The effect of site of starch digestion on performance of broiler chickens

A growth trial with 420 broiler chickens (35 per experimental unit) was conducted in order to evaluate whether bird performance (Days 0–38) is affected by site of starch digestion. Two diets were formulated with the same calculated apparent metabolisable energy, digestible lysine, and digestible starch content. The diets contained starch sources with known amounts of rapidly digestible starch (RDS, starch digested until the posterior jejunum) and slowly digestible starch (SDS, starch digested in the ileum). Diets were either high (H) or low (L) in SDS content. RDS and SDS contents were 298 and 52 g/kg for the H diet and 345 and 7 g/kg for the L diet, respectively. Starch in the H diet was supplied by waxy maize, peas and sorghum and starch in the L diet was supplied by tapioca and common maize. Birds receiving the H diet consumed more feed (P<0.10), grew faster (P<0.01) and had a lower feed conversion ratio (P<0.01) than birds receiving the L diet. The results suggest that broiler chickens perform better on diets containing a minimal amount of slowly digestible starch. Future experiments are necessary to investigate the relation between amount of slowly digestible starch and performance of broiler chickens.