Galactooligosaccharides reduce infection caused by Listeria monocytogenes and modulate IgG and IgA levels in mice

The effect of galactooligosaccharides (GOS) on infection caused by Listeria monocytogenes and levels of immunoglobulins (IgG and IgA) was studied in mice. β-Galactosidase extracted from native strains of Streptococcus thermophilus was used for GOS production. Seventy two mice were divided in to four groups; normal control group (NCG), pathogenic control group (PCG), and test groups 1 and 2. NCG and PCG were fed with standard rodent diet and the remaining groups were fed with standard diet supplemented with GOS (6% of diet). Six mice from each group were sacrificed on days 2, 5 and 8 post-challenge. Lower counts of L. monocytogenes were observed in the intestine, liver and spleen of groups fed with GOS. Feeding of GOS augmented the IgA (small intestine) and IgG (blood) concentration in mice. Findings of the study indicate that GOS have potential to modulate the immune system along with a protective effect against L. monocytogenes.