FOR THE PAST FEW DECADES, IN-FEED SUB-THERAPEUTIC ANTIBIOTICS AND THERAPEUTIC LEVELS OF ZINC HAVE BEEN USED IN THE PIG INDUSTRY TO ENHANCE GROWTH PERFORMANCE AND HEALTH. HOWEVER, WITH THE IMPLEMENTATION OF THE U.S. VETERINARY FEED DIRECTIVE IN 2017 THAT BANNED SUB-THERAPEUTIC ANTIBIOTIC USE FOR GROWTH PROMOTION, AND WITH THE EUROPEAN MEDICINES AGENCY'S COMMITTEE FOR MEDICINAL PRODUCTS FOR VETERINARY USE BAN OF PHARMACOLOGICAL LEVELS OF ZINC OXIDE IN SWINE DIETS BY 2022, PRODUCERS ARE LOSING CRITICAL PRODUCTION TOOLS. ALTHOUGH DIRECT AND INDIRECT EFFECTS OF ANTIBIOTIC GROWTH PROMOTERS (AGPS) HAVE BEEN PROPOSED, THERE IS A SURPRISING LACK OF KNOWLEDGE INTO THE EXACT MODE OF ACTION OF AGPS, INCLUDING ZINC OXIDE, ON THE GIT AND HOST NUTRIENT UTILIZATION. OUR RESEARCH IS AIMED AT INCREASING KNOWLEDGE OF THESE PROCESSES. SPECIFICALLY, WE PLAN TO TEST OUR HYPOTHESIS THAT FIRST PASS METABOLISM AND UTILIZATION OF NUTRIENTS BY THE INTESTINAL TISSUES IS A MAJOR CONTRIBUTING FACTOR LIMITING NUTRIENT AND ENERGY SUPPLY FOR EFFICIENT LEAN TISSUE AND WHOLE BODY GROWTH. NEW KNOWLEDGE UNEARTHED THROUGH OUR RESEARCH HAS THE POTENTIAL TO BE USED BY VETERINARIANS AND FEED PRODUCERS TO DEVELOP PRODUCTS THAT CAN IMPROVE NURSERY-GROWER PIG HEALTH, WELLBEING, AND PERFORMANCE.