The use of prebiotics based on oligo- and disaccharides in poultry farming - a mini review

In meat poultry farming, technologies of chick feeding and growing allow getting a carcass ready for sale for a short period (35-42 days). Such a high growth rate is due not only to proper feeds, but also to various feed additives (E.V. Yaskova et al., 2015). The ban of antibiotics-based growth stimulants in the European Union determines the search for alternative natural substances that provide similar effects. A promising group of such substances is prebiotics (D.S. Uchasov et al., 2014) which provide an increase in the efficiency of nutrient utilization, have a positive effect on the blood morphobiochemistry, poultry natural resistance, productivity, meat quality and economic efficiency (I.V. Chervonova, 2016). This mini review systematizes data on disaccharides as potential modulators of the intestinal microbiome profile and growth stimulants of broiler chickens when antibiotics are rejected. Several groups of substances with a prebiotic effect are widely used as ingredients of premixes and compound feeds. Currently, mono-, oligo-, di- and polysaccharides are being studied as promising prebiotics. The search for new biologically active substances with a multifactorial effect on broiler chickens is relevant. Feed additives used in poultry farming contain components with prebiotic properties. These components are oligo- and disaccharides (maltose, lactose, sucrose, lactulose, fructooligosaccharides, galactooligosaccharides, soy oligosaccharide), polysaccharides (cellulose, pectins, inulin, dextrin, etc.), monosaccharides (xylitol, raffinose), amino acids (arginine, valine, glutamic acid), antioxidants (vitamins A, E, C, carotenoids, selenium salts), organic acids (citric, acetic, propionic), plant and microbial extracts (carrot, corn, rice, garlic, potato, yeast), algae extracts. The prebiotic preparations based on organic acids (lactic, lemon, fumaric, formic) and lactulose are mostly used (E.V. Shatskikh et al., 2008). Natural prebiotics include fructans (fructooligosaccharides, short-chain fructooligosaccharides, oligofructose, inulin), mannooligosaccharides from Saccharomyces cerevisae , soy oligosaccharides and galacto- or transgalactooligosaccharides (D. Charalampopoulos et al., 2009). Lactulose, a synthetic structural isomer of lactose (4-O-β-D-galactopyranosyl-D-fructofuranose) consists of fructose and galactose linked by a β-1,4-glycoside bond. It is an odorless white crystalline substance highly soluble in water. Synthetic disaccharides are 1.5 times sweeter than lactose and can crystallize from an alcoholic solution. β-Glycoside bonds in disaccharides are not hydrolyzed by digestive enzymes (H. Rutloff et al., 1967). Therefore, disaccharides pass through the stomach and small intestine without degradation and, being unchanged, reach the large intestine (L.N. Skvortsova, 2010). In addition, lactulose has the highest index of prebiotic activity. It stimulates lacto- and bifidobacteria in the large intestine, promotes the restoration of normal microbial profile, declines pH in the colon, inhibits conditionally pathogenic microbes, improves the absorption of nutrients, and increases immunity (V.S. Buyarov et al., 2012; V.S. Buyarov et al., 2015). Commercial feed additives based on oligo- and disaccharides as a prebiotic component may contain various substances, including trehalose, lactulose, and inulin. All of them have restorative, immunostimulating, therapeutic and prophylactic properties, contribute to the restoration of intestinal microbial community, change the final microbial products, and prevent the occurrence of inflammation and infectious diseases (C. Schumann, 2002; K.M. Tuohy et al., 2002; J.H. Cho et al., 2014).