The nutritive value for broiler chickens of pelleting and enzyme supplementation of a diet containing barley, wheat and rye

Abstract

A diet based on barley (40%), wheat (25%), and rye (7%) was given as a mash diet or as dry or steam pelleted diets to a total of 384 broiler chickens. Diets were given with or without the addition of a fibre-degrading enzyme preparation. Pelleting increased the water solubility (at 38°C) of starch and crude protein. There were, however, no notable effects on the solubility of dietary fibre components following pelleting or enzyme supplementation. Buffer extracts from pelleted diets had a high relative viscosity, while mash diets gave the lowest relative viscosity. Enzyme supplementation diminished the high viscosity obtained for pelleted diets and reduced sticky droppings. Pelleting increased weight gain for chickens receiving the unsupplemented diets by ∼ 30% and for those fed on the enzyme-supplemented diets by ∼ 20%. This improvement, which was similar at both 14 and 20 days of age, was mainly due to a greater feed intake, particularly with the steam pelleting. Enzyme supplementation improved weight gain by 11–24%, and was more effective in the unpelleted diets and at Day 14. This improvement was due to both a higher feed intake and a better feed conversion efficiency. Pelleting tended to increase ileal digestibility of the unsupplemented diet while enzyme supplementation had a similar effect on the unpelleted diet. The latter treatment also increased whole-tract digestibility.