Enables fatty acid synthase activity. Involved in ether lipid biosynthetic process; mammary gland development; and myeloid leukocyte differentiation. Acts upstream of or within cellular response to interleukin-4; epithelial cell development; and fatty acid biosynthetic process. Located in glycogen granule. Is expressed in several structures, including adipose tissue; alimentary system; nervous system; sensory organ; and skeleton. Orthologous to human FASN (fatty acid synthase). [provided by Alliance of Genome Resources, Apr 2022]