Physiological, antimicrobial, intestine morphological, and immunological effects of fructooligosaccharides in pigs

In pig nutrition, there are some periods when natural alternatives toantibiotics are more required, such as during suckling and weaning.Fructooligosaccharides (FOSs) are a group of prebiotics applied as feedingredients in animal nutrition since their positive effects on growthperformance, immunological parameters, intestinal microbiota, and gutmorphology are reported. Accordingly, FOS may be candidate molecules toimprove the mentioned properties in pigs. Previous studies defined FOS as inhibitingthe activity of pathogens and increasing the colonization of beneficialbacteria in the gut, although metabolites of FOS decreased the intestinal pHvalue. Beneficial effects on digestive-enzyme activities and on proteindigestion were determined in some studies. All of the three types of FOS(inulin, oligomeric fructans, and short-chain FOSs) promoted the microbialcomposition of the gut by increasing the colonizations of Lactobacillus, Bifidobacterium, andPrevotella genus. FOS also affected the immune response directly and indirectly andincreased vaccine-specific IgA, serum IgG, and IgE levels. Moreover, FOSenhanced the activation of T cells and altered the secretions of somecytokines. Levels of vaccine-specific IgG could not be increased after FOSsupplements. In most cases, FOS modified intestinal morphologicalparameters, such as longer villi, villus-height-to-crypt-depth ratio, andthicker mucosa, which could suggest better absorptive functions. Results arecontradictory on growth performance, which might be influenced by the chemicalstructure, the duration, and the dose of FOS, so further studies arerequired. This review aims to gather information regarding immunological,antimicrobial, intestine morphological, and growth performance properties offructooligosaccharides in pigs.