** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** MEDICALLY IMPORTANT ANTIBIOTICS HAVE BEEN PHASED OUT FOR ROUTINE LIVESTOCK APPLICATIONS IN THE U.S. SINCE 2017. NOVEL APPROACHES ARE NEEDED TO ADDRESS AN URGENT NEED FOR EFFECTIVE ANTIBIOTIC ALTERNATIVES. WE RECENTLYREVEALED SEVERAL CLASSES OF EPIGENETIC COMPOUNDS TO SYNERGIZE STRONGLY TO INDUCE THE SYNTHESIS OF HOST DEFENSE PEPTIDES (HDP), A CRITICAL COMPONENT OF INNATE IMMUNITY. THESE DISCOVERIES PROVIDED A TIMELY OPPORTUNITY TO INVESTIGATE THE POTENTIAL OF THESE COMPOUNDS AS NOVEL ANTIBIOTIC ALTERNATIVES. THE LONG-TERM GOAL OF OUR RESEARCH IS TO DEVELOP HDP-INDUCING COMPOUNDS AS NEXT-GENERATION ANTIBIOTIC ALTERNATIVES FOR LIVESTOCK USE. THE OVERALL GOALS OF THIS GRANT ARE TO FURTHER SCREEN FOR THE BEST COMBINATIONS OF EPIGENETIC COMPOUNDS IN HDP INDUCTION AND DISEASE ALLEVIATION IN A CHICKEN MODEL OF NECROTIC ENTERITIS AND ALSO REVEAL THEIR MECHANISM OF ACTION. THREE SPECIFIC OBJECTIVES ARE PROPOSED TO 1) IDENTIFY THE BEST COMBINATIONS OF EPIGENETIC COMPOUNDS THAT ARE HIGHLY POTENTTO INDUCE HDP GENE EXPRESSION BOTH IN VITRO AND IN VIVO, 2) DETERMINE THE EFFICACY OF SELECTED COMPOUND COMBINATIONS IN THE ALLEVIATION OF NECROTIC ENTERITIS, AND 3) REVEAL THE MOLECULAR MECHANISMS BY WHICH EPIGENETIC COMPOUNDS INDUCE HDP SYNTHESIS AND MODULATE HOST IMMUNITY. WE EXPECT TO IDENTIFY SEVERAL COMBINATIONS OF EPIGENETIC COMPOUNDS SHOWING A STRONG SYNERGY IN HDP INDUCTION AND DISEASE ALLEVIATION BY ENHANCING THE ACCESSIBILITY OF THE HDP GENE PROMOTERS. THE OUTCOMES OF THE RESEARCH WILL LEAD TO THE DEVELOPMENT OF SMALL-MOLECULE EPIGENETIC COMPOUNDS AS THE FIRST-OF-ITS-KIND CLASS OF ANTIBIOTIC ALTERNATIVES FOR DISEASE CONTROL AND PREVENTION IN LIVESTOCK.