Fructooligosaccharides (FOS) are short-chain prebiotic fibers used in pet food to support intestinal health. They are not digested in the upper gut and are instead fermented by beneficial microbes in the colon, producing short-chain fatty acids. FOS is particularly valued for helping support Bifidobacterium and Lactobacillus populations.
Identity Card
| Chemical Class | Oligosaccharide |
| Source | Chicory root, sugar cane |
| Function | Prebiotic / gut support |
| Chain Length | Short-chain fructose units |
| Suggested Use | Low inclusion |
| Debate Level | Low |
VetKriter Assessment
4/5 Quality Score
FOS is a useful functional ingredient with solid prebiotic value. In well-formulated amounts it can support microbial balance and intestinal physiology, although excessive use may contribute to gas or softer stools.
FOS vs Inulin vs MOS
| Prebiotic | Source | Main Action | Fermentation Speed |
|---|---|---|---|
| FOS | Chicory, sugar cane | Supports bifidobacteria | Fast |
| Inulin | Chicory root | Supports bifidobacteria and mineral absorption | Moderate |
| MOS | Yeast cell wall | Pathogen binding and mucosal support | Lower direct fermentation |
| GOS | Lactose-derived | Supports bifidobacteria | Fast |
Related VetKriter Tools
References
- Flickinger, E. A., Van Loo, J., & Fahey, G. C. (2003). Nutritional responses to inulin and oligofructose in domesticated animals. Critical Reviews in Food Science and Nutrition, 43(1), 19-60.
- NRC. (2006). Nutrient Requirements of Dogs and Cats. National Academies Press.