Importance of considering non-starch polysaccharide content of poultry diets

The contribution of dietary fibre in feed ingredients is still inadequately accounted for during feed formulation, despite extensive evidence of its impact on bird performance, litter quality and digestibility of other nutrients, and its high level in plant-derived feed ingredients. True dietary fibre is defined as the total quantity of non-starch polysaccharides (NSP) and lignin. In contrast to other nutrients, NSP vary substantially in composition, both among different feed ingredients and among batches of the same ingredient. Consequently, NSP display variable characteristics in final feeds. NSP have traditionally been recognised as anti-nutritive, through their impact on digesta viscosity and as a nutrient diluent in poultry rations. However, more recently, there is growing interest in their capacity to stimulate gastrointestinal function, improve gut health and act as a source of energy, partially via prebiotic properties. Recent developments in methods for measuring NSP have increased precision when estimating the dietary fibre component of feed ingredients and diets, yet there is still a lack of application of NSP values in both research and industry diets for poultry. Determining the fate of fibre post-ingestion is challenging, due to the complexity of its structural components and limited understanding about how fibre interacts with other dietary nutrients within the intestinal tract environment. The aim of this review is to highlight the importance of considering NSP values when formulating poultry rations, based on evidence from scientific studies presenting the direct impact dietary NSP has on gastrointestinal health and bird performance.