Effect of dietary supplementation with fructo-oligosaccharides on fecal flora of healthy cats.

Objective: To investigate changes in the fecal flora of healthy cats after dietary supplementation with fructo-oligosaccharides (FOS).
Animals: 12 healthy, barrier-maintained, specific-pathogen-free-derived adult cats.
Procedure: Fresh fecal samples for quantitative and qualitative bacteriologic examination were collected from each cat after ingestion of a replete dry (basal) diet for a minimum of 8 weeks. The diet was then supplemented with 0.75% FOS, and another fecal sample was collected after 12 weeks.
Results: Mean +/- SD fecal aerobic, anaerobic, and total bacterial counts (log10 colony-forming units per gram of feces [CFU/g]) did not differ significantly between diets (8.3 +/- 0.8, 9.2 +/- 0.6, 9.4 +/- 0.4, respectively, for the basal diet; and 8.4 +/- 0.8, 9.7 +/- 0.7, and 9.8 +/- 0.7, respectively, for the FOS diet), although there was a trend for higher numbers of anaerobes and total bacteria associated with the FOS diet. Members of the genus Bacteroides, Clostridium perfringens, Escherichia coli, lactobacilli, and Plesiomonas shigeloides were the most prevalent bacteria isolated. Compared with samples from cats fed basal diet, there was a trend for increased mean counts of lactobacilli (P = 0.02) and Bacteroides spp (P = 0.05) after FOS supplementation, and a trend for decreased mean numbers of Escherichia coli (P = 0.03) and Clostridium perfringens (P = 0.08) to be associated with the FOS diet. Supplementation of FOS resulted in a median 164-fold increase in numbers of lactobacilli, 13.2-fold increase in Bacteroides spp, 98% reduction in numbers of C perfringens, and 75% reduction in numbers of E coli.
Conclusions: Supplementation of the diet with FOS resulted in alteration of the fecal flora of cats.