Abstract: As a kind of animal feed additive,natural plant extracts with various bioactive ingredients,including alkaloid,saponin,polysaccharide,polyphenols,volatile oils,、etc,are ideal substitutes of antibiotics.They have the function of improving animal immunity and regulating the physiological metabolism.At the same time,natural plant extracts have no drug residues and drug resistance.This paper focuses on the promoting intestinal health,regulating immunity,antioxidation,hormone stimulation,anti-stress and rumen fermentation to explore the regulation mechanism of the natural plant extracts in healthy breeding.

Key words: plant extracts, alternative antibiotics, healthy breeding