J. Gen. Appl. Microbiol., 53, 191–200 (2007)

The gastrointestinal tract of animals harbors microbial flora. Lactic acid bacteria and bifidobacteria are members in the flora of many animals. The organisms have been reported to have several health-promoting effects on host animals (Nagao et al., 2000; Ouwehand et al., 2002), and thus the flora of the organisms in feces and/or gastrointestinal contents have been actively studied on many animals (Gueimonde et al., 2004; Mitsuoka and Kaneuchi, 1977; Walter et al., 2001). Yuyama reported a beneficial aspect of lactic acid bacteria for horses. The administration of the living cell mixture of Lactobacillus salivarius, L. reuteri, L. crispatus, L. johnsonii, and L. equi prevented diarrhea and enhanced the growth of horses treated with probiotics, compared with placebo-controlled horses (Yuyama et al., 2004). A negative aspect of lactic acid bacteria was that Streptococcus bovis and five different Lactobacillus spp. affected horse laminitis (Bailey et al., 2003; Mungall et al., 2001). Bifidobacteria are predominant in gastrointestinal microbial flora of many animals (Mitsuoka and Kaneuchi, 1977), and promote the health of hosts, such as prevention of diarrhea, shortMolecular profiling of Lactobacillus, Streptococcus, and Bifidobacterium species in feces of active racehorses