A microbial oil is obtained from Labyrinthulomycetes in which a gene for fatty acid biosynthesis has been disrupted or an expression of the gene has been inhibited to highly accumulate the fatty acid. The microbial oil typically contains: (a) 1.5% or more of arachidonic acid (AA) based on a total amount of fatty acid; (b) 0.2% or more of dihomo-γ-linolenic acid (DGLA) based on the total amount of fatty acid; (c) 0.04% or more of eicosatetraenoic acid (ETA) based on the total amount of fatty acid; (d) 3.8% or more of eicosapentaenoic acid (EPA) based on the total amount of fatty acid; (e) 13.7% or less of n-6 docosapentaenoic acid (n-6DPA) based on the total amount of fatty acid; and (f) 43.9% or less of docosahexaenoic acid (DHA) based on the total amount of fatty acid.

A method for producing a microbial oil includes the steps of: genetically modifying a labyrinthulid by disrupting and/or silencing a gene, or by transforming another gene in addition to the disruption and/or gene silencing of the gene; culturing the labyrinthulid, such that a fatty acid composition accumulated in the labyrinthulid comprises an increased EPA content; and collecting the microbial oil having the increased EPA content from the labyrinthulid. The increased EPA content is not less than 3.3% of a total fatty acid composition.

A microbial oil is obtained from Labyrinthulomycetes in which a gene for fatty acid biosynthesis has been disrupted or an expression of the gene has been inhibited to highly accumulate the fatty acid. The microbial oil typically contains: (a) 1.5% or more of arachidonic acid (AA) based on a total amount of fatty acid; (b) 0.2% or more of dihomo-?-linolenic acid (DGLA) based on the total amount of fatty acid; (c) 0.04% or more of eicosatetraenoic acid (ETA) based on the total amount of fatty acid; (d) 3.8% or more of eicosapentaenoic acid (EPA) based on the total amount of fatty acid; (e) 13.7% or less of n-6 docosapentaenoic acid (n-6DPA) based on the total amount of fatty acid; and (f) 43.9% or less of docosahexaenoic acid (DHA) based on the total amount of fatty acid.