Mechanism of Action of Plant Extracts in Preventing Post-Weaning Diarrhea in Piglets: A Review

Post-weaning diarrhea (PWD) in piglets is a common multifactorial disease in global swine production. Traditional prevention and control strategies relying on high-dose zinc oxide and antibiotics face limitations due to antimicrobial resistance and environmental concerns. This review systematically elucidates the mechanisms of action of plant extracts as alternative interventions against PWD, focusing primarily on categories such as polysaccharides, polyphenols, essential oils, and alkaloids. This review discusses how plant extracts exert their effects through various mechanisms, including improving feed intake, enhancing antioxidant and immune capacities, modulating gut microbiota, repairing intestinal barrier function, and inhibiting pathogens-to alleviate diarrhea induced by weaning stress and pathogenic infections. The findings indicate that plant extracts offer advantages such as multi-target effects, natural origin, and a low propensity for inducing resistance, highlighting their promising potential as alternatives to conventional additives. However, challenges related to compositional complexity, stability, and bioavailability require further investigation and optimization.