Figure 1.

The interaction between intestinal microbiota and probiotics and prebiotics (by figdraw). The interaction between probiotics and intestinal microbiota tends to be antagonistic. Probiotics will compete with the intestinal flora for nutrients and inhibit the colonization of the intestinal microbiota through secreting antimicrobial peptides and bacteriocins. On the other hand, probiotics or intestinal microbiota will metabolize the prebiotics to produce organic acids (e.g., short-chain fatty acids and lactic acid), which lower the pH in the intestinal tract. Eventually, the number of beneficial bacteria increases, the number of pathogenic bacteria decreases, and the intestinal microecology reaches balance with the action of low pH value and substances such as antimicrobial peptides and bacteriocins.