Dietary fiber (DF) was first described in 1953 in relation to pregnancy toxemia in women between 1940 and 1950. Interestingly, today we are still finding relationships between DF and reproductive performance. For example, in sows DF has been linked to satiety, insulin sensitivity, reducing constipation and farrowing duration, and improving milk yield during lactation. In addition, beneficial effects of DF on microbial fermentation, gizzard function, intestinal morphometry, immune function, satiety, and behavior in layers, breeders, or broilers have been observed. However, the beneficial effects of DF are not unequivocal. DF is also considered an anti-nutrient with impacts on digesta viscosity, entrapment of nutrients and thereby reducing digestibility, and diluting the nutrient density of the diet. Some of this confusion is related to the complexity of DF and the lack of precision when using the term DF. As analytical techniques improve, so does our knowledge of DF and the major components that are described within the term (i.e. total, soluble, and insoluble non-starch polysaccharides [NSP], and lignin) and their concentration within cereals, protein meals, and by-product meals used in animal feed. The use of accurate, reliable, and cost-effective near-infrared (NIR) spectroscopy to measure the NSP and lignin content in feed ingredients will enable real-time, accurate feed formulation, targeting ingredient concentrations to provide beneficial concentrations of these fractions in the diet, as well as improve enzyme efficacy and recommendations. This means diets could be formulated to include feed ingredients or additives with specific NSP or oligosaccharide fractions to promote beneficial bacterial fermentation, gut function through production of short-chain fatty acids, and minimize protein fermentation and pathogenic bacterial growth. As well as measuring the benefits of the DF fractions on animal performance and microbial populations, the use of non-invasive biomarkers may provide an insight into the effects of DF fractions on intestinal integrity, nutrient utilization, and immune function and resilience, especially under enteric challenges such as coccidiosis, E coli, and Clostridium perfringens. As our understanding and ability to measure DF and its fractions improves, so does our ability to harness the beneficial effects of DF, mitigate detrimental effects with optimal feed formulations, exogenous enzymes, and feed additive supplementation, and maintain intestinal homeostasis and function for optimal performance.

Walk, C. 2025. Fiber and performance: connecting the dots for optimal performance. 2025 Poultry Science Association Annual Meeting, Abstract 577S.