Pigs are a popular form of livestock, with high economic values in food, clothing, cosmetics, and medical industries. More than one billion pigs butchered each year worldwide, and the main consuming countries are in Asia as dietary food source. The weaning stage is considered one of the most critical periods in swine production, where piglet performance can be seriously affected and where they are predisposed to the overgrowth of opportunistic pathogens [1]. Piglet diarrhea or "scour" can be common at both the neonatal and the post-weaning stages. It is a common cause of mortality and is often closely associated with poor hygiene, inappropriate husbandry (e.g., early weaning), stressful environment and inappropriate feeding factors. Poor hygiene can lead to overgrowth of pathogenic bacteria in the environment. Escherichia coli (E. coli) strains are common within the first week of life, and again in the first week after weaning. The weaning process increases the stress on piglets, and thus their susceptibility to viral and bacterial infections. Diarrhea in these older piglets tends to be less severe, and mortality rates lower than in pre-weaning piglets. Potential sources of diarrhea at this stage include E. coli, Rotavirus, TGE (Transmissible gastroenteritis), salmonellosis, Campylobacter and Brachyspira hyodysenteriae [2]. Therefore, uses of antibiotics or medications are almost inevitable during the weaning process in the past. However, due to the increasing problem of drug resistance of bacteria, the use of antibiotic growth promoters for prevention of diarrheal diseases in piglets has been banned since 2006 [3]. Coincidentally, due to the concern of environmental and food safety, the use of medicinal zinc oxide (ZnO) must be phased out by 2022 [4]. Thus, alternative strategies are urgent needs to prevent diarrhea and promote the health in weaner piglets. Various natural