Role of insoluble non-starch polysaccharides in poultry nutrition

This paper reviews and presents new evidence for the role of insoluble fibre (nonstarch polysaccharides and lignin) in poultry nutrition. Insoluble fibre affects gut functions and modulates nutrient digestion. Thus, digestibility of starch is higher and digesta passage rate faster when a moderate level of insoluble fibre is present in the diet. The effect of insoluble fibre on gut functions stems from its ability to accumulate in the gizzard, which seems to regulate digesta passage rate and nutrient digestion in the intestine. Furthermore, there are indications that diets high in insoluble fibre are preventative of cannibalism outbreaks in laying hens. It is hypothesized that with nutrients disappearing from the lumen faster and digesta moving through the gut quicker, birds spend longer time eating and less time pecking each other. However, the ability of insoluble fibre to exert these effects appears to be related, in part, to particle size as fine grinding diminishes its stimulatory influence on the gizzard. More research is underway on the physical and chemical structure of fibre on gut functions, nutrient digestion and bird behaviour.