Jennifer Little BSc Hons MSc RNutr PgCert
Equinutrition
Independent Equine Nutritionist

Saccharomyces cerevisia is a type of yeast that has been supplemented in horses diets for several decades. Typically it is supplemented to improve the digestibility of a horses diet by supporting the process of fibre fermentation in the hindgut [1,2,3]. However, subsequent research has demonstrated that S.cerevisia and its metabolites can also influence the immune system and its response to infection and inflammation [4].

Inflammation is an essential feature of the immune response, and a level of inflammation is required to prevent bacteria or viruses from causing disease. But, in situations where inflammation becomes systemic it results in the immune system being in a chronic state of activation, with the continual release of pro-inflammatory chemicals called cytokines. This can result in damage to tissues and organs, and in horses it is associated with potentially fatal conditions such as, colic, pleuropneumonia, laminitis and endotoxemia [5]. It also appears that horses are highly sensitive to a group of bacteria, known as Gram-negative bacteria, increasing their susceptibility to systemic inflammation and associated diseases [5].

Firstly, there are several measures we can employ day to day as owners to reduce our horses exposure to environmental bacteria, viruses and toxins.
These measures can include:

• Feed Hygiene: Ensuring feeds are stored in clean, water and rodent proof storage containers. Storing bagged feeds in the bag inside of these containers, rather than decanting the contents into larger bins. Disposing of feeds stored for an extended period of time. Disposing of any feed with a damp, softened, discoloured, dusty or mouldy appearance. Ensuring feed buckets, troughs, scoops, stirrers are all cleaned between uses.

• Yard & Field management: Ensuring muck-heaps are well maintained and removed regularly, stables and fields are routinely cleared of wet bedding and faeces. Quarantine procedures for new horses are observed. Injury risk hazards are managed and minimised. Stables and field shelters are kept clear of dust build-up and good ventilation is established.

• Supporting overall health: Ensuring appropriate diets are provided for ideal body condition, work load and breeding status. General good husbandry, including but not limited to, worm control management, dental work, environmental enrichment and boredom and stress alleviation measures.

Secondly we can support the immune systems ability to respond when exposed to these environmental pathogens.
These measures can include:

• Ensuring vaccination procedures are adhered to
• Ensuring a fully balanced diet providing sufficient fibre, protein, fats, carbohydrates, vitamins, minerals and essential amino acids for each individuals horses needs.
• Ensuring ideal body condition and weight is maintained.
• Minimising stressful situations
• Ensuring workload and management is appropriate for the individual horse.
• Ensuring all veterinary prescribed medications are administered as recommended.
• Supplementation of the diet with S.cerevisia

In addition there is now new evidence that the daily supplementation of S.cerevisia in horses could offer a level of protection against inflammation becoming chronic or systemic after exposure [5].

References

[1] Elghandour, M.M., Chagoyan, J.C.V., Salem, A.Z., Kholif,A.E., Castaneda, J.S.M., Camacho, L.M., Buendia, G., 2014 Invitro fermentative capacity of equine faecal inocula of 9 fibrous forages in the presence of different doses of Saccharomyces cerevisiae. J. Equine Vet Sci 34, 619-625
[2] Elghandour, M.M., Mellado, M., Kholif, A.E., Salem, A.Z., Barbabosa, A., Ballinas, S., Esquivel, A., Odongo, N.E., 2016 Faecal gas production of ten common horse feeds supplemented with Saccharomyces cerevisiae. J. Equine Vet Sci 47, 1-8
[3] Elghandour, M.M., Kholif, A.E., Lopez, S., Mendoza, G.D., Odongo, N.E., Salem, A. Z., 2016 In vitro gas, methane and carbondioxide productions of high fibrous diet incubated with faecal inocula from horses in response to the supplementation with different live least additives. J. Equine Vet Sci 38, 64-71
[4] Russell, S.L., Gold, M.J., Willing, B.P., Thorson, L., McNagny, K.M., Finlay, B.B., Perinatal antibiotic treatments affects microbiota, immune responses and allergic asthma. Gut Microbes 4, 158-164
[5] Lacerenza, M.D., Arantes, J.a., Reginato, G.M. et al 2024. Effects of β-glucan supplementatin on LPS-Induced Endotoxemia in horses. Animals 914) 474