Abstract: A feed additive composition comprising a direct fed microbial (DFM) in combination with a phytase derivable from Citrobacter spp. and a method for improving the performance of a subject or for improving digestibility of a raw material in a feed (e.g. nutrient digestibility, such as amino acid digestibility), or for improving nitrogen retention, or for avoiding the negative effects of necrotic enteritis or for improving feed conversion ratio (FCR) or for improving weight gain in a subject or for improving feed efficiency in a subject or for modulating (e.g. improving) the immune response of the subject, or for promoting the growth of beneficial bacteria in the gastrointestinal tract of a subject or for reducing populations of pathogenic bacteria in the gastrointestinal tract of a subject, or for reducing nutrient excretion in manure, which method comprising administering to a subject a direct fed microbial (DFM) in combination with a phytase derivable from Citrobacter spp.