Organic minerals and why they should be part of the racehorses diet
/Article by Catherine Rudenko
What are organic minerals and why should these be part of racehorse diets?
Chelated minerals, commonly known as ‘organic minerals’ have been around since the 1980s and were quickly adopted into feeds for production animals as benefits relating to health, production and physical gains became apparent through a growing body of research and proven results on farms. Early in the 1990s organic minerals appeared in horse feeds with most brands adopting a partial replacement concept, using a low inclusion of organic minerals alongside inorganic minerals.
By early 2000 researchers began querying if diets could be reliant fully on organic minerals, working on the basis that ‘nature identical’ minerals would require lower feeding rates and could still deliver the same level of performance whilst also benefitting the environment.
Fast forward to today and some feed companies, including equine, are now operating with organic minerals only. Is this the future of mineral nutrition for racehorses?
What is an organic mineral and where do minerals come from?
Most mineral additives come from inorganic compounds such as oxides, sulphates, carbonates and phosphates. Interactions between inorganic minerals combined with lower levels of digestibility means inclusion levels are often high in feeds to ensure dietary needs are met. Variability in forage is also a factor in why mineral levels often run well above recommended intakes as well as catering for the ‘more is better’ mindset in the marketplace.
Over-formulating and over feeding of mineralised feeds or supplements does not get better results. In fact, quite the opposite. There is a fine balance between minerals, which actively compete with each other for absorption in the body. Then there is the question of energy efficiency as processing excessive and unnecessary nutrients requires energy within the body.
Organic minerals offer an interesting alternative, having a greater bioavailability, not competing for the same absorption sites, reducing effects of interactions, and wastage of nutrients excreted into droppings. The excretion of minerals was a key driver behind the increased use of organics in the agri sector as the impact of farming on the environment continues to be closely scrutinised. The benefits of using organic minerals aren’t just about animal health and performance, they are also about environmental responsibility.
What is an organic mineral?
Organic minerals are trace elements, also known as micro minerals, that are complexed or otherwise associated with an organic molecule. Most commonly referred to as chelated minerals. The term organic mineral is used quite broadly, and there are several different types of organic minerals used in animal feeds. Copper, zinc, manganese and iron are available in chelated form, whilst selenium is available in organic yeast.
How are they made?
Creating an organic mineral is a process of reacting the inorganic mineral salt with a suitable non-metal entity known as a ligand. Ligands are mostly single amino-acids or small peptides (chains of amino acids). Once bonded the mineral becomes part of a biologically stable, and more available structure.
The key word is stability as this influences how that mineral behaves when fed, as the digestive system presents several challenges, including varying levels of pH. As a general rule, minerals organically bound with peptides (amino acid chains), that have a greater potential to form bonds, create more stable organic minerals than those based on a single amino acid.
Chelation of minerals is the process used for zinc, copper, iron and manganese. Selenium is a little different, belonging to a different group of elements, that are difficult to chelate in the same manner. For that reason, organic selenium is also derived from selenised yeast, a form commonly used in equine feeds and for which equine specific research is available.
How do chelates work?
Mineral stability and resilience to some of the challenges of the digestive tract is one part of the success story behind chelated organic minerals. Binding with amino acids also means that organic minerals utilise different pathways for absorption compared to inorganic minerals. This improves absorption and reduces competition with other minerals.
As the ‘what goes in’ with organic minerals is more stable and is easily absorbed there is less needed to meet requirements and still provide benefits to health and performance. On a feed tag or supplement label the number might look lower but the efficacy is greater.
When reviewing your feed choices and looking at all the numbers it is worth asking the question as to what form of mineral is being used, not just the milligrams per kilogram value in the brochure. The mineral source is not always declared on a website or datasheet but by law is noted on the feed label in the additive section, so it is worth walking out to the feed room and taking a look.
The whole concept of using chelated minerals is to “do more with less”. That is the challenge as Steve Elliott, Global Vice President of Companion Animal at Alltech describes it, and what Alltech have set out to prove is possible.
There are multiple papers on the benefits and efficacy of organic minerals in farm animals. There is however much less equine specific research available. That does not mean organic minerals aren’t good for horses, or don’t work as well, it’s just that horses aren’t generally for eating (which influences spend on research) and they are harder to research.
What research likes is specific measurables that can easily be linked back to a change in diet, such as live weight gain or milk production. As we don’t fatten horses to eat, or use them for milk, the measurables in horses are harder to work with. Increased performance has too many other variables involved, such as ground conditions, rider etc. As such, we have to work with a smaller pool of data on horses specifically and combine that knowledge with other species with similar digestive systems.
What is known from other species?
Inclusion of organic chelates in animal feeds has been a common practice for the last 40 plus years. Typical inclusion levels are 30-40% of the total mineral being provided as organic, with the remainder as inorganic. At that level there is plenty of research to show a positive effect. Inclusion levels much below that rate of inclusion are questionable. Just because a feed or supplement says ‘contains chelated minerals’ does not guarantee they are included at a meaningful or effective level.
More recently the use of organics only has been the area of interest for research. This is an area Alltech have been heavily involved in, and at present have conducted 253 trials, resulting in 131 peer-reviewed papers.
One of the key questions when considering organics is how much less can be fed versus traditional inorganic minerals in the daily diet. Just how much better are they? From other species the answer is a whole lot less, with research into poultry and swine showing less than half the amount is needed compared to inorganics mineral sources.
What about horses?
Whilst there are no feed tables specifically for horses referencing organic mineral and inorganic mineral requirements there is enough evidence to give confidence that organic minerals could be, and already are being, used as the sole micro mineral source for horses.
Horse feeds are typically generously fortified or over-fortified against requirements. For horses in training where feed intake is easily 4 times that of a sport horse the daily intake of copper, zinc, manganese and selenium is often significantly above requirement. For example, horses in training are often consuming copper at 250-300% of requirement.
With the source of copper being either dominantly, or entirely inorganic, the level given is not necessarily, in fact it is quite unlikely, to be twice or three times as good as feeding the required level. High intakes will result in greater losses into faeces, having little benefit to the horse, and having a negative impact on the environment.
There are equine feed companies already working with organics only, including Guabi Horse Feeds in Brazil and McCauleys feeds in the USA. Working closer to daily requirements, rather than high dosing, and using organic minerals only, these companies are proving organics are a real option for performance and racing horses just as much as they are for other animals.
What benefits do organic minerals bring?
Minerals such as selenium, manganese, iron, copper and zinc are added to feeds and provided in supplements for two reasons, to address the shortfall and variation in mineral content from forages, and to provide levels above basic requirements with the aim of enhancing performance or using nutrition as a therapeutic tool.
Organic mineral research orientates around improved uptake and efficacy within the body, trying to improve as an aspect of performance related to that mineral. Each mineral has its own role in animal health.
Selenium
Selenium has many roles in the body. Primarily, its role in regulation of the antioxidant system. Following the uptake of selenium by the body, selenium becomes incorporated into numerous selenium-dependent enzymes and proteins, which play many major biological roles.
Selenium is also a mineral which is regulated, having a maximum permitted level in the daily diet for horses, as whilst being beneficial selenium can also be toxic. When looking at feeding horses in training additional selenium should only be given if feed and forage levels have been assessed and factored into the daily intake.
Major biological roles of selenium-containing proteins
Research into organic selenium benefits for poultry, swine and cattle includes:
Improved disease resistance
Improved antioxidant defence
Improved retention of selenium in muscle and tissue
Improved fertility
Improved growth rates
Improved selenium content in milk and colostrum
Equine specific research has also shown the same effect on mare’s milk and colostrum.
Copper, Zinc, Manganese and Iron
Each of these minerals has a role to play in health and performance. When researching efficacy for organic minerals these are often grouped in research as the objective is to determine if replacing this group in part or in full improves the finished feed.
Copper is one of the most important micro minerals for horses. It has many key roles including, mobilising iron stores, correct functioning of enzymes, maintaining elastic tissues, proper skeletal growth and development, and its role as an antioxidant.
Zinc has a broad reach in the body, being an enzyme activator or co-factor, as well as being part of over 200 proteins. Zinc is required for normal functioning of insulin and for normal glucose utilisation. It is also important for a functioning immune system, healing of wounds and neurological functions.
Manganese is involved in bone formation, fatty acid synthesis and amino acid metabolism. Unlike copper and zinc that are naturally low in forages, the level of manganese can be sufficient to meet daily requirements. Variability in levels found within forage is high and supplementation is common practice to cater for this risk.
Iron is part of hemoglobin, the component of red blood cells that allows oxygen to be carried to tissues. Iron deficiency is rare as the horse has a high ability to conserve iron. Approximately 67% of the body’s iron is stored in red blood cells in the form of hemoglobin.
Red blood cells are formed within the body and remain in circulation for around 150 days. When they die, the iron they contain is recycled and used to build new red blood cells. As such, there is rarely a time where iron is lost from the body. The exceptions to that being horses with high worm burdens, horses with gastric ulcers that cause blood loss, and horses suffering from EIPH (Exercise Induced Pulmonary Haemorrhage). Iron is found in good quantities in feed ingredients and forages, sufficient in most cases to meet requirements. Iron is often added to feeds at low levels to ‘top-up’ naturally occurring iron.
Research from other species including farm, aquatic and dog show, organic minerals when fed in combinations, have benefits including:
Improved bone mineral content
Increased growth rates and weight gains
Improved milk and colostrum mineral profile
Increased total antioxidant capacity
Improved gut morphology
Improved availability in the presence of antagonists
In horses, a study looking at the influence of oxalates, a substance that reduces calcium uptake, researchers were able to demonstrate that organic minerals were better able to prevent bone resorption compared to inorganic minerals. Diets contained organic copper, zinc, manganese and selenium.
How does the environment benefit?
One of the achievements of organic minerals is reduced mineral leaching, an important consideration for farm animals. Alltech have investigated this in horses also, looking at the effect of their organic minerals (Bioplex) on fecal mineral excretion and fecal mineral leaching potential.
In this research horses were fed one of three diets, a standard diet with no mineral supplementation (CON) or diets containing either inorganic (ING) or organic added minerals (ORG). In both diets with added minerals there were increased mineral levels found in droppings. The diets were supplemented to be higher than requirements (120-380% NRC), which replicates what is commonly found in industry feeds. The organic zinc and copper levels found in the manure were lower than inorganic levels, demonstrating better uptake in the body.
Both supplemented diets resulted in increased levels of phosphorus leaching from the manure, although the organic mineral diet resulted in numerically lower levels of phosphorus leaching than inorganic. The same pattern was seen for sulphur.
Manure from all diets was then used to grow tall fescue grass to determine if the diet influenced grass growth. Grass was grown using the manure from the horses fed the three different diets, with water on its own (WAT), and a liquid nutrient solution (NUT).
Grass grown with manure from horses fed diets supplemented with organic minerals (ORG) had 16% greater biomass than grass grown with manure from diets supplemented with inorganic minerals (ING).
So are organic minerals a good choice for horses in training?
Whilst the majority of research is from other species the science is sound, and the benefits found are equally relevant for horses in training. The majority of feed companies already use chelated minerals in their feeds to provide a proportion of minerals in this format, albeit at varying levels. What is less common, at least in equine, is the total replacement of trace elements with organic formats only, but it is being done and done successfully.