Three trials with were conducted to evaluate the effects of diets with 53% rye (diet C) or 53% wheat (diet T) supplemented or not with xylanase enzymes (0.06%) on nutrient digestibility and metabolizable energy and the performance and development of the broiler chicken digestive tract. A diet with 53% corn was used as control. In trial 1, dry matter, organic matter and apparent fat digestibilities corrected for nitrogen (EMAn) were lower in rye diets than in wheat diets (2556 kcal/kg vs 2842 kcal/kg) and were lower in the set of these diets than in the control diet. The organic matter digestibility and EMAn in the rye were also lower than those of the wheat diets. Xylanase supplementation did not affect the digestive use of the rye or wheat diets. In trial 2, growing broiler chickens fed the rye diets showed the lowest weight gain and EMAn intake and the worst feed conversion ratio between 8 and 35 days of age. The feed conversion ratio was 2.17 with rye diets and 1.88 with the corn diet. Xylanase supplementation on rye or wheat based diets did not improve feed conversion. In trial 3, birds fed on rye diets for 31 days showed longer duodenum-jejunum and ileum and lower carcass yield than birds fed the control diet (71.6% vs 74.4%). The wheat based diets did not affect these parameters. Pancreas and liver weights were not affected by the feeds.
digestibility; digestive tract; feed conversion; non-starch polysaccharides; weight gain
