CEREAL GRAINS AS A SOURCE OF STARCH BASED ENERGY
There is thus the possibility that significant amounts of undigested starches pass through to the caecum or colon (large intestine or hind gut), where they are not welcome, are rapidly fermented by bacterial degradation resulting in lactic acid production, gas, heat and ammonia build up and leading to lower hindgut pH. The resulting acidic environment kills the good bacteria in the hind gut and as these bacteria die they produce endotoxins which can cause all sorts of complications in horses such as acidosis, fatigue, nervous behaviour, gastro-intestinal upsets such as colic, can lead to reduced performance and is known to be one of the major causes of laminitis in horses.
STARCHES IN CEREAL GRAINS
Oat grain, which has a small starch molecule, is highly digestible in the horse’s small intestine by the enzyme amylase thus making oats the safest grain to feed to horses in its natural form (85% starch digestion in the small intestine – Meyer 1995). The same, however, cannot be said for other cereal grains such as maize, barley or wheat, which, in terms of energy content, equal or exceed that of oats and are therefore highly desirable cereals for use in high energy horse feeds.
These grains have large starch molecules which are not easily digested by amylase in the small intestine. This means that one of the goals of feeding high starch (energy) diets to horses lie in maximising the grains digestibility in the small intestine. This is achieved by opening up the starch molecules within the grains and breaking them up into smaller components in a modified structure, making them more accessible to enzymatic absorption.
Starch molecules found in cereal grains are complex polysaccharides located in granules embedded in a protein matrix and linked within the granules by hydrogen bonds into a crystalline structure. It is the disruption of these granules that leads to improved enzymatic digestion.
Failure to understand the anatomy of the gastro-intestinal tract and the digestive physiology of the horse is more often than not the source of many feeding errors including nutritional management and feed formulation. As most of the goodness in these raw cereal grains is stored in this inaccessible starch structure these must first be processed to make it digestible and beneficial to the horse.
Various methods have been used to try and achieve the above objective such as cracking, crimping, grinding, milling, steam heating, flaking and extruding with more or less success and more recently micronizing with great success. The problem with some of these processes is that while digestibility in the small intestine is increased to varying degrees, it is often done at the expense of other nutritional factors such as protein & vitamin absorption. Micronizing on the other hand not only increases the digestibility of cereal grains substantially, but does so without compromising the nutritional integrity of these feeds.
THE MICRONIZING PROCESS
The aim of feed processing is to change the physical and/or chemical form of the raw cereal starch structure resulting in greater feed availability. Micronization is a patented and advanced processing technique which uses the infrared wavelength as a source of energy. The micronizing process makes use of a narrow band within the infrared spectrum with a wavelength of between 1.7 and 3.4 micronization. (Please note that this is not microwave energy so the process is entirely safe).
Travelling at the speed of light, infrared energy is extremely efficient at generating heat in absorbent materials by causing the constituent molecules of the material to vibrate at very high frequencies (80 to 170 million megacycles per second) which causes rapid internal heating and a rise in water vapour. Micronizing is a highly reliable, consistent and short time high temperature process which uses humidity, heat and mechanical pressure (shearing) to achieve the conditions essential for optimum cooking and starch gelatinisation with minimum loss of water.
Micronizing is a relatively new technology in the equine feed industry that is set to revolutionize the way we feed horses. Micronizing is a method of processing grains using infrared technology to heat and vibrate the starch molecule followed by a rolling or flaking process. The resulting increase in gelatinisation dramatically improves digestion of barley and maize starch in the small intestine. Increased starch digestion in the small intestine promotes weight gain or growth and reduces the risk of starch overload of the hindgut. It also reduces the need to feed as much grain per meal. Micronized grains are therefore safer to feed due to better absorption and reduced risk of starch overload of the caecum which can cause colic, laminitis, acidosis or diarrhoea. Micronized grains have improved palatability after roasting so horses eat them better. In summary, Micronizing is magic!
MICRONIZING AND MICRONIZATION
In brief the process entails the following:
- Pre-cleaned cereals are soaked until they reach 18-20% moisture content. Starch which is insoluble in water can absorb relatively large amounts of liquid. This causes the starch granules to swell prior to treatment. This process is reversible in the absence of adequate heat.
- The preconditioned cereals are cooked with infrared radiant energy for a short period of time (50 secs), at approximately 90ºC causing a rapid rise in internal water vapour pressure, irreversibly forcing apart the hydrogen bonds within the starch granules.
- This process causes the grain to become soft and turgid (platisized), swell, fracture and gelatinise. Immediate flaking, using a heavy duty mechanical flaking mill, creates a stretching action in the grain which causes further physical and chemical changes in the starch structure thus completing the gelatinisation process considerably and enhancing the grains digestibility and feed value.
- The flaked cereals are then cooled and ready for use.
Since micronization of grains started in the mid 70’s, the methodology has been continually improved upon and perfected. Considerable sums of money have been invested for these developments both in engineering design and university projects to quantify and improve the value of micronized products. The process is now widely used by the human, animal feed, horse feed, pet food and brewing industries, and micronization is today utilised in over 42 countries throughout the world to add value to natures produce.
FEATURES AND BENEFITS OF MICRONIZATION
- The cooking period of cereal grains is critical because if the grain is overheated, starch retro gradation occurs rendering the starch to again be less susceptible to enzyme action hence less digestible by the horse. With micronizing there is total control of the cooking process. The controlled temperature and short cooking time involved in the micronizing process ensure that protein, vitamins and amino acids remain intact and are not denatured due to excess heat and/or long cooking time.
- Micronization converts the starches to sugars and the process greatly enhances palatability and flavour of the grain. The final product has an appealing and attractive appearance, is dust free, with good colour retention of the natural grain.
- Many vegetable protein sources in the raw state contain toxic enzymes (example soya and linseed) and other anti nutritional factors which obstruct digestion. Micronization is one of the most efficient and economical answers to consistent eradication of these toxic enzymes without loss of lysine or other heat sensitive amino acids. A very agreeable toasted nutty flavour which is very palatable, replaces the stringency associated with some of these grains, whilst maintaining the beneficial high energy oil level in the final product with excellent shelf life as well, due to lipoxygenase inactivation which occurs during the micronizing process.
- Increased digestibility makes feeding micronized products more efficient and should lead to increased weight gain and reduced total grain intake.
- Micronized grains have a long and extended shelf life.
- Micronization ensures a more rapid rate of starch digestion. Studies conducted at the University of Newcastle UK noted that different methods of processing maize resulted in the following improvements in the rate of starch digestibility:
|Starch in small intestine||Cracked||Steam Flaked||Micronized|
|First 30 minutes||8%||35%||55%|
|First 1 hour||12%||50%||80%|
As high digestibility is directly related to the rate of glucose released (energy) this leads to good efficiency and performance giving optimum starch, protein and amino acid digestibility.
- The micronizing process guarantees high digestibility. Work on starch digestibility at the University of Newcastle UK have shown that:
The digestibility of barley increases from 32% to 98% with micronization, that of wheat from 28% to 90% and maize from 43% to somewhere around 90%.
- Some recent work conducted by Dr. Cuddeford (BSc, MSc, PhD Royal Vet School, Edinburgh) and McLean in 1999 and published in recent advances in Equine Nutrition concluded that “Micronized feeds are more readily digested by the horse in the small intestine than extruded and steam flaked grains” and also indicated that “Micronizing barley was even more effective than extrusion in increasing pre-caecal starch digestion”. The following table gives an indication of some of these findings.
CAPSTONE PRODUCTS THAT CONTAIN MICRONIZED GRAINS INCLUDE:
- Capstone Perform Time
- Capstone Track Time
- Capstone Race Time
- Capstone Race13
- Capstone Cool Time
- Capstone Stud Time
- Capstone Show Time
- Capstone Flexi Time