Design of an in vivo model system to assess enzyme supplementation by lactic acid bacteria: the case of alpha-galactosidase delivery by lactobacilli

CLIER, F.; LEBLANC, J.G.; SAVOY DE GIORI, G.; JUILLARD, V.; SESMA, F.; RABOT, S.; PIARD, J.-C.

Egmond aan Zee, Holanda

Simposio; The 8th Symposium on Lactic Acid Bacteria; 2005

Federation of European Microbiological Societies (FEMS) , Netherlands Society for Microbiology (NVvM).

 Beside its excellent nutritional status, soy contains high level of the alpha-galactosides raffinose and stachyose. These sugars are digested neither by man nor by monogastric mammals, due to a natural alpha-galactosidase (alpha-Gal) deficiency. Consequently, soy-borne alpha-galactosides reach the large intestine where they are fermented by the resident microbiota, among which are gas-producing microorganisms. The subsequent important gas production induces gastrointestinal disorders including flatulence, nausea and diarrhea. To circumvent these soy consumption-associated drawbacks, we tested the ability of alpha-Gal+ lactobacilli to degrade alpha-galactosides in the small intestine of rats. A model system has been developed making use of rats monoassociated with a commensal Clostridium butyricum strain and of respiratory chambers in which the specific gases produced by colonic fermentation can be monitored. This model system was validated by intragastric inoculation of the rats with either native soymilk or soymilk in which alpha-galactosides had been previously degraded by enzymatic treatment. Native soymilk induced a significant gas production in rats while treated soymilk did not. Using this model, we showed that live preparations of alpha-Gal+ lactobacilli strains that were co-administered intragastrically with the native soymilk were able to alleviate the flatulence. This suggests that appropriate lactic acid bacteria are able to supplement alpha-Gal deficiencies of the host. This model system will be used to investigate thoroughly the effects of various cellular and molecular parameters on the efficiency of the targeted biological activity, paving the way for the development of a dedicated LAB strain.