<；P>；PROBLEM TO BE SOLVED: To provide a peptide which prevents and treats viral and bacterial infection in livestock including poultry by activating their immune systems and to provide a feed containing the same. <；P>；SOLUTION: The immunity-activating peptide is a peptide obtained by subjecting the blood of livestock to treatment with subcritical water or treatment with a protease. The peptide is especially desirably one prepared by treating the blood prepared by removing fibrin from blood in advance. And, the feed is a feed containing the immunity-activating peptide. The peptide and the feed can activate the immune systems of livestock, so that they can prevent and treat diseases caused by various viruses or bacteria. <；P>；COPYRIGHT: (C)2010,JPO&INPIT
