Effects of structure and xylanase treatment of brewers' spent grain on performance and nutrient availability in broiler chickens

1. A factorial (2 x 3) feeding trial was set up to investigate the effects of coarse or finely ground brewers' spent grain (BSG) and xylanase treatment, either with no xylanase, top-dressed with xylanase or pre-treated with xylanase. 2. The experimental diets shared the same basal formulation and were fed to male broiler chickens (Ross 308) housed in individual cages from 12 to 29 d of age. 3. Xylanase pre-treatment reduced the dietary concentration of arabinoxylan by 15-30%. Pellet durability increased when BSG was ground. 4. Feed utilisation was significantly higher (6%) when the birds were given coarse BSG rather than ground BSG, whereas there was no significant effect of enzyme treatment. Apparent metabolisable energy was unaffected by the dietary treatments. 5. The overall starch digestibility was high (99%), with no dietary differences, whereas ileal protein digestibility was low (57%). Xylanase top-dressing tended to improve ileal protein digestibility but, in general, xylanase treatment had no major effect on overall performance in male broilers given diets with BSG.