Prebiotics and dietary fibers are nondigestible ingredients that may confer benefits to the host by selectively stimulating beneficial intestinal bacteria and microbial-derived metabolites that support gut and host health. This experiment evaluated the effects of a blend of prebiotics and dietary fibers on apparent total tract digestibility (ATTD) and fecal metabolites related to gastrointestinal health in adult dogs. Four diets containing either 5% cellulose (control; CT), 5% dietary fiber and prebiotic blend (FP), 0.02% saccharin and eugenol (SE), or 5% fiber blend plus 0.02% saccharin and eugenol (FSE) were formulated to meet or exceed the AAFCO (2017) nutritional requirements for adult dogs. Eight adult female beagles (mean age 4.2 ± 1.1 yr; mean BW = 10.8 ± 1.4 kg; mean BCS = 5.8 ± 0.6) were randomly assigned to 1 of the 4 dietary treatments using a replicated 4 × 4 Latin square design. Each experimental period consisted of 14 d (10 d of diet adaptation and 4 d of total and fresh fecal and total urine collection). All animals remained healthy throughout the study, with serum metabolites being within reference ranges for adult dogs. All diets were well accepted by the dogs, resulting in similar (P > 0.05) daily food intakes among treatments. Likewise, fecal output and scores did not differ (P > 0.05) among dietary treatments, with the latter being within the ideal range (2.5–2.9) in a 5-point scale. All diets were highly digestible and had similar (P > 0.05) ATTD of dry matter (81.6%–84.4%), organic matter (86.4%–87.3%), and crude protein (86.6%–87.3%). However, total dietary fiber (TDF) digestibility was greater for dogs fed the FSE diet (P < 0.05) in contrast with dogs fed the CT and SE diets, whereas dogs fed FP diets had intermediate TDF digestibility, but not different from all other treatments. Fecal acetate and propionate concentrations were greater (P < 0.05) for dogs fed FP and FSE diets. Fecal concentrations of isobutyrate and isovalerate were greater for dogs fed CT (P < 0.05) compared with dogs fed the other three treatments. No shifts in fecal microbial richness and diversity were observed among dietary treatments. Overall, the data suggest that dietary supplementation of fiber and prebiotic blend was well tolerated by dogs, did not cause detrimental effects on fecal quality or nutrient digestibility, and resulted in beneficial shifts in fecal metabolites that may support gut health.

An integrated study on the effect of renal diet on mineral metabolism, fibroblast growth factor 23 (FGF-23), total antioxidant capacity, and inflammatory markers has not been performed previously. In this study, we evaluated the effects of renal diet on mineral metabolism, oxidative stress and inflammation in dogs with stage 3 or 4 of chronic kidney disease (CKD). Body condition score (BCS), muscle condition score (MCS), serum biochemical profile, ionized calcium (i-Ca), total calcium (t-Ca), phosphorus (P), urea, creatinine, parathyroid hormone (PTH), FGF-23, interleukin 6 (IL-6), interleukin 10 (IL-10), tumor necrosis factor alpha (TNF-α) and total antioxidant capacity (TAC) were measured at baseline (T0) and after 6 months of dietary treatment (T6). Serum urea, P, t-Ca, i-Ca, PTH, FGF-23, IL-6, IL-10, TNF-α and TAC measurements did not differ between T0 and T6. Serum creatinine (SCr) was increased at T6 and serum PTH concentrations were positively correlated with serum SCr and urea. i-Ca was negatively correlated with urea and serum phosphorus was positively correlated with FGF-23. Urea and creatinine were positively correlated. The combination of renal diet and support treatment over 6 months in dogs with CKD stage 3 or 4 was effective in controlling uremia, acid–base balance, blood pressure, total antioxidant capacity, and inflammatory cytokine levels and in maintaining BCS and MCS.

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 y; 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&lt;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.

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