228. Effects of Dietary Yeast Glycobolite Supplementation on Fecal Quality, Gut Permeability, and Indices of Hydration in Training Sled Dogs.

Abstract Intense exercise experienced by sled dogs can lead to increased water turnover, compromised intestinal permeability and reduced fecal quality. The objective of this study was to assess the effects of dietary yeast glycobolite supplementation on fecal quality, gut permeability and indices of hydration [serum osmolality (Osmo), hematocrit (Hct), total protein (TP), and sodium (Na)] in training sled dogs. Twenty-two client-owned Siberian huskies and 2 Alaskan huskies (13 females; 11 males) with a mean (±SD) age of 5.6 ± 2.7 yr and body weight (BW) of 21.9 ± 2.7 kg were used. Dogs were blocked by sex, age, BW and training history and allocated into two diet groups: an extruded commercial control diet (Ctl; n = 12) or the Ctl diet top-dressed with yeast glycobolite at 0.1 g/kg BW daily (Trt; n = 12). Eight dogs underwent a low-intensity exercise regimen (<16 km/week) and 16 dogs a high-intensity exercise regimen (<50 km/week) through a 10-week incremental training period. Each week, BW was recorded, and food allotments were adjusted to maintain BW. Gut permeability was assessed using chromium-labeled ethylenediamine tetra-acetic acid (Cr-EDTA) on weeks -1 and 10. Blood samples were collected pre-marker administration and at 8 post-administration timepoints over 6 h. Incremental area under the curve (I-AUC) was calculated for Cr-EDTA concentrations. Fasted blood samples were collected to measure indices of hydration on weeks -1, 1, 5 and 10 and stool collection and scoring were conducted on the same weeks. All data were analyzed using PROC GLIMMIX of SAS with dog as a random effect and week, diet and training intensity as fixed effects, and week as a repeated measure. Fecal scores were analyzed using PROC FREQ to compare fecal quality. Significance was declared when P ≤ 0.05 and a trend when 0.05 < P ≤ 0.10. No overall diet effect on fecal scores was detected (P = 0.123), but Trt dogs had lower fecal scores at week 1 relative to Ctl (P = 0.025). Fecal scores increased by week in both diet groups (P = 0.003). I-AUC for Cr-EDTA decreased across weeks (P = 0.004), suggesting reduced gut permeability with training, but the change from week -1 to week 10 did not differ between Ctl and Trt dogs (P = 0.143). No diet effect was observed for any hydration indices across the study (P > 0.10), but all indices decreased by week (P ≤ 0.05). At week 10, TP tended to be higher in Trt dogs compared to Ctl (P = 0.065). Yeast glycobolite supplementation improved fecal quality at the onset of exercise-induced stress and may maintain TP at peak training but did not influence indices of hydration or gut permeability beyond effects from the 10-week training period in sled dogs.