A kind of feed additive includes the slow release layer on the outer surface of a core and a formation what core, and wherein the core includes ferrous glycine misfit object, L- from amino acid, DL- methionine and hay bacillus.一種飼料添加物,包含有一核心以及一形成於該核心的外表面上的緩釋層,其中該核心包含有亞鐵甘胺酸錯合物、L-離胺酸、DL-甲硫胺酸以及枯草桿菌。