Federal farm loan bonds issued by the federal land banks, debentures issued by federal intermediate credit banks, and debentures issued by banks for cooperatives pursuant to said acts (all of such bonds and debentures being hereinafter called farm credit securities) are hereby designated as security for every character of public funds, and especially for the purpose of securing deposits made in designated depositories, of funds of the State of Mississippi, and of funds of the various counties, municipalities, levee boards, supervisors districts, school districts, rural electrification associations and authority, or any other public or municipal subdivisions which may now or hereafter exist in the State of Mississippi. Existing laws as to the designation of proper depositories for public funds are in nowise hereby disturbed.