The Role of Yeast Saccharomyces cerevisiae in Supporting Gut Health in Horses: An Updated Review on Its Effects on Digestibility and Intestinal and Fecal Microbiota

Abstract

To support the overall health of horses, it is essential to maintain an optimal gut health (GH) status, which encompasses several physiological and functional aspects, including the balance and functionality of intestinal microbial populations and, accordingly, the effective digestion and absorption of nutrients. Numerous biotic and abiotic stressors can lead to an imbalance of GH, such as the quality of forages and the composition of diet, e.g., the inclusion of high energy-dense feeds to meet the energy requirements of performance horses. To support the digestive function and the intestinal microbial populations, the diet can be supplemented with feed additives, such as probiotic yeasts, that promote the ability of cellulolytic bacteria in the hindgut to digest the available fiber fractions, finally increasing feed efficiency. Among the different yeasts available, S. cerevisiae is the most used in horses’ nutrition; however, results of digestibility trials, as well as data on intestinal and fecal microbial populations, are sometimes contradictory. Therefore, the purpose of this review is to summarize the effects of S. cerevisiae on in vivo and in vitro digestibility, providing an updated overview of its effects on the intestinal and fecal microbial population.

Diversity and functional prediction of fungal communities in different segments of mongolian horse gastrointestinal tracts

“…Compared with traditional culture methods, high-throughput sequencing technology is an efficient, rapid, and accurate approach to analysing microbial community composition, especially for studying microbial species with harsh environmental requirements [ 40 ]. At present, studies on equine intestinal microbiota have mostly focused on the bacterial diversity of stool samples [ 4 , 7 , 12 , 41 , 42 ], but these studies have limitations. Indeed, it should be borne in mind that stool samples can only represent the microbial structure of the distal part of the hindgut (colon and rectum) and cannot truly reflect the composition of the entire gastrointestinal microbial community.…”

“…However, the stability of the GIT microbiota is easily influenced by intrinsic (host) and extrinsic (environmental) factors [ 3 ], such as species [ 4 ], age [ 5 ], geographic location [ 6 ], transportation [ 7 , 8 ], exercise stress [ 8 ], diet [ 9 ], and season [ 10 ]. Impairment or dysregulation of the equine GIT and its microbiome may lead to pathological responses [ 10 – 12 ]. Studies have revealed that diarrhoea in horses is closely related to changes in the composition and structure of intestinal microbiota [ 13 , 14 ].…”

Current Understanding of Equine Gut Dysbiosis and Microbiota Manipulation Techniques: Comparison with Current Knowledge in Other Species

“…However, in a randomized and controlled prospective study using a similar supplement with a larger sample size, supplementation had no significant effect on the clinical outcome (diarrhea, leucopenia, appetite, survival) [ 139 ]. Some conflicting results on the effects of Saccharomyces suggest that dosage and diet might influence their efficacy [ 143 , 146 ]. A recent review on the use of Saccharomyces in horses has been published [ 146 ].…”

“…Some conflicting results on the effects of Saccharomyces suggest that dosage and diet might influence their efficacy [ 143 , 146 ]. A recent review on the use of Saccharomyces in horses has been published [ 146 ].…”

From probiotics to postbiotics: Concepts and applications

“…They can colonize the intestines and modulate the composition and activity of the gut microbiota. Commonly used probiotic genera include Lactobacillus, Bifidobacterium, yeast, Bacillus, and genetically modified organisms [17][18][19][20][21]. These microorganisms can help balance the intestinal microbiota and enhance nutrient absorption in animals.…”