Research note: a consistent low starch digestibility observed in pelleted broiler chicken diets containing high levels of different wheat varieties

Ileal digestibility in 21-day-old broiler chickens given cold-pelleted diets containing 770 g/kg DM of four different varieties of wheat, barley or oats was studied. The major objective was to study variation in starch digestibility of wheat diets, and to compare digestibility between grain species. Titanium dioxide was used as a marker. Each of the four ileal samples per diet consisted of chyme from Meckel’s diverticulum to the ileo–caeco–colonic junction from three birds. Average coefficient of apparent ileal starch digestibility was lower than 0.83 in all wheat varieties studied. Starch digestibility increased significantly (P<0.01) when diets were supplemented with non-starch polysaccharide-degrading enzymes, reaching average values between 0.89 and 0.93. Average starch digestibility of barley and oats diets not supplemented with enzymes was 0.96 and 0.99, respectively. The results indicate that wheat starch may be poorly digested by broilers, and that enzyme supplementation does not fully alleviate this problem.