from fat in the total amount of energy expended, should

obviously be high.  Thus, birds use fats to provide more than 90% of

the required energy in prolonged flights, during which they work at

over twice the maximum aerobic rate of small mammals.  As well, birds

flying in conditions in which the loss of water from the system is

excessive, ie, in very hot weather, may ease this stress by increasing

the relative contribution of energy from protein in the total

expenditure of energy.

Hence, as Professor Mulligan suggests, there could be a special role

for a pool of body protein that can be utilized rapidly by pigeons to

supply the amino acids that are then converted to glucose and thus,

glycogen, and probably fat as well.  He adds that this could be

accomplished nicely by adding a small amount of an animal source of

protein, say in the form of a high protein livestock pellet containing

fish meal or other animal meal, during the week before shipping.

Professor Mulligan cautions against using beans or peas as a source of

this protein, because he feels that this could be counter-productive

-- perhaps because in general terms, animal or fish meal sources of

protein often supply a wider range of amino acids, including the

essential amino acids, than a number of sources from plants.

Today, as racing diets evolve, there seems to be some trend toward the

use of low levels of peas or beans -- but with other sources of

protein containing a wide range of essential amino acids -- and higher

levels of fats and carbohydrates.

Taking a cue from the work of Professor Mulligan, and building on the

knowledge derived from the work with shore birds, we can increase the

level of protein in the diet early in the week, through the use of

feeds containing a wide range of all amino acids, for repair and

maintenance of all tissues.

Although there are cautions against the use of peas or beans for this

purpose, perhaps one of the most useful nutrients would be the

addition of a non-medicated high protein livestock pellet containing

soy, fish or other meal as sources of protein that contain many of the

essential amino acids, and/or the addition of peanuts, hemp, rapeseed

(canola), flax (linseed), hulled sunflower seeds for their fairly

broad range of essential amino acids.  Not only do the grains listed

contain a fairly broad range of amino acids, obviously they have

abundant levels of fat that can also begin the refuelling process.

Such a repair/maintenance approach would not only add to the pool of

protein available for use during flight, but also would also supply

much needed fat, to which the important high carbohydrate grains could

also be added.  Because there is no storage depot for proteins as

there is for carbohydrates and fats, perhaps once a higher level of

protein for repairs has been fed earlier in the week, the use of high

protein pellets/grains fed at lower level (1-5%) throughout the week,

would ensure that by shipping day, all the essential amino acids are

in place for the race.

It is evident that the marathon-flight oriented fanciers mentioned

earlier may well have a practical point regarding the use of high

protein feeds to prepare their birds for these events.  However, my

reading of their approach would suggest that at least in the past,

they relied much too heavily, and in my view, for far too long in the

preparatory period, on protein in the form of peas and beans which

were a very high priority, at the expense of carbohydrate and fat.

Even so, taking a cue from their experiences, we can see the value of

feeding a certain level of protein -- as long as this protein contains

a wide range of essential amino acids.

Finally, on a philosophical note - on the matter of defining

'endurance' flights of pigeons -- except for extraordinary

circumstances such as the report many years ago of a pigeon that

returned to France after being released several months earlier in

Vietnam, and former 2000+ mile endurance flights by certain strains of

pigeons in the USA -- flights of pigeons don't compare at all with the

marathon performances of shore birds.  Pigeons are not migratory

birds, their flights are not voluntary, and under (their) natural

circumstances, flights of a number of hours are not a routine part of

their lives.  The home range of the rock dove from which racing

pigeons are descended, is limited to a relatively few miles. Thus,

racing pigeons represent a rock dove that has been selected and

developed over time to home quickly from increasing distances.

>From the perspective of the pigeon, which is not descended from a

 

 

migratory bird, all flights - training and racing - may well be

'endurance' flights that require a certain baseline level of high-

quality protein for maintenance/repair, as well as to supply glucose

to brain and muscle, and to restore components of the Citric Acid

Cycle.  As well, in the final days before shipping, appropriate levels

of carbohydrates and fats tailored to the distance to be flown as well

as to the projected conditions of the race are obviously needed as the

most important fuels for flight.

*****

 

[Fair Play]

Hope you got permission the reproduce that - there is a name for it ;D ;D ;D I would think it is all about getting the balance right it's all very well down on paper but do we ever get the perfect conditions to fly pigeons in this country so its another thing in practice

One mans meat is another mans poison - Anon

[Guest CS]

Fair play, me and Gordon regular e-mails each other...hes a  top  guy

[jimmy white]

very interesting article cs  

[homebird]

hi in horse racing they feed oil as a lipid(fat) can be veg or soya at 1pt per day this is split into three feeds and is equal to 3 lbs of oats in energy value.the reason is that as a horse gets fitter he tends to eat less so they use oil to put a layer of fat that will be used as an imediate energy source .thus helping him to work and keep  condition on.High protein can have an adverse afect on a horse that can lead to muscles tying up .Interval training conditions the horse to work with or without oxygen and developes the all important red blood cell count. heat disapation and muscle mass are big factors thats why some race horses apeer lean ie long distance or big, sprinters as i am new to pigeon racing i am interested if there is a noticable mark in the builds between the different familys ?  and thier diets.

[jazzman]

yes a very nice read  

[Tic eye Hen]

Very interesting! Does Gordon race pigeons? How has he done??

 

 

[Guest]

There's been one or two well-off-the-mark remarks about posting articles ranging from 'other peoples work' to 'infringing copyright'.

 

Like Craig, Gordon has provided me with information on questions I have asked on behalf of members here, and I know that much of that info has been provided to me in the form of an article.

 

The general rule is any article or extract must be attributed to the author (s) - the opening post clearly shows author's name & address - it must be used for educational purposes - as here, we are after all passing on knowledge to others - and it must be provided free of any charge - there is no subscription charge either to access this article, or pigeonbasics website.

[Fair Play]

All I asked had he permission to reproduce the article( ;D ;D ;D) all very well to fit a name to it does not proove he poster has or had permission. CS could have put "Jack the Ripper" he didn't.

CS came straight back to inform me that he did have permission that's good enough for me so I wouldn't go making mountains out of molehills :'( :'(

Let he who is free from sin cast the first stone - The Bible :

[Guest]

:'( :'( Let he who is free from sin cast the first stone - The Bible :

 

Who wrote that book and do you have permission to quote from it?  ;D

 

 

[Fair Play]

Far too many authors took a thousand years but you have my full blessing to carry out the research and "May your God go with you" Dave Allen

[DOVEScot]

 

Who wrote that book and do you have permission to quote from it?  ;D

 

 

;D ;D ;D ;D ;D

[DOVEScot]

I think you could put all the same food/feeding theories into any creature and cross reference them, strong, fast, endurance ect all require the same elements.

But the actual breakdown some of the this report shows is interesting to some regards quantities and breakdown of groups

[Guest]

Far too many authors took a thousand years but you have my full blessing to carry out the research and "May your God go with you" Dave Allen

 

Well I would need another author 'Jules Verne' and a loan of his creation 'The Time Machine' to do a really good on that one.  ;D

 

 

[Guest]

There are at least another 2 articles on the site by Gordon Chalmers, both to do with feeding pigeons.