TABLE OF CONTENTS; LIST OF TABLES; LIST OF ABBREVIATIONS; CHAPTER 1 GENERAL INTRODUCTION AND WORK HYPOTHESIS; CHAPTER 2 EVALUATION THROUGH LITERATURE DATA ON STANDARDIZED ILEAL DIGESTIBILITY AND BASAL ILEAL ENDOGENOUS LOSS OF AMINO ACIDS ASSOCIATED WITH BARLEY IN PIGS; CHAPTER 3 STANDARDIZED ILEAL DIGESTIBILITY OF AMINO ACIDS IN EIGHT GENOTYPES OF BARLEY FED TO GROWING PIGS; CHAPTER 4 DETERMINATION OF BASAL ILEAL ENDGENOUS LOSSES AND STANDARDIZED ILEAL DIGESTIBILITY OF AMINO ACIDS IN BARLEY FED TO GROWING PIGS; CHAPTER 5 GENERAL DISCUSSION; CHAPTER 6 SUMMARY; CHAPTER 7 ZUSAMMENFASSUNG.