The relationship between physico-chemical properties of fibre and their effects on the gut weight of chickens

Two experiments were conducted to observe the effects of different types of soluble and insoluble non-starch polysaccharides (NSP) on digesta viscosity and gastrointestinal weight of laying hens. In experiment 1, four diets were offered, viz, wheat-based (wheat), millrun-based (millrun), barley-based (barley), and barley diet with added enzyme (barley + enzyme). Gut viscosity was high (P<O.OI) on birds fed wheat and barley diets. Birds fed the barley diet had a higher (P<0.05) caecal weight. Addition of enzyme to the barley diet reduced (P<O.Ol) jejunal viscosity and caecal weight. There was no significant effect of diet on feed intake (FI) and egg production. In experiment 2, six different diets were used. The first four diets were: wheat-based (wheat); oat-based (oats), millrun-based (millrun), and rice hull-based (ricehull). Diets 5 and 6 were the wheat diet plus 0.2% manno-oligosaccharides (MOS) and 0.2% fructo-oligosaccharides (FOS), respectively. There was no effect of diet on gut viscosity and egg production. The oat diet had a higher (P<0.05) FI and gizzard weight. Soluble NSP and physical structure of oats seemed to be responsible for the increase in FI and gizzard weight.