Feeding Digestive Supplements Nutritional Information

By Katie Williams M.Sc. (Dist) B.Sc (Hons) R Nutr

Digestive enhancing ingredients have been available for horses for a number of years now but what developments have there been in that time.

The Role of Bacteria in the Gut

Mammals do not possess enzymes that are able to digest fibre and so herbivores, who obviously have to be able to obtain nutrients from fibrous material to survive, rely on a population of micro-organisms to do it for them. Relatively speaking, vegetation has a low concentration of nutrients, and so herbivores have to eat large amounts which they achieve by eating for at least 16 to 18 hours every day. The digestive system of the horse is therefore adapted to receiving an almost continuous flow of low nutritional value food.

As fibrous material should make up at least 50% of every horse's diet, it is vital that it is digested efficiently which is why the microbial population is so important to the overall health of the horse.

Definitions

The term probiotics can be used to describe products that contain either bacteria or yeast which is a fungus as they are both 'live' and have positive effects on the health of the gut. It is important to understand that there is a difference between the two as they work in different ways. If you are purchasing a probiotic product, make sure you check exactly what it contains and if you are in any doubt contact the company for advice. In contrast, prebiotics are substances that have an effect on the microbial population in the gut but are not actually live.

Yeast

There are different types of yeast that are added to feeds and supplements. They can be divided into two main categories which are live yeast and dead yeast. Live yeasts are often referred to as yeast cultures which simply means that the medium on which the yeast was grown is also included. Live yeasts should be approved under EU legislation for use in horses as they are considered to be an additive; currently the only approved live yeast is Yea-Sacc1026, a brand name for saccharomyces cerevisiae, which is used by many feed and supplement manufacturers. To gain approval, evidence supporting the efficacy, safety and quality of the product has to be demonstrated for the specific age groups that the product is seeking approval for.

The most beneficial effect of feeding live yeast to horses is that it increases fibre digestion which simply means that a horse should be able to get more out of the fibre it eats. If the fibre is making a greater contribution to the horse's requirements then less concentrates should be required which is ideal for any horses that are prone to digestive upsets or over-excitable behaviour.

Several companies have a pure Yea-Sacc1026 supplement in their range (Dengie's is called Dengie Natural Vitality Digestive Health.  Click here for more information on this product) and it usually offers a cost effective way to help promote better utilisation of the fibre in your horse's diet. The feeding rate for Yea-Sacc1026 is 10 grams per day and so a 1kg pot lasts 100 days. The retail price does vary but is around the £25 per 1kg tub which means that feeding Yea-Sacc1026 costs around 25p per day.

Research suggests that adding live yeast to the feed when starch was fed helped to counteract some of the negative effects that usually occur in the hind gut in response to starchy meals. This shouldn’t be seen as a “safety net” as high starch diets have other negative effects that are detrimental to the horse's health and well-being but it does support the inclusion of yeast in performance horse rations.

Prebiotics

There are two types of prebiotics in common usage in horse feed, one being short chain fructo-oligosaccharides (FOS) and the other being mannan-oligosaccharides (MOS). Oligosaccharides literally means a 'few sugars' and the fructo- and mannan- bit indicates what type of sugars they are. The bonds that join these sugars together can't be broken down by the enzymes in the horse's gut and so the energy they contain is inaccessible to the horse which is why oligosaccharides have an effect on the bacteria in the gut.

A study presented at the Equine Nutrition Conference in Hannover 2005, investigated the effects of FOS prebiotics in different parts of the digestive tract. The researchers found that horses supplemented with FOS had less acidic digestive tracts than those that weren't supplemented and suggested that this could help to reduce the risk of problems such as gastric ulcers. Obviously this research would need to be repeated before a definite claim could be made.

Mannan-oligosaccharides are actually more than just sugars and are in fact the yeast cell walls that contain the sugar. Whereas FOS prebiotics are often referred to as a 'lunch box' for specific bacteria that have important functions in the gut, MOS are of benefit because they stick to pathogenic bacteria such as E. coli and Salmonella and carry them out of the gut.

Probiotics

The use of probiotics in horses usually generates considerable debate as there has been little research specific to horses. Research that was published in 2004 identified only one strain of bacteria, Lactobacillus pentosus, that was capable of making its way through the horse’s digestive system to where it is needed and being able to grow. It was also able to inhibit Clostridium difficile in lab tests which is significant as this is the bacteria associated with causing diarrhoea. For this bacteria to become licensed for use as a probiotic suitable for horses it will require approval by the EU which requires a huge dossier of evidence demonstrating its safety and efficacy. It is highly unlikely that there will be sufficient funds for this research to occur in the short term.

Which supplement should I use?

This really depends on a number of different factors. Apart from good-doers, all horses would theoretically benefit from being able to get more out of the fibre that they consume which means that a yeast supplement could be fed to most individuals. Although yeast has to be fed on an on-going basis, it is such good value for money that it is well worth doing, particularly as you may be able to feed less concentrate feed.

Anecdotal reports suggest that FOS prebiotics are useful for older horses, particularly if they are prone to loose droppings. Several of the 'veteran' compound feeds contain prebiotics and although they would probably provide a lower level than a supplement, they may be sufficient to reduce the risk of problems occurring. Alternatively you could feed a supplement on top but at reduced levels. Manufacturers are not required to declare the level of inclusion on the bag and so if you want to find out how much is in the feed you will need to contact them to find out.

Probiotics can be fed long term but can also be used around a potential problem period. As stressful situations are known to disrupt the microbial population, it is possible to use a supplement the day before, the day of and the day after travelling for example.

Dengie's Natural Vitality Digestive Healthy Plus has a combination of probiotics, prebiotics and yeast.  If you would like more information on this product click here.