Effects of Saccharomyces cerevisiae supplementation on apparent total tract digestibility of nutrients and fermentation profile in healthy horses

Abstract

SummarySupplementation with Saccharomyces cerevisiae (SC) in horses may have some potential to modify microbial populations and thereby improve fibre digestibility. The aim of this study was to investigate the effects of SC on apparent total tract digestibility (ATTD) of nutrients, with a special focus on fibre digestion in healthy horses. The fermentation profile of microbial populations was another focus of interest. Twelve geldings were randomly assigned to three groups. The basal diet consisted of cracked corn (2 g starch/kg body weight [BW]) and hay (1.2 kg/100 kg BW). During adaptation (3 weeks) and the total faecal collection period (5 days), cracked corn was fed once daily either as control (0 g SC) or supplemented with 1 or 3 g SC (1 g SC = 2 9 10 10 colony-forming units [cfu]). There was a 4-week wash-out period between the different SC regimes. Faeces were sampled by rectal collection for the analysis of pH, nitrogen, lactic acid, short-chain fatty acids (SCFA) and SC. In faeces, mean SC cfu was significantly lower than the quantity supplemented: 0 g SC, no detection; 1 g SC, 1.1 9 10 6 cfu; 3 g SC, 3.6 9 10 6 cfu. Apparent total tract digestibility of crude fibre varied approximately 40%without any treatment-related effects. Short-chain fatty acids, lactic acids and pH in faeces were not significantly affected by SC supplementation. Saccharomyces cerevisiae supplementation was not associated with any changes in the fermentation profiles, and fibre digestion accordingly remained unchanged in intact and healthy horses. Taking into account that fibre digestion remained unchanged and recovery rate of SC in faeces was mariginal, colonization and proliferation of SC in the healthy equine intestinal tract seems to be unlikely.

Dietary composition and yeast/microalgae combination supplementation modulate the microbial ecosystem in the caecum, colon and faeces of horses

“…In equine studies, in vivo evaluation of nutritional solution effects on the hindgut microbiota was performed either by studying directly caecum or colon content using fistulated horses (8,9,14,15) , or, more frequently, using faeces, which is non-invasive and less labour-intensive (16)(17)(18)(19)(20)(21)(22) . However, to our knowledge, no study has ever verified that changes observed in the faeces under supplementation were consistent with those in the hindgut microbial ecosystem.…”

Beeinflussung der equinen Mikrobiota durch Fütterung und Probiotika: aktueller Stand der Forschung und rechtliche Grundlagen

“…Dabei ergab sich eine Abnahme der SC-Konzentration vom Zäkum (4,4 x 10 6 KBE/ml) zum Kolon (5,6 x 10 4 KBE/ml) um zwei Zehnerpotenzen [39]. Im Kot ließen sich bei Gabe von SC lediglich 220 ± 283 KBE/g isolieren statt der erwarteten 1,1 x 10 6 ± 1,7 x 10 5 KBE/g unter der Bedingung, dass SC weder verdaut noch kolonisiert wird [48].…”

“…Diese Daten deuten darauf hin, dass SC vermutlich das saure Magenmilieu überlebt und an seinen Wirkungsort im Dickdarm gelangen kann. Dort findet jedoch wahrscheinlich keine Ansiedlung dieser Hefen statt, sondern ihre Konzentration nimmt aufgrund von Fermentationsprozessen durch die wirtseigene Mikrobiota im Verlauf des Dickdarms sukzessive ab [48].…”

Free fecal water in the horse – an unsolved problem

“…Die Detektion der Toxine A und B über Immunassays, zellzytotoxische Assays oder eine PCR, zum Nachweis der für die Toxinbildung verantwortlichen Gene des Bakteriums, stellen sensitivere Methoden dar (Jones 2000, Weese et al 2000, Jones 1989). (Mackenthun et al 2013). …”