Nutritional properties of fibre-rich barley products fed to broiler chickens

The chemical composition of roller-milled fractions of barley from a commercial plant was studied and a fraction rich in mixed-linked β-glucans selected. This fraction contained 560 g kg^?1 starch, 120 g kg^?1 crude protein, 170 g kg^?1 dietary fibre and 70 g kg^?1 mixed-linked β-glucans. An unprocessed, drum-dried or extrusion-cooked fraction was used as the major ingredient in diets for broiler chickens. The diets were fed with or without a supplementary fibre-degrading enzyme preparation in order to evaluate specifically the nutritional effects of the soluble dietary fibres. Processing significantly retarded growth, cumulative feed intake and feed conversion efficiency of the diets fed without enzyme supplementation, while the supplementation significantly improved all three parameters for each diet. Generally, processing decreased plasma triglycerides and total cholesterol and increased the ratio between high-density lipoproteins (HDL) and total cholesterol of chickens fed diets without enzyme supplementation. The enzyme supplementation increased the triglyceride and total cholesterol values and decreased the HDL/total cholesterol ratio, with more pronounced effects for chickens fed the processed diets.