Effects of dietary short-chain fructooligosaccharides on the intestinal microflora of horses subjected to a sudden change in diet.

Prebiotic compounds, such as short-chain fructooligosaccharides (scFOS), have been shown to improve health, welfare, or both, in several species, but few studies have been conducted in horses, despite the sensitivity of their hindgut microflora. We hypothesized that prebiotic oligosaccharides, known to be able to stabilize the intestinal microflora in other species, would be of importance in horses. Our study was designed to evaluate the effect of scFOS supplementation on the equine intestinal microflora and to assess its effectiveness in reducing hindgut microbial disturbances related to sudden diet changes. Four adult geldings were allotted by weight into 2 groups and assigned to diets with and without (control) scFOS supplementation for 21 d in a crossover design. Cecal and colonic contents were collected through cannulas to assess the effect of an abrupt incorporation of barley in the diet of horses on microbial populations and fermentation variables. The addition of barley to the control diet caused substantial changes in the colonic microflora, such as increases (P < 0.05) in the concentration in total anaerobes, lactobacilli, streptococci, and lactate-utilizing bacteria. The scFOS supplementation reduced the barley intake-related changes. In contrast to the control diet, Lactobacillus and Streptococcus populations did not increase. Although the colonic d-lactate concentration increased (P < 0.05) after the meal of barley in the control group, it did not accumulate with scFOS supplementation. These data indicate that a scFOS supplementation would be effective in reducing disruptions of the microbial populations in the equine hindgut under stressful situations like acute starch overloads.