WHAT ARE FRUCTO-OLIGOSACCHARIDES OR FOS ?

Roles of dietary fiber

Searching for high-digestibility diets leads to lower the fibrous part of the food. However, dietary fibers are undispensable in dog’s and cat’s diets:

• on one hand, they stimulate the digestive transit. This motor role is mainly ensured by “ inert ” fiber, like cellulosis. This type of fiber is also called “ non-fermentescible fiber ”, because they cannot be used as a source of nutrients by bacteria ;
• on the other hand, they “ feed ” the intestinal bacterial flora, and so, they supply to the intestinal cells the energy they require. Actually, 70 % of the energy used by these cells come from products generated by bacterial fermentation in the large intestine. When there is no fermentescible fiber in the diet, the large intestine cells become progressively atrophied.

Fructooligosaccharides = highly fermentescible fibers

Fructo-oligosaccharides or FOS are special carbohydrates, that can be classified in the category of fermentescible fibers. Non-digested, but rapidly fermented by the bacterial intestinal flora, they generate the production of short-chain fatty acids or SCFA (acetate, propionate and butyrate), necessary to the maintenance and the renewal of the cells that line the large intestine.

Index of in vitro fermentation of the main fiber sources used in petfood (= total production of SCFA in 24 h in mmol/g of organic matter) Source of fibers index of fermentation mmol / 24 h /g of organic matter Cellulosis 0,2 Peanut hulls 0,9 Arabic gum 1,0 Psyllium 1,4 Soya husks 1,4 Beet pulp 2,5 Fructooligosaccharides 5,7 (From Sunvold)

FOS = prebiotics

FOS are in favour of the settlement of a beneficial bacterial flora (bifidobacteria and lactobacillus), whose positive effects on the health of the digestive tract are now well-known:

• inhibition of the growth of pathogenic bacteria
• stimulation of the immunitary system
• positive effect on digestion and absorption of nutrients
• synthesis of vitamines undispensable to the metabolism (ex: folic acid).

Presence of fructooligosaccharides Stimulation of the growth bifidobacteria and lactobacillus Production of lactate (39 %), acetate (36 %), propionate (19 %) and butyrate (6 %) Acidification of the intestinal lumen Limitation of the proliferation of potentially dangerous bacteria (Clostridies, Escherichia coli, Salmonella…) Protection of the digestive tract: “ barrier effect ” (From Reinhardt)

However, the FOS incorporation level should not go over 2 % in the food, or they promote the production of rather loose or liquid stools. This is due to their almost total degradation in the large intestine, in association with the fact that they encourage the bacterial proliferation.

In order not to deteriorate the quality of the stools, FOS must be accompanied by another source of fiber, less likely to be fermented by the flora, i.e beet pulp.

Conclusion

FOS are included in:

• all the Canistar/Felistar products as in Junior and Mature Adult products of VetSize range,
• in Starter, product recently launched for the weaning of puppies and for feeding pregnant / lactating bitches,
• in Maxi Energy.

Donated by the Borg Cardona and Co. Ltd. visit Borg Cardona website