Indigenous lactic acid bacteria from bovine feces as dual-purpose inoculants: A review of isolation, probiotic characterization, and napier grass silage quality under tropical conditions

บทคัดย่อ

Securing enough roughage during Thailand's dry season largely depends on Napier grass (Pennisetum purpureum) silage. However, ensiling this forage is quite challenging. Its naturally low water-soluble carbohydrates and high buffering capacity, along with intense tropical heat, make the silage vulnerable to rapid aerobic spoilage. To make things worse, standard commercial lactic acid bacteria (LAB) inoculants, which are usually taken from temperate regions, often do not work well in such hot and humid conditions. This review looks at the potential of using indigenous LAB sourced directly from ruminant feces as a local solution. These microbial strains have co-evolved in the harsh environment of the gastrointestinal tract, so they naturally show strong tolerance to acid and bile, heat resistance, and unique antimicrobial properties. While existing studies from other tropical areas show that ruminant-adapted LAB can improve silage fermentation and stability after opening, there is almost no empirical data on Thai bovine-fecal LAB. There is also growing interest in the "dual-purpose" role of these indigenous strains, which could serve as both silage inoculants and direct-fed rumen probiotics. However, recent in vitro tests are merely promising, and this dual function is still just a hypothesis that requires thorough in vivo testing. To clarify a path forward, this paper highlights critical research gaps. It argues that systematic strain-level characterization and field-based comparisons with commercial additives are urgently needed. Building a solid evidence base is essential before promoting these strains as a reliable strategy for tropical feed security.