Effects of a Saccharomyces cerevisiae fermentation product on fecal characteristics, metabolite concentrations, and microbiota populations of dogs undergoing transport stress.

Previously, a Saccharomyces cerevisiae fermentation product (SCFP) positively altered fecal microbiota, fecal metabolites, and immune cell function of adult dogs. Our objective was to determine the fecal characteristics, microbiota, and metabolites of SCFP-supplemented dogs subjected to transport stress. All procedures were approved by the Four Rivers Kennel IACUC prior to experimentation. Thirty-six adult dogs (18 male, 18 female; age: 7.1 ± 0.77 yr; body weight: 28.97 ± 3.67 kg) were randomly assigned to be controls or receive SCFP supplementation (250 mg/dog/d) (N = 18/group) for 11 wk. At that time, fresh fecal samples were collected before and after transport in a hunting dog trailer with individual kennels. The trailer was driven 40 miles round trip for about 45 min. Fecal microbiota data were evaluated using Quantitative Insights Into Microbial Ecology 2, while all other data were analyzed using the Mixed Models procedure of Statistical Analysis System. Effects of treatment, transport, and treatment × transport were tested, with P < 0.05 being considered significant. Transport stress increased fecal indole concentrations and relative abundances of fecal Actinobacteria, Collinsella, Slackia, Ruminococcus, and Eubacterium. In contrast, relative abundances of fecal Fusobacteria, Streptococcus, and Fusobacterium were reduced by transport. Fecal characteristics, metabolites, and bacterial alpha and beta diversity measures were not affected by diet alone. Several diet × transport interactions were significant, however. Following transport, relative abundance of fecal Turicibacter increased in SCFP-supplemented dogs, but decreased in controls. Following transport, relative abundances of fecal Proteobacteria, Bacteroidetes, Prevotella, and Sutterella increased in controls, but not in SCFP-supplemented dogs. In contrast, relative abundances of fecal Firmicutes, Clostridium, Faecalibacterium, and Allobaculum increased and fecal Parabacteroides and Phascolarctobacterium decreased after transport stress in SCFP-supplemented dogs, but not in controls. Our data demonstrate that both transport stress and SCFP alter fecal microbiota in dogs, with transport being the primary cause for shifts. SCFP supplementation may provide benefits to dogs undergoing transport stress, but more research is necessary to determine proper dosages. More research is also necessary to determine if and how transport stress impacts gastrointestinal microbiota and other indicators of health.

The objective of this study was to determine the fecal characteristics, microbiota, and metabolites of dogs supplemented with a Saccharomyces cerevisiae fermentation product (SCFP) and subjected to transport stress. Thirty-six adult dogs were randomly assigned to a control diet or an SCFP-supplemented diet (N = 18 per group) and fed for 11 wk. At that time, a transport stress challenge was conducted. Fresh fecal samples were collected for measurement of general characteristics, microbiota, and metabolites before and after transport stress. Transport stress increased fecal indoles and Actinobacteria, Collinsella, Slackia, Ruminococcus, and Eubacterium populations and decreased fecal Fusobacteria, Streptococcus, and Fusobacterium populations. Fecal characteristics, metabolites, and bacterial alpha and beta diversity measures were not affected by diet alone, but several diet × transport interactions were significant. Following transport, fecal Turicibacter increased in SCFP-supplemented dogs, but decreased in controls. Following transport, fecal Proteobacteria, Bacteroidetes, Prevotella, and Sutterella increased in controls, but not in SCFP-supplemented dogs. Fecal Firmicutes, Clostridium, Faecalibacterium, and Allobaculum increased and fecal Parabacteroides and Phascolarctobacterium decreased after transport stress in SCFP-supplemented dogs, but not in controls. Our data demonstrate that both transport stress and SCFP alter fecal microbiota in dogs. SCFP supplementation may provide benefits to dogs undergoing stress, but proper dosages need to be determined.

Effects of a Saccharomyces cerevisiae fermentation product on fecal characteristics, metabolite concentrations, and microbiota populations of dogs subjected to exercise challenge.

The objective of this study was to determine the fecal characteristics, microbiota, and metabolites of dogs fed a Saccharomyces cerevisiae fermentation product (SCFP) and subjected to exercise challenge in untrained and trained states. Thirty-six adult dogs (18 male, 18 female; mean age: 7.1 yr; mean body weight: 29.0 kg) were randomly assigned to control or SCFP-supplemented (250 mg/dog/d) diets and fed for 10 wk. After 3 wk, dogs were given an exercise challenge (6.5 km run), with fresh fecal samples collected pre- and post-challenge. Dogs were then trained by a series of distance-defined running exercise regimens over 7 wk (two 6.4 km runs/wk for 2 wk; two 9.7 km runs/wk for 2 wk; two 12.9 km runs/wk for 2 wk; two 3.2 km runs/wk). Dogs were then given exercise challenge (16 km run) in the trained state, with fresh fecal samples collected pre- and post-challenge. Fecal microbiota data were evaluated using QIIME2, while all other data were analyzed using the Mixed Models procedure of SAS. Effects of diet, exercise, and diet*exercise were tested with P < 0.05 considered significant. Exercise challenge reduced fecal pH and ammonia in both treatments, and in untrained and trained dogs. After the exercise challenge in untrained dogs, fecal indole, isobutyrate, and isovalerate were reduced, while acetate and propionate were increased. Following the exercise challenge in trained dogs, fecal scores and butyrate decreased, while isobutyrate and isovalerate increased. SCFP did not affect fecal scores, pH, dry matter, or metabolites, but fecal Clostridium was higher in controls than in SCFP-fed dogs over time. SCFP and exercise challenge had no effect on alpha or beta diversity in untrained dogs. However, the weighted principal coordinate analysis plot revealed clustering of dogs before and after exercise in trained dogs. After exercise challenge, fecal Collinsella, Slackia, Blautia, Ruminococcus, and Catenibacterium were higher and Bacteroides, Parabacteroides, Prevotella, Phascolarctobacterium, Fusobacterium, and Sutterella were lower in both untrained and trained dogs. Using qPCR, SCFP increased fecal Turicibacter, and tended to increase fecal Lactobacillus vs. controls. Exercise challenge increased fecal Turicibacter and Blautia in both untrained and trained dogs. Our findings show that exercise and SCFP may affect the fecal microbiota of dogs. Exercise was the primary cause of the shifts, however, with trained dogs having more profound changes than untrained dogs.

The objective of this study was to determine the fecal characteristics, microbiota, and metabolites of dogs fed a Saccharomyces cerevisiae fermentation product (SCFP) and subjected to exercise challenge in untrained and trained states. Thirty-six adult dogs were randomly assigned to control or SCFP-supplemented (250 mg/d) diets and fed for 10 wk. An exercise challenge was administered while dogs were in an untrained state and a trained state (after 7 wk of an exercise regimen), with fresh fecal samples collected pre- and post-challenge. Exercise challenge reduced fecal pH and ammonia in all dogs. After the exercise challenge in untrained dogs, fecal indole, isobutyrate, and isovalerate concentrations were reduced, while acetate and propionate concentrations were increased. Following exercise challenge in trained dogs, fecal scores and butyrate concentrations decreased, while isobutyrate and isovalerate increased. SCFP reduced fecal Clostridium over time vs. controls. Beta diversity analysis revealed clustering of dogs before and after exercise in trained dogs. After exercise challenge, over 10 bacterial genera were altered in untrained and trained dogs. Our findings show that exercise and SCFP may affect the fecal microbiota of dogs, but exercise was the primary cause of the shifts and trained dogs had more profound changes than untrained dogs.

Effects of a Saccharomyces cerevisiae fermentation product on fecal characteristics, nutrient digestibility, fecal fermentative end-products, fecal microbial populations, immune function, and diet palatability in adult dogs1.

Yeast products may serve as functional ingredients due to their benefits on host health but vary greatly in source, composition, and functionality, justifying research in host species of interest. In this study, a Saccharomyces cerevisiae fermentation product (SCFP) was investigated as a dietary supplement for adult dogs. Adult female beagles (n = 12; mean age = 3.3 ± 0.8 yr; mean BW = 10.3 ± 0.68 kg) were fed the same diet, but supplemented with three levels of SCFP (125, 250, and 500 mg/d) or a placebo (sucrose) via gelatin capsules in a replicated 4 × 4 Latin square design. Fecal samples for nutrient digestibility, fecal characteristics and microbial populations as well as blood samples for immune indices were collected after a 21-d adaptation phase in each period. A separate palatability test was conducted to examine palatability of an SCFP-containing diet (0.2% of diet). All data, except for palatability data, were analyzed by Mixed Models procedure of SAS (version 9.4). A paired t-test was conducted to analyze data from the palatability test. Supplementation of SCFP did not affect total tract apparent macronutrient and energy digestibilities or fecal characteristics. Fecal phenol and total phenol + indole concentrations decreased linearly with SCFP dosage (P < 0.05). Relative abundance of Bifidobacterium was greater (P < 0.05), while Fusobacterium was lower (P < 0.05) in SCFP-supplemented dogs. Total white blood cell counts were decreased by SCFP (P < 0.05). The percentage of natural killer cells and antigen-presenting cells were not altered by SCFP. However, when comparing control vs. all SCFP treatments, SCFP-supplemented dogs had greater (P < 0.05) major histocompatibility complex class II presenting B cell and monocyte populations than control dogs. IFN-γ secreting helper and cytotoxic T cells increased linearly with SCFP consumption (P < 0.05). Immune cells derived from SCFP-supplemented dogs produced less (P < 0.05) TNF-α than those from control dogs when cells were stimulated with agonists of toll-like receptors 2, 3, 4, and 7/8. A linear increase (P < 0.05) in serum IgE with SCFP dosage was noted. In the palatability test, a 1.9:1 consumption ratio was observed for the SCFP-containing diet vs. control diet, demonstrating a preference (P < 0.05) for SCFP. Results of this study suggest that SCFP supplementation may be beneficial to adult dogs by positively altering gut microbiota, enhancing immune capacity and reducing inflammation.

Characterization of bovine ruminal and equine cecal microbial populations enriched for enhanced nitro-toxin metabolizing activity.

The nitrotoxins 3-nitro-1-propionic acid (NPA) and 3-nitro-1-propanol (NPOH) are produced by a wide variety of leguminous plants, including over 150 different species and varieties of Astragalus potentially grazed by livestock. These toxins are known to be detoxified by at least one ruminal bacterium but detoxification by bacteria from other gut habitats is not known. In the present study, mixed populations of bovine ruminal and equine cecal microbes were enriched for NPA-metabolizing bacteria via consecutive 24-72 h culture in a basal minimal rumen fluid-based medium supplemented with 4.2 mM NPA and H2 as the energy source. Rates of NPA metabolism by the respective populations increased from 58.4 ± 4.8 and 8.6 ± 11.6 nmol NPA/mL per h during initial culture to 88.9 ± 30.6 and 50.2 ± 30.9 nmol NPA/mL per h following enrichment. Results from 3-tube most probable number tests indicated that numbers of NPA-degrading microbes increased 2.1 and 1.8 log10 units during enrichment from numbers measured pre-enrichment (3.9 × 10³ and 4.3 × 10¹ cells/mL for ruminal and equine cecal populations, respectively). Hydrogen, formate, and to a lesser extent, DL-lactic acid, served as electron donors to the enriched populations and CO2 or formate were needed to maintain high rates of NPA-metabolism. The NPA-enriched populations were able to metabolize nitrate which, being a preferred electron acceptor, was antagonistic to NPA metabolism. Supplemental NPA was inhibitory to methanogenesis. Fermentation balance estimates indicated that only 47.6% of carbon available in potential substrates was recovered in headspace CO2, volatile fatty acids or unmetabolized NPA after 72 h incubation of NPA-enriched populations that had metabolized 98% of 8.4 mM added NPA. Overall, these results reveal low level carriage of NPA-metabolizing, CO2 or formate-requiring bacterial populations in the equine cecum yet support the concept that Denitrobacterium detoxificans-like organisms may well be the functional agents of NPA and NPOH detoxification in the populations studied here.