4.2. Fecal microbial populations
It is generally accepted that the overgrowth of coliform bacteria (the potential pathogens for animals and humans) would cause diarrhea, and the supplemental probiotic could help to inhibit the development of potential intestinal pathogens and decrease the diarrhea incidence (Melin et al., 2004; Shu et al., 2001). For example, Huang et al. (2004) reported that supplemental probiotics decreased counts of E. coli and aerobic bacteria, increased counts of Lactobacillus sp. and anaerobic bacteria in the gastrointestinal tract, and decreased diarrhea in weaned pigs. Ross et al. (2010) reported that pig fed with lactobacilli positively