Prebiotics are non-digestible oligosaccharides that can selectively stimulate the growth of beneficial bacterial in the hindgut (Gibson and Roberfroid, 1995). To be consider a prebiotic, the oligosaccharides must be resistant to digestion and absorption, be fermented in the hindgut, and selectively stimulate the growth of non-pathogenic bacteria in the hindgut (Gibson et al., 2004). Bifidobacteria and lactobacilli growth is beneficial for gut health due to short chain fatty acids (SCFA) production. Short chain fatty acids reduce the pH, eliminate enteric pathogens, and also stimulate gut development and integrity. Essentially, prebiotics serve as substrates for fermentation and production of SCFA by beneficial bacteria.
The most common prebiotics are inulin, lactulose, fructo-oligosaccharides, and transgalacto-oligosaccharides, which are considered to be easily fermentable carbohydrates by beneficial bacteria in the hindgut. Prebiotics have been found to be efficient against pathogenic bacteria in pigs (Tran et al., 2016) and most prebiotic effects have been consistent at the gut level (van der Aar et al., 2017). However, results in performance have been inconsistent with use of prebiotics, probably due to differences in stage of production, health status, and husbandry practices (Jacela et al., 2010a; Liu et al., 2018).