January/February 2018 AQHA JAN_FEB 2018 WEBSITE | Page 32

Antioxidants for your horse

HYGAIN Feeds By Dr Clair Thunes
Vitamin E and selenium – a vitamin and a mineral . On first glance these two compounds appear to be very different from each other . However , on closer examination it turns out that they have something in common , they are examples of antioxidants .
What is an antioxidant ?
Antioxidant is a term that is seen more and more frequently in equine nutrition as we learn about their importance in human health . They are key factors in the fight against cellular level damage and inadequate levels of these important compounds can result in a decreased ability to fight off illness and chronic disease . Commonly found in fruits and vegetables they are just one of the reasons why we humans are encouraged to eat plenty of these important foods each day .
Natural antioxidant sources in the horse ’ s diet
Consuming enough plant material to insure abundant levels of these key nutrients is likely not a problem for horses in their native setting where a broad range of plant matter is consumed each day . However , the diets of domesticated horses can be quite bland with little variety day-to-day . Additionally , processing of forages for storage , such as making hay , can reduce the levels of these naturally occurring compounds , as they are often heat sensitive . Some of them will deteriorate over time as well meaning that levels will be lower in hay stored for several months than when first baled .
While research into these compounds is not as extensive in the equine literature , we do know that inadequate intakes of some of these key antioxidants can have negative implications on your horse ’ s performance and health .
The function of antioxidants in the horse
Before we discuss some of the antioxidants more commonly added to equine rations let ’ s look in more depth at what antioxidants do . The simplest definition of an antioxidant is that it is a molecule that prevents the oxidation of another molecule .
Cells are made up of many molecules and in turn these molecules are made up of atoms . As you may recall from High School chemistry , atoms have a number of positively charged particles ( protons ) and negatively charged particles ( electrons ). Electrons are arranged in ring around the atom with a specific number of electrons in each ring . To improve overall stability , atoms try to maximise the number of electrons in the outer most ring and sometimes this is achieved by sharing electrons with neighboring atoms which allows molecules to bind together and create stable structures .
If these bonds break apart an odd number of electrons may be left in an atom ’ s outermost shell . Atoms with an odd number of electrons are inherently unstable and are known as free radicals . They take on the mission of finding an electron that can be stolen to create an even pair , and become stable , as quickly as possible . Often this electron is stolen from a neighboring molecule leaving the molecule that was attacked with an odd number of electrons such that it now becomes a free radical . If left
unchecked , a cascade of stealing can occur as one molecule attacks and steals an electron from another until the reactions are stopped , which is called the oxidative process . Because free radicals are a byproduct of the oxidative processes within the cell the process is sometimes described as “ oxidative damage ” or “ oxidative stress ” and free radicals are thought of as “ bad ”. However , it is important to remember that free radicals are natural byproducts of the oxidation of carbohydrates , fats and proteins for use as energy — processes that are necessary for our bodies to function . This means that when horses work , free radicals are generated due to energy stores being utilised for work . Free radicals are inevitable and can also be beneficial . Oxidation is used as a way for the body to neutralise infections and viruses . Only when oxidation becomes excessive does significant damage occur , which will
be more likely if inadequate levels of antioxidant compounds are available Antioxidant compounds are special in that they are able to donate an electron to a free radical and yet they remain equally stable whether they have an odd or even number of electrons in their outer ring . Antioxidants are like scavengers looking for oxidation reactions that they can end . Therefore , antioxidants are vital to preventing significant and long term cellular damage .
Areas of your horse ’ s body that may be negatively impacted by oxidation in the face of inadequate antioxidants include : muscle function , cell membrane integrity , immune function , neurological function , vision and many others .
Added sources of antioxidants
Due to their importance , some antioxidants are frequently added to commercial feeds , the most common being vitamin E and selenium . Vitamin E is a term used to describe a family of compounds known as tocopherols and tocotrienols of which there is an alpha , gamma , delta and omega form of each . Some have greater vitamin E activity than others . When found naturally occurring in the plants several forms exist and they are often referred to as mixed tocopherols .
Page 32 • The Australian Quarter Horse Magazine • January • February • 2018