PSVII-35 Fecal innocula from horses fed DigestaWell® Fiber improves in-vitro dry matter digestibility of commercial hays in horses

Abstract

Abstract Enhanced microbial activity in the equine hindgut increases nutrient availability, reduces fecal waste, and adds value to low quality forages. The encapsulated dietary supplement DigestaWell® Fiber (DF; fibrolytic cofactors, methionine, B vitamins) has been shown to improve in-vitro digestibility measures of common hays fed to horses. However, its in-vivo effect on dry matter (DMd) and ADF digestibility (ADFd) is unknown. The objectives of this study were to test whether fecal innocula from horses fed DF would result in improved DMd or ADFd relative to innocula from unsupplemented horses consuming alfalfa or coastal bermudagrass hays. Utilizing a crossover design, four Quarter Horse mares were fed 2% BW daily alfalfa hay (AF; 32.8% NDF, 27.1% ADF) or coastal bermudagrass hay (CB; 63.2% NDF, 35.4% ADF), with or without oral DF supplementation (32 g/d), for 14d. Fresh feces were collected to serve as inoculum in an ANKOM Daisy II incubator at 37.5°C to determine in-vitro DMd and ADFd at 48h or 72h. Forage samples were run in triplicate. Data were transformed to approximate normality, then analyzed using a repeated measures mixed model in SAS with main effects of forage, treatment, incubation time, feeding period, and significant interactions. Across forages and incubation times, in-vivo DF supplementation improved DMd (P < 0.01). Across incubation times, DF improved ADFd of both AF (P < 0.0001) and CB (P = 0.04), but not DMd. Across forages, DF improved both DMd and ADFd at 48h (P < 0.001 and P = 0.003, respectively) but not at 72h (P = 0.29 and P = 0.27, respectively). Taken together, and combined with previous findings, these results provide further evidence that DF improves forage digestibility, presumably due to improved microbial fermentation in the equine hindgut.