Dietary supplementation of a Saccharomyces cerevisiae fermentation product attenuates exercise-induced stress markers in young horses

Abstract

Mitigation of exercise-induced stress is of key interest in determining ways to optimize performance horse health. To test the hypothesis that dietary supplementation of a Saccharomyces cerevisiae fermentation product would decrease markers of exercise-induced stress and inflammation in young horses, Quarter Horse yearlings (mean ± SD; 9 ± 1 mo) were randomly assigned to receive either no supplementation (CON; n = 8) or 21 g/d Saccharomyces cerevisiae fermentation product (10.5 g/feeding twice daily; SCFP; n = 10) top dressed on a basal diet of custom-formulated grain, as well as ad libitum Coastal bermudagrass hay. After 8 wk of dietary treatments, horses underwent a 2-h submaximal exercise test (SET) on a free-stall mechanical exerciser. Serum was collected before dietary treatment supplementation (wk 0), and at wk 8 pre-SET, and 0, 1, and 6 h post-SET, and analyzed for concentrations of cortisol and serum amyloid A (SAA) by commercial ELISA, and for cytokine concentrations by commercial bead-based ELISA. Data were analyzed using linear models with repeated measures in SAS v9.4. From wk 0 to 8 (pre-SET), serum cortisol decreased (P = 0.01) and SAA did not change but neither were affected by diet. Serum concentrations of all cytokines decreased from wk 0 to 8 (P ≤ 0.008), but granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), and interleukin-8 (IL-8) decreased to a greater extent in CON than in SCFP horses (P ≤ 0.003). In response to the wk 8 SET, serum cortisol increased in all horses (P < 0.0001), but returned to pre-SET levels by 1 h post-SET in horses receiving SCFP. At 6 h post-SET, cortisol concentrations in CON horses returned to pre-SET concentrations, while cortisol declined further in SCFP horses to below pre-SET levels (P = 0.0002) and lower than CON (P = 0.003) at that time point. Serum amyloid A increased at 6 h post-SET in CON (P < 0.0001) but was unchanged through 6 h in SCFP horses. All cytokines except G-CSF increased in response to the SET (P < 0.0001), but showed differing response patterns. Concentrations of IL-1β, IL-6, and tumor necrosis factor alpha (TNFα) were lesser (P ≤ 0.05), and concentrations of G-CSF and IL-18 tended to be lesser (P ≤ 0.09) in SCFP compared to CON horses throughout recovery from the SET. In summary, 8 wk of dietary supplementation with 21 g/d of SCFP may mitigate cellular stress following a single, prolonged submaximal exercise bout in young horses.

Responses to an intra-articular lipopolysaccharide challenge following dietary supplementation of Saccharomyces cerevisiae fermentation product in young horses

“…Similar to PGE 2 , CPII, C2C, and the ratio of CPII to C2C were not affected by diet during the pre-LPS period. The horses in the current study received no forced exercise outside of the previously described submaximal exercise test, which occurred 4 wk prior to the LPS challenge ( Valigura et al, 2021 ). As opposed to horses at rest, forced exercise in young horses is more commonly associated with alterations within the joint space due to repetitive hyperextensions and concussions that are generated during early training and exercise ( Palmer and Bertone, 1994 ).…”

“…While PGE 2 was the only biomarker evaluated to understand intra-articular inflammation in the current study, it would be of benefit to quantify and determine any dilutional effects of other synovial biomarkers related to inflammation, including cytokines, to obtain a more elaborate understanding of intra-articular inflammation. It was reported that horses supplemented with SCFP had lower serum concentrations of inflammatory cytokines, interleukin ( IL )-1β, IL-6, and tumor necrosis factor-alpha, when compared with CON horses throughout the recovery period following the submaximal exercise test at day 56 ( Valigura et al, 2021 ). However, possible cytokine levels in serum and their potential relationship with joint cytokines at the time of the LPS challenge were not evaluated, as serum cytokines were only analyzed surrounding the exercise test at day 56, and the evaluation of synovial cytokines was outside of the scope of the current study.…”

“…Composited hay and grain samples were analyzed by a commercial laboratory (Equi-Analytical Laboratories, Ithaca, NY) for nutrient composition ( Table 1 ). On day 56, all horses performed a 2-h submaximal exercise test for a related study ( Valigura et al, 2021 ) to evaluate the effects of SCFP supplementation on markers of exercise-induced stress and inflammation. This exercise test represented the only forced exercise that horses received for the duration of the study.…”

Responses to an intra-articular lipopolysaccharide challenge following dietary supplementation of Saccharomyces cerevisiae fermentation product in young horses

“…While PGE 2 was the only biomarker evaluated to understand intra-articular inflammation in the current study, it would be of benefit to quantify and determine any dilutional effects of other synovial biomarkers related to inflammation, including cytokines, to obtain a more elaborate understanding of intraarticular inflammation. It was reported that horses supplemented with SCFP had lower serum concentrations of inflammatory cytokines, interleukin (IL)-1β, IL-6, and tumor necrosis factoralpha, when compared with CON horses throughout the recovery period following the submaximal exercise test at day 56 (Valigura et al, 2021). However, possible cytokine levels in serum and their potential relationship with joint cytokines at the time of the LPS challenge were not evaluated, as serum cytokines were only analyzed surrounding the exercise test at day 56, and the evaluation of synovial cytokines was outside of the scope of the current study.…”

“…Body condition scores (BCSs) were also obtained by three independent observers using the 1 to 9 scale described by Henneke et al (1983). Composited hay and grain samples were analyzed by a commercial laboratory (Equi-Analytical Laboratories, Ithaca, NY) for nutrient composition (Table 1 (Valigura et al, 2021) to evaluate the effects of SCFP supplementation on markers of exerciseinduced stress and inflammation. This exercise test represented the only forced exercise that horses received for the duration of the study.…”