Protective

function

Structural function

Metabolic function

1.Pathogen displacement.

2. Nutrient & receptor competition with pathogen

3. Production of antimicrobial factors e.g. bacteriocins, lactic acids .

1. Barrier fortification.

2. Induction of IgA Antibody

3. Immune system development

1. Control intestinal epithelial cell differentiation & proliferation.

2. Metabolize dietary carcinogens.

3. Synthesize vitamins e.g. vit-K, biotin, folate.

4. Ferments non-digestible dietary residue

5. Iron absorption

6.Salvage of energy.