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

Dietary intervention may be a valuable strategy to optimize the intra-articular environment in young horses to prolong their performance career. To test the hypothesis that dietary supplementation of a Saccharomyces cerevisiae fermentation product would reduce markers of joint inflammation and increase markers of cartilage metabolism following a single inflammatory insult, Quarter Horse yearlings (mean ± SD; 9 ± 1.0 mo) were balanced by age, sex, body weight (BW), and farm of origin and randomly assigned to: 1.25% BW/d (dry matter basis) custom-formulated concentrate only (CON; n = 9) or concentrate top dressed with 21 g/d Saccharomyces cerevisiae fermentation product (SCFP; n = 10) for 98 d. Horses had ad libitum access to Coastal bermudagrass hay. On d 84, one randomly selected radial carpal joint from each horse was injected with 0.5 ng lipopolysaccharide solution (LPS). The remaining carpal joint was injected with sterile lactated Ringer’s solution as a contralateral control. Synovial fluid obtained before supplementation (d 0) and on d 84 at pre-injection h 0, and 6, 12, 24, 168, and 336 h post-injection was analyzed for prostaglandin E2 (PGE2), carboxypeptide of type II collagen (CPII), and collagenase cleavage neopeptide (C2C) by commercial assays. Rectal temperature, heart rate, respiration rate, carpal surface temperature, and carpal circumference (CC) were recorded prior to each sample collection and for 24 h post-injection. Data were analyzed using linear models with repeated measures. From d 0 to 84, synovial C2C declined (P ≤ 0.01) and the CPII:C2C ratio increased (P ≤ 0.01) in all horses with no effect of diet. In response to intra-articular LPS, synovial PGE2 increased by h 6 (P ≤ 0.01) and returned to baseline by h 336, CPII increased by h 12, remained elevated through h 168 (P ≤ 0.01), and returned to baseline by h 336, and C2C increased by h 6 (P ≤ 0.01) but did not return to baseline through h 336 (P ≤ 0.01). Post-intra-articular injection, PGE2 levels were lower in SCFP than CON horses (P = 0.01) regardless of injection type. Synovial CPII and the CPII:C2C ratio demonstrated stability during the LPS challenge in SCFP compared to CON horses (P ≤ 0.01). Clinical parameters were not influenced by diet but increased in response to repeated arthrocentesis (P ≤ 0.01). Dietary SCFP may favorably modulate intra-articular inflammation following an acute stressor and influence cartilage turnover in young horses.

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

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.

89 Effects of Saccharomyces cerevisiae fermentation product on fecal microbiota populations of dogs subjected to exercise challenge

Previously, a Saccharomyces cerevisiae fermentation product (SCFP) was demonstrated to positively alter fecal microbiota, fecal metabolites, and circulating immune cell functionality in adult dogs. The objective of this study was to determine the fecal characteristics, microbiota, and metabolites of trained dogs subjected to an exercise challenge. All procedures were approved by the Four Rivers Kennel IACUC prior to experimentation. Thirty-six adult dogs (mean age: 7.1 y; mean BCS: 4.9) were used. Dogs were randomly assigned to control or SCFP-supplemented (250 mg/d) diets, trained, and fed for a few mo prior to exercise challenge. Fresh fecal samples were collected for the measurement of fecal characteristics, microbiota, and metabolites before and after an exercise challenge (10 mile run). Fecal microbiota data were evaluated using QIIME2. All other data were analyzed using the Mixed Models procedure of SAS, with treatment and exercise as fixed effects, dog as random effect, and P < 0.05 considered significant. For both treatments, fecal scores and butyrate and propionate concentrations were lower and fecal pH and ammonia, isobutyrate, isovalerate, and total BCFA concentrations were higher after exercise challenge. SCFP did not affect fecal scores, pH, dry matter, or fermentative end-product concentrations after exercise challenge. Alpha-diversity or beta-diversity (unweighted PCoA plot) were not affected by SCFP before or after exercise challenge. The weighted PCoA plot, however, showed clustering of dogs before exercise and after exercise, regardless of treatment. Fecal Collinsella, Slackia, Turicibacter, Blautia, Dorea, Ruminococcus, Faecalibacterium, Catenibacterium, Clostridium (Erysipelotrichaceae family), and Eubacterium relative abundances were higher, while fecal Bacteroides, Parabacteroides, Prevotella (Prevotellaceae family), Phascolarctobacterium, Fusobacterium, Suttella and Anaerobiospirillum relative abundances were lower after exercise challenge. SCFP increased fecal Lactobacillus compared to controls. Our data demonstrate that exercise and SCFP alter fecal microbiota in dogs. Higher SCFP dosages may provide greater changes and may be of interest in future studies.

88 Effects of Saccharomyces cerevisiae fermentation product on microbiota populations of dogs subjected to travel stress

Previously, a Saccharomyces cerevisiae fermentation product (SCFP) positively altered fecal microbiota, fecal metabolites, and function of circulating immune cells in adult dogs. The objective of this study was to determine the fecal characteristics, microbiota, and metabolites of dogs subjected to travel stress. All procedures were approved by the Four Rivers Kennel IACUC prior to experimentation. Thirty-six adult dogs (mean age: 7.1 y; mean BCS: 4.9) were used. Dogs were randomly assigned to control or SCFP-supplemented (250 mg/day) diets and fed for a few months prior to a travel stress challenge. Fresh fecal samples were collected for the measurement of fecal characteristics, microbiota, and metabolites before and after travel stress. Fecal microbiota data were evaluated using QIIME2. All other data were analyzed using the Mixed Models procedure of SAS, with P < 0.05 considered statistically significant. There were no differences between treatments on fecal characteristics, metabolites, and bacterial alpha and beta diversity measures. However, fecal Turicibacter increased in dogs fed SCFP (0.8% to 1.2%, P = 0.03), but decreased in dogs fed control (1.2% to 0.7%, P = 0.03). Fecal Prevotella (5% to 7%, P = 0.004), Oscillospira (0.07% to 0.1%, P = 0.004) and Sutterella (3% to 4%, P = 0.01) increased after travel stress in dogs fed control. In contrast, fecal Clostridium (11% to 15%, P = 0.01), Faecalibacterium (6% to 8%, P = 0.003), and Allobaculum (1% to 2%, P = 0.02) increased and fecal Phascolarctobacterium (1.4% to 1.1%, P = 0.001) decreased after travel stress in dogs fed SCFP. Our data demonstrate that both travel stress and SCFP alter fecal microbiota in dogs.

PSIV-29 The effects of Saccharomyces cerevisiae fermentation product on the performance of creep fed Boer cross kids in regards to average daily gain and weaning weights on alfalfa and grain supplementation

The objectives of this study were to determine the effects of Saccharomyces cerevisiae fermentation product on creep fed kids and to determine their average daily gain (ADG) to improve the final weaning weights. Boer-cross kids and nannies were used for the study. This study was conducted over a period of five weeks from April to May 2019 at Sul Ross State University feedlot. Animals were divided into two groups based on birth weights and twinning with 4 nannies and 6 kids per group. Both groups were fed a base diet of Bermuda/alfalfa hay and a 14% CP goat pellet at rate 0.11kg/h/d and 12% sweet feed for the kids was offered with top-dress and ad libitum alfalfa hay in creep feeders. The fermentation product Saccharomyces cerevisiae was offered in a top-dress with 0.11 kg of ground corn to the treatment kids at 4g per head per day. The body weight (BW) were measured 1x a week to calculate ADG on kids and feed samples were collected 2x a week and dried in a 55C oven and ground through a 1mm Wiley mill screen for later analysis for DM, NDF, ADF, ash, and CP. We observed a significant effect in overall group feed intake (P < 0.001) with the treatment group consuming more than the control, but there was not a significant difference in ADG of kids between the groups (P > 0.23). The small sample size may have hindered the experiment, and it would be beneficial to repeat the experiment with a larger number of animals. Overall, the Saccharomyces cerevisiae fermentation product did not significantly improve ADG or weaning weights in creep-fed Boer-cross kids.

162 The Effects of a Saccharomyces Cerevisiae Fermentation Product on the Digestibility of an Annual Rye Grass Hay Based Finishing Diet for Lambs

Interest in the use of yeast fermentation products has grown in recent years as a natural feed additive for the growth of ruminants in a feedlot setting. The purpose of this study was to determine if the supplementation of a Saccharomyces cerevisiae fermentation product (SCFP) had an effect on apparent digestibility in Katahdin lambs offered an annual ryegrass hay-based finishing diet. Six Katahdin wethers (n = 6) were divided into two groups CON and TRT and placed into individual metabolism crates in a temperature-controlled room, (21.1° C), and fitted with fecal collection bags. Lambs were offered a TMR diet that was formulated to be isocaloric and isonitrogenous at 14% CP, and annual ryegrass hay based with a top dress of ground corn to be used as a carrier. The TRT received the yeast supplement at a rate of 4g/head/day. The diet was offered ad libitum with orts collected daily to maintain a 5% refusal rate. Lambs were housed in the metabolism crates for 1-wk before the start of the study for adjustment, followed by 4 days of data collection. Feed, orts, fecal, and urine samples were collected and recorded daily during the collection period for each wether and compiled by animal for chemical analysis of DM, NDF, ADF, CP, and ether extract. Indigestible ADF was used as a digestibility marker to determine apparent digestibility. Data were analyzed by PROC GLM for statistical significance. There was no statistical significance found for apparent digestibility of DM (CON=64.6 ±2.5; TRT=63.4±2.5), CP (CON=65.0 ±2.1; TRT=65.9±2.1), NDF (CON=41.2±1.9; TRT=43.0±1.9), or ADF (CON=26.1 ±4.7; TRT=33.8±4.7) between the two groups (P > 0.05). This study concluded that the supplementation of a SCFP had no significant effect on the apparent digestibility of Katahdin wether lambs that were offered an annual ryegrass hay-based finishing diet.