Role of supplemental oligosaccharides in poultry diets

Abstract

<p>Commercial application of oligosaccharides in poultry diets as alternatives to antibiotics has increased in recent years. The primary oligosaccharides used in poultry diets are xylo-oligosaccharides (XOS), fructo-oligosaccharides (FOS), mannan-oligosaccharides (MOS) and galacto-oligosaccharides (GOS). Oligosaccharides are produced by enzymatic hydrolysis of polysaccharides, or direct extraction from plant materials. Numerous research trials have examined the effects of oligosaccharide supplementation on both broiler and laying hen performance and health, with supplementation levels ranging from 2 mg/kg to 20,000 mg/kg. Positive effects of oligosaccharides include improved nutrient digestibility, intestinal health morphology, immune responses, and relative abundance of gut microbiome populations, which translate into improvements in production performance. However, some studies present a lack of positive effects of oligosaccharides. This absence of consistency between studies appears to be attributable to the fibre content and composition of the test diets. Additionally, application of non-starch polysaccharide-degrading enzymes into poultry diets generates oligosaccharides in the birds' gastrointestinal tract, but bird responses to these enzymes are inconsistent. This suggests that it may be more beneficial to supplement oligosaccharides directly into the diet than to rely on <i>in situ</i> manufacture by the bird. Feeding combinations of oligosaccharides with enzymes or probiotics has been shown to have positive synergistic effects, but there is a scarcity of data in this area, particularly in laying hens. This review examines recent research in oligosaccharide application in broiler and laying hen diets, and identifies areas in this field that warrant further investigation.</p>