enzymes

[AntonioLao]

They are one of the three chemicals of life. The other two are classified as enzyme helpers: vitamins and hormones. The following discussions will be based loosely on the book by Isaac Asimov: The Chemicals of Life written about fifty years ago circa 1954. Although these facts might be outdated, they can only serve as a point of departure for certain knowledge and understanding of what enzymes are with the hope that further investigations can lead to better comprehensions of an important subject of modern biochemistry, microbiology, and genetic science.

One dictionary of biochemistry defines enzyme as any of a group of catalytic proteins that are produced by living cells and that mediate and promote the chemical processes of life without themselves being altered or destroyed. One handbooks of biology describes it as a protein that acts as a catalyst and any metabolic living thing typically contains several thousand different enzymes that control its metabolism. More detailed descriptions give it as organic compounds that catalyze biochemical reactions which act with a substrate to produce complex products of the reactions. The names of most end in –ase, added to the substrate (e.g. lactase) or the reaction (e.g. hydrogenase). Enzymes are extremely efficient catalysts and very specific to particular reactions. They may have a nonprotein part (cofactor), which may be an inorganic ion or an organic constituent (coenzyme). They are active locally and both substrate and enzyme change shape during reaction. They are sensitive to their environment such as the presence of other substances, pH basic and acidity, and temperature. Normally, without enzymes biochemical reactions of life are very slow. What enzymes do is to reduce the need of activation energy using the simple model of the lock and key hypothesis.

[labelwench]

Digestive enzymes are the ones that I have most studied. My Mother, now in her mid-seventies, has an auto-immune disorder and finds that taking a digestive enzyme supplement is helpful.

For myself, I practice food combining and try to eat considerable raw or 'live foods' and significantly fewer processed foods than most people I know. I have commented before that we could lose 85% of the 'food-like products' in most grocery stores and I hypothesize that we would all be healthier as a result.

When I raced sled dogs professionally, I worked with a company to formulate a high fat, high protein diet that was suitable for animals racing over 100 miles per day in extreme conditions of -40F and colder. The formula was excellent but never went to market as Purina bought out the small Alberta based competition, LOL, so that says something.

For horses as well, as close to a natural diet and regime as one can contrive is conducive to their health, productivity and longevity. Sudden changes of diet can cause illness and even death, so persons contemplating horse ownership would do well to research the digestive system of these powerful, yet delicate animals, and understand the important role that enzymes play in their well-being.

Raw foods and digestive enzymes

Let's get back to enzymes. Raw foods are rich in enzymes. Enzymes are needed for the digestive system to work. They are necessary to break down food particles so they can be utilized for energy. The human body makes approximately 22 different digestive enzymes which are capable of digesting carbohydrates, protein and fats. Raw vegetables and raw fruit are rich sources of enzymes.

While all raw foods contain enzymes, the most powerful enzyme-rich food is sprouted seeds, grains, and legumes. Sprouting increases the enzyme content in these foods enormously.

Lack of digestive enzymes can be a factor in food allergies. Symptoms of digestive enzymes depletion are bloating, belching, gas, bowel disorders, abdominal cramping, heartburn and food allergies.

All of us loose our ability to produce concentrated digestive enzymes as we grow older. In cases where age is a factor, or where lack of digestive enzymes causes food allergies, supplementation may be helpful. You may also want to explore food combining.

http://www.healingdaily.com/detoxifi...et/enzymes.htm

[AntonioLao]

labelwench,
I saw the movie Seabiscuit and the jockey gave Seabiscuit a sugar cube. What is the nutritional significant if I might ask?

[labelwench]

labelwench,
I saw the movie Seabiscuit and the jockey gave Seabiscuit a sugar cube. What is the nutritional significant if I might ask?

The example you use, has little nutritional significance and is more about the psychological reinforcement of reward, IMO.

Horses have a natural enjoyment of 'sweet' and their natural diet includes plenty of sugar, in the form of the variety of grasses, forage, fruits and vegetables that they will elect to ingest, when at liberty to make their own selections.

Recognizing this preference, trainers use sugar cubes, apple and carrot slices, polo mints and grain based commercial treats as a training incentive. High sugar feed supplements are also used when horses are in training, hard work, and lactation, and oats, corn, barley, sugar beet, molasses, alfalfa pellets and cubes, are just a few of the constituent ingredients used.

Understanding the relationship between the horse's nutritional requirements and the diet we provide, has created at least as many problems as solutions for the horse, as few people understand the Glycemic Index in relation to the digestive system of the equine.

The horse tends to live a longer life in our care, yet also suffers far more health problems because of our intervention.

I am preparing a more detailed reply on sugar in relation to horses on another of your threads....

[AntonioLao]

Just wondering why there haven't been a Triple Crown winner since Affirmed of 1978?

[labelwench]

The speculation for some time has been that the Thoroughbred Horse has reached the top of it's evolutionary potential. This may be, in part, because it has a closed gene pool.
There is nowhere left to evolve to. When one limits diversity, as through such constrained breeding criteria, one will get an individual that is quite consistent in type. The trade-off for such consistency, is limited options for future change.

Evolution
Is it reasonable to suppose that the evolution of speed in horses has reached its limits? In a restricted sense, the answer is yes. The equipment used in horse racing, and the surfaces of the tracks on which these races are contested, did not change appreciably during the years when speeds were increasing in the Triple Crown races, and they have not changed since. Nor were there any apparent breakthroughs in training or nutrition that led to the increases in speed in thoroughbreds in the first half of the twentieth century. It seems likely, then, that the initial increase in speed in horses was due primarily to selective breeding. If this is true, evidence from the Triple Crown races suggests that the process of selective breeding of thoroughbreds (as practiced in the US) is incapable of producing a substantially faster horse: despite the efforts of the breeders, speeds are not increasing, and current attempts to breed faster horses may instead be producing horses that are more fragile (Drape, 200. The fastest speed in two of the Triple Crown races was set in 1973 by the same horse, Secretariat, and he was initially credited with a speed equal to the record in the third race (the Preakness Stakes) as well. (The timer malfunctioned in that race, however, and Secretariat's subsequently established official speed is slightly slower.) Thus, Secretariat approached the predicted absolute maximum speeds in all three of his Triple Crown races and therefore may represent a good approximation of the ultimate individual thoroughbred in races 1.25–1.5 miles long.

In a larger sense, however, the equine data presented here are preliminary at best. It may well be possible that different criteria for selective breeding of horses could produce a faster animal. Thoroughbreds have been recognized as a separate breed since the 1700s, and regulation of the breed has constrained its gene pool: thoroughbreds are less genetically diverse than other breeds of horses (Cunningham et al., 2001). The breed is effectively a closed lineage descended from as few as 12–29 individuals (Cunningham et al., 2001; Hill et al., 2002), and 95% of the paternal lineages in present-day thoroughbreds can be traced to a single stallion, The Darley Arabian. Selective breeding starting with different equine stock could perhaps yield faster horses. In this sense, then, the results presented here do not necessarily address the question of the maximum speed for the species Equus cabillus.

http://jeb.biologists.org/cgi/content/full/211/24/3836

And here is a scientific article comparing Thoroughbreds with Draft breeds. Lots of math in this one....

http://jap.physiology.org/cgi/content/full/84/6/2052

[AntonioLao]

Can we then imply that the best genes were already predetermined at the beginning of evolution? Unless of course, they are improved by certain forced or spontaneous mutations.

[labelwench]

Can we then imply that the best genes were already predetermined at the beginning of evolution? Unless of course, they are improved by certain forced or spontaneous mutations.

An interesting question.

In my opinion, based on over three decades of working with, observing and breeding dogs and horses, I would lean toward the premise that a closed gene pool, as results from 'purebred registries', is detrimental to evolution, although helpful in setting certain charcteristics, which we may choose as desirable.

Nature does not tend to such exclusity, as a rule, although certain species are almost a closed gene pool through their requirements of a very narrow niche. Koala bears are one example that comes to mind, as they have a limited option of suitable nutrition sources.

This is one example where, to my way of thinking, human intervention in selective breeding of horses, dogs etc., has escalated the rate at which the potential of existing genetics has been reached, and yet, by closing or narrowing the input of new genetic material, we have imposed limitations, where natural selection may have continued to provide new opportunity, and possibly greater potentials for speed, endurance etc.

One of the reasons that I have chosen the Morgan horse for this environment, is that the breed is founded on one prepotent sire, of mixed breed, who was then bred to a number of mares of diverse origin, which has resulted in this breed being capable of great diversity and intelligence in it's ability to interact with our species and fulfill our diverse range of expectations of this animal.

That it is also pleasing to the eye, an easy keeper, and possessed of great strength, speed, agility and endurance, as well as being low maintenance, are additional attributes.

[AntonioLao]

Who would have the power to close these genes pools? I beginning to think that evolution has less to do with natural selection than to do with mutation. To mutate or not to mutate that is the question as Shakespeare would say to be or not to be. Those who refuse to mutate will become extinct.

[labelwench]

Who would have the power to close these genes pools? I beginning to think that evolution has less to do with natural selection than to do with mutation. To mutate or not to mutate that is the question as Shakespeare would say to be or not to be. Those who refuse to mutate will become extinct.

The involvement of humans in selective breeding and closed breeding populations would certainly be one example of limiting gene pools. Mutations can still occur, but will be selected against, in most cases, as they are not the traits that the 'breed standard' is selecting for. One such example is the white coat variant of the German Shepherd dog.

In 1959 the German Shepherd Dog Club of America (GSDCA) adopted the exclusively colored breed standard of the parent German breed club. White-coated German Shepherd Dogs were officially barred from competition in the American Kennel Club conformation ring in the United States starting in 1968. AKC-registered white German Shepherd Dogs may still compete in performance events.

An individual organism's phenotype results from both its genotype and the influence from the environment it has lived in. A substantial part of the variation in phenotypes in a population is caused by the differences between their genotypes.[34] The modern evolutionary synthesis defines evolution as the change over time in this genetic variation. The frequency of one particular allele will fluctuate, becoming more or less prevalent relative to other forms of that gene. Evolutionary forces act by driving these changes in allele frequency in one direction or another. Variation disappears when an allele reaches the point of fixation — when it either disappears from the population or replaces the ancestral allele entirely.[36]

Variation comes from mutations in genetic material, migration between populations (gene flow), and the reshuffling of genes through sexual reproduction. Variation also comes from exchanges of genes between different species; for example, through horizontal gene transfer in bacteria, and hybridization in plants.[37] Despite the constant introduction of variation through these processes, most of the genome of a species is identical in all individuals of that species.[38] However, even relatively small changes in genotype can lead to dramatic changes in phenotype: chimpanzees and humans differ in only about 5% of their genomes.[39]