Antibody response to Influenza booster vaccination in Franches-Montagnes stallions supplemented with Equi-Strath® : a randomized trial

Saccharomyces cerevisiae fermentation product improves robustness of equine gut microbiome upon stress

Introduction

Nutritional and environmental stressors can disturb the gut microbiome of horses which may ultimately decrease their health and performance. We hypothesized that supplementation with a yeast-derived postbiotic (Saccharomyces cerevisiae fermentation product-SCFP) would benefit horses undergoing an established model of stress due to prolonged transportation.

Methods

Quarter horses (n = 20) were blocked based on sex, age (22 ± 3 mo) and body weight (439 ± 3 kg) and randomized to receive either a basal diet of 60% hay and 40% concentrate (CON) or the basal diet supplemented with 21 g/d Diamond V TruEquine C (SCFP; Diamond V, Cedar Rapids, IA) for 60 days. On day 57, horses were tethered with their heads elevated 35cm above wither height for 12 h to induce mild upper respiratory tract inflammation. Fecal samples were collected at days 0, 28, and 56 before induction of stress, and at 0, 12, 24, and 72 h post-stress and subjected to DNA extraction and Nanopore shotgun metagenomics. Within sample (alpha) diversity was evaluated by fitting a linear model and between sample (beta) diversity was tested with permutational ANOVA.

Results

The SCFP stabilized alpha diversity across all time points, whereas CON horses had more fluctuation (P < 0.05) at 12, 24, and 72 h post-challenge compared to d 56. A significant difference between CON and SCFP was observed at 0 and 12 h. There was no difference in beta-diversity between SCFP and CON on d 56.

Discussion

Taken together, these observations led us to conclude that treatment with SCFP resulted in more robust and stable microbial profiles in horses after stress challenge.

Herbal yeast product, Equi-Strath®, alters the antioxidant status of stallion semen

Effects of a plasmolysed yeast product enriched with herbs, malt, honey and orange syrup on semen characteristics and oxidative status in stallions were evaluated. Twenty stallions (mean age ± standard deviation = 9.5 ± 4.5 years) were randomly divided into a treatment group (n = 10) receiving 0.06 mL/kg bodyweight of plasmolysed herbal yeast, and a control group (n = 10) receiving the same amount of placebo daily in the feed for 10 weeks. Ejaculates were collected weekly from all stallions starting at Week 0. Volume, sperm concentration, motility, and velocity were evaluated immediately, 24 and 48 h after cooled storage at 5 °C. At the two storage time points, membrane lipid peroxidation was determined using the BODIPY-C₁₁. Additionally, blood samples were collected at Weeks 0, 1, 5 and 9, and analysed for antioxidant status, consisting of superoxide dismutase, cholesterol, thiobarbituric acid reactive substances, and non-esterified fatty acids. Due to the nature of the data, the Mann-Whitney U test was applied as preliminary analysis. The BODIPY-C₁₁ in the semen was less at 24 h and greater at 48 h after collections in Week 1 to 3 (P < 0.01) and Week 1 to 10 (P <  0.05) compared with Week 0 in the treatment compared to control group. There were no significant differences between groups for all values for other seminal and blood variables evaluated. In conclusion, feed supplementation with plasmolysed herbal yeast temporarily improved the antioxidant status of stallion semen, which might be of benefit for preservation of cooled semen.