A PRACTICAL UNDERSTANDING OF CHELATED TRACE MINERALS

by: Stephen B. Blezinger
PhD, PAS


It's fairly well understood by most producers that minerals have to be supplemented to cattle at all stages of production if they want optimal performance. The different formulations for mineral supplements are as numerous as stars in the sky. There is also an array of forms that these supplements can take. And while some producers continue to insist that a good mineral program consists of red, white and yellow salt blocks (it doesn't), in general the industry understands that a good program consists of a high quality, palatable, weather tolerant, loose mineral product properly fed in a well-designed feeder. And this is AFTER an evaluation has been made of the animal's requirements and the other mineral sources the animal has access to (forages, other supplements, water).

One particular area that continues to stump producers (and many corporate, extension and academic industry members) is the value and use of “chelated” minerals in these programs. This article will serve to, hopefully, shed some light on these questions and help develop a more practical understanding of a number of questions concerning chelated trace minerals.

What's in a name, some definitions

Just the term “chelated” has created a variety of questions for years so let's start by discussing what “chelated” means. The word chelated describes the form in which a given mineral may be found. Generally, minerals are included in a supplement in an “inorganic” form. This means that the overall mineral is all “rock” whether it is found in this form in nature or is refined or manufactured into an all metal form. For example, one of the most common ingredients in a mineral supplement is calcium. Generally, the calcium in most supplements comes from two sources. One source is from calcium carbonate. This is found in nature most commonly in limestone. The limestone is mined, finely ground to specific screen sizes and then sold to a supplement manufacturer. This is about as simple as it comes and is considered to be in an inorganic form. A second common source may be Mono-Calcium Phosphate or Di-Calcium Phosphate, either of which are manufactured products created by reacting either calcium chloride or calcium hydroxide with phosphoric acid. Again, these are considered inorganic materials.

The same situation exists with other minerals in common supplements. Take zinc (Zn) for instance. Zinc is found in nature as an ore in combination with other materials. It is mined and refined/processed into various forms, one of the most common being Zinc oxide. Zinc oxide has been used as a supplement in livestock diets for years but has been shown to be very poorly absorbed by cattle. Zinc oxide can be reacted with sulfuric acid to produce Zn Sulfate which is currently the most commonly used source of Zn in cattle supplements. However, even this inorganic source of Zn is not well absorbed by the animal (better than Zn Oxide) but it is reasonably inexpensive. The examples here are similar and common for most of the other mineral sources used in supplements.

The poor absorption rates in animals, particularly of the trace minerals is part of what prompted the research into and development of the chelated sources.

First, understand what chelated minerals are. As opposed to “inorganic” mineral sources that are all metal or all “rock,” chelated minerals, for the most part are considered “organic.” They are created by reacting (often a fermentation process) the metal or inorganic form of a given mineral with an organic molecule. This can include an amino acid, a group of amino acids (known as a peptide) or even a short protein segment, known as a proteinate. Additionally it might include a carbohydrate, an organic acid such as an acetate or propionate or other organic molecules. Subsequently, these mineral sources are also referred to by a variety of names including chelated, organic, complexed, etc. While there are some sources of the macro minerals (calcium, magnesium, potassium) that are found in this form, when we discuss “chelated” minerals, generally this is referring to the trace minerals and particularly Zn, copper (Cu) and manganese (Mn). There are sources of selenium (Se) that are considered organic because they are found in selenium yeast where the Se is actually part of the yeast cell. Additionally, a form of iodine known as EDDI or Ethylene Diamine Dihydriodide is also considered organic. But again, for the most part the discussion here pertains to Zn, Cu and Mn, all important trace minerals.

The intended focus of feeding a chelated mineral source is to increase the absorption of these nutrients beyond what can be absorbed from inorganic sources. Numerous studies have been undertaken over the years with varying results. In general, based on the research overall, it is believed that these chelated, organic forms are in fact more available to the animal. In other words for a given amount fed in a supplement, more of the mineral in question is absorbed. Subsequently, the amount of mineral stored or circulating in the animal is believed to increase. This is referred to as improving the mineral “status” of the animal. Much of the research over time has shown that feeding a particular chelated source has resulted in a variety of performance improvements such as better immune response, improved reproductive performance, reduced incidences of foot and hoof problems, improved appetite and so on. The list of areas within the animal that are affected by trace mineral availability is extensive and in the event that even a marginal deficiency of a given trace mineral is present, correcting this deficiency by using a chelated form can show advantages in a variety of areas.

Something that many producers and even some nutritionists don't really understand is that feeding more of an inorganic source may not correct a problem. Since inorganics are considerably less expensive than chelated forms in many cases nutritionist or producer may simply opt to fee more of a given mineral. In many cases the intestine, where trace minerals are commonly absorbed, can and will regulate absorption efficiency. If a given trace mineral is found at low levels in the diet the gut will increase absorptive efficiency for that mineral. Conversely, if excessive levels of a given trace mineral are found in the diet, the gut will decrease absorptive efficiency so that potential toxicity will be offset. Thus, the result in overfeeding inorganic trace elements because they are inexpensive can and will decrease absorptive efficiency and will result in the animal secreting more in the manure.

Research has shown that by feeding a portion of the trace mineral from a chelated or organic source overall absorption is increased resulting in a better status of that trace mineral in the animal. Originally, companies selling chelated minerals promoted feeding 100% of the mineral level from their source. Over time it has been determined that this is extremely expensive as well as not overly effective. We now understand that the rumen environment has a demand for these minerals as well. Chelated minerals largely function by protecting the mineral from microbial activity which can result in insoluble or unavailable forms of the mineral created in the rumen. Depending on the exact type of chelate (discussed below), the mineral itself is protected from this activity in the rumen and subsequently released upon transport through the abomasum (true stomach) of the animal where the pH is much lower than in the rumen and other compartments. The pH and other enzymatic activity cause the chelate molecule to release or transfer to other molecules in the intestine which facilitate the transport of that mineral across the intestinal wall and into the blood stream.

All this said, the rule of thumb for including chelated mineral sources in a cattle nutrition supplement has been to include trace minerals from chelated sources at around 30 percent of the total supply and the rest from inorganics. This results in an improvement in the availability to the animal while maintaining a supply for the rumen microbes. Additionally, this helps keep costs under control for the producer.

As mentioned previously, chelated minerals are available in a number of forms including amino acid complexes, proteinates, carbohydrates (polysaccharides), etc. Research, university and company have shown the various forms to have an effect of some type of another. These effects have not been shown to be consistent and there is no definitive data which shows one form or another to be the best. Also, different companies have pursued varying levels of research on their product. This is potentially one way to differentiate the products when selecting the source to use. Products that have been researched under a wider variety of conditions, production types, diet types, forage types, etc. and that can show a positive response under a larger number spectrum of conditions may be preferential. A qualified nutritionist can help navigate through the data. One thing that should be understood is that the amount of comparative research with the various products is very limited. This is a fairly common situation with many different products and product types in the cattle feeding and supplementation industry. For the most part the universities do not have the budgets to conduct this type of research and most companies are not willing to take the chance that a study they run (fund) with a competitors product may not show their product to be the best.

As indicated the various forms of these trace minerals has resulted from and in the creation of a number of companies whose focus at some levels is to sell their specific form of these minerals. Some of the companies most commonly noted to produce these products include:

Alltech - proteinates

Balchem - proteinates

Phibro/Prince – glycinates

Novus – proteinates, amino acid complexes, glycinates

Qualitech – polysaccharide (carbohydrate)

Trouw – proteinates

ZinPro – amino acid complexes, proteinates, carbohydrates

These are not all the suppliers in the United States. Plus the number of chelated mineral suppliers from China seems to increase very day. Because these sources tend to be less expensive, some manufacturers are utilizing these sources. Given the importance of these sources in a supplement, use of a quality product is imperative. Remember, these products are not created equally when it comes to effectiveness or cost.

Something New

A source of trace minerals (Zn, Cu, Mn) that is relatively new to the cattle nutrition industry is known as hydroxy trace mineral (Intellibonds®, MicroNutrients, Indianapolis, IN). This type of trace mineral source does not include an organic component as a conventional chelated mineral does. However, it has a crystalline structure formed by covalent (very strong) bonds within a crystalline matrix. This makes the molecule much stronger than that typically found in inorganic sources. Because it is bound to what is known as a hydroxy (OH) group it is consistently insoluble at more neutral pH ranges such as those found in the rumen. Thus, when these hydroxyl trace minerals are fed to ruminants they pass unscathed through the rumen. Because of their chemistry and their structure these sources solubilize in the abomasum and gastrointestinal areas where the pH ranges are lower making the mineral more available to the animal.

Hydroxy minerals are very stable and simpler to handle than many inorganic or organic sources. Other suggested advantages include (Arthington, 2015):

1) More stable than sulfate sources. One particular advantage to this is that in the field, sulfates have a tendency to breakdown and leach out of the supplement when in a self -feeder exposed to high moisture conditions. Hydroxy forms, with increased stability show little or no breakdown in these situations.

2) The more unstable sulfate sources can also facilitate oxidative losses of fat soluble vitamins such as Vitamins A, D and E. Use of Hydroxy forms have been shown to significantly reduce these losses.

3) Hydroxy forms have been suggested to be more bioavailable than sulfate sources.

4) They are believed to show greater resistance to the formation of insoluble complexes such as those commonly seen with Copper, sulfur and molybdenum.

5) Supplements where hydroxy forms were used have been shown to be more palatable particularly to calves when compared to supplements using other sources.

6) The hydroxy sources are highly concentrated allowing for greater flexibility in formulation space.

Finally, researchers are suggesting that because of the bioavailability attributes of the hydroxy mineral forms, lower levels of these minerals may be fed and will still meet the animal's requirements. This research is ongoing.

Conclusions

The use of chelated mineral sources in cattle supplements has become common. However, there are still many questions and still many unknowns about the various sources of chelated mineral products. These questions can make selecting a specific source challenging. Working with a nutritionist to review the data and information available can help in determining which source to use. Finally, based on continued research, other products are emerging that are worth consideration when developing the mineral supplementation program.

Copyright 2016 – Dr. Stephen B. Blezinger. Dr. Steve Blezinger is a nutritional and management consultant with an office in Sulphur Springs, TX. He can be reached by phone at (903) 352-3475 or by e-mail at sblez@verizon.net. For more information please visit Facebook/Reveille Livestock Concepts.







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