A feed additive composition comprising a direct fed microbial (DFM), in combination with a xylanase (e.g. endo-1,4-b-d-xyIanase) and a b-glucanase (and optionally a further fibre degrading enzyme), wherein the DFM is selected from the group consisting of an enzyme producing strain a C5 sugar-fermenting strain a short-chain fatty acid-producing strain a fibrolytic, endogenous microflora-promoting strain or combinations thereof. The DFM may be selected from the group consisting of: Bacillus subtilis AGTP BS3BP5, Bacillus subtilis AGTP BS442, B. subtilis AGTP BS521, B. subtilis AGTP BS918, Bacillus subtilis AGTP BS1013, B. subtilis AGTP BS1069, B. subtilis AGTP 944, B. pumilus AGTP BS 1068 or B. pumilus KX11-1, Enterococcus faecium ID7, Propionibacterium acidipropionici P169, Lactobacillus rhamnosus CNCM-l-3698, Lactobacillus farciminis CNCM-l-3699, a strain having all the characteristics thereof, any derivative or variant thereof, and combinations thereof and the further fibre degrading enzyme may be selected from the group consisting of a cellobiohydrolase (E.C. 3.2.1.176 and E.C. 3.2.1.91), a b-glucosidase (E.C. 3.2.1.21), a b- xylosidase (E.C. 3.2.1.37), a feruloyl esterase (E.C. 3.1.1.73), an a-arabinofuranosidase (E.C. 3.2.1.55), a pectinase (e.g. an endopolygalacturonase (E.C. 3.2.1.15), an exopolygalacturonase (E.C. 3.2.1.67) or a pectate lyase (E.C. 4.2.2.2)), or combinations thereof.