The total arabinoxylan (TOT-AX) content (g/kg DM) and digestibility (I) and the water-extractable arabinoxylan (WE-AX) content (g/kg DM) and digestibility (II) at the level of the caeca for broilers fed the control diet, and the diets supplemented with Bel10, Bel100, Bel1000, Eco10, Eco100 and Eco1000 at 11 and 36 d old. Capital letters A, B indicate a significant difference for the effect of endoxylanase preparation at a particular broiler age (Bel vs. Eco) (P < 0.05, interaction age × enzyme). Small letters a, b, c in white circles denote a significant difference for dose (10 vs. 100 vs. 1,000 mg/kg) at a particular age and endoxylanase preparation (P < 0.05, interaction age × dose and enzyme × dose). Error bars denote the standard error of the represented means (SEM). The arrows denote a significant overall age difference (P < 0.05). ∗, ∗∗ indicate treatment means which differ significantly at P ≤ 0.10 and P < 0.05, respectively from the control mean; analysed according to the posthoc Dunnett's test (n = 5). Error bars denote the standard error of the represented mean (SEM).