SHORT-CHAIN FATTY ACIDS ARE THE MAIN PRODUCTS OF MICROBIAL FERMENTATION IN THE RUMEN. THEY ARE ALSO THE MAIN ENERGETIC SUBSTRATE FOR THE RUMINANT AND CAN ACT AS METABOLIC REGULATORS. ONE OF THE PHYSIOLOGICAL PROCESSES THAT SHORT-CHAIN FATTY ACIDS CAN REGULATE IN RUMINANTS IS FEED INTAKE. MOST OF THE RESEARCH IN THE AREA HAS BEEN AMASSED INTO THE HEPATIC OXIDATION THEORY. THE HEPATIC OXIDATION THEORY PROPOSES THAT PROPIONATE, ONE OF THREE MAJOR SHORT-CHAIN FATTY ACIDS, OXIDATION IN THE LIVER REGULATES FEED INTAKE BUTTHERE ARE SOME CIRCUMSTANCES THAT FEED INTAKE CAN BE REGULATED BY ACETATE, ANOTHER SHORT-CHAIN FATTY ACID, THAT ARE NOT IN ACCORDANCE WITH THETHEORY. FURTHERMORE, THE HEPATIC OXIDATION THEORY DOES NOT CONSIDER THE POTENTIAL THAT SHORT-CHAIN FATTY ACIDS CAN REGULATE FEED INTAKE THROUGH THE STIMULUS OF THE GASTROINTESTINAL SYSTEM TO PRODUCE ANOREXIGENIC PEPTIDES. UNDERSTANDING THE PHYSIOLOGICAL FACTORS THAT REGULATE FEED INTAKE IS IMPORTANT AS AN ACCURATE PREDICTION OF INTAKE IS THE BACKBONE OF NUTRITIONAL MANAGEMENT OF ANY LIVESTOCK SPECIES.AN IN VITRO EXPLANT SYSTEM OF BOVINE GASTROINTESTINAL TISSUEAND A CANNULATED ANIMAL MODEL WILL BE USED TO DETERMINE IF THE ANOREXIGENICEFFECT OF SHORT-CHAIN FATTY ACIDS IS ASSOCIATED WITH THE PRODUCTION OF GUT ANOREXIGENIC PEPTIDES.THE RESULTS WILL BE COMMUNICATED IN THREE MAJOR WAYS:1) ABSTRACT PRESENTATIONS AT RELEVANT SCIENTIFIC CONFERENCES, 2) PEER-REVIEWED PUBLICATIONS IN SCIENTIFIC JOURNALS, AND 3) EXTENSION TALKS WITH PRODUCERS OF THE NORTHEAST AREA OF THE US AND FARM TOURS WITH 4H AND FFA STUDENTS AT PENN STATE. THE MAJOR GOAL OF THIS PROPOSALIS TO FURTHER OUR UNDERSTANDING OF SHORT-CHAIN FATTY ACID AS METABOLIC REGULATORS OF FEED INTAKE IN THE LACTATING RUMINANT. FURTHERING OUR UNDERSTANDING OF FEED INTAKE REGULATION BY SHORT-CHAIN FATTY ACIDS, ESPECIALLY ACETATE,IS WARRANTED DUE TO THE RECENT INCREASE IN INTEREST OF ACETATE SUPPLEMENTATION TO INCREASE MILK FAT PRODUCTION IN THE DAIRY INDUSTRY.