PROBLEM TO BE SOLVED: To provide a salt-containing food processing residual liquid capable of maintaining an antioxidant action of polyphenol, and a feed compounding a residue.SOLUTION: The salt-containing food processing residual liquid and the residue-compounding feed are the salt-containing food processing residual liquid-containing formula feed obtained by mixing a salt-containing food processing residual liquid concentrate and a feed-compounding agent, wherein the salt-containing food processing residual liquid concentrate contains polyphenols, and is desalinated to the range in which the antioxidative function of the polyphenols can be maintained by making a salt remain.